On 21 May 2016, the pilot of a Kavanagh Balloons E-240, registered VH-VBM (VBM), planned to conduct a one-hour scenic flight from Bundoora, Victoria (Vic.) with nine passengers. Prior to commencing the flight, the pilot obtained the relevant weather forecasts and observations. The wind was from the north to north-west at 5 to 10 kt. The pilot therefore assessed the balloon would track in a southerly direction and nominated potential landing sites at Burnley and Dendy Park in Brighton (Figure 1).
Figure 1: Approximate track of VH-VBM and relevant locations[1]
Source: Google earth, annotated by ATSB
At about 0700 Eastern Standard Time (EST), the balloon departed Bundoora in company with five other balloons. About 35 minutes later, the balloon arrived overhead Burnley. The pilot of VBM elected to continue to Dendy Park, along with another balloon from the same operator, to extend the flight to one hour. At that time, the pilots of four other balloons, which had been operating in company with VBM, elected to climb into a more westerly wind to track to Moorabbin Airport, Vic.
At about 0800, the balloon in company with VBM landed safely at Dendy Park. The wind speed was about 10 kt as VBM approached Dendy Park. As the balloon descended to land, the pilot sighted a light pole directly in the balloon’s path (Figure 2). The pilot then lit the balloon’s burners to climb over the pole, however, a second light pole stood directly in the balloon’s path on the far side of the available landing area. Due to the balloon’s height and the wind, the pilot assessed that the balloon may collide with the second pole if the pilot attempted a landing and therefore elected not to land in the park.
Figure 2: Dendy Park showing light poles
Source: Google earth, annotated by ATSB
The pilot then attempted to land in a golf course beyond the park, but the balloon did not track towards a safe landing area. The balloon continued at low level over parkland, however, the pilot also assessed this area to be unsafe for landing.
At about 0820, the balloon crossed the coast and tracked out over Port Phillip Bay. The pilot commenced a climb into a more westerly wind to track towards land. At about 0825, the pilot contacted air traffic control (ATC) and requested a clearance to climb to 5,000 ft. About 90 seconds later, the pilot advised that they were now at 4,000 ft and may require emergency assistance. At that time, the pilot stated that the balloon had an estimated 30 minutes of fuel remaining.
At about 0830, the balloon tracked back over land. The pilot advised ATC that in the 5 minutes it would then take to descend and land, the balloon would track back over water. The pilot elected to descend to conserve fuel and prepared for a water landing. The pilot briefed the passengers and descended about 1 km from shore. The pilot then enacted the company emergency procedures. Air traffic control recordings showed that at 0841, when asked by ATC if it was their ‘intention to ditch the balloon at the moment’, the pilot confirmed that it was.
At about 0845, the pilot established contact with the crew of a nearby vessel. The pilot coordinated with the crew of the vessel to arrange the evacuation of passengers. The passengers evacuated one or two at a time onto the vessel over the next 30 minutes (Figure 3).
After evacuating the passengers, the pilot conducted a climb to about 2,000 ft back into more favourable winds and subsequently landed safely at Mount Martha, Vic. (Figure 1).
The pilot and passengers were uninjured, and the balloon was not damaged.
Figure 3: Evacuation of passengers from VBM to vessel
Source: ABC News
Pilot comments
The pilot provided the following comments:
The ground crew assisting the balloon which landed before VBM, were available to assist the landing at Dendy Park. The pilot felt that a successful landing could not be assured even with the assistance of ground crew.
The company emergency procedures for conducting a water landing were available and clear. This greatly reduced stress and ensured the pilot and passengers were well prepared for a possible water landing.
It was not their sole intention to ditch the balloon. Ditching was one possible scenario and the pilot was preparing the balloon and passengers for that situation should it eventuate.
If they encountered similar weather conditions in future, the pilot would launch from further east. The north-easterly surface wind experienced was not forecast. In the future, the pilot would look for indicators of this wind prior to selection of a launch site.
Landing in a 10 kt wind is normally manageable, however, the light pole was in the balloon’s path (at Dendy Park).
At the time the emergency was declared, the estimated endurance was 30 minutes. Once the passengers had been evacuated the balloon endurance was greatly increased.[2]
Carriage of life jackets
No life jackets were carried on board VBM for this flight.
As the planned flight, including the expected departure and approach paths, did not include an over water component, there was no requirement to carry life jackets based on Civil Aviation Order 20.11.
Civil Aviation Safety Authority (CASA) comments
CASA provided the following comments:
While the evacuation was conducted in an appropriate manner, the locality of a suitable vessel with competent crew may have had a significant positive effect on the safe rescue, which under the circumstances, was a fortunate rather than a well-planned emergency procedure.
The company’s operations manual requires that, as soon as the balloon crosses the coastline, the ground crew be contacted and an emergency telephone call made. Immediately after this, a MAYDAY[3] is to be declared. This did not occur until the balloon was 1km out over the bay. As the pilot did not did not make a PAN or MAYDAY call as required, ATC did not have notice to apply the appropriate degree of severity to the incident. This was confirmed by Victoria Police during their incident debrief where it was highlighted that there was no communication or coordination between ATC and ground-based emergency services.
Safety message
This incident provides a good example of the value of effective emergency procedures. Despite having completed thorough pre-flight planning and preparation including weather and field selection, a number of factors combined to create a difficult situation for the pilot. Thorough emergency procedures along with regular training greatly reduced workload in the incident and assisted the pilot in achieving a safe outcome.
Declaring an emergency early, through the use of standard phrases such as ‘MAYDAY’ is vital in clearly communicating a requirement for emergency assistance or advising of an emergency situation. This enables ATC to provide assistance and coordinate emergency services without delay. The Airservices Australia safety bulletin What happens when I declare an emergency? provides further information on the actions taken by ATC once an emergency is declared.
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 potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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.
On 22 April 2016, at about 1440 Eastern Standard Time (EST), an instructor and student were conducting circuit training in a Robinson R22 helicopter, registered VH-JKH (JKH), at Ballina Byron Gateway Airport, New South Wales. The helicopter was positioned about two thirds of the way down runway 06 (Figure 1) when the crew broadcast on the common traffic advisory frequency (CTAF) that they were rolling for take-off on runway 06.
Very soon after that broadcast, the pilot of another helicopter operating at the aerodrome alerted the crew of JKH that there was an aircraft rolling for take‑off on runway 06 behind them, and suggested that JKH expedite clearing the runway.
A Cessna 182 aeroplane, registered VH-YKM (YKM), had entered the runway at the intersection of taxiway A (Figure 1), and was taking‑off on runway 06, towards the helicopter (which was still on the runway). The instructor in JKH took control of the helicopter from the student, rejected the take-off and vacated the runway to the northern grass, as the aircraft continued its take‑off run.
Although the pilot of YKM was unaware at the time, their broadcasts on the CTAF prior to commencing take‑off had not been successfully transmitted. As the aeroplane climbed through about 400 ft above ground level, the pilot sighted the helicopter (JKH) to their left over the grass.
The pilot of YKM later found that although the aircraft radio was on, and was set to the CTAF, the radio microphone was not fully plugged in. In this condition, none of their broadcasts on the CTAF had been successfully transmitted.[1] The pilot of YKM had not heard any broadcast from JKH and did not see the helicopter on the runway, despite checking to see that the runway was clear before entering.
Figure 1: Ballina Byron Gateway Airport diagram
Source: Airservices Australia – annotations by the ATSB
Operator comment
The operator of JKH commented that after the event, they checked from the position on the taxiway where YKM entered the runway to verify if they could see where the helicopter would have been. They established that they could – but advised that this needs to take into consideration that they knew what they were looking for.
ATSB comment
The pilot of the helicopter who alerted the crew of JKH to the aircraft rolling for take-off on runway 06 is commended for their situational awareness, and speaking up when the potential for a collision became apparent. That pilot may have played an important role in averting a more serious occurrence.
Safety message
Pilots are encouraged to check the performance of radio communications systems as part of their pre-flight procedures. Aerodrome frequency response units at non-towered aerodromes allow pilots to confirm that they have the correct frequency selected, and that their radio communications system is transmitting. Nonetheless, as this incident highlights, an AFRU does not necessarily provide an indication to a pilot that their transmissions are inaudible or otherwise ineffective. Additionally, this incident highlights the importance of a thorough lookout prior to entering a runway. Not hearing any broadcasts on the CTAF does not necessarily mean that other aircraft are not operating in the area.
