Runway excursion

Safety summary

What happened

On the morning of 26 December 2021, the pilot of a Geraldton Air Charter, Gippsland Aeronautics GA-8 Airvan prepared for an air-transport flight from Geraldton, Western Australia to East Wallabi Island. During the preparations, the pilot decided to carry an additional passenger from another flight, which was also scheduled to depart for East Wallabi Island. The pilot later reported that the rearrangement of the passengers resulted in the preparations for the flight being rushed.

Earlier in the day, the pilot had operated a flight in a Cessna 172 with an emergency position indicating radio beacon (EPIRB) positioned on their right hip. The pilot was aware that this would obstruct the flap lever in the Airvan and intended to move the EPIRB to their left hip prior to the East Wallabi flight, but during the rushed preparations, forgot to move it.

As the aircraft approached East Wallabi Island, the pilot attempted to select full flap for the landing, but the EPIRB obstructed the flap lever movement and prevented it from locking into the full flap position. Multiple further attempts to select full flap were unsuccessful, and the approach was continued with only the first stage of flap extended.

During the landing flare, the aircraft floated more than the pilot expected and touched down about midway along the runway (about 350 m from the end of the runway). After touch down the pilot applied normal braking but, as the aircraft approached the end of the runway, they realised an overrun was imminent and applied maximum braking. Despite that, the aircraft did not stop on the runway and overran it by about 15 m. The pilot and passengers were not injured, and the aircraft was substantially damaged in the accident.

What the ATSB found

The ATSB found that an emergency position indicating radio beacon worn by the pilot prevented the selection of full flap. The pilot possibly did not comprehend the effect of the reduced flap setting and continued the approach with the inappropriate flap setting.

During the subsequent landing, the aircraft floated significantly beyond the intended landing point. The pilot did not recognise the risk of a runway overrun and did not conduct a go around or apply sufficient braking to stop the aircraft on the remaining runway.

What has been done as a result

Following the accident, the operator modified their operating procedures to recommend that a process of threat and error management be conducted before all flights.

Safety message

This accident emphasises the need for careful flight preparation. Taking time to confirm that all required actions have been completed prior to departure minimises the chance of in-flight complications. To ensure effective flight preparation, the Civil Aviation Safety Authority publication: Visual Flight Rules Guide advises pilots to ‘give yourself time to review information free from distractions when making pre-flight decisions…avoid flying under time pressure’.

It also underlines the importance of commencing a missed approach early when the approach and landing deviate from the plan and a safe landing cannot be assured.

The Civil Aviation Authority of New Zealand publication: Good Aviation Practice, Mountain Flying recommends that pilots ‘always have a clearly defined decision point where you can go-around if you are not happy that a safe landing is achievable.’ This is especially relevant for operations involving short runways.

The investigation

The occurrence

On the morning of 26 December 2021, the pilot of a Geraldton Air Charter, Gippsland Aeronautics GA-8 Airvan prepared for an air-transport^[1] flight from Geraldton, Western Australia to East Wallabi Island. The flight was planned to carry 6 passengers.

While preparing for the flight, the pilot decided to carry an additional passenger from another flight, which was also scheduled to depart for East Wallabi Island. The pilot later reported that the rearrangement of the passengers resulted in the preparations for the flight being rushed.

Earlier in the day, the pilot had operated a flight in a Cessna 172 with an emergency position indicating radio beacon (EPIRB) positioned on their right hip. The pilot was aware that this would obstruct the flap lever in the Airvan and intended to move the EPIRB to their left hip prior to the East Wallabi flight, but during the rushed preparations, forgot to move it.

At about 1030 Western Standard Time,^[2] the flight departed for East Wallabi Island with the pilot and 7 passengers on board (Figure 1).

As the aircraft approached the Island, the pilot positioned the aircraft to join the right base leg of the circuit for runway 36, extended the first stage of flap and observed the windsock indicating a northerly wind.

Figure 1: Flight overview

Source: Google Earth, annotated by ATSB

The pilot turned onto the final leg of the circuit and attempted to select full flap for the landing, but the EPIRB obstructed the flap lever movement and prevented it from locking into the full flap position. Multiple further attempts to select full flap were unsuccessful, and the approach was continued with only the first stage of flap extended.

Runway 36 was 667 m long with a slight downslope. The pilot aimed to touch down in the turnaround area of the runway (Figure 2). As the aircraft crossed the runway threshold at about 70 knots, the pilot reduced engine power to idle and flared ^[3] the aircraft. During the flare, the aircraft floated more than the pilot expected and touched down near the parking area about midway along the runway (about 350 m from the end of the runway).

Figure 2: East Wallabi Island airstrip

Source: Google Earth, annotated by ATSB

After touch down, the pilot followed the operator’s normal practice of retracting the flaps and then applied normal braking. As the aircraft approached the end of the runway, the pilot realised an overrun was imminent, and applied maximum braking. Despite that, the aircraft overran the runway by about 15 m (Figure 3). The pilot and passengers were not injured, however the aircraft was substantially damaged, including detachment of a main landing gear leg.

Figure 3: VH-WSB after the runway excursion

Source: Operator

Aircraft wing flaps

The Airvan is fitted with manually operated wing flaps with three, selectable positions: retracted, first stage (14° down) and full (38° down). The position of the flaps is determined by notches engaged by the operating lever positioned on the cabin floor to the right of the pilot’s seat. In the retracted and first stage positions, the lever remained below the level of the pilot’s seat bolster. In the full flap position, the lever protruded above the level of the bolster (Figure 4). The aircraft flight manual stated that ‘landings are normally conducted with full flaps’.

Figure 4: Airvan flap lever

Note: The flap lever rests below the pilot seat bolster and is not visible in the retracted and first stage positions (left). The flap lever protrudes above the bolster in the full flap position (right).

Source: Operator

The Civil Aviation Safety Authority publication Flight Instructor Manual (Aeroplane) provides the following information for a landing conducted without flaps which is also applicable (but to a lesser extent) when landing with a flap setting less than full:

The descent path may be flatter, making judgment more difficult…Due to the absence of drag there may be a longer float period.

Landing information

The aircraft departed Geraldton at a calculated take-off weight of about 1,696 kg.^[4] The pilot reported the temperature on East Wallabi Island as 28° C. Using this data and assuming no head or tailwind component, the ATSB calculated that after touching down the aircraft required a landing roll of about 190 m to stop using full flaps (the selected first stage flap position should not have significantly altered that distance).

The United States Federal Aviation Administration publication: Airplane Flying Handbook, Chapter 9 Approaches and Landings provided the following information for pilots who encounter floating during landing:

The recovery from floating is dependent upon the amount of floating and the effect of any crosswind, as well as the amount of runway remaining. Since prolonged floating utilizes considerable runway length, it must be avoided especially on short runways or in strong crosswinds. If a landing cannot be made on the first third of the runway, or the airplane drifts sideways, execute a go-around.

Operator’s investigation

The operator’s internal investigation identified that the pilot did not have a full understanding of aircraft drag, effects of flaps, and ground effect. The investigation also noted that the operator’s normal practice of retracting flaps immediately after touchdown to maximise brake effectiveness may have led to the pilot prioritising flap retraction ahead of immediately applying braking action.

Pilot information

The pilot held a Commercial Pilot Licence (Aeroplane) and had a total flying experience of 1,227.6 hours including 528.3 hours in the Airvan. In the previous 90 days, the pilot had flown 80.6 hours, including 29.7 in the Airvan.

The pilot reported being well rested, but mildly unwell on the day. However, there was no indication that the illness reduced their performance. Similarly, the pilot’s general health, fatigue, or distraction were not considered to have contributed to the accident.

Training

The pilot was employed by the operator in July 2019. From that time until November 2019 and again in May 2020 and July 2021, the pilot underwent operator training and proficiency checks that included:

• stabilised approaches
• GA-8 Airvan operations
• East Wallabi Island operations
• short runway landings
• go arounds
• landings

These operator training and checks did not assess the specifics of aircraft drag, effects of flaps or ground effect as they were considered adequately covered during pilot licence testing.

Safety analysis

As the aircraft approached East Wallabi Island, the EPIRB positioned on the pilot’s right hip obstructed the flap lever and prevented their locking in the full flap position. The pilot did not consider a go around to allow for trouble shooting or repositioning of the EPIRB and continued the approach with just the first stage of flap extended. That configuration increased the required landing distance compared to the use of full flaps, although there was still sufficient runway length available to land safely.

During the landing flare the reduced drag of the first stage flap setting, possibly combined with a higher than normal approach speed, led to a longer float. While a go around should again have been considered after the aircraft floated significantly beyond the intended landing point, from the touchdown point it was possible to stop the aircraft in the remaining runway using maximum braking. However, possibly due to the priority given to retracting the flaps and the pilot not immediately recognising the risk of an overrun, maximum braking was not applied until insufficient runway remained to prevent the overrun.

Findings

From the evidence available, the following findings are made with respect to the runway overrun involving Gippsland Aeronautics GA-8, VH-WSB at East Wallabi Island, Western Australia on 26 December 2021

Contributing factors

• An emergency position indicating radio beacon worn by the pilot prevented the selection of full flap. The reduced flap setting significantly increased the required landing distance.
• During the landing, the aircraft floated significantly beyond the intended landing point. The pilot did not recognise the risk of a runway overrun and did not conduct a go around or apply sufficient braking to stop the aircraft on the remaining runway.

Safety actions

Safety action by Geraldton Air Charter

Following the accident, the operator modified operating procedures to recommend a process of threat and error management be conducted before all flights.

Sources and submissions

Sources of information

The sources of information during the investigation included the:

• aircraft operator
• pilot

References

Civil Aviation Safety Authority 2006, Flight Instructor Manual Aeroplane

Civil Aviation Safety Authority 2021, Visual Flight Rules Guide

Civil Aviation Authority of New Zealand 2021, Good Aviation Practice - Mountain Flying

Federal Aviation Administration of The United States 2021, Airplane Flying Handbook

Submissions

Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section allows a person receiving a draft report to make submissions to the ATSB about the draft report.

A draft of this report was provided to the following directly involved parties:

• operator
• pilot

Submissions were received from:

• operator
• pilot

The submissions were reviewed and, where considered appropriate, the text of the report was amended accordingly.

Purpose of safety investigations The objective of a safety investigation is to enhance transport safety. This is done through: identifying safety issues and facilitating safety action to address those issues providing information about occurrences and their associated safety factors to facilitate learning within the transport industry. It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action. Terminology An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2022 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

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1. The flight was operated under Civil Aviation Safety Regulations Part 135 (Air transport operations - smaller aeroplanes).
2. Western Standard Time (WST): Universal Coordinated Time (UTC) + 8 hours.
3. Flare: the final nose-up pitch of a landing aeroplane used to reduce the rate of descent to about zero at touchdown.
4. The maximum take-off weight of the aircraft was 1,814 kg.

The ATSB has commenced a transport safety investigation into a runway excursion (veer-off) during landing involving a Boeing 777-300ER aircraft, operated by Qatar Airways, at Brisbane Airport, on the night of 30 November 2021.

The aircraft was being operated on a scheduled passenger flight from Auckland, New Zealand. The captain was the pilot flying, and the flight crew was cleared to land on runway 01R.

The flight crew reported that, during the instrument approach, the aircraft encountered heavy rain and turbulence. At about 300 ft above the ground and still in rain, the flight crew established and maintained clear visual reference to the runway lighting and surrounds. Passing about 200 ft, the first officer announced the aircraft was drifting right of the runway centreline. The captain corrected the deviation. As the aircraft was about to touchdown, under the influence of a variable and gusting crosswind, the aircraft drifted right. The aircraft landed to the right of the runway centreline and, shortly after touchdown, the right main landing gear contacted and destroyed four runway edge lights positioned on the sealed runway strip, before the aircraft returned towards the runway centreline.