Most occurrences reported to the ATSB at non-towered aerodromes involve conflicts between aircraft, or between aircraft and ground vehicles. In particular, active runways should be approached with caution. The ATSB publication A pilot’s guide to staying safe in the vicinity of non-towered aerodromes, stated that a large number of the conflicts between aircraft involved:
ineffective communication between pilots operating in close proximity
the incorrect assessment of other aircraft’s positions and intentions
relying on the radio as a substitute for an effective visual lookout
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 potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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.
On 15 May 2016, a Qantas Airways Airbus A380 aircraft, registered VH-OQD, operated flight QF7 from Sydney, New South Wales to Dallas-Fort Worth, Texas, United States.
About two hours prior to the aircraft’s arrival in Dallas-Fort Worth, a passenger alerted the cabin crew to the presence of smoke in the cabin. The cabin crew then initiated the basic fire drill procedure.
Two of the cabin crew proceeded to the source of the smoke with fire extinguishers. At the same time, the customer services manager (CSM) made an all stations emergency call on the aircraft interphone to alert flight crew and other cabin crew to the presence of smoke.
The cabin crew located the source of the smoke at seat 19F, in Zone F, on the upper deck (Figure 1). The crew removed the seat cushions and covers from seat 19F while the CSM turned off the power to the centre column of the seats. When the seat was further dismantled, the crew found a crushed personal electronic device (PED) wedged tightly in the seat mechanism. The cabin crew assessed that the crushed PED contained a lithium battery.
Figure 1: Cabin diagram showing the seat from where the smoke emanated
Source: Qantas, modified by ATSB
By that time, the PED was no longer emitting smoke, however, a strong acrid smell remained in the cabin. The crew then manoeuvred the seat and freed the PED (Figure 2). The crew placed the PED in a jug of water, which was then put in a metal box and monitored for the remainder of the flight.
The flight crew did not receive any abnormal indications or warnings.
No passengers were injured, and the aircraft was not damaged in the incident.
Figure 2: Crushed PED after removal from seat
Source: Qantas
Operator comments
The aircraft operator commented that it has been estimated over one billion lithium batteries are transported by air every year, with potentially hundreds carried on single sectors on large aircraft. As such, both cabin crew and passenger education remains a key component to managing these events. Raising passenger awareness of the potential hazards of PEDs commences at check-in, through to the pre-flight safety demonstration, and aims to minimise the risk of PED thermal runaway events.
Qantas Airlines’ basic fire drill is based on a teamwork approach, with the division of duties between three central crew and as many supporting crew as available and required. This division of duties allocates the responsibilities of fighting the fire, retrieving equipment and ensuring lines of communication with the flight deck remain uninterrupted.
ATSB comment
Similar occurrences
The ATSB has received 17 notifications of similar incidents of lithium battery thermal events in aircraft over the past 6 years.
The ATSB investigation AO-2014-082 details an example where a short circuit between lithium batteries initiated a fire in an aircraft cargo hold.
Safety message
This incident provides an excellent example of an effective response to an emergency situation. The crew were able to quickly implement the basic fire drill procedure which defined the roles and responsibilities of the responding crew. This enabled a rapid and coordinated response to the smoke event using all available resources. The effective implementation of this procedure also ensured the flight crew were kept informed as the situation developed.
This incident also highlights the hazards of transporting lithium-ion battery powered PEDs. The Civil Aviation Safety Authority web page Travelling safely with batteries and pamphlet Is your luggage safe? provide information on the safe carriage of lithium-ion batteries and lithium-ion powered devices aboard aircraft.
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 potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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.
On 16 May 2016, the pilot of a Maule MT-7-235 aircraft, registered VH-DRS, conducted a private flight from Greenfields airstrip (near Noosa), Queensland, with two passengers on board.
The aircraft departed Greenfields airstrip at about 1220 Eastern Standard Time (EST) and flew to Gympie ALA, where the aircraft was refuelled. The aircraft then departed from Gympie and flew north towards Maryborough before returning to Greenfields along a coastal route.
The aircraft joined the circuit at Greenfields on the downwind leg for runway 09. The pilot turned on to the final approach at about 800 ft above ground level, with an airspeed of about 70 kt. The pilot noticed they were getting low on the approach and at about 500 ft, they increased the power to regain their approach path. The pilot subsequently assessed that the aircraft was too high and lowered the nose to re-intercept the approach path.
The pilot flared the aircraft for landing, the aircraft landed heavily and bounced into the air. As the aircraft landed again, the nose wheel touched down first (before the main landing gear) with sufficient force that the nose wheel strut fractured. The nose landing gear and propeller then dug into the ground and the aircraft rotated over its nose and slid a short distance inverted before coming to rest.
The pilot and one passenger were uninjured, the other passenger sustained minor injuries, and the aircraft sustained substantial damage (Figure 1).
Figure 1: Accident site showing damage to VH-DRS
Source: Aircraft owner
Pilot comments
The pilot provided the following comments:
they taxied the full length of the strip before departure from Greenfields and noted the grass surface was in good condition
they had flown about five flights, totalling about 20 hours in the last 12 months
the pilot’s previous flight was about 4 to 5 weeks prior to the accident flight
the pilot had not operated the Maule aircraft with more than one passenger on board prior to the accident flight
the pilot thought that the higher all-up-weight of the aircraft with an extra passenger on board contributed to a higher sink rate on final than they expected
the pilot commented that they should have performed a go-around, rather than continuing with the landing manoeuvre.
ATSB comment
Currency versus proficiency
At the time of the accident the pilot was current for passenger-carrying operations, having conducted at least three take-offs and three landings in the last 90 days. However, it was more than one month since their last flight, which was also a local area scenic flight. The take-off and landing phases of flight are critical phases of flight, since the aircraft is operating closer to the stall speed and with less height to recover from a control problem, relative to cruise flight. The requirement for three take-offs and three landings in the last 90 days is a regulatory requirement of currency, but this does not guarantee proficiency. When flying infrequently, proficiency in take-offs and landings can be improved by dedicating a portion of the flight to practicing circuits. The United States Federal Aviation Administration safety briefing September/October 2010 described this as ‘imbuing the quantity of all your flying, however limited, with quality.’
Safety message
Go-around
The pilot commented that conducting a go-around could have prevented an unstable approach and initial bounce from escalating to an accident. General aviation pilots should set their own criteria for when to conduct a go-around manoeuvre, so that they can recognise and respond to the conditions in a timely manner. This will assist pilots to develop a mindset, which the Flight Safety Foundation (FSF) refers to as ‘go-around-prepared’. FSF Approach-and-landing Accident Reduction (ALAR) briefing note 6.1 emphasises the need to be ‘go-around-prepared’ or ‘go-around-minded’ because the execution of a go-around is an infrequent manoeuvre. FSF ALAR briefing note 7.1 provides further information on unstable approaches and how to develop personal lines of defence.
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 potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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.
On 13 May 2016, the student pilot of a Cessna 172S aircraft, registered VH-EWZ (EWZ), was conducting solo circuits at Moorabbin Airport, Victoria. The runway in use was runway 35 right (35R), and the wind was west to north-westerly at 10 to 20 kt. At the same time, the pilot of a Cessna 172R aircraft, registered VH-SYH (SYH), was also conducting circuits. SYH was the aircraft immediately ahead of EWZ in the circuit.
The student pilot of EWZ completed eight circuits. During that time, the wind, in particular the crosswind, increased and was subsequently reported as 9 to 15 kt from the left of runway 35R.
At the completion of their circuit training, the pilot of SYH landed and taxied clear of runway 35R, stopping on taxiway E facing north-west (Figure 1). Soon after SYH landed, at about 1059 Eastern Standard Time (EST), EWZ was on the final approach for another touch-and-go landing.[1]
The pilot reported that during the landing, EWZ touched down heavily to the left of the runway centreline.[2] The pilot then applied full power to continue the take-off. As the power increased, the aircraft yawed to the left and ran off the runway. At that time, the pilot of EWZ sighted SYH on the taxiway, reduced the power to idle and applied full right rudder in an effort to avoid SYH.
Figure 1: Moorabbin Airport showing location of collision
Source: Google earth – annotated by ATSB
The underside of the left wing of EWZ contacted the top of the right wing of SYH (Figure 2). EWZ came to a stop on the grass to the left of runway 35R. Both aircraft sustained minor damage and the pilots were uninjured (Figure 3).
Figure 2: Damage to right wing of VH-SYH
Source: Aircraft operator
Figure 3: Damage to left wing of VH-EWZ
Source: Aircraft operator
Pilot comments
Pilot of VH-EWZ
The pilot of EWZ provided the following comments:
In the previous circuits, they had conducted a go-around[3] when they were not comfortable with the approach. On the accident circuit, they assessed that the approach was normal, and elected to continue to land.
As they applied power to take-off, the aircraft yawed[4] left. They assessed that they may not have applied sufficient rudder input to counter the yaw effect of the increase in power.
They were using a higher power setting than normal on final approach to maintain the desired approach path due to the crosswind.
Operator comments
Operator of VH-SYH
The operator of VH-SYH provided the following comment:
In their experience on this aircraft type, yaw induced by crosswind has the potential to be significantly greater than left yaw induced by propeller effects. They suggested that the left yaw induced by the reported crosswind from the left, coupled with not so strong left yaw from propeller effects, combined to create the strong left yaw reportedly experienced.
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 safety action in response to this occurrence.
Operator of VH-EWZ
As a result of this occurrence, the aircraft operator has advised the ATSB that they are taking the following safety actions:
Company instructors have reviewed the landing technique they were using and teaching. A video demonstration of approach and landing technique was recorded, both for staff training purposes and as a training tool.
Safety message
This incident highlights the importance of knowing your own limits. Pilots should use a ‘personal minimums’ checklist to help control and manage flight risks through identifying risk factors including weather conditions that may affect aircraft handling.
This incident also underlines the importance of applying correct technique during all phases of flight, including take-off and landing. The CAA NZ – Flight Instructor Guide - Crosswind Circuitprovides useful information for crosswind operations.
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 potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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] Touch-and-go landing is a manoeuvre which is common when learning to fly fixed-wing aircraft. It involves landing on a runway and taking off again without coming to a full stop. Usually the pilot then circles the airport in a defined pattern known as a circuit and repeats the manoeuvre. This allows many landings to be completed in a short time.
[2] The ATSB obtained recorded data from the incident flight for EWZ. The data showed the aircraft touched down slightly to the right of the runway centreline.
[3] A go-around, the procedure for discontinuing an approach to land, is a standard manoeuvre performed when a pilot is not completely satisfied that the requirements for a safe landing have been met. This involves the pilot discontinuing the approach to land and may involve gaining altitude before conducting another approach to land.
[4] Term used to describe the motion of an aircraft about its vertical or normal axis.
On 12 May 2016, the pilot of a Robinson R22 Beta II helicopter, registered VH-WGB, was conducting aerial work at a property about 221 km east-north-east (ENE) of Port Hedland, Western Australia.
The pilot was observing two other helicopters engaged in aerial mustering for the benefit of the pilot’s own learning experience. The pilot’s attention was divided between flying the helicopter at about 200 ft above ground level and observing the mustering helicopters, which were operating between ground level and about 200 ft.
At about 1030 Western Standard Time (WST), while manoeuvring the helicopter to observe the mustering operation, the pilot commenced a level 180° turn to the left into wind. At the time the helicopter entered the left turn, it was flying at about 40 kt airspeed with about a 15 kt tailwind component.
Just prior to exiting the turn, the pilot felt the helicopter ‘kick’. The helicopter then yawed[1] rapidly to the right and pitched nose down. The pilot applied left pedal in an attempt to counteract the yaw, however, the helicopter did not respond normally to pedal[2] or cyclic[3] control inputs. The pilot also lowered the collective[4] and reduced the throttle. The helicopter pitch attitude[5] oscillated between a steep nose-down and a level attitude as the helicopter rotated towards the ground. As the helicopter neared the ground, the pilot applied aft cyclic, increased the throttle and raised the collective, which levelled the helicopter attitude and reduced the rate of descent.
The helicopter collided with the ground in a level attitude. The helicopter skids and seat collapsed following ground contact. During the accident sequence, the main rotor blades severed the tail boom. The pilot’s helmet struck the cyclic and the pilot sustained minor injuries. The aircraft was substantially damaged (Figure 1).
Figure 1: Accident site showing damage to VH-WGB
Source: Aircraft Operator
Pilot comments
The pilot provided the following comments:
the wind was steady at about 15 kt from the south-east with occasional gusts to 20 kt
the pilot was not sure what the ‘kick’ was, but thought it was due to the wind
the pilot did not recognise a low gravity (weightless) situation and may have applied incorrect cyclic technique, resulting in the main rotor striking the tail boom
the pilot thought that the tail boom was severed shortly after the kick because there was no response from the pedals to counteract the yaw and the helicopter immediately entered a nose down spiral
the pilot’s helmet was damaged during the collision, when it struck and broke the cyclic (Figure 2)
wearing the helmet probably prevented a more serious injury from occurring.
Figure 2: Damage to pilot’s helmet
Source: Helicopter pilot
Loss of tail rotor effectiveness
The United States Federal Aviation Administration (FAA) Helicopter flying handbook
The FAA Helicopter flying handbook chapter 11: Helicopter emergencies and hazards stated that loss of tail rotor effectiveness (LTE) is an uncommanded rapid yaw towards the advancing blade and is an aerodynamic condition caused by a control margin deficiency in the tail rotor. Tail rotor thrust is affected by numerous factors, including relative wind, forward airspeed, power setting and main rotor blade airflow interfering with airflow entering the tail rotor. There are several wind directions, relative to the nose of the helicopter which are conducive to LTE, including the following:
285–315°, which can lead to turbulent airflow from the main rotor disc interfering with the tail rotor
210–330°, which can lead to the development of unsteady airflow through the tail rotor.
The FAA handbook warns that a combination of factors in a particular situation can lead to more anti-torque required from the tail rotor than it can generate. In addition, low speed flight activities are a high-risk activity for LTE. The FAA handbook provided the following recovery technique for a sudden unanticipated yaw:
apply forward cyclic control to increase airspeed
if altitude permits, reduce power
as recovery is affected, adjust controls for normal forward flight.
The Robinson Helicopter Company advised that to avoid an unanticipated yaw, pilots should be aware of conditions (a left crosswind, for example) that may require large or rapid pedal inputs. They recommend practising slow, steady-rate hovering pedal turns to maintain proficiency in controlling yaw.
Low gravity (G) conditions
The FAA Helicopter flying handbook
The FAA handbook chapter 11 stated that semi-rigid rotor systems are especially susceptible to hazards from manoeuvres involving low accelerations of gravity (low-G or weightless) because the helicopter is designed to be suspended from the main rotor. In a low-G condition, such as abruptly pushing the cyclic forward, the helicopter airframe is not supported by the main rotor mast, which may allow the main rotor blades to exceed their normal flapping limits and contact the airframe.
The FAA handbook advised that in a low-G situation the pilot should first apply aft cyclic to return the lift and weight forces to balance and always adhere to the manufacturer’s manoeuvring limitations and advisory data.
The Robinson helicopter company issued safety notice SN-11 in October 1982, which stated:
Pushing the cyclic forward following a pull-up or rapid climb, or even from level flight, produces a low-G (weightless) flight condition. If the helicopter is still pitching forward when the pilot applies aft cyclic to reload the rotor, the rotor disc may tilt aft relative to the fuselage before it is reloaded.
ATSB comment
When the pilot manoeuvred the helicopter into wind, it flew through two relative wind directions conducive to an LTE event. The pilot commented that they entered the turn at about 40 kt airspeed, but was actively scanning between flying the helicopter and observing the aerial mustering activity. It is likely that during the turn, the airspeed combined with the relative wind direction to initiate an LTE event. The recommended actions to recover from an LTE include the application of forward cyclic to increase airspeed. This could place the helicopter into a low-G condition if an abrupt forward cyclic input is made, and increase the risk of striking the tail boom if the forward cyclic input is followed by an abrupt and/or large aft cyclic input.