After the landing was completed and the aircraft had exited the runway, aircraft systems alerted the flight crew of low pressure in one on the right main landing gear tyres. The flight crew stopped the aircraft on the taxiway and requested an inspection of the aircraft. Damage to four right main landing gear tyres was observed, and the aircraft was towed to the international terminal. There were no injuries to passengers or crew.

A runway inspection observed ground debris and subsequently runway 01R was closed to clean up and replace the destroyed runway edge lights.

As part of the investigation, the ATSB has interviewed the flight crew, and reviewed evidence obtained from the airport operator. The ongoing investigation will review data from the aircraft's flight data recorder, weather information and recorded audio and surveillance data.

 A final report will be released at the conclusion of the investigation. Should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify relevant parties, so that appropriate safety action can be taken.

Safety summary

What happened

On the afternoon of 28 September 2021, a Fokker F100 aircraft, registered VH-FKD, departed Perth airport for a scheduled passenger flight to Laverton, Western Australia, with two flight crew, three cabin crew, and 75 passengers.

The aircraft landed uneventfully at Laverton, and the captain took control of the aircraft to taxi towards the end of the runway and complete the routine backtrack manoeuvre. The aircraft was positioned on the left-side at the end of the runway consistent with operator guidance, and the captain commenced a right turn by rotating the nose-wheel handwheel (tiller). The captain was unable to achieve full tiller rotation, even when using the force of both hands, and attempted to tighten the turn by applying the right inboard brake, and asymmetric thrust, but this did not have the desired effect. The crew decided to continue the turn, resulting in the aircraft nose-wheel briefly leaving the side of the runway, and onto the runway strip. The aircraft then returned to the runway and taxied to the terminal.

A post-flight inspection identified damaged insulation in the nose-wheel area and a torn universal joint boot on the tiller shaft.

What the ATSB found

The ATSB found that a torn boot on a universal joint probably restricted the operation of the aircraft’s nose-wheel steering system, preventing the aircraft from completing the turn on the runway. The flight crew decided to continue the turn, resulting in the nose-wheel leaving the runway surface, increasing the risk of damage to the aircraft.

What has been done as a result

The operator has commenced a fleet wide inspection of the tiller assembly universal joint boots which is expected to be completed by February 2022.

Safety message

The risk in this incident could have been reduced by availing options such as having airport staff inspecting the runway strip surface before turning onto it. When flight crews encounter such an unexpected event and there is sufficient time to assess available options, they should utilise available resources to determine the safest course of action.

The investigation

The occurrence

At 1436 Western Standard Time (WST)^[1] on 28 September 2021, a Fokker F100 aircraft, registered VH-FKD (Figure 1), operated by Alliance Airlines, departed Perth Airport for a scheduled passenger flight to Laverton, Western Australia, with 75 passengers on board. The crew comprised the first officer (pilot flying)^[2], the captain (pilot monitoring) and three cabin crew.

Figure 1: VH-FKD

Source: Supplied

Following an uneventful landing at about 1536, the captain took control of the aircraft to taxi towards the end of the runway and complete the routine backtrack manoeuvre^[3] (Figure 2). The aircraft was positioned on the left-side at the end of the runway consistent with operator guidance, and the captain commenced a right turn by rotating the nose-wheel handwheel (tiller). The captain was unable to achieve full tiller rotation, even when using the force of both hands, and attempted to tighten the turn by applying the right inboard brake, and asymmetric thrust, but this did not have the desired effect. During the turn, the aircraft nose-wheel briefly left the side of the runway, and onto the runway strip^[4] – the ground area adjacent to the runway – before returning to the runway and taxiing to the terminal (Figure 3).

Figure 2: Laverton Airport

Source: Google Earth, annotated by ATSB

Figure 3: Nose-wheel tyre marks

Source: Operator, annotated by ATSB

After disembarking, the captain inspected the aircraft and nose-wheel, which appeared undamaged, and requested engineering support be flown into Laverton for a more detailed inspection. There were no injuries to passengers or crew, and subsequent inspection identified no damage to the aircraft.

Context

Captain

The captain held an Air Transport Pilot Licence (Aeroplane), and had 9,248 hours of flying experience, of which over 6,337 hours were on the Fokker F100. The captain made the following comments and observations about the incident.

• The crew did not notice any nose-wheel steering issue while taxiing at Perth, but no tight turns were required.
• Halfway through the turn at Laverton, the captain realised the aircraft would not make the turn on the runway but decided to continue for two reasons:
  • The airport had a single runway and no ground support equipment for the aircraft, so stopping on the runway would prohibit other aircraft from landing.
  • The ground next to the runway was compact dirt (based on knowledge of previous runway excursion incidents there).
• The tiller resistance felt normal up until it could not be turned further, and then felt like pushing against a hard rubber wall. The two left turns (after the backtrack turn) during taxi back to the terminal felt normal.
• The wind at the time of the runway excursion – south‑south‑east at about 8 kts – did not affect the aircraft’s turning ability as they successfully conducted tight turns in other Fokker F100 aircraft in stronger wind conditions.

Aircraft

The Fokker F100 aircraft was a regional jet produced by the Netherlands-based manufacturer, Fokker, until 1997. The Australian F100 fleet is currently the largest in the world, comprising some 66 aircraft operated by four high capacity or charter operators. The majority of the national fleet service the fly-in fly-out mining and resource industry.

Nose-wheel steering system

The aircraft’s nose-wheel steering system comprised various shafts, pulleys, and cables, which direct hydraulic pressure to turn the nose-wheel when the tiller is rotated, or when the rudder pedals are pushed. The rudder pedals provide a very limited turning angle, so the tiller is used when making most turns, and is located on the left side (captain’s side) of the aircraft cockpit (Figure 4). The tiller is connected to the steering system via a shaft fitted with two universal joints (upper and lower). The universal joints are covered by protective boots.^[5]

Figure 4: Fokker 100 cockpit (exemplar)

Source: Joel Baverstock, annotated by ATSB

Post-flight repairs

The post-flight examination of the steering system at Laverton identified a correctly secured, but torn insulation blanket, which was contacting the nosewheel cable drum (Figure 5). A torn protective boot on the upper universal joint was also found (Figure 6). The insulation blanket was taped at the torn section and re-secured away from the cable drum, and the torn boot was removed. A taxi test was then successfully carried out before the return flight to Perth.

During subsequent maintenance, the torn blanket and handwheel assembly were replaced. The aircraft operator made the following findings with respect to the incident.

• Based on torn insulation blanket’s inspection, the reinforcing strands of the blanket covering material were not considered to have sufficient strength to cause the tiller resistance felt by the captain.
• The torn boot was suspected to have been caught in the joint universal joint, causing the resistance in the right turn and was subsequently freed during the two left turns while taxiing taxi to the terminal.

A fleet wide inspection of the handwheel assembly universal joint is expected to be completed by February 2022.

Figure 5: Torn insulation surrounding cable drum

Source: Operator, annotated by ATSB

Figure 6: Torn protective boot

Source: Operator, annotated by ATSB

Past maintenance

The nose-wheel area containing the cable drum is located behind access panels and is subject to a general zone inspection every 10,000 flight hours or 10 years, and this includes an inspection of insulation blanket condition. The aircraft last underwent this inspection in 2015. This nose-wheel area is also accessed for various other scheduled component inspections, most of which were completed in 2019. No maintenance findings in relation to insulation blankets in the cable drum area were recorded during those inspections.

The nose-wheel steering system is subject to a functional check every 5,000 flight hours, which includes a test of the torque required to turn the tiller, and steering angle achieved when turning the tiller full left and right. This check was successfully performed on the aircraft in 2019.

Safety analysis

The maintenance findings and the captain’s statement indicate that it’s likely the torn boot reduced the universal joint’s range of motion, restricting the operation of the aircraft’s nose-wheel steering. This restriction reduced the aircraft’s turning ability, preventing it from completing the turn on the runway. It could not be determined how or why the boot was torn.

Although runway strips are designed to reduce the risk of damage, there is no assurance that aircraft can safely manoeuvre on them. While the excursion onto the runway strip in this event did not result in aircraft damage, there was no assurance that the strip was clear of hazardous debris. However, had the aircraft remained on the runway, other aircraft would not have been able to land there safely, including delivery of ground support equipment to manoeuvre the aircraft along the runway. Nevertheless, options such as having the airport staff inspect the runway strip before turning on it were available.

Findings

From the evidence available, the following findings are made with respect to the taxiing excursion involving Fokker F100, VH-FKD, Laverton Airport, Western Australia, on 28 September 2021.

Contributing factors

• A torn boot on a universal joint probably restricted the operation of the aircraft’s nose-wheel steering system, preventing the aircraft from completing the turn on the runway.
• The flight crew decided to continue the turn, resulting in the nose-wheel leaving the runway surface.

Sources and submissions

Sources of information

The sources of information during the investigation included the:

• the captain
• Alliance Airlines
• Bureau of Meteorology.

Submissions

Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section allows a person receiving a draft report to make submissions to the ATSB about the draft report.

A draft of this report was provided to the following directly involved parties:

• Alliance Airlines, including the aircraft captain
• Civil Aviation Safety Authority.

Alliance Airlines provided a submission, which was reviewed and, where considered appropriate, the text of the report was amended accordingly.

Purpose of safety investigations The objective of a safety investigation is to enhance transport safety. This is done through: identifying safety issues and facilitating safety action to address those issues providing information about occurrences and their associated safety factors to facilitate learning within the transport industry. It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action. Terminology An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2022 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

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1. Western Standard Time (WST): Coordinated Universal Time (UTC) + 8 hours.
2. Pilot Flying (PF) and Pilot Monitoring (PM): procedurally assigned roles with specifically assigned duties at specific stages of a flight. The PF does most of the flying, except in defined circumstances; such as planning for descent, approach and landing. The PM carries out support duties and monitors the PF’s actions and the aircraft’s flight path.
3. An airport ground procedure which involves the use of any portion of a runway as a taxiway for an aircraft to taxi in the opposite direction from which it will take off or has landed.
4. The defined area surrounding each side of the runway, and including the runway, intended both to reduce the risk of damage to aircraft inadvertently running off the runway and to protect aircraft flying over it during take-off, landing, or missed approach.
5. The protective boot is intended to keep contaminants, such as dirt, out of the greased universal joint.

Safety summary

What happened

On the morning of 9 January 2020, a Fokker 100 registered VH-NHY and operated by Network Aviation conducted a regular public transport service from Perth to Newman, Western Australia.

The weather forecast for Newman Airport included heavy rain, moderate to severe turbulence below 5,000 ft and a 25 kt crosswind. At the time the aircraft departed Perth, Newman Airport had received about 88 mm of rain since 0900 the previous morning.

After a stable approach, the aircraft touched down in moderate rain, at or before the touchdown zone, at a speed 16 kt above the reference landing speed for the configuration. The crosswind at the time was recorded as gusting to 35 kt. The flight crew experienced lower than expected braking performance and reported aquaplaning during the landing roll. The pilot flying used the aquaplaning response technique to maintain directional control and subsequently commanded maximum reverse thrust.

The aircraft stopped 70 m beyond the end of the runway inside the runway end safety area. There were no injuries to crew or passengers and an inspection of the aircraft found that the loose gravel had damaged some of the landing gear components

What the ATSB found

The combination of the approach speed required by the prevailing wind conditions and the poor braking effectiveness in the wet conditions resulted in the aircraft overrunning the runway.