Safety message
Loss of tail rotor effectiveness and low-G conditions
To avoid the conditions which could lead to main rotor blade/fuselage contact accidents, the Robinson R22 Pilot’s operating handbook recommends the following procedures for pilots:
maintain cruise airspeeds between 60 kt and less than 0.9 VNE[6], but no lower than 57 kt
use maximum power on revolutions per minute at all times during powered flight
avoid sideslip during flight and maintain in-trim flight at all times
avoid large, rapid forward cyclic inputs in forward flight, and abrupt control inputs in turbulence.
Effectiveness of helmets in helicopter operations
The United States Army referenced two United States Army Aeromedical Research Laboratory studies of helmet effectiveness in USAARL report 93-2. The first study from the period 1957–1960 found that fatal head injuries were 2.4 times more common among unhelmeted occupants of potentially survivable helicopter accidents than among occupants wearing the army’s APH-5 helmet. The second study from the period 1972–1988 found that the risk of fatal head injury was 6.3 times greater in unhelmeted occupants of potentially survivable helicopter accidents than among occupants wearing the army’s SPH-4[7] helmet.
In a separate study (report 98-18) the Army Aeromedical Research Laboratory reviewed 459 accidents in the period 1990–1996 where helmet visor use was verified. They found that visor use was attributed to preventing facial injury in 102 (22.2%) accidents and reducing injury in 13 (2.8%) accidents.
This accident highlights the effectiveness of wearing a helmet to prevent a more serious injury. ATSB report AO-2014-058 provides an account of a serious head injury to an R22 pilot who was not wearing a helmet. In a later ATSB report, AO-2015-134, the operator commented that the pilot of an R22 accident would have suffered more serious head injuries if he was not wearing a helmet.
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 potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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On 23 April 2016, a Virgin Australia Boeing 737-8FE aircraft, registered VH-YIW, operated as VA91 from Auckland, New Zealand to Faleolo Airport in Apia, Samoa, with the intent to conduct a return flight that day. The departure from Apia was planned to be completed before the arrival of an approaching tropical cyclone.
During the landing on runway 08, while correcting for a left drift from the runway centreline, the aircraft touched down in a nose-down, right wing-low attitude. This resulted in the right engine nacelle contacting the runway. The flight crew were not aware the nacelle strike had occurred, as the landing, while firm, was not assessed by the flight crew to be outside of normal landing parameters.
What the ATSB found
The ATSB identified that due to heavy rain, darkness and limited visual cues, the flight crew did not detect the aircraft's banked, nose-low attitude immediately prior to landing. Additionally, the subsequent routine flight crew and engineering inspections did not identify damage to the nacelle over the aircraft’s next four flights.
It was also found that the pilot flying was probably experiencing a level of fatigue that has been demonstrated to adversely influence performance.
What's been done as a result
Following this occurrence, the operator modified its aircraft external inspection procedures for flight crew and engineering staff. The flight crew training material was updated to reflect the inspection procedures in the flight crew operating manual, which stated that crew shall inspect the underside of engine nacelles. This action was supported by an internal flight operations update issued on 29 April 2016, re-emphasising that exterior inspections were to be conducted in accordance with the flight crew operating manual’s procedures.
The engineering daily inspection task card for pre‑flight inspections before extended operations was strengthened by issuing engineering technical advisories including the requirement to conduct checks of the underside surfaces of the engine nacelles during normal operation and also when there was indication of an increased likelihood of a nacelle strike on landing.
The operator also identified and implemented a number of improvements in the management of hazards associated with significant events, including cyclones.
Safety message
Detecting airframe damage, particularly to the underside of the engines, can be difficult due to the location not being within normal visual reference. Airframe damage in this location is more likely to be detected by thorough visual inspections of the lowest parts of the airframe before flight and during daily inspection.
While checking for damage in this inconspicuous location can be difficult, and influenced by an expectation that no damage is present, flight crew and engineers are reminded that damage can occur without flight crew awareness.
Safety issues and actions
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.
Virgin Australia Airlines Pty. Ltd.
The operator has modified its training in relation to flight crew external inspections to include a specific visual inspection of the underside of engine nacelles, as per the procedure outlined in the flight crew operations manual.
The operator has also modified the procedures for engineering external daily inspections to include a specific visual inspection of the underside of engine nacelles.
International roaming on the Virgin Australia International fleet has been introduced to enable automatic downland of QAR data immediately after shutdown at all Australian and International Airports.
Context
Aircraft information
General information
VH-YIW is a Boeing 737-8FE (B737) aircraft, powered by two wing‑mounted CFM-56-7B24/3, high bypass turbofan engines. In its configuration at the time of the occurrence, it was capable of carrying 176 passengers, and 6 crew.
Damage to aircraft
The right engine nacelle was damaged by briefly contacting the runway during the touchdown in an incident known as a ‘nacelle strike’ (Figure 1). The landing gear tyres also sustained some lateral or sideways wear damage during the event. Detailed inspection of the right engine identified that the:
lower right engine nacelle skin was holed by abrasion damage
lower surfaces of the right engine fan and reverser cowlings were damaged
right engine fan path abradable lining was worn (Figure 2).
Figure 1: VH-YIW No. 2 engine nacelle
Source: Operator’s investigation report, annotated by the ATSB.
Figure 2: VH-YIW right engine abradable lining.
The blue area shows where the rotating engine blades have contacted the abradable lining
Source: Operator’s investigation report, annotated by the ATSB.
The operator requested a design engineer to report on the potential damage. The report stated:
…the very minimal damage to the inner liner indicates that the energy of the impact was primarily absorbed by the cowl structure buckling as the initial contact occurred.
The design engineer’s report also concluded that:
…the continued flight with damage to the engine cowling posed no critical aerodynamic, structural or mechanical safety risk to the aircraft.
Personnel information
Qualifications and experience
The captain held an Air Transport Pilot Licence (Aeroplane) and had a total of about 10,000 hours’ flying experience, of which about 6,000 were on the Boeing 737 aircraft. The captain commenced flying with the operator in 2003 and held a valid class 1 aviation medical certificate.
The first officer (FO) held an Air Transport Pilot Licence (Aeroplane) and had a total of about 5,300 hours’ flying experience, of which about 1,100 were on Boeing 737 aircraft. The FO commenced flying with the operator in 2007 and held a valid class 1 aviation medical certificate.
Both flight crew had operated to Apia on many occasions, including at night and in rain.
Recent history
Both the captain and the first officer were based in Auckland. They both had the same duty periods during 20–24 April 2016, as indicated in Table 1. All times in this section are specified in the local time for the flight crew, which was or New Zealand Standard Time (NZST).[4]
Table 1: Actual duty time information for the flight crew for the period 20–24 April 2016
Date
Work activity
Duty start
Duty end
Duty time
Time free (of duty)
20 Apr 2016
Day off
21 Apr 2016
Day off
22 Apr 2016
Auckland–Apia–Auckland
1510
0205
10.9 hours
13.2 hours
23 Apr 2016
Auckland–Apia (pod strike)
1510
2300
7.8 hours
15.0 hours
24 Apr 2016
Apia–Auckland
1400
2050
6.8 hours
Source: Virgin Australia, modified by the ATSB.
The crew conducted flights from Auckland to Apia and return on the 22 April. Originally, they were scheduled to operate the flight from Auckland to Apia on 23 April, then overnight at Apia before operating a flight from Apia to Sydney on 24 April. Due to the approaching cyclone, the crew were unsure whether the flight on 23 April would be cancelled or their schedule would be changed to include a return flight (same as 22 April). After they awoke on 23 April they were advised that they would be conducting the same schedule as 22 April.
The flight to Apia on 23 April landed at 2007 NZST. The return flight was postponed due to the weather conditions and the crew stayed the night in Apia and operated the return flight to Auckland the next day.
The captain reported that he normally had 6–7 hours’ sleep a night and he had been sleeping normally up until the night of 22 April, after their flight arrived back in Auckland at 0135 on 23 April. On that night he reported getting 3–4 hours’ sleep (uninterrupted), waking at about 0700 because he often found it difficult to sleep beyond his normal waking time. He stated that he felt ‘okay’ during the flight to Apia on the 23 April.
The first officer reported that he normally had 7–8 hours’ sleep a night and slept normally in the nights prior to the 23 April flights, waking at about 1000 that morning after 7 hours’ sleep (uninterrupted). He said he felt alert at the beginning and towards the end of the flight to Apia on the 23 April, and okay during the middle part of the flight.