The ATSB also found that despite assessing the weather as a threat, the flight crew did not identify the potential effect of the rainfall on the stopping distance. Additionally, neither the operator nor the regulator had guidance to allow the crew to recognise the conditions at the time as a hazard to the operation.

Prior to the occurrence, the runway had been examined and found to be requiring maintenance to ensure an adequate level of surface friction, however no maintenance was performed.  

What has been done as a result

Following the occurrence, the operator circulated additional guidance and procedures to flight crew for identifying runway water contamination and to ensure appropriate speed control on approach and landing.

Since the occurrence, the Civil Aviation Safety Authority has published guidance, reflecting research from the United States Federal Aviation Authority, that found landing on ungrooved runways in moderate rain has the potential to significantly affect braking performance.

Safety message

Active precipitation, particularly moderate to heavy rainfall, is one of many factors that can influence the stopping distance of an aircraft. Water on a runway that is not grooved can significantly reduce the ability of the aircraft to slow down. In wet weather, additional conservatism is encouraged when calculating the required landing distances.

Operators and pilots are encouraged to review the latest guidance and tools available in relation to maintaining safety on runways and the factors that cause runway overruns.

The occurrence

On 9 January 2020, a Fokker 100 registered VH-NHY and operated by Network Aviation (a subsidiary of the Qantas Group), was conducting a regular public transport service from Perth to Newman, Western Australia.

Pre-flight, departure and cruise

The flight crew arrived at the airport at about 0430 Western Standard Time^[1] to prepare for the flight. During the pre-flight briefing, the flight crew received the weather forecast for Newman, which included:

• crosswind gusting to 25 knots
• moderate to severe turbulence below 5,000 ft
• visibility of 7,000 m
• cloud cover^[2] broken at 800 ft
• heavy rain

As a consequence of the significant weather, the captain requested additional fuel to provide for a potential diversion to an approved alternate, Port Hedland Airport. The weather observation from Newman Airport at the time indicated that the cumulative rainfall since 0900 the previous day was 87.6 mm.

The aircraft departed Perth at 0536 with 5 crew and 88 passengers on-board. Due to the unfavourable weather, the captain assumed the role of pilot flying and the first officer (FO) was pilot monitoring.^[3]

During the cruise phase, the FO requested the latest Newman meteorological aerodrome report from Melbourne Centre. The controller provided updated observations for the destination, which included:

• wind 150^o at 19 knots, gusting to 30 knots
• a reduction in visibility (reduced to 2,500 m)
• cloud covers of scattered at 700 ft, broken at 1,100 ft and broken at 1,600 ft
• recorded (actual) rain (1.6 mm within preceding 10 minutes, equivalent to 9.6 mm/hour).^[4]

The approach

The captain reported that due to the potential for windshear during the final approach segment, a flaps 25 (rather than flaps 42) with speed brake extended approach was selected, resulting in a faster than usual final approach speed (V_APP)^[] . The operator’s procedures (see the section titled Operator documentation and guidance) and the Fokker flight manual required an additional 10 knots be added to the usual reference landing speed (V_REF^[6] + 5 knots) to account for wind, bringing the final approach speed to 153 knots.

The captain reported not calculating the landing field length required on the day as they routinely operated to Newman and knew that the performance of the aircraft would allow for landing at maximum landing weight in dry or wet conditions. At interview, the captain recalled that the required landing field length for flaps 25 and maximum landing weight, the configuration and weight on the day, was about 1,750 m.

Prior to commencing the approach briefing, the flight crew interrogated the Newman aerodrome weather information service (AWIS).^[7] The information they received was consistent with the previous weather observations provided by Melbourne Centre, except the wind direction had changed to 130^o. Due to the wind direction the crew elected to conduct an approach to runway 05.

As part of the approach brief, the flight crew identified the weather as the primary threat to the operation and discussed a potential diversion to Port Hedland. Their discussions were focussed on the cloud base and the visibility required to conduct the approach, the expectation of windshear, turbulence and the strong crosswind. The rainfall rate and potential for runway contamination or reduced braking effectiveness were not discussed.

At 0655, 17 minutes prior to landing, the flight crew reinterrogated the AWIS. The visibility had reduced to 1,200 m and the rainfall rate had increased to 4.8 mm in 10 minutes (28.8 mm per hour). The captain commented to the FO that the reduced visibility was likely related to a rain shower.

Flight recorder data indicated that the approach was within the operator’s stable approach criteria. Recorded values of airspeed during the final approach and landing showed fluctuations consistent with gusty conditions. At the decision height, coincident with the FO beginning to state ‘no contact’,^[8] the captain announced that the runway was in-sight and continued the approach.  

At interview, the FO explained that they^[9] were unable to see the runway due primarily to two factors. The FO was not familiar with the approach, which had a 6º offset angle between the approach path and the runway, causing the nose of the aircraft to point right of the centreline. This difference between the approach course and the runway heading was exacerbated by the crosswind from the right of the runway, further pushing the nose of aircraft to the right of the centreline.

At the time that the captain announced that the runway was in sight, the aircraft was 3.4 km from the runway threshold, which was the required visibility for the approach.

The flight crew reported that during the approach the rainfall was of a moderate intensity. The aerodrome reporting officer (ARO) reported observing a slight increase in the rain intensity just prior to the aircraft landing but considered it to be moderate rain.

Landing

At 0712, the time of the landing, a maximum crosswind gust of 35 knots was recorded.^[10] This was the highest recorded gust between 0700 and 0730. The crosswind limit for the Fokker 100 is 35 knots. The aircraft touched down at 154 knots airspeed and a groundspeed of 159 knots (Figure 1). The touchdown was positive^[11] and at, or slightly before, the touch down zone.

Figure 1: Flight data from the occurrence landing

Source: ATSB

Eleven seconds after landing, the captain requested assistance with the brakes^[12] from the FO. The recorded deceleration during this part of the landing was medium to low (less than 0.25 G) and reduced further as the landing roll progressed (Figure 1). Throughout the landing, there were directional oscillations about the runway heading as the aircraft weathercocked into the strong crosswind.

The captain reported that the aircraft aquaplaned during the landing. Approximately 20 seconds after touching down, the aquaplaning response technique was conducted. This involved reducing manual braking (brake pressure) with the intent of regaining traction and stowing the thrust reversers to increase directional stability. After completion of the aquaplaning response technique, maximum reverse thrust was applied which provided high deceleration (greater than 0.5 G) just before the aircraft departed the runway.

The aircraft stopped about 70 m beyond the upwind runway threshold, off the runway surface, within the runway end safety area^[13] (Figure 2). There were no injuries and the passengers and crew disembarked via the front stairs and were transported to the terminal.

Figure 2: Image taken of the aircraft stopped within the runway end safety area

Source: Network Aviation

A visual examination of the tyres identified some deep scratches, likely due to the abrasive surface of the runway end safety area. An inspection of the aircraft found that the loose gravel had damaged some of the landing gear components.

__________

1. Western Standard Time (WST): Coordinated Universal Time (UTC) + 8 hours.</li
2. Cloud cover: in aviation, cloud cover is reported using words that denote the extent of the cover – ‘few’ indicates that up to a quarter of the sky is covered, ‘scattered’ indicates that cloud is covering between a quarter and a half of the sky, ‘broken’ indicates that more than half to almost all the sky is covered, and ‘overcast’ indicates that all the sky is covered.</li
3. Pilot flying (PF) and pilot monitoring (PM): procedurally assigned roles with specifically assigned duties at specific stages of a flight. The PF does most of the flying, except in defined circumstances; such as planning for descent, approach and landing. The PM carries out support duties and monitors the PF’s actions and the aircraft’s flight path
4. The Bureau of Meteorology definition of heavy rainfall is greater than 6 mm/hr (see the section titled Federal Aviation Administration (FAA) Safety Alert for Flight Operators (SAFO) 19003)
5. VAPP is the final approach speed. The airspeed to be maintained down to 50 ft over the runway threshold. Usually determined as VREF plus a margin for wind.
6. VREF is the reference landing speed, defined to provide suitable safety margin during landing. Usually it is 1.3 times the stall speed with full flaps or selected landing flaps.
7. The AWIS provides actual weather conditions, via telephone or radio broadcast, from Bureau of Meteorology (BoM) automatic weather stations, or weather stations approved for that purpose by the BoM.
8. A ‘no contact’ call informs the captain that the FO does not have the runway in sight.
9. The ATSB uses gender neutral pronouns, including using the singular version of ‘they’.
10. The BoM Automatic Weather Station records highest wind gust for each minute.
11. A positive touchdown is a firm landing, encouraged when there is a risk of aquaplaning, to ensure good contact between the tyres and the runway surface.
12. The aircraft was not equipped with auto braking. However, an anti-skid system was fitted.
13. Runway end safety area is an area at the end of the runway (off the runway), clear of hazards, that limits the consequences when aircraft overrun or undershoot a runway.

Context

Pilot information

At the time of the occurrence, the captain had 5,594.7 hours total flying time with 1,963.4 hours on the Fokker 100. The captain had flown regularly to Newman, the last time being the week prior.

The first officer had 2,920.5 hours total flying time with 182.8 hours on the Fokker 100. It was the first officer’s second time flying into Newman.

Runway information

Newman Airport runway 05/23 was 2,072 m long, 30 m wide and ungrooved (lateral grooving is used to improve braking performance in wet conditions).

The most recent maintenance on the runway surface was a retexturing and excess rubber removal completed in June 2018 after a Civil Aviation Safety Authority (CASA) audit found that severe pavement bleeding and flushing^[14] was occurring at the touchdown zones.

On the morning of the occurrence, the aerodrome reporting officer^[15] (ARO) at Newman Airport inspected the runway at 0500 and again at 0630, 45 minutes before the aircraft landed. This was in accordance with the ARO’s procedures for the runway to be inspected ‘as soon as practicable prior to the first RPT [regular public transport] flight’. At those times, the ARO recalled a significant amount of standing water on the grass strips on either side of the runway. However, the ARO described that the main runway surface appeared clear of any noticeable standing water and was serviceable throughout the morning.

About a year after the occurrence, an image was taken of the runway showing standing water on the runway after rainfall (Figure 3). 

Figure 3: Image of standing water on the runway at Newman Airport.

Source: Qantas

Friction tests

Aerodrome operators were required to ensured that runway friction levels were above minimum limits^[16] as detailed in Part 139 (Aerodromes) of the Manual of Standards 2017, version 1.14, which was current at the time. In order to demonstrate compliance, the friction was required to be periodically tested via one of the prescribed methods. The Manual of Standards also specified the ‘maintenance planning level’ for friction, which is the level that if the measured friction falls below the aerodrome operator must initiate appropriate corrective maintenance action to improve the friction and ensure ongoing safety of the runway.

A runway friction test was conducted in March 2019. The test took continuous skid resistance measurements at 3 and 6 m offsets from the centreline at 65 km/h and 95 km/h. These measurements were averaged over 10 m to produce a continuous data plot of the friction. A 100 m rolling average was also included in the friction test report.

The report described the differences between the 65 and the 95 km/h test indicating that the 65 km/h test was affected more by the microtexture of the surface and the 95 km/h test was more affected by the macrotexture. Low friction values for the 65 km/h test indicated that the fine texture may be filled with rubber. The 95 km/h test gave an indication of how fast water was able to escape from the surface. The report also stated that seasonal variation can affect the friction measurements by up to 15 per cent.

The continuous friction measurements for the 95 km/h test recorded numerous measurements below the maintenance planning level and some measurements below the allowable minimum friction levels (Figure 3). However, when averaged over 100 m, the lowest friction measurements were at maintenance planning level. The Manual of Standards had no requirement, nor did it specifically permit the averaging of the friction measurements.

Figure 4: Results from runway friction report

These plots show the data from the 95 km/h test at 3 m offset from centreline. The upper image shows 10 m averages considered to the continuous friction measurement, the lower image is the same data using 100 m rolling averages.

Source – Fulton Hogan

The report did not mention the friction values below the minimum design limit and concluded that:

• there were sections of the runway at maintenance planning level
• the runway met the surface friction requirements as specified in the Manual of Standards.

Several weeks after the occurrence the runway was re-tested via the same method. The friction values recorded in the 2020 test were generally higher (i.e. better grip). However, there were still areas in the touch down zones that were at maintenance planning level. No rubber removal or surface maintenance had been performed between the 2019 and 2020 tests.

Aquaplaning

The three types of aquaplaning are dynamic, viscous and reverted rubber.

• Dynamic aquaplaning occurs at high-speed and is the result of water being unable to be forced away from under the tyre. This creates a layer of water underneath the tyre thereby reducing the coefficient of friction.
• Viscous aquaplaning is a similar phenomenon but can occur at lower speeds and relies on a low coefficient of friction of the runway surface, usually due to rubber build up. The smooth surface enables a small film of water to cause the tyre to slip during braking.
• Reverted rubber aquaplaning is the breakdown of the tyre material from heat generated as part of the braking or as a result of a skid or lockup. Reverted rubber aquaplaning is the only type of aquaplaning that leaves evidence marks on the tyre surface.

Runway contamination

The Civil Aviation Order (CAO) 20.7.1B defined a contaminated runway as a runway that has more than 25 per cent of the runway surface area within the required length and width being used covered by:

• water, or slush, more than 3 mm deep; or
• loose snow more than 20 mm deep; or
• compacted snow or ice, including wet ice.

Advice from runway subject matter experts indicated that strong crosswinds can increase the chances of the windward side of the runway being contaminated. This is because the wind effectively slows or stops the water from draining along the built-in slope away from the centreline.

Federal Aviation Administration (FAA) Safety Alert for Flight Operators (SAFO) 19003

In response to several landing events where the braking coefficient was found to be less than what was expected for a wet runway, the United States Federal Aviation Administration (FAA) issued Safety Alert for Flight Operators (SAFO) 15009 in August 2015. In 2019, this SAFO was updated with

While the FAA recognised that landing overruns on wet runways usually involved multiple contributing factors, their analysis of those landing events raised concerns regarding stopping performance assumptions. The cause of the braking underperformance was not fully understood, but the FAA in SAFO 15009 cited possible factors relating to runway conditions including texture, drainage, puddling in wheel tracks and active precipitation. Specifically, the analysis showed that, 30‑40 per cent of additional stopping distance may be required in certain cases where the runway was very wet, but not flooded.

As a result of the above, the FAA suggested that whenever there is likelihood of moderate or greater active rain on a smooth (ungrooved) runway, or heavy rain on a grooved or porous friction course runway, landing distance calculations should be done assuming the surface is contaminated.

There is no standard definition of rainfall intensity across the aviation industry. However, the World Meteorological Organization^[17] stated:

While there is no agreed international definition regarding rainfall intensity, some use the following criteria: Heavy rain is defined as rates in excess of 4 mm per hour while heavy showers are defined as rates in excess of 10 mm per hour. Showers are further classified as being violent if the rate exceeds 50 mm per hour, although these are normally considered to be rates typical for tropical regions.

The below table includes the published definition from the FAA and the Australian Bureau of Meteorology (BoM).

Table 1: Comparison of rain intensity definitions between FAA and BOM

Calculation of required landing field length

Civil Aviation Order (CAO) 20.7.1B (Aeroplane weight and performance limitations) specified that landing distance required shall be 1.67 times the distance required to bring the aeroplane to a stop on a dry runway. For wet runways, an additional 15 per cent margin is to be added be added making the landing field length required 1.92 times the distance required to bring the aeroplane to a stop on a dry runway.

The Fokker 100 airplane flight manual (AFM) provided the required landing field length for flaps 25 for the aircraft weight as 1,520 m. In line with the CAO, the manual stated that if forecasts or observations indicate the runway may be wet, the required landing field length was an additional 15 per cent of the distance in dry conditions. This brought the required length to 1,748 m. These lengths were predicated on the aircraft being at the reference landing speed (V_REF) at 50 ft above the runway threshold.

Fokker provided advice to the ATSB that they recognised that in normal operation the threshold crossing speed is often higher than V_REF. In those cases, the landing distance may be larger than the landing distances determined during the certification flight tests of the aircraft. However, the increase will not be larger than the 1.67 factor used in the AFM graphs for required landing field length for dry conditions.

Operator documentation and guidance

Runway contamination

The weather briefing section of the Flight Administration Manual (FAM) indicated that the possibility of runways being contaminated at the departure and destination airports should be considered during the planning process. Network Aviation policy did not approve operations on contaminated runways. However, limited guidance within the documented material was provided on how to determine if the runway was contaminated, and moderate or heavy rain were not identified as possible runway contaminants.

The Fokker 100 Aircraft Operating Manual (AOM) contained a section for operating on contaminated runways. The section contained the CASA definition of contaminated runways and additional information on possible runway contamination. The section stated that a runway may also be considered contaminated in conditions including:

A runway with a smooth/slippery surface (rubber deposits / oil) or a recently resurfaced runway covered with a thin layer of water (less than 3mm) […] may have a considerably reduced friction (slippery wet runways).

In heavy rain showers even on runways with a good drainage.

The section also stated that:

The magnitude of the effects of runway contamination are determined in general by: […]

- The runway surface condition and texture, grooved or non-grooved runways;

- The weather conditions (cross wind, gust, actual precipitation);

- The aircraft configuration (flaps, reversers, autobrakes, speedbrakes)

Advice was sought from the operator on how flight crew were expected to assess if a runway was contaminated. The operator indicated that the flight crew should check NOTAM’s^[18] prior to departure for any published runway unserviceability. During the flight, they should monitor the aerodrome weather information service (AWIS) broadcast, noting that the AWIS broadcast does not include any reference to standing water. There was also an expectation that the ARO strip inspection prior to the arrival would identify if the runway was contaminated and if so, contact the arriving aircraft. There was no guidance relating rainfall intensity to runway contamination.

Aircraft configuration selection

The configuration section of the AOM stated that:

Flaps 42 should be used when landing on contaminated runways or runways with reduced braking action.

The windshear section of the AOM encouraged flight crew to consider using flaps 25 for landing and increasing approach speed if weather conditions were such that a windshear may possibly exist, but a safe approach and landing was thought to be feasible. The manual also stated that considerations should be given to the increased landing distance as a result of the increased approach speed.

Approach briefing

The approach briefing section of the Flight Crew Operating Manual (FCOM) listed inclement weather and adverse runway conditions as elements to brief as required. In accordance with the manual, the approach briefing consisted of five modules; Charts, Terrain, Weather, Operational and Plus. With Plus being the section of the approach brief for the crew to identify any threats not previously discussed.

The ‘runway state’ was a line item within the Operational section of the briefing, however, there was no additional information provided on how to assess the runway state.

Regulator guidance

At the time of the occurrence, there was a Civil Aviation Advisory Publication (CAAP) 235-05 which had advisory information on landing distance. However, this did not reflect the latest FAA guidance on the potential contamination and reduction in braking performance resulting from active moderate or heavy precipitation on an ungrooved runway.

In October 2020, 10 months after the occurrence, CASA published an update to the CAAP 235-05 - New performance provisions for CAO 20.7.1B and CAO 20.7.4. Section 3 of the update, titled Landing Distance, included advice on landing in very wet conditions. Included was the information from, and a reference to, the FAA SAFO 19003 (discussed above) identifying moderate active precipitation and ungrooved runways as being risks to landing performance.

Related occurrences

In 2015, an Australian registered Boeing 737 landing at Christchurch, New Zealand, in wet conditions, did not decelerate as expected and stopped 5 m from the runway end. The ATSB investigation (AO-2015-046) found that the reduced braking effectiveness was likely as a result of water on the runway.

Relevant publications

In 2008, the ATSB published a two-part research report (AR-2008-018) titled Runway Excursions with the objective of analysing international and Australian trends in runway excursions. Part 1 of the report explored the contributing factors associated with runway excursions between 1998 and 2007. Water-affected and contaminated runways was one of the contributing factors identified.

In May 2009, the Flight Safety Foundation published a Runway Safety Initiative that provided practical guidance and tools for operators to lower the risk of runway excursions.

__________

14. ‘Bleeding and flushing’ of pavement refers to the bituminous substance that holds the asphalt aggregate together seeping up to the surface.
15. An ARO’s main duties relate to safety and include inspecting runways, reporting hazardous situations and facilitating repairs. These duties include ensuring the safety of runways.
16. The MOS stated that if the measured friction level fell below the relevant Minimum friction level values, the aerodrome operator must promulgate by NOTAM, that the runway pavement fell below minimum friction level when wet. Additionally, corrective maintenance action must be taken without delay. This requirement applied when friction characteristics for either the entire runway or a portion thereof were below the minimum friction level.
17. Aviation | Hazards | Precipitation | World Meteorological Organization (wmo.int)
18. NOTAM or Notice(s) to Airmen give information on the establishment, condition or change in an aeronautical facility, service, procedure, or hazard.

Safety Analysis

After touching down on runway 05 at Newman Airport the aircraft did not decelerate as expected. The captain, sensing the aircraft aquaplane, conducted the aquaplaning response technique and subsequently applied maximum reverse thrust, stopping the aircraft 70 m beyond the upwind runway threshold. This analysis will cover the speed at touchdown, the braking effectiveness, and the environmental conditions at touchdown; as well as the information available to the flight crew to conduct their threat assessment and the condition of the runway.

Landing speed, wind conditions and braking performance

The flight crew selected the approach speed based on the known environmental conditions. The selection was a correct application of the guidance for the forecast turbulence, due to the possibility of windshear conditions. The flaps 25 approach along with the additional mandated speed margins, due to the wind conditions, resulted in a higher approach airspeed than for a flaps 42 approach.

The final approach speed was flown as planned however, the aircraft did not slow after crossing the threshold and entering the flare. During this period, a higher groundspeed than airspeed was recorded indicating a possible unforecast tailwind component, which may have limited the ability to reduce the speed. A higher touchdown speed requires a longer stopping distance due to the additional energy to be dissipated by the deceleration devices. As a general rule, a 10 per cent increase in approach speed results in a 20 per cent increase in the required landing distance.

During the landing roll, after the captain (pilot flying) asked for assistance with applying the brakes, it is highly likely that the maximum manual braking effort was being applied. During this same period, the recorded deceleration was low, indicating that the braking effectiveness was reduced. The captain’s report of aquaplaning is consistent with this low deceleration and the directional oscillations recorded during the landing.

The crosswind conditions combined with the aquaplaning increased the difficulty of maintaining directional control. In accordance with the advice in the Aircraft Operating Manual in relation to aquaplaning response, the crew were limited in the amount of reverse thrust that could be applied as the priority was on maintaining the directional stability and keeping the aircraft on the centreline. Without the crosswind, it is likely that the captain could have engaged maximum reverse thrust much earlier in the landing roll, which would have significantly reduced the landing distance.

Given the magnitude of the runway overrun (70 m), it is highly likely that if either the landing speed had been reduced, the braking effectiveness had been normal or there had been less crosswind, the overrun would not have occurred.