Both crew assessed that they were fit and appropriately rested to conduct the flight on 23 April. They also both reported eating normally prior to and during the flight.
The operator’s fatigue risk management system (FRMS) included the use of a biomathematical model and other processes to assess to suitability of planned duty periods. The minimum length of time off duty at home base was 12 hours, and the maximum planned duty period for a duty period with two sectors starting during 1300–1759 was 12.25 hours.
As part of its FRMS, flight crew could also take a short period of controlled rest at their flight deck seats during flights (for flights of over 3 hours under specified conditions). Neither pilot could recall taking a controlled rest during the flights on 22 or 23 April. Both pilots said they had previously used controlled rest on other flights to ensure they were alert on approach.
Meteorological information
A summary of the available and obtained weather information is shown in Figure 3.
Figure 3: Image of the flight and the weather information available at different times
Source: Google maps, annotated by the ATSB
Information available prior to the flight
The operator was aware of TC Amos, and had been monitoring its progress to assess its effect on company operations. The United States joint typhoon warning center (JTWC) issued advisory information (commonly known as ‘advisories’) at 1200 and 2100 on 22 April, and at 0000 and 0900 on 23 April. These advisories were numbered eleven to fourteen respectively.
The weather forecasts contained in the advisories had minor changes between the sequential forecasts, with the last being the most significant. Advisory No. 11, issued at 1200 on 22 April, forecast that TC Amos would be a category three cyclone located to the west of Samoa, and would be still approaching the island after the planned return flight had departed from Apia.
Advisory No. 12 was issued nine hours later, at 2100 on 22 April (Figure 4). It detailed that the tropical cyclone may turn right and pass to the south of Samoa and that TC Amos was due to pass the island at 0600 on 24 April, about one day after the proposed flights. However, the forecast expressed uncertainty on the direction of this turn. The advisory stated the next advice would be in 6 hours’ time, at 0300 on 23 April.
Based on the information from Advisory No. 12, the operator’s cyclone management team (CMT) convened and made operational decisions about flights that could be affected by TC Amos. The occurrence flight was planned on the basis that VH-YIW would have departed from Apia before the cyclone had a significant impact on the airport. All other flights to Apia were cancelled until after the cyclone’s passage, and overflying aircraft could not use Apia as a flight planning alternate airport.
Prior to departure, the flight crew were provided with a briefing package including information from Advisory No. 12. The package included information on the weather system associated with TC Amos, which was forecast to start influencing Samoa and the surrounding region during the time of the flight. The package indicated that for the estimated time of arrival for VH-YIW, the centre of TC Amos would be approximately 260 km west of Faleolo airport with forecast crosswinds at the airport expected to be about 20 kt (within the aircraft’s operational limit).
Figure 4 : JTWC Cyclone Advisory No. 12, issued 2100 on 22 April – the forecast provided to the flight crew. The four-digit number gives the date and hours in UTC (Z) when the cyclone was forecast to be in that location. The concentric circles are isotachs - lines of constant wind speed surrounding the cyclone
Source: JTWC, annotated by the ATSB.
The flight crew did not receive Advisory No. 13, issued at 0000. This forecast expected the cyclone would pass 80 km closer to Apia at about the same time as forecast in the previous advisory, with a 10 kt reduction in peak intensity, still providing adequate time for the return flight to be completed (Figure 5). Advisory No. 13 was assessed by the CMT as not altering any operational requirements and consequently was not passed to the flight crew.
At the time of the planned flights into and out of Samoa during the evening of 23 April, bands of heavy rain were expected in the vicinity of the airport, however the winds were forecast to be within the aircraft’s operational limitations.
Figure 5: JTWC Cyclone Advisory No: 13, issued 0000 23 April – the last forecast issued before the incident
Source: JTWC, annotated by the ATSB.
In-flight information
The aircraft took off from Auckland at 0433 and landed at Apia at 0807.
During the pre-flight briefing, the crew received the aerodrome forecast for Faleolo Airport. The forecast was issued on 22 April at 2148, and was valid from 0000 for the next 24 hours, unless it was amended or updated. Aerodrome forecasts are issued at scheduled times, or in response to significant weather changes. The aerodrome forecast issued at 2148 was re-issued at 0357 and was updated several times before the aircraft landed at 0807.
Forecast conditions, visibility reduction associated with rain showers and thunderstorms, required the operator to carry sufficient fuel to continue to an alternate aerodrome, and the carriage of holding fuel.
After departing Auckland, the flight crew obtained an amended aerodrome forecast. This forecast required the same operational restrictions, however identified the onset of possible thunderstorms to start three hours earlier than previously expected, at 0900.
The flight crew contacted Faleolo tower inflight and obtained the observed weather conditions from the controller prior to landing.
Information that became available after the flight
Cyclone Advisory No: 14 was issued at 0900 and advised that the cyclone was now moving twice as fast as previously forecast and was about 170 km west north-west of Apia at the time of landing.
Advisory 14 also detailed that TC Amos was expected to pass about 25 km north of Apia 14 hours earlier than first predicted (Figure 6). The forecast also indicated the airport would be exposed to sustained winds over 64 kt on the following morning (24 April) as the cyclone passed close by.
Figure 6: JTWC Cyclone Advisory No: 14, issued 0900 on 23 April – issued after landing
Source: JTWC, annotated by the ATSB.
Communication
During the flight, the crew requested and received numerous weather updates from the operator’s flight following service via the aircraft communication, addressing and reporting system.
The flight crew reported initial difficulty contacting air traffic control (ATC) at Faleolo tower using very high frequency radio. They were subsequently able to make contact with ATC using high frequency radio just prior to the top of descent. ATC provided surface observations at the airport to the crew, who asked to be updated on any weather changes throughout the descent.
The crew also coordinated with ATC for a missed approach clearance to FL140[5], instead of the normal 4,000 ft. This change was reportedly made to facilitate a diversion to Nadi if it became necessary.
Aerodrome information
General information
Faleolo runway 08/26, is about 3,000 m long and 45 m wide with 7 m sealed shoulders on each side. The control tower is located to the south of the parking apron at the eastern end of the runway. The runway has edge lighting, which was considered to be ‘quite bright’ by the occurrence flight crew, and runway centre-line lighting was not installed. There is a 150 m stop‑way before the threshold of the runway and the runway has a marked downhill slope from the threshold to about halfway along the runway, descending 49 ft.
Runway 08 was reportedly prone to what is referred to as ‘black hole effect’ at night (see the section titled Black hole approach). This phenomenon is particularly relevant when aircraft approach airports at night over the sea or unlit terrain.
The runway was equipped with a precision approach path indicator that provides vertical approach path information for crew as guidance to their height in relation to the runway.
Runway damage
During landing, the aircraft first contacted the runway at about 834 m along and to the left of the centreline of runway 08. The right main undercarriage was first to touch down, followed by the nose wheels, and then the left main undercarriage.
Recorded aircraft data indicated that the aircraft landed with a 5° yaw to the right, greater than10° of right roll, and nose-down attitude of more than 2°.
The impact damage visible on the runway due to contact with the nacelle was mostly due to paint transfer over a relatively localised area, and consisted only of superficial damage to the runway surface (Figure 7).
Figure 7: Runway 08 surface marks and nacelle paint transfer
Source: Operator, annotated by the ATSB
Flight recorders
The aircraft was equipped with a flight data recorder (FDR) and cockpit voice recorder (CVR). Due to the elapsed flight time between the occurrence and its detection, the CVR was overwritten. However, the occurrence was able to be downloaded from the FDR and analysed by the ATSB.
The FDR recorded that the autopilot was disengaged at 260 ft above ground level (AGL) and at about 240 ft AGL, the Take-Off Go-Around (TOGA) function was activated (which the flight crew reported as inadvertent), followed by the auto-throttle disconnection. The auto-throttle remained disengaged for the remainder of the flight.
Data indicated that the aircraft began to drift left of the centreline at about 20 ft AGL. At touchdown, the maximum recorded bank angle was 10.3° right wing-low, and the recorded pitch angle was about 2.5° nose-down. The corresponding vertical acceleration at touchdown was 1.95 G.