Threat identification

During the approach briefing, the flight crew correctly identified the primary threat as the significant weather. However, their focus was primarily on the wind and the visibility. Despite the forecast for heavy rain obtained before the flight and the aerodrome weather information service providing observations of heavy rain occurring there was no consideration of the effect of the rainfall on the runway state or the braking performance.

The faster flaps 25 approach was selected to address the identified threat of possible windshear. However, this selection (compared to the standard flaps 42 approach) further increased the risks associated with reduced runway braking performance. The crosswind was discussed in relation to the selection of the runway but was not identified as possibly affecting the ability of the aircraft to brake effectively or reducing the drainage of water from the runway surface on the windward side.

The approach briefing procedure provided a prompt to discuss the runway state. However, there was no information available to the crew to enable them to identify the potential for a significant reduction in braking performance posed by the active moderate rainfall. As a result, had the crew identified and discussed the threat, the options for them to manage the threat were limited to their own judgement. Therefore, it is possible that even if the flight crew had identified the threat, they would have continued the approach. There was no information reasonably available to the crew to assist them to identify the runway as potentially water contaminated by the active rainfall.

Operator and regulator documentation

Network Aviation policy did not permit operations on contaminated runway however, flight crews were not provided with adequate information to identify all possible runway contaminated situations. At the time of the occurrence, the only information relevant to the conditions on the day within the operator’s document suite was advisory information in relation to heavy rain being a possible contaminant of the runway. There were no specific procedures to identify the rainfall intensity or relating to conducting approaches during active precipitation.

The United States Federal Aviation Administration (FAA) safety alert for flight operators (SAFO) provided a practical means to assess the potential for runway contaminations based solely on the type of runway surface (grooved or ungrooved) and the rain intensity at landing. Using the FAA document and guidance on rainfall intensity it would have been possible for the crew to determine that there was a potential for poor braking performance and take some mitigating action.

At the time of the occurrence, the lack of Civil Aviation Safety Authority (CASA) advisory information reflecting the FAA alert regarding the potential effect of active moderate or heavy rainfall on braking performance, reduced the likelihood that the operator would have the appropriate guidance for mitigating this hazard.

Runway condition

The flight crew and the aerodrome reporting officer (ARO) reported moderate rain at the time of the landing. The lack of grooving on the runway reduced the ability of water to drain from the runway surface. The FAA SAFO advised that moderate rain on an ungrooved runway can cause a significant reduction in braking performance. The heavy rain prior to the final approach and the ARO’s observations in relation to the water accumulation around the runway meant that drainage of water from the runway may have been slower than usual at the time of landing. The high crosswind at the time of landing would also have slowed the drainage of water on the windward side of the runway.

The runway friction measurements taken in 2019 had values below the recommended maintenance planning levels and some measurements below the minimum friction limits as specified by the Manual of Standards. Although still safe for operations, at the levels recorded, it would generally be expected that maintenance should be performed in the lower friction areas to ensure ongoing safe operation on the runway.

The water pooling observed a year after the occurrence may have been present at the time of the occurrence but would have been hard to identify during active precipitation.

Had there been additional maintenance performed on the runway, there would have been an increase in the overall friction of the runway. However, while an increase in friction may have affected the outcome on the day, it is not possible to conclusively state that the overrun would not have occurred.

Findings

From the evidence available, the following findings are made with respect to the runway overrun involving VH-NHY at Newman Airport on 09 January 2020.

Contributing factors

• The combination of the approach speed required by the prevailing wind conditions and the poor braking effectiveness in the wet conditions resulted in the aircraft overrunning the runway.

Other factors that increased risk

• During the flight, the potential for the heavy or moderate rainfall to significantly impact the landing distance was not recognised by the flight crew and therefore not considered as a threat.
• Despite technical examination of the runway identifying areas requiring maintenance to maintain the surface friction, no corrective action was taken.
• The operator's documentation required crew to consider contamination of runways at the departure and destination airports. However, the provided definition and guidance did not include the means to identify water contamination from active rainfall. (Safety Issue)
• CASA advisory publications did not include information regarding the potential for reduction in braking performance resulting from active moderate or heavy rainfall. (Safety Issue)

Safety issues and actions

Operator guidance

Safety issue number: AO-2020-002-SI-01

Safety issue description: The operator's documentation required crew to consider contamination of runways at the departure and destination airports. However, the provided definition and guidance did not include the means to identify water contamination from active rainfall.

Regulator guidance

Safety issue number: AO-2020-002-SI-02

Safety issue description: Civil Aviation Safety Authority (CASA) advisory publications did not include information regarding the potential for reduction in braking performance resulting from active rainfall.

Safety action not associated with an identified safety issue

Additional safety action by Network Aviation

Network Aviation advised that they have taken the following proactive safety action in response to this occurrence:

• Flight Crew experienced scenarios of potentially contaminated runway during the 2021 1A/1B cyclic training program.
• Network Aviation have engaged with the aerodrome reporting officer to confirm reliability of aerodrome weather information service.
• Runway overrun protection system has commenced implementation and fitment to the A320 fleet.
• Flight Operations governance amended to provide enhanced and embedded F100/A320 Touchdown Zone scatter plot reporting to monitor runway excursion risk.
• Implemented pre-cyclic quiz for all pilots - verifying knowledge of runway surface condition requirements
• Qantas group and other airlines sharing consistent approaches to contaminated runways, ensuring aligned procedures.
• Benchmarking and sharing Runway Excursion Risk flight data analysis program data across Qantas group to drive continuous improvement.

Sources and submissions

Sources of information

The sources of information during the investigation included:

• Network Aviation
• flight recorder data
• the involved flight crew
• the duty aerodrome reporting officer and East Pilbara Shire council
• aerodrome subject matter experts
• Bureau of Meteorology.

Submissions

Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section allows a person receiving a draft report to make submissions to the ATSB about the draft report.

A draft of this report was provided to the following directly involved parties:

• Network Aviation
• flight crew
• East Pilbara shire council
• Civil Aviation Safety Authority
• Fokker
• Dutch Safety Board

Submissions were received from:

• Network Aviation
• the flight crew
• East Pilbara shire council
• Civil Aviation Safety Authority

The submissions were reviewed and, where considered appropriate, the text of the report was amended accordingly.

Glossary

AFM                 Airplane flight manual

AOM                Aircraft operating manual

ARO                Aerodrome reporting officer

AWIS               Aerodrome weather information service

BoM                 Bureau of Meteorology

CAAP              Civil Aviation Advisory Publication

CAO                Civil Aviation Order

CASA              Civil Aviation Safety Authority

FAA                 United States Federal Aviation Administration

FAM                 Flight administration manual

FCOM              Flight crew operations manual

FO                   First officer

ICAO               International Civil Aviation Organization

PF                   Pilot flying

PM                  Pilot monitoring

RPT                 Regular public transport

SAFO              Safety Alert for Flight Operators

V_APP               Final approach speed

V_REF               Reference landing speed

WMO              World Meteorological Organization

Purpose of safety investigations & publishing information

Purpose of safety investigations The objective of a safety investigation is to enhance transport safety. This is done through: identifying safety issues and facilitating safety action to address those issues providing information about occurrences and their associated safety factors to facilitate learning within the transport industry. It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action. Terminology An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2021 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

Safety summary

What happened

On 2 January 2020, at about 1415 Eastern Standard Time, the pilot of a Gippsland Aeronautics GA8 aircraft, operated by Air Fraser Island and registered VH-BNX, conducted a local scenic flight at Fraser Island, Queensland, with seven passengers on board. After the 13-minute flight, the aircraft returned to land on the same beach landing area it had taken off from.

During the approach, the pilot saw a vehicle moving close to the runway. To remain clear of the perceived vehicle hazard, the pilot opted to land about a third of the way down the marked runway. Shortly after the first touchdown, the aircraft became airborne again. The pilot reported that he had pulled back on the control column to raise the aircraft nose off the ground, in order to minimise the discomfort to passengers as the aircraft passed over holes in the sand.

After passing the holes, the aircraft landed and the pilot attempted to brake. However, the aircraft was still at speed as it approached the end of the runway, beyond which was a washout. As the aircraft overran the runway, the pilot reported raising the nose to lift the aircraft over the washout, concerned that the aircraft would flip if the nose wheel struck the water. Immediately beyond the washout, the aircraft pitched forwards heavily onto the nose landing gear, which collapsed. The propeller struck the sand and the aircraft came to a halt.

The aircraft sustained substantial damage, but there were no injuries to the pilot or passengers.

What the ATSB found

The pilot did not conduct a go-around despite several cues to do so, including sighting a vehicle near the runway and when becoming airborne again after the first touchdown. The aircraft subsequently landed with insufficient runway remaining to prevent a runway overrun. The overrun was onto a section of beach unsuitable for a landing roll due to a washout.

The pilot did not obtain passenger weights or use standard weights to calculate the aircraft weight and balance prior to the flight from which to assess the required landing distance.

Safety message

This accident is a reminder to pilots to be go-around minded. This is of particular importance when operating at a runway in conditions where the full available runway length is required for a safe landing and no obstacle-free overrun area exists.

The Flight Safety Foundation Approach-and-landing accident reduction tool kit Briefing note 6.1 – Being prepared to go around, stated that the importance of being go-around prepared and go-around minded must be emphasised because a go-around is not a frequent occurrence.

The investigation

Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of findings that affect safety and possible safety actions.

The occurrence

On 2 January 2020, at about 1415 Eastern Standard Time,^[1] the pilot of a Gippsland Aeronautics GA8 aircraft, operated by Air Fraser Island and registered VH-BNX, conducted a local scenic flight at Fraser Island, Queensland, with seven passengers on board. After a 13-minute flight, the aircraft approached Cornwell’s beach aeroplane landing area (ALA), from where it had taken off.

Cornwell’s ALA was located on the east coast of Fraser Island (Figure 1). The runway, which was on the beach, was 500 m long and marked with traffic cones. The wind was 5-10 kt from the east-north-east and the beach was busy, with vehicles on the beach and campers in the sand dunes. There were also vehicles parked on the edge of the clearway, which extended 100 m either end of the runway.

Figure 1: Fraser Island and Cornwell’s aeroplane landing area

Source: Google Earth, annotated by ATSB

As the pilot commenced a straight-in approach from the south, he communicated with ground crew via radio and was advised that all vehicles were stationary. As the aircraft neared the runway, the pilot saw a car moving close to the runway area. A ground crewmember tried to get the driver to stop and the car then changed direction and moved clear of the runway. To ensure the aircraft remained clear of the vehicle hazard, the pilot opted to move his aiming point further along the runway, and the aircraft touched down a third of the way down the marked runway and well beyond the runway threshold markers.

About half way along the runway, there were 10 cm-deep ‘melon holes’^[2] in the sand. Video footage taken from inside the aircraft indicated that it touched down briefly, then became airborne again. The pilot reported that approaching the holes, he had extended flap and pulled back on the control column in an attempt to lift and hold the aircraft nose wheel off the ground, to minimise the discomfort to passengers. After passing the holes, the pilot reported that he lowered the nose and attempted to brake. The safety manager later paced out the distance from where the aircraft landed after passing the holes, and reported that approximately 100 m of runway remained.

The aircraft was still at speed as it approached the end of the runway. As the aircraft overran the runway, the pilot raised the nose to get the aircraft over a washout, concerned that it would flip if the nose wheel struck the water. Immediately beyond the washout, the aircraft pitched forwards heavily onto the nose landing gear, which collapsed. The propeller struck the sand and the aircraft came to a halt (Figure 2). The video footage showed that less than 5 seconds elapsed between the landing and when the aircraft stopped.

The aircraft sustained substantial damage. There were no injuries to the pilot or passengers. The pilot and front passenger were wearing four-point harnesses and rear passengers wore over-shoulder harnesses with lap sash seatbelt. The pilot reported he had verified that everyone was wearing their seatbelts and had headsets on so he could communicate with them before commencing engine start.

Figure 2: VH-BNX at the accident site

Source: Air Fraser Island

Context

Pilot qualifications and experience

The pilot held a commercial pilot licence (aeroplane) issued in July 2018, a single-engine aeroplane class rating, and a valid Class 1 medical certificate. He commenced training in beach operations at Air Fraser Island on 14 January 2019 and was employed as a pilot on 5 March 2019. Since then, he had accrued 300-350 hours in GA8 aircraft conducting beach operations.

Air Fraser Island pilots underwent beach operations flight checks every 90 days in accordance with their operations manual. The pilot’s last beach operations and 6-monthly route check was completed successfully on 18 October 2019. The flight included circuits, soft-field take-offs and landings, and emergency operations.

Aircraft information

The aircraft had 10,844.4 hours total time in service at the start of the accident day. The maintenance release (MR)^[3] current on the day was issued on 30 December 2019 following a 100-hourly inspection. The aircraft had subsequently flown 6.7 hours and made 31 landings. No defects were recorded on the MR. The daily inspection certification on the MR had been signed for 2 January.

The chief engineer advised that the operator’s aircraft fleet generally made 200-300 landings every 100 hours and the safety manager stated that on a busy day, pilots would conduct 20 to 30 take-offs and landings. The number of landings per hours flown for VH-BNX was normal for Air Fraser Island’s operations. Nearly all the landings were soft- and short-field landings on beach runways. This high number of landings and salty, sandy environment had resulted in ongoing unscheduled maintenance of aircraft landing gear, particularly brakes.

Brakes

Unscheduled brake maintenance

Air Fraser Island’s chief engineer reported that unscheduled maintenance of the brake system consisted of replacing brake pads, discs, calliper o rings, bearings, master cylinders and undercarriage bushes. They found that when pilots have sand on their shoes and put their feet on the (brake) pedals, the sand drops on top of the master cylinders, eventually works its way down into the cylinders and wears out the o rings.

Sand in the master cylinders wearing the o rings can result in leakage of brake fluid and has the effect of making the brakes feel spongy. Pilots reported that when the brakes felt spongy on landing, they would pump the brake pedals a few times, and the pressure would return and the brakes would stop the aircraft effectively. In response to finding sand in the master cylinders, in November 2019, the aircraft operator commenced a program of replacing all the master cylinder and calliper o rings at every 100-hourly inspection. The chief engineer advised that the master cylinders, calliper o rings and brake pads on VH-BNX had been replaced during the 100-hourly inspection, 3 days before the accident.

Daily inspection

The Air Fraser Island operations manual, stipulated that in the pilots’ daily inspection of aircraft, special attention must be given to brakes. Pilots were required to check the brake disc rotor for cracking and corrosion, brake linings for wear and callipers to look for any signs of brake fluid seepage. The pilot of VH-BNX reported that company pilots checked the brake fluid and topped it up when needed, as part of the daily inspection.

Braking during the occurrence

The pilot reported that he attempted to brake when the aircraft was beyond the melon holes, but that the left brake felt spongy. Before the first flight of the day, he had conducted the daily inspection on the aircraft and had not found any issue with the brakes. He had also checked the brakes when at about 900 ft during the approach, by depressing the pedals, at which stage the brake pressure felt normal.

After the accident, the chief engineer tested the left brake by pushing the pedal with his hand and found that the brake was hard and did not find any defect with the brakes. The safety manager and chief pilot also inspected the tyre tracks in the sand from the accident landing. The left tyre track was different from the right, in which the tyre grooves were distinct. They assessed that the left tyre track was indicative of the left wheel having locked up and skidded across the surface of the sand. The nose wheel track was not very distinct, consistent with the pilot’s attempt at raising the aircraft nose.

Aeroplane landing areas

The company operations manual specified that beach runways were to be established in accordance with the Civil Aviation Safety Authority (CASA)

Runway length

The CAAP stated that ‘a runway length equal to or greater than that specified in the aeroplane’s flight manual or approved performance charts or certificate of airworthiness, for the prevailing conditions is required (increasing the length by an additional 15% is recommended when unfactored data is used).’

The pilots were required to use soft-field landing technique, as described in the company operations manual:

The pilot in command shall use sufficient braking to enable the aircraft to slow to a taxi speed as soon as possible after touchdown. Constant back pressure should be maintained on the control column whilst braking to relieve nose wheel pressure.

The landing technique described in the pilot operating handbook for the GA8 aircraft, was consistent with a short-field technique:

The aircraft approaches with idle power down to the 50 feet height point at the given airspeed appropriate to weight. After touch down maximum wheel braking is used to bring the aircraft to a stop.

From the performance charts in the pilot operating handbook, the take-off distance required was greater than the landing distance. The chief pilot reported that landing distance required was about two thirds of that required for the take-off roll. From the performance charts, the aircraft operator had derived a standard take-off ground roll distance required of 480 m. This was based on 30 ºC temperature, maximum take-off weight, nil wind, a ‘short dry grass or gravel’ runway surface and the recommended increase of 15 per cent as the data was unfactored. From the calculated distance, the ground crew were to mark out 500-metre-long runways where possible. However, the safety manager commented that if a runway length of 350-500 m was all that was available, the pilots could still operate on the runway but would take fewer passengers and/or less fuel.

The operations manual stipulated that pilots ‘must calculate the take-off and landing distance required for a flight considering take-off/landing distance available, aircraft weight, pressure/density height and obstacles.’ Additionally, the pilot must ensure that all passenger (and cargo) weights were calculated prior to loading the aircraft, using standard or actual passenger weights, but not a combination of the two.

The passenger manifest was completed after the accident. Standard weights were not used, but passengers later reported that they did not provide their weights to the ground crew when completing the manifest. The accuracy of the recorded weights was unknown. The aircraft take-off weight on the manifest was 1,767 kg, less than the maximum take-off weight of 1,814 kg.

Based on the power-off landing chart, at 30 °C, the manifest aircraft weight, nil wind and slope, short dry grass or gravel surface and without consideration of 50 ft obstacle clearance, the landing distance required was about 480 m and the landing roll required was 200 m. There was no published data for sand runways.

Runway ends

The CAAP further stated that ‘Both ends of a runway…should have approach and take-off areas clear of objects above a 5% slope for day [operations].’ The CAAP contained no recommendations or guidance regarding the suitability or nature of the ground under the approach and take-off areas similar to the requirement for obstacle-free areas above. The safety manager reported that the highest obstacle they needed to climb above on the beach were 5 m high tour buses. They used a clearway of at least 100 m at the end of the runways, marked with bollards to distinguish the clearway markers from the runway touchdown cones.

The clearways were used to ensure obstacle clearance and their surfaces were not intended to be used for take-off or landing ground roll. The safety manager advised that soft sand, pooling water, washouts and dips were all suitable in the clearway in accordance with the CAAP.

Comparison with certified aerodromes

Certified aerodromes are intended to accommodate aircraft with more than 30 passenger seats conducting air transport operations. As such, the requirements surrounding certified aerodromes are in excess of those for ALAs.

The International Civil Aviation Organization (ICAO) Annex 14: Aerodromes, stated that for non‑instrument runways less than 800 m (code 1 runway), there shall be a runway strip^[4] beyond the runway end of a distance of at least 30 m. It also recommended that a runway end safety area^[5] of at least 30 m should be provided at each end of the runway strip.

Similarly, the CASA Manual of Standards for Part 139 - Aerodromes indicated that, for certified aerodromes, a runway strip shall extend at least 30 m from the end of the runway. However, the standards did not require a non-instrument code 1 runway to have a runway end safety area. The runway strip requirement was to ensure, in the case of a runway excursion (overrun and veer-off), the aircraft had enough room to stop, reducing the risk of damage to an aircraft and injury to occupants.

Although these standards were not applicable for ALAs, in this occurrence, the pooling water at the end of the runway increased risk of aircraft damage and occupant injury in the event of a runway excursion.

In an investigation into an accident in 2018, where an aircraft overran the runway of an ALA and collided with a watercourse (AO-2018-025), the ATSB identified a safety issue that CAAP 92-1(1) did not have guidance for the inclusion of a safe runway overrun area at ALAs. The ATSB issued a safety recommendation to CASA in October 2019 to include guidance for the inclusion of runway end safety areas at ALAs in CAAP 92-1(1).

Cornwell’s aeroplane landing area

Cornwell’s runway used on the accident flight was 500 m long and 15 m wide, marked with touchdown cones, and 100 m clearways beyond either end, marked by bollards and a sign. It was a ‘high beach’ landing area, set towards the dunes and either side of the runway was hard sand. There was a length of about 50 m with melon holes mid-strip and an ankle-deep freshwater soak, or washout, at the northern end of the runway.

Earlier in the day, ground crew had driven up and down the strip, assessing that the melon holes did not pose undue risk. Other company pilots had also inspected the strip and landed there with no issues. Prior to the accident flight, the pilot had landed VH-BNX on the Cornwell’s runway with no passengers on board. On that landing, the aircraft stopped before the melon holes, using less than half the available runway distance.

The safety manager assessed that on the accident flight, the aircraft landed with less than 100 m runway remaining beyond the melon holes, which was insufficient distance to stop with the aircraft fully loaded, and the conditions on the day.

The pilot subsequently reported that he may have misidentified the end of the runway, mistaking the end-of-clearway bollards beyond the landing strip to be the end-of-runway cones. He further commented that at the time, he had thought there was ample distance remaining to stop, until he saw the washout.

Go-around procedures

The chief pilot and safety manager emphasised that because of the short-field (minimum length) landing areas and dynamic beach conditions, pilots were trained to conduct a go-around if safety could not be assured at any stage during approach or landing. The company operations manual specified both missed approach and go-around procedures (Figure 3). The chief pilot reported that pilots must conduct an orbit (missed approach procedure), if, during the approach, they saw anything that could encroach on the runway. In this case, he advised that the pilot should have conducted a 2-minute orbit and communicated with ground crew via radio to clear vehicles from the area.

The manual stated that the go-around procedure was to be flown ‘if the go-around is initiated during the final approach or landing phase.’

Figure 3: Extract from operations manual depicting missed approach and go-around procedures

Source: AIAC annotated by ATSB

Safety analysis

Fraser Island beaches posed a very dynamic aircraft operating environment. Potential hazards included vehicles, people, animals and changing tides and sand conditions. To mitigate and manage the hazards, the operator used runway markers, ground crew and reinforced the importance of, and pilot skills in, conducting go-arounds when safe landing could not be assured. Additionally, to enable better control of landing areas, the operator used runways of the minimum safe length for take-off and landing, which necessitated that pilots use short-field and soft-field techniques. This meant that both landing beyond the runway threshold and becoming airborne again during the landing phase, increased the risk of a runway overrun.

Furthermore, because there were few high obstacles on the beaches, going around was less likely to result in a collision than encountering unsuitable surfaces beyond the designated landing area. The pilot was proficient at conducting go-arounds and the reason he omitted to do so in this occurrence, could not be determined.

Although the aircraft was still on the beach during the runway overrun, the area beyond the runway contained a washout unsuitable for a landing roll. The pilot’s action in raising the aircraft nose prior to the washout likely prevented a more serious outcome.

The pilot reported that the left brake was spongy and that this had affected his ability to stop the aircraft. The aircraft operator also reported that there had been a history of brake issues due to the operating environment. However, the maintainer inspected the brakes after the accident and other than accident damage, could not reproduce a fault with the brakes. While the ATSB could not determine whether the brakes had been functioning correctly at the time of the accident, in any event, there was almost certainly insufficient runway remaining to stop given the aircraft weight and conditions.