The recorded wind speed reduced from about 36 kt at 300ft AGL to about 22 kt at touchdown. The crosswind wind limits of the aircraft were not exceeded throughout the approach and landing. The recorded data also showed that the aircraft did not exceed the stable approach criteria during the approach and landed in the expected touchdown area, albeit laterally displaced to the left of the centreline.
Maintenance information
Engineering inspections
The aircraft was required to undergo a daily inspection and an additional ‘extended range operations’ inspection when the planned flight was more than 60 minutes’ flying time (at ‘one engine inoperative’ speed) away from the nearest airport suitable for emergency landing.
Daily inspection
The daily inspection task card required that an engineer perform:
…a visual check of the following components for obvious signs of damage, and indications of bird‑strike or foreign object damage...
The subsequent list included the:
…inlet cowl inner and outer surfaces.
Additionally, if other damage was found, the engineer was required to compare the damage with the limits in the applicable detailed inspection procedure. Following this event, the operator strengthened its inspection procedures. On 4 May 2016, the operator issued technical advisories to expand on this inspection item. The advice stated:
To fully achieve the inlet cowl outer surfaces inspection engineers must do a visual check on the underside surfaces of the inlet cowl.
The advisory was updated with more detail on 24 May 2016.
Extended range operations inspection
A different external inspection was also conducted using a different inspection schedule before every extended operations flight. Flights between Australia or New Zealand and Samoa were classified as extended range operations.
The extended range operations inspection includes an external walk around. This item required the engineer to ’carry out a walk around check for airframe condition and obvious damage by visually inspecting from the ground, and paying attention’ to a list of aircraft components, including engine inlets and fan blades.
Flight crew inspections
Flight crew are required to conduct a pre-flight external visual inspection before flight. This inspection is to ensure the aircraft is in sound operating condition from the previous flight and to identify any potential flight safety hazards.
Flight crew conduct pre-flight inspections in accordance with a documented procedure. The Flight Crew Operations Manual provided the procedure for the external inspection. This includes a diagram with the inspection sequence and the items to be inspected at each area of the aircraft. Following a nacelle strike in Dublin, Ireland in 2009 where the nacelle damage was not detected for the next two sectors, the aircraft manufacturer updated the inspection procedures.
Subsequently, the operator’s documented procedure in its Flight Crew Operations Manual was amended in October 2011 to include, for each engine, ‘Exterior surfaces (including the bottom of the nacelles)’.
The documented procedure was also supported by pilot training material that was intended to provide practical instruction on how to implement the procedure. However, the pilot training material had not been updated to include the specific requirement to inspect the bottom of the nacelles for damage.
Following the occurrence, the operator’s flight crew exterior inspection training package was updated to reflect the 2011 amendment in the Flight Crew Operations Manual, including the requirement to inspect the bottom of the nacelles.
Post-incident inspections
Two engineering daily inspections, one separate engineering extended range operations inspection, and two pre-flight inspections were carried out following the incident. Subsequent to this, various flight crew and engineers also inspected the aircraft during the pre-flight, daily and extended range operations inspections for the following three sectors.
The nacelle damage was not detected until the analysis of flight data prompted a subsequent inspection, about ten operating hours after the strike occurred.
Organisational information
Cyclone management team
The operator had a process, including a documented procedure, to activate its cyclone management team (CMT) if a cyclone was forecast to be within 370 km of an airport that would be used within the next 24 hours. The procedure also provided guidance on assessing the suitability of a landing airport in regard to the forecast wind strength.
During the CMT meeting at 2100 on 22 April, the team considered the identified risks to the operation. They determined that the flight was operationally safe with a number of added risk mitigators.
Following this occurrence, the operator identified and implemented a number of improvements in the management of hazards associated with significant events, including cyclones.
Flight dispatch and following
Prior to departure, flight crew are required to obtain all relevant operational information and are required to obtain inflight updates to ensure they have accurate and up to date information to assist with operational decision-making.
The operator maintained a flight dispatch and flight following function in which relevant operational information was collected and provided to flight crew.
Flight dispatch
Flight dispatch prepared and submitted operational flight plans on behalf of flight crew, who received an operational flight-briefing package before flight. The Group Operations Manual suite contained the Flight Dispatch Policy Manual. This contained guidance material and procedures for the Flight dispatch team to provide the following functions:
acquisition, collation and evaluation of NOTAM, meteorological and other operational information in support of flight-planning activities
The evaluation of navigational, meteorological, aircraft performance and flight-planning-related operational factors specifically associated with the dispatch and continuation of ‘extended range operations’
The provision of verbal pre-flight briefings and briefing updates to the flight crew of individual flights (upon request), to supplement the standard briefing documentation routinely provided to the crews.
Flight following
Flight following services were provided primarily to enhance and contribute to the safety of a flight. The occurrence flight met the criteria to receive a flight following service, including the provision of operationally critical information, such as that associated with tropical cyclones.
Flights that included sectors with extended diversion times had extra requirements, including special procedures for flight dispatch, the operations controller and the flight following function. Flight following is defined as an operational information service provided jointly by the duty operations controller and flight dispatcher to provide advice and information to assist in the safe and efficient conduct of extended range operations, including the provision of advice and information at the request of the captain, either before or during flight.
The occurrence flight was an extended range operation and as such, the flight dispatch division was also responsible for plotting current information on tropical cyclones on a display to assist with flight planning and flight following and to continually monitor and evaluate relevant operational information to assess its impact on extended range operations. Information on non-normal variances which may impact the continuation of the flight under extended range operations procedures shall be promptly communicated to the captain.
Approach to land
Go-around manoeuvre
The flight crew were required to maintain a stabilised approach from 1,000 ft above the aerodrome elevation until touchdown. If the approach became unstable during this segment, the crew were required to conduct the missed approach procedure.
The crew had planned, prepared and were ready to conduct a missed approach at Apia. They had briefed that if they initiated a missed approach procedure, the aircraft would be diverted to Nadi, Fiji instead of conducting another approach.
In the last four seconds of the approach, the flight path deviated sufficiently to require multiple flight control inputs to keep the aircraft on the desired flight path for landing.
The operator’s flight procedures stated that during this phase of flight:
…should it become apparent that the aircraft will touch down significantly short of the touch down aiming point, or beyond the end of the touch down zone (1000 m/3000 ft from the threshold or first third of the runway, whichever is less), the pilot flying shall initiate a go-around.
The aircraft remained within the touch down zone and over the runway prior to runway contact. A go-around was not required unless initiated by the flight crew at their discretion. The crew reported that they believed that the aircraft remained within the stabilised approach criteria for landing and were comfortable to continue to land.
Spatial disorientation
In 2007, the ATSB published a report An overview of spatial disorientation as a factor in aviation accidents and incidents.[6] The report identified several types of visual illusions that may impact a pilot’s ability to land an aircraft safely.
Runway shape and slope illusions
At a given altitude and distance from a runway, the slope of a runway will affect the amount of runway visible to a pilot. For a down-sloping runway such as Apia, this will result in less of the runway being visible. Pilots may perceive this lack of visibility as the flight path being below the correct approach path and as a result, the pilot may fly a higher-than-normal approach to achieve the runway visibility that would be present on a level runway.
Both flight crew identified this runway as having a significant down slope, which increased the difficulty of landing at Samoa. They also reported heavy rain on approach, which did affect visibility. However, both crew had a high level of experience operating into this airport and did not report any issues relating to the slope or visibility of this approach.
Black hole approach
A black hole approach is a term used by pilots to characterise an approach path at night with no visual cues between the aircraft and the intended runway on final approach to land. Black hole illusion occurs when darkness and an absence of visual cues, such as lights, may induce a false perception of altitude and/or attitude.
When the environment along the approach path is dark, with only the distant runway or airport lights providing visual stimuli, an illusory or false sense of height and/or attitude may be perceived. The absence of peripheral visual cues provides a false illusion of height to the pilot, often resulting in the inadvertent reaction to fly the aircraft lower than the normal approach path.
Runway centre line illumination
Runway lighting and, in particular, runway centre line and touchdown zone lighting accentuate approach rate cues and height appreciation. Runway 08 at Apia, did not have centre line lighting.
Bright runway lights may create the impression of being closer to the runway (hence on a steeper glide path). The crew reported that the runway lighting at the airport was particularly bright.
These visual illusions may affect a pilot’s ability to judge the correct time to initiate a flare to land.