The pilot subsequently reported that he may have mistaken the clearway bollards for the runway marker cones, thereby assessing that he had more stopping distance than actually remained. However, the bollards were deliberately different from the marker cones to mitigate against this misidentification. Additionally, the pilot had previously overflown the runway, which was the normal length used by the operator, and then landed on it, prior to the accident flight. Whether this misidentification contributed to the accident could not be determined.

The passenger manifest was completed after the accident. However, this was required to be completed prior to flight, as it included passenger weights from which to calculate aircraft take-off weight and assess take-off and landing distances.

Findings

These findings should not be read as apportioning blame or liability to any particular organisation or individual.

• The pilot did not conduct a go-around including when faced with a vehicle hazard, landing well beyond the runway threshold and becoming airborne again during the landing. This resulted in the aircraft landing with insufficient runway remaining and a runway overrun onto an area of the beach unsuitable for the landing roll.
• The pilot did not obtain passenger weights or use standard weights to calculate the aircraft weight and balance prior to the flight from which to assess the required landing distance.

Sources and submissions

Sources of information

The sources of information during the investigation included the:

• pilot
• ground crew
• aircraft operator
• aircraft maintainer
• Civil Aviation Safety Authority.

Submissions

Under Part 4, Division 2 (Investigation Reports), Section 26 of the Transport Safety Investigation Act 2003 (the Act), the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. Section 26 (1) (a) of the Act allows a person receiving a draft report to make submissions to the ATSB about the draft report.

A draft of this report was provided to the pilot, ground crewmember, aircraft operator, aircraft maintainer, aircraft manufacturer and the Civil Aviation Safety Authority.

Submissions were received from the aircraft manufacturer and pilot. The submissions were reviewed and, where considered appropriate, the text of the report was amended accordingly.

Purpose of safety investigations The objective of a safety investigation is to enhance transport safety. This is done through: identifying safety issues and facilitating safety action to address those issues providing information about occurrences and their associated safety factors to facilitate learning within the transport industry. It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action. Terminology An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2020 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

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1. Eastern Standard Time (EST): Coordinated Universal Time (UTC) + 10 hours.
2. Melon holes: holes in the sand the size and shape of melons.
3. Maintenance release: an official document, issued by an authorised person as described in Regulations, which is required to be carried on an aircraft as an ongoing record of its time in service (TIS) and airworthiness status. Subject to conditions, a maintenance release is valid for a set period, nominally 100 hours TIS or 12 months from issue.
4. Runway strip: A defined area including the runway and stopway, if provided, intended: a) to reduce the risk of damage to aircraft running off a runway; and b) to protect aircraft flying over it during take-off or landing operations.
5. Runway end safety area: An area symmetrical about the extended runway centre line and adjacent to the end of the strip primarily intended to reduce the risk of damage to an aircraft undershooting or overrunning the runway.

Section 21 (2) of the Transport Safety Investigation Act 2003 (TSI Act) empowers the ATSB to discontinue an investigation into a transport safety matter at any time. Section 21 (3) of the TSI Act requires the ATSB to publish a statement setting out the reasons for discontinuing an investigation. The statement is published as a report in accordance with section 25 of the TSI Act, capturing information from the investigation up to the time of discontinuance.

Overview of the investigation

On 2 December 2019, the ATSB commenced an investigation into a runway overrun involving a Gippsland Aeronautics GA-8, VH-MTX, at Rurruwuy, Northern Territory.

The aircraft departed Garrthalala for Rurruwuy at 1240 Central Standard Time^[1] on a chartered passenger flight, with the pilot and three passengers on board. The pilot described the conditions at Rurruwuy as a ‘turbulent, thermally day’ and she elected to land on Runway 11 based on the windsock direction.

On final approach, the pilot noticed the airspeed was 2 knots above the planned reference landing approach speed. The pilot then assessed she was too high for her aiming point, which was the first tyre marker, and chose to aim for the second. The aircraft touched down beyond the second tyre marker, but then lifted off the runway. When the aircraft touched down again, it was beyond the halfway point of the runway.

The pilot attempted to stop the aircraft, but it overran the end of the runway resulting in substantial damage. There were no injuries to the pilot or passengers. Once the aircraft had stopped, the pilot noted that the windsock had shifted during the approach, favouring a landing on Runway 29.

Due to its relatively short length, Rurruwuy was classified by the operator as a ‘Marginal Airstrip’ for a GA-8, which meant specific pilot training was required. The pilot had completed this training prior to the occurrence.

As a result of the occurrence, the operator organised a pilot training day to discuss stabilised approaches.

As part of its investigation, the ATSB interviewed the pilot, and obtained information such as flight plans, photographs, maintenance information and details of the operator’s training procedures.

ATSB comment

Unexpected events during the approach and landing can exacerbate what is often a high workload period. Following standard operating procedures and correctly monitoring the aircraft and approach parameters provides assurance that an approach can be safely completed. If the criteria for safe continuation of an approach are not met, a go-around should be initiated.

Based on a review of the available evidence, the ATSB considered it was unlikely that further investigation would identify any systemic safety issues. Consequently, the ATSB has discontinued this investigation.

The evidence collected during this investigation remains available to be used in future investigations or safety studies. The ATSB will also monitor for any similar occurrences that may indicate a need to undertake a further safety investigation.

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[1]     Central Standard Time: Coordinated Universal Time (UTC) + 9.5 hours

What happened

At about 0845 Western Standard Time^[1] on the 16 September 2018, a Cessna 207, registered VH-MIA (MIA), operated by Kalbarri Scenic Flights, took off to conduct a scenic flight from Kalbarri, West Australia (WA), to East Wallabi Island, WA. A pilot and three passengers were on board the aircraft.

The pilot had conducted a short scenic flight lasting about 45 minutes earlier that morning. She had around 30 minutes between flights to prepare the aircraft for the second flight.

The pilot advised that she briefed the passengers on the safety aspects of the aircraft before taking off. The flight proceeded past the township of Kalbarri and then along the shoreline before heading to East Wallabi Island, part of the Abrolhos Islands, at about 2,500 ft above mean sea level.

The aircraft overflew the island and the pilot reported that she observed the windsock was indicating an easterly wind, which was a crosswind for both runways. She decided to join runway 36 on the mid-crosswind leg of the circuit. The pilot reported that she touched down on the runway abeam the taxiway (see Figure 2), which normally gives her enough runway length to stop the aircraft. However, on this occasion, she could not stop the aircraft and overran the runway end by approximately 1 metre (Figure 1). The aircraft was not damaged and there were no injuries to the pilot or passengers.

Figure 1: VH-MIA after runway excursion

Source: Sue McAuliffe

Runway strip

The runway strip on East Wallabi Island is a privately owned unsealed strip. It is 637 m long and 30 m wide. The pilot reported that it slopes down slightly in the middle and has soft sand at one end. The windsock is on the western side of the runway on a slight hill.

Figure 2: East Wallabi Island runway and Kalbarri, North Island and East Wallabi Island

Source: Google Earth, annotated by ATSB

Weather at East Wallabi Island

East Wallabi Island does not have a dedicated weather forecasting service, but weather observations from North Island, which is 20 km north-west of East Wallabi Island, indicated that the wind was from the south at approximately 8 knots. This would indicate that the wind was almost all tailwind at the time the aircraft landed.

Pilot comments

The pilot reported she had checked the weather before they had departed on the first flight that morning.

The pilot reported that the approach and landing appeared normal until the aircraft did not slow after the aircraft touched down on the runway. She had slowed the aircraft to 80 kts on the final leg of the approach and touched down at the normal speed. She applied brakes as normal, released and then reapplied the brakes, to ensure the wheels did not lock, as this was a gravel strip.

The pilot reported that she used the position of the taxiway along the runway as her decision point as to whether she was going to conduct a go-around. As everything felt normal at that stage, she did not conduct a go-around.

The pilot reported that she was not fatigued. She had a day off the day before the incident. She had slept normally and had risen at her normal time of around 0530. She had arrived at the airport at around 0700, which gave her plenty of time to prepare for the flights. She was not feeling time pressure and the workload for the flight was normal.

She also advised that she had flown to the island a number of times and knew the strip well.

Operator comments

The operator reported that the aircraft was loaded within the aircraft limits.

The operator has discussed the incident with the pilot. They have stressed the importance of checking the windsock on the final leg of the circuit to ensure there is no downwind component, especially on a short runway. The operator and the pilot have also discussed the importance of using all available weather data, in particular the observations page on the Bureau of Meteorology website before going flying.

Previous occurrences

A review of the ATSB occurrence database for similar occurrences identified that in the last 10 years there were 14 incidents where a tailwind contributed to a runway excursion on landing. Of these, 11 were excursions where the aircraft ran off the end of the runway. Seven of these aircraft sustained substantial damaged.

Safety analysis

While the pilot advised she had checked the wind as they overflew the runway to join the circuit for runway 36, weather information received from the Bureau of Meteorology indicated that there was a southerly wind at the time the aircraft landed. The ATSB could not clarify if the pilot misread the windsock or the wind direction had momentarily changed when they joined the circuit and returned back to the southerly direction before the aircraft landed. The aircraft most likely landed with a tail wind component resulting in a faster ground speed at touchdown and the aircraft overrunning the end of the runway.

The pilot’s decision to land the aircraft adjacent to the taxiway reduced the available stopping distance available. Using the full runway strip, would probably have allowed the pilot to stop the aircraft on the runway.

Findings

These findings should not be read as apportioning blame or liability to any particular organisation or individual.

• It is likely that the aircraft landed with a tailwind component resulting in the aircraft overrunning the runway.
• The pilot’s chosen landing position did not use the full runway strip length, reducing the stopping distance available.

Safety message

This incident highlights the importance of, where possible, landing with a headwind. Landing with a tailwind could result in an increase in the required landing distance by 21 per cent for the first 10 kts of tailwind, according to the United States’ Federal Aviation Administration advisory circular no. 91-79A Mitigating the risks of a runway overrun upon landing. They also advise that for some smaller general aviation aircraft (for example a Cessna 152), the landing distance required will increase by 10 per cent for every 2 kts of tailwind. If a pilot is not expecting a tailwind component, there is a significant risk that the aircraft will overrun the runway when operating on a short runway. One way of reducing the chances of landing with a tailwind is to include a check of the windsock during pre-landing checks and to conduct a go-around if a tailwind is detected.

Runway excursions continue to be a safety concern around the world with the Transport Safety Board of Canada recently releasing its Watchlist 2018, which lists runway overruns as one of its two aviation safety concerns for 2018.

Purpose of safety investigations The objective of a safety investigation is to enhance transport safety. This is done through: identifying safety issues and facilitating safety action to address those issues providing information about occurrences and their associated safety factors to facilitate learning within the transport industry. It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action. Terminology An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2019 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

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1. Western Standard Time (WST): Coordinated Universal Time (UTC) + 8 hours.

Preliminary report released 08 May 2018

This preliminary report details factual information established in the investigation’s early evidence collection phase and has been prepared to provide timely information to the industry and public. Preliminary reports contain no analysis or findings, which will be detailed in the investigation’s final report. The information contained in this preliminary report is released in accordance with section 25 of the Transport Safety Investigation Act 2003.

Sequence of events

On 18 March 2018, at about 0909 Eastern Daylight-saving Time,^[1] a Van’s Aircraft Inc. RV-6A, registered VH-OAJ (OAJ), took off from the Somersby aeroplane landing area (ALA), New South Wales, with only the pilot on board for a 20-minute flight to Camden. While at Camden, the pilot assisted with activities at a gliding club located on the airport. At about 1546, OAJ took off from Camden on a return flight to Somersby (Figure 1).