Related occurrences
A number of similar nacelle strike events have been identified involving Boeing 737 aircraft. The conditions were not the same in all the occurrences, but they all had environmental phenomena present that increased pilot workload during landing.
Air Accident Investigation Unit Ireland investigation report No. 2011-007 Engine pod strike, Dublin Airport, Ireland, on 19 November 2009
On 19 November 2009, at 1245 UTC, a Boeing 737-8AS aircraft, registered EI-DAI was operating a scheduled flight from Rome’s Ciampino airport, Italy, to Dublin, Ireland. The weather at Dublin was forecast to be blustery during the day. The first officer (FO) was the pilot flying and the captain was the pilot monitoring.
On the leg to Dublin, a full briefing was carried out including flap selection, runway length with regard to flap setting, the landing chart and windshear. At Dublin the aircraft joined the approach traffic sequence for landing. There was a strong wind from the southwest, which the captain estimated as 70 kt at 3,000 ft. The captain rechecked the limits after the control tower provided a wind report and concluded that it was within limits. Although conditions were blustery the captain reported that the approach was normal given the conditions and the aircraft was configured ahead of normal and flown with plus 15 kt added due to wind.
At about 300 ft the aircraft was slightly left of the localiser. The captain called this out and the FO corrected it promptly. The captain said that the approach was normal until about 25 ft when the left wing dropped due to the wind. The captain assisted the FO with a control input.
According to the captain’s report, the aircraft was now steady on profile and a flare was initiated; the aircraft did not seem to descend and at this point the captain closed the thrust levers. Simultaneously, the left wing dropped again as the aircraft descended to the runway. The captain said that the aircraft landed quite benignly albeit with the left wing low. The captain reported that at no stage did he or the FO suspect ground contact.
Subsequently, a different crew operated the aircraft on the next two sectors to and from Poland. On arrival back in Dublin, the captain for these Polish sectors learned that a member of the public had reported the earlier nacelle scrape.
Transportation Safety Board of Canada investigation report A05A0161, wing ground strike, Halifax Airport, Canada, on 25 December 2005
On 25 December 2005, at 1924 Atlantic Standard Time,[7] A Boeing 737-700 aircraft, registered C‑GWJF, was on a scheduled passenger flight from Toronto, Ontario, to Halifax, Nova Scotia. About 10 minutes before landing, the crew was advised that another aircraft had just landed on runway 14, and that the pilots of that aircraft had reported that they had the runway lights visual at 250 ft above ground level (AGL). This was 50 ft above the decision height for the ILS approach to Runway 14.
Just before touchdown on runway 14 in low-visibility conditions, the aircraft rolled right and moved toward the right side of the runway. The aircraft then rolled to the left, and the left wing struck the runway. None of the passengers or crew members were injured, and the aircraft taxied to the terminal.
The aircraft touched down firmly on the left main landing gear at about 2,500 ft from the runway threshold, between the centreline and the right edge of the runway, with 16° of left bank. Concurrently, the left wing contacted the runway surface for about 0.5 second. The left main landing gear strut then extended to nearly full length, and the left bank increased to 18°. The left wing contacted the runway again for approximately 2 seconds, and simultaneously, the aircraft heading deviated left to 136°, or 8° left of the runway heading.
The aircraft settled onto both main landing gears five seconds after the left main gear made contact, approximately 3,550 ft beyond the runway threshold. After the nose gear touched down, heavy wheel braking was used to slow the aircraft. Eight seconds after nose gear touchdown, after being prompted, the pilot flying applied reverse thrust on both engines. Deployment of reverse thrust occurred approximately 5,300 ft beyond the runway threshold. The aircraft slowed to taxi speed with approximately 500 ft of runway remaining. The aircraft taxied uneventfully to the assigned gate at the terminal.
United Kingdom Air Accidents Investigation Branch investigation EW/2009/02/08, engine pod strike, Leeds Bradford Airport, UK, on 21 February 2009
On 21 February 2009, at 1401 UTC, a Boeing 737-33A aircraft, registered G-CELD, was landing on Runway 32 at Leeds Bradford Airport. As the aircraft approached the flare, at about 30 ft AGL, a speed loss of 10 kt occurred. The captain called ’speed slow’ and placed his hand near the throttles, with the FO applying a small amount of power.
The captain then felt the aircraft sink so applied a ’handful of power’, covering the FO’s hands as he did so, adding ’you’ll need more than that’. At some point after this, the FO thought he heard the captain say ’I have control’ to which he responded by taking his hands off the controls in accordance with the company standard operating procedures. The FO added that his ’feet remained on the rudder pedals as there was no time to remove them’. Both pilots then recalled a pronounced wing drop to the right, immediately prior to the aircraft touching down.
G-CELD encountered windshear at about 30 ft AGL and became unstable in the flare. As a result, and unbeknown to the crew at the time, the right engine nacelle contacted the runway. Inspection of the runway revealed a 15 m scrape mark on the threshold, with associated paint matching G‑CELD’s engine cowling.
An aftercast was obtained from the Meteorological Office. It stated that it was likely that there was no abnormal wind flow regime although the wind was strong and gusty. The gustiness was not abnormal, but reductions in speed of 10 to 15 kt over a short period of time/distance were likely.
United Kingdom Air Accidents Investigation Branch investigation EW/2009/11/09, Engine pod strike, Bristol Airport, UK, on 19 November 2009
On 19 November 2009, at 2124 UTC, a Boeing 737-8AS aircraft, registered EI-DAL, was on a scheduled flight from Dublin, Ireland to Bristol Airport. The crew were both based at Bristol and aware of the local conditions prevalent during strong crosswind approaches and landings on runway 27. The captain was the pilot flying, the runway surface was dry and it was dark.
During the landing flare, the captain de‑crabbed the aircraft at 15 ft and closed the thrust levers at about 10 ft. The aircraft experienced a wing drop to the left, which the captain corrected, quickly followed by a more severe wing drop to the right as the right main landing gear touched down.
Although the crew did not believe an engine had contacted the runway, the captain said to the FO he would have a look after they shut down.
The company engineers observed the landing and mentioned that it looked ’pretty scary’ and considered that the wingtip may have made contact with the runway. Whilst the passengers were disembarking, the engineers inspected the aircraft and found damage under the right engine. The damage was confined to the engine cowl and thrust reverser duct.
On 23 April 2016, a Virgin Australia Boeing 737-8FE aircraft, registered VH-YIW, was operating a scheduled passenger service as flight VA91 from Auckland, New Zealand to Faleolo Airport, Apia, Samoa. Due to tropical cyclone Amos (TC Amos) being predicted to arrive in the vicinity of Samoa in the early hours of the following morning, the operator planned for VH-YIW to conduct a return flight on the same day, using the same flight crew. The captain was the pilot flying and the first officer was the pilot monitoring.[1]
Before the flight, TC Amos was west of Samoa, moving eastward. At 2100 Coordinated Universal Time,[2] about seven and a half hours before the planned take-off, the operator’s cyclone management team (CMT) reviewed the weather information associated with the cyclone, and determined that the flight could continue with additional risk mitigation in place. Specifically, the aircraft was required to carry maximum fuel, to allow for 60 minutes’ holding fuel at Samoa and for possible diversion to an alternate landing at Nadi, Fiji. Furthermore, engineering coverage was required at Samoa, or an engineer had to be carried on board from Auckland.
Three hours later, at 0000, a new cyclone advisory was issued. There was no significant change to the cyclone forecast based on the new advisory. However, the updated information was not used when planning the flight, nor was it assessed by the CMT. The aerodrome forecast indicated that a night landing could be still be safely conducted at Apia.
The flight departed from Auckland at 0433. During the flight, the crew sought and received regular weather updates from the operator’s flight following service[3] (flight following). As part of the updates received, the crew obtained terminal area forecasts and meteorological aerodrome reports for Apia. The crew were not provided with the cyclone advisory that was issued at 0000, although it was assessed by flight following and available to the crew on request.
While planning for the descent, approach and landing, the crew decided they would not commence the descent until they had received a weather report from the aerodrome tower controller. The crew reported difficulty contacting the tower through standard very high frequency radio, and eventually made contact using the high frequency radio and obtained a weather report. Based on that report, the crew decided they would conduct one approach and if they could not land, they would divert to Nadi.