Figure 1: Flight path of VH-OAJ from Camden Airport to the Somersby ALA

Image shows OAJ’s flight path in yellow. The approach to the Somersby ALA and landing flight path are inset. Source: Google earth and OzRunways, annotated by the ATSB

Approaching the Somersby ALA from the south, the pilot conducted a circuit around the airfield before descending for a landing to the north on runway 35 (Figure 1 insert).^[2] A witness located at the ALA, who was very familiar with the airfield and the aircraft, reported that he observed OAJ approaching faster than normal. The touch down point was also further down the runway than would be expected for a landing in that direction. The aircraft was also seen to bounce several times during the landing. The aircraft then ran off the end of the runway before impacting the side of a small watercourse and coming to rest (Figure 2). The witness did not observe OAJ run off the runway end.

As a result of the impact, the pilot was hospitalised with serious injuries. Two days later the pilot died from his injuries.

Figure 2: View of the accident site showing VH-OAJ, looking back along the runway

Source: ATSB

Pilot information

The pilot held a Private Pilot (Aeroplane) Licence that was issued on 22 February 1971 and last completed a review on 2 May 2017 in OAJ. The pilot held a valid Class 2 Aviation Medical Certificate and was required to wear distance vision correction and have vision correction available for reading while exercising the privileges of the licence.

Aircraft information

The Van’s Aircraft Inc. (Van’s) RV-6A is a kit-built, two-seat aircraft with a low-wing and fixed undercarriage. Construction of OAJ was completed in 1998 and it was first registered with the Civil Aviation Safety Authority on 3 June 1998. The accident pilot became the registration holder on 7 May 2007. OAJ was fitted with a Textron Lycoming O-320 piston engine.

Wreckage and impact information

The ATSB identified marks on the runway consistent with the wheels on OAJ, at the initial touchdown point described by the witness. Multiple other marks consistent with the left and right wheels skidding were identified near the end of the runway (Figure 3).

Figure 3: Northern end of runway 35. Marks in the surface of the runway consistent with wheel skid and the tail of VH‑OAJ visible in the background

The white markers indicate the extent of the identified wheel skid marks. Source: ATSB

The on-site examination of OAJ identified that the flaps were in the fully deployed position and all flight controls were functional. The brakes were tested and found to be operational. Damage to the aircraft included:

• crushing damage to the right wingtip consistent with impact with the watercourse
• fracture and deformation of the engine mounts
• crushing of the propeller spinner
• buckling deformation of the fuselage behind the cockpit
• the control rod for the right flap was fractured, but consistent with other impact damage
• the inboard rib of the right wing had cracked, leaking some fuel.

The exact quantity of fuel on board at the time of the accident could not be determined due to leakage of some fuel, but both the left and right tanks were near full when examined.

Ongoing investigation

The investigation is continuing and will include consideration of the following:

• recorded data
• witness reports
• pilot medical information
• factors that increased the potential for serious injury from the accident.

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The information contained in this web update is released in accordance with section 25 of the Transport Safety Investigation Act 2003 and is derived from the initial investigation of the occurrence. Readers are cautioned that new evidence will become available as the investigation progresses that will enhance the ATSB's understanding of the accident as outlined in this web update. As such, no analysis or findings are included in this update.

Purpose of safety investigations The objective of a safety investigation is to enhance transport safety. This is done through: identifying safety issues and facilitating safety action to address those issues providing information about occurrences and their associated safety factors to facilitate learning within the transport industry. It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action. Terminology An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2018 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

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1. Eastern Daylight-saving Time (EDT): Coordinated Universal Time (UTC) + 11 hours.
2. The runway number represents the magnetic heading of the runway in tens of degrees rounded to the nearest unit. Thus, runway 35 has a magnetic heading of approximately 350°.

What happened

On the afternoon of 23 March 2017, the pilot of Gippsland Aeronautics GA-8 Airvan, VH-AZH, prepared for a departure from Avoid Island aeroplane landing area (ALA)^[1] (Figure 1), Queensland (Qld) for a passenger charter flight to Mackay, Qld.

The company had elected to split the load of five passengers and cargo between two aircraft, a Cessna 206 and the GA-8.^[2] On board the GA-8 were the pilot and three passengers, along with 30 kg of cargo and 92 kg of fuel, resulting in a take-off weight of 1,521 kg.^[3]

While preparing for the departure, the pilot observed a 5–10 kt wind from the south-east and elected to use runway 14 for take-off. Runway 14 was a grass runway, 800 m long and included a slight rise in the middle. At the end of the runway was a vertical drop of about 2 meters down to a rocky beach.

Figure 1: Avoid Island ALA

Source: Google Earth, annotated by ATSB

At about 1555 Eastern Standard Time (EST), the pilot in the GA-8 commenced the take-off run ahead of the Cessna 206. During the take-off run, the pilot maintained slight back pressure on the control column to minimise the weight on the aircraft nose wheel. The rotation^[4] speed for the take-off was 58 kt. The pilot elected to use a point about halfway along the runway as the decision point for the continuation of the take-off, this point was located just after the crest in the runway. As the aircraft passed the decision point, the pilot noted that the airspeed was about 40 knots and engine indications were normal. As the aircraft performance was satisfactory, the pilot elected to continue the take-off.

As the aircraft continued on the downhill side of the crest, the aircraft encountered a soft patch of runway surface, resulting in a slight deceleration. As performance quickly returned, the pilot did not consider this to be an issue.

As the aircraft approached the end of the runway, just prior to reaching the rotation speed, the pilot felt a significant deceleration. The pilot identified that insufficient runway remained to stop the aircraft, and in an attempt to avoid the aircraft falling over the vertical drop, elected to continue the take-off.

The aircraft did not take-off before overrunning the runway and became airborne as it passed over the vertical drop at a speed of about 50 kt. While manoeuvring to avoid large rocks and obstacles (Figure 2), the pilot maintained a nose high attitude to minimise the effect of any impact. The aircraft was unable to maintain height and descended over about a further 100 m until the landing gear and underside of the rear fuselage impacted rocks. As the aircraft decelerated, the impact through the rudder pedals forced the pilot’s ankle against the control column.

Figure 2: Accident site

Source: Operator, annotated by ATSB

After the aircraft came to rest, the passengers began to evacuate the aircraft. The pilot secured the aircraft and assisted the passengers with the evacuation. After securing the aircraft, the pilot then contacted the pilot of the Cessna 206 and advised them not to attempt to take-off.

The pilot of the Cessna 206 taxied that aircraft to the end of runway 14, contacted emergency services and provided assistance to the occupants of the GA-8.

The pilot of the GA-8 suffered a fractured ankle, the passengers were uninjured in the accident.

Pilot comments

The pilot of VH-AZH provided the following comments:

• The pilot landed on runway 14 at Avoid Island ALA about 15 minutes prior to the accident flight. After landing, the pilot taxied the full length of the runway before turning around to return to the threshold of runway 14 to meet the passengers. While taxing, the pilot did not detect the soft patches in the runway. The pilot observed that the grass was dense and about 100 mm in length.
• Performance calculation charts in the GA-8 pilot operating handbook did not provide for a runway with long wet grass and both an uphill and downhill component. Therefore, the pilot had used the ‘worst case’ scenario when calculating the take-off distance required^[5] for runway 14 at Avoid Island ALA. The pilot calculated the take-off distance required to be 590 m when assuming a two percent upslope for the entire take-off run and short dry grass.
• The wind conditions at the time of the take-off were not consistent. A change in wind speed or direction may have contributed to the accident.
• The company chief pilot operated from Avoid Island ALA three days prior to the accident flight and found the ALA to be in good condition.

Operator comment

The operator of VH-AZH provided the following comments:

• After the accident, the grass on the runway was mowed and the runway was inspected. The operator found the significant deceleration toward the end of the take-off run was the result of an area of soft runway surface and mud. During the pilot’s taxi after the previous landing, and during the accident take-off run, this area had been concealed by grass.
• The pilot had received training at Avoid Island ALA and had recently operated to the ALA.

Weather and prior rainfall

The pilot reported 5–10 kt of wind from the south-east, cloud at about 1,500 ft and patches of drizzle in the Avoid Island area at the time of the accident.

Avoid Island did not have recorded weather observation data. Weather stations at nearby locations, Middle Percy Island and St Lawrence (Figure 3), reported the below rainfall totals^[6] over the days prior to, and the day of the accident (23 March).

Table 1: Rainfall totals at Middle Percy Island and St Lawrence

Figure 3: Avoid Island location

Source: Google Earth, annotated by ATSB

Safety analysis

The Chief Pilot had visited the island three days prior to the accident flight and found the ALA in good condition, however, rainfall over the intervening period created soft patches in the runway surface.

The operator chose to split the load between two aircraft to provide more margin for the operation and the pilot calculated that sufficient runway was available for the GA-8 take-off. However, the soft patches, along with wet grass, prevented the aircraft from completing the take-off in the runway available.

Findings

• The soft patches in the runway surface, concealed by grass, very likely degraded aircraft performance during take-off. The location of the soft patches towards the end of the runway prevented the aircraft taking off before the runway end.

Safety action

Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following proactive safety action in response to this occurrence.

Aircraft operator

As a result of this occurrence, the aircraft operator has advised the ATSB that they are taking the following safety action:

Aeroplane landing area management

The operator has taking over management of maintenance of the Avoid Island ALA. This will enable the operator to ensure that the ALA is suitable for proposed operations.

The operator is investigating the feasibility of works to improve drainage on the ALA.

The guidance documents for all regularly used ALAs have been updated and significantly expanded.

More rigorous pilot training of ALA operations will be conducted in future. The operator is investigating the use of an ALA which simulates the conditions of Avoid Island ALA and also has a cross runway to provide for crosswind training and assessment.

Safety message

When operating from an ALA, the pilot must take great care to ensure that the ALA condition is suitable for the proposed operation. ALA operations can present numerous and varied challenges which may affect the safety of flight. In this case, the Chief Pilot had visited the island just three days prior, however, rainfall over those three days had greatly impacted on the serviceability of the ALA. In addition, the dense grass present created difficulties in identifying the soft patches of runway.

The Civil Aviation Safety Authority advisory publication:

The surface of a landing area should be assessed to determine its effect on aeroplane control and performance. For example, soft surfaces or the presence of long grass (over 150 mm) will increase take-off distances while moisture, loose gravel or any material that reduces braking effectiveness will increase landing distance.

Aviation Short Investigations Bulletin Issue 61

Purpose of safety investigations The objective of a safety investigation is to enhance transport safety. This is done through: identifying safety issues and facilitating safety action to address those issues providing information about occurrences and their associated safety factors to facilitate learning within the transport industry. It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action. Terminology An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2017 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

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1. Aeroplane landing area: An area of ground suitable for the conduct of take-off and landing of aeroplanes.
2. The Cessna 206 can be fitted with up to five passenger seats, the GA-8 can be fitted with up to seven passenger seats.
3. The structural maximum take-off weight of VH-AZH was 1,905 kg.
4. Rotation: the positive, nose-up, movement of an aircraft about the lateral (pitch) axis immediately before becoming airborne.
5. Take off distance: The horizontal distance required for an aircraft to accelerate from stationary, take-off and climb over a 50 ft (15 m) obstacle. As runway 14 at Avoid Island ends with small bushes, the remaining climb to 50 ft may be calculated to be conducted over the beach and water after clearing this obstacle.
6. Daily rainfall for the listed day is the 24 hour total rainfall from 0900 on the day prior until 0900 on that day.