During the approach, the crew reported observing heavy rainfall on the aircraft’s weather radar display. The crew also reported that the conditions were not as turbulent as previously expected. On approach to land, the crew established visual reference with runway 08 at about 700 ft above ground level, and continued the approach. The captain disconnected the autopilot at 260 ft and then inadvertently activated the take-off/go-around (TOGA) function. He immediately realised, corrected this action and then deactivated the auto throttle as originally planned.
After about 20 seconds of manual flying on final approach, the aircraft started to drift left. The aircraft touched down about six seconds later. During those six seconds, both flight crew became aware of the aircraft’s left drift and the captain manoeuvred the aircraft to return to the runway centreline. At 0807, the aircraft landed on the right main landing gear wheels first, followed by the nose wheels, then the left main gear wheels. Flight data indicated that the aircraft was not pitched nose-up to flare for landing before touchdown. The crew taxied to the terminal and discussed the landing.
The weather conditions remained within the aircraft’s operating limitations, and were therefore suitable, during the approach and landing. While neither crew reported that it was a hard landing, the first officer considered it firmer than normal and consequently checked the landing data. Having only been informally shown how to access this information, the first officer recalled identifying the touchdown as 1.45 G landing with a 10° right roll. This alleviated his concerns of a hard landing and he communicated this to the captain.
Unknown to the crew, the right engine nacelle had briefly made contact with the runway during the landing and sustained damaged. There were no reported injuries as a result of the occurrence.
In preparation for the return flight, the captain and the engineer both conducted independent external pre-flight aircraft inspections in the heavy weather conditions. During this time, the weather deteriorated further and the crew postponed the return flight until the next day. The following day, and with a significant improvement in the weather, the captain and the engineer both conducted separate external pre-flight checks of the aircraft in preparation for the day’s flying. Neither inspection detected the right engine nacelle damage.
At least four separate external visual inspections were conducted on the aircraft between landing at Apia, and taking off the next day. No external airframe damage was detected or reported from either the crew or engineer before it departed.
Two days later, the operator’s flight data section detected the aircraft had encountered a designated hard landing with a significant angle of bank at Apia. Delays in uploading the data to the operator’s flight data system occurred due to the operator not having immediate data download capabilities at overseas ports. This data was uploaded on return of the aircraft from its overseas sectors to Australian ports. This, coupled with an Australian public holiday, meant a further day’s delay before the information was interpreted by the operator’s maintenance watch function. Subsequently, maintenance watch required the aircraft to undergo inspection on arrival from Port Moresby, Papua New Guinea into Brisbane, Queensland on 26 April.
Following the conduct of four sectors after the Apia landing, damage to the right engine nacelle was detected. Additional inspection identified lateral wear damage on the outer right landing gear tyre.
From the evidence available, the following findings are made with respect to the engine nacelle strike and continued operation involving a Boeing 737-8FE, registered VH-YIW and operated by Virgin Australia Airlines Pty. Ltd. that occurred at Faleolo Airport, Apia, Samoa on 23 April 2016. These findings should not be read as apportioning blame or liability to any particular organisation or individual.
Contributing factors
The aircraft drifted left during short final in heavy rain on an approach at night. The pilot flying started to correct the drift, however the aircraft was not flared and the wings were not level as it touched down. This led to the nose and right wing being low, resulting in an engine nacelle strike.
Due to heavy rain, darkness and limited visual cues, the flight crew did not detect the aircraft's banked, nose-low attitude immediately prior to landing which increased the likelihood of an engine nacelle strike.
The operator’s pre-flight external inspection procedure mandated that flight crew check under the engine nacelle for damage. This was not routinely done by flight crew and not included in the flight crew training material.
Although the operator had a maintenance task card for daily inspections of the Boeing 737, it did not contain a specific requirement to inspect underneath the engine nacelle. This contributed to the damage to the right engine nacelle not being identified during in post-occurrence maintenance inspections.
Other factors that increased risk
Due to limited sleep in the previous 24 hours, the captain was probably experiencing a level of fatigue that has been demonstrated to adversely influence performance.
Safety analysis
Introduction
The flight departed Auckland with an approaching tropical cyclone in the vicinity of Apia. At the time of departure, the effects of the tropical cyclone where not expected to adversely impact the safety of the flight.
The approach to land was conducted within the aircraft’s operational limitations at night and in heavy rain. During the touch down, the right engine nacelle momentarily contacted the runway.
Damage from the runway contact to the engine nacelle was not detected after landing or during any of the pre-flight and engineering inspections for four subsequent sectors.
The following analysis examines the weather information provided to the flight crew and the human factors associated with the approach leading to the nacelle strike. It further examines the visual inspection methods that should have provided opportunities to detect the aircraft damage.
Flight briefing and monitoring
TC Advisory No. 13 was not provided to the flight crew prior to departure or during the flight. The operator’s flight following service was in receipt of Advisory No. 13, which was available if requested by the crew.
However, the updated information contained in Advisory No. 13 did not contain any significant change from the previous forecast and was not deemed by flight following to contain operationally critical information and therefore was not actively provided to the flight crew. The flight crew utilised requested aerodrome forecasts and observed weather reports from Apia air traffic control to prepare the aircraft for landing in Samoa.
Human factors aspects
Fatigue
Fatigue can have a range of adverse influences on human performance, including slowed reaction time, decreased work efficiency, reduced motivational drive, increased variability in work performance and more lapses or errors of omission (Battelle Memorial Institute 1998), as well as various effects on decision making (Harrison and Horne 2000).
Sleep is vital for recovery from fatigue, with both the quantity and quality of sleep being important. Most people need at least 7–8 hours of sleep each day to achieve maximum levels of alertness and performance. Research has shown that obtaining less than 5 hours’ sleep in the previous 24 hours is inconsistent with a safe system of work (Dawson and McCulloch 2005), with some research indicating less than 6 hours sleep can increase risk (Thomas and Ferguson 2010, Williamson and others 2011). In addition to sleep, a number of other factors can influence fatigue levels, including time of day, time awake and the nature of work activities.
In this case, the captain reported having 3–4 hours’ sleep the night before the occurrence flight, and he had been awake for 13 hours at the time of the engine nacelle strike occurrence. He also stated that he did not feel fatigued, but most people generally underestimate their level of fatigue (Battelle Memorial Institute 1998). The first officer had significantly more sleep prior to the occurrence flight.
Overall, primarily due to restricted sleep in the previous 24 hours, it is likely the captain was experiencing a level of fatigue during the occurrence flight likely to have a demonstrated effect on performance. However, there was insufficient evidence to conclude he was experiencing a significant level of fatigue. In addition, it is difficult to conclude that the captain’s performance during the landing was influenced by fatigue. Other factors, such as reduced visual cues and environmental conditions, can explain the handling events, and the environmental conditions and context during the approach is likely to have elevated the crew’s arousal level.
The occurrence at Apia occurred during the first of two flights scheduled for the flight crew that day. Had the duty period proceeded as planned, it is likely that both flight crew would have been experiencing a higher level of fatigue towards the end of the second flight. However, both flight crew may have been able to enhance their alertness during that flight by taking controlled rest.
Overall, the flight crew’s scheduled flights on 23 April met the requirements of the operator’s fatigue risk management system. Nevertheless, this occurrence highlights the importance of ensuring that both flight crew and an operator adequately consider a flight crew member’s circumstances before extending duty periods.
Workload
Workload refers to the interaction between a specific individual and the demands associated with the tasks that they are performing. High workload leads to a reduction in the number of information sources an individual will search, and the frequency or amount of time these sources are checked (Staal 2004). It can result in an individual’s performance on some tasks degrading, tasks being performed with simpler or less comprehensive strategies, or tasks being shed completely (Wickens and Hollands 2000). An individual’s capacity to manage task demands at any point in time can be affected by a wide range of factors such as experience, training, task recency, familiarity with a situation and fatigue.
Neither pilot reported the workload during the approach as being too high to manage. They briefed for the approach and were actively monitoring the weather conditions, and they addressed the increased requirements for radar scanning successfully. However, final approach is normally known as a period of high workload for pilots, particularly at night. In this case, the workload was further increased by the changing weather conditions. The difficulty in communications with the tower, the crosswind, manual control of the aircraft and the potential influence of fatigue also added to this workload.
When the captain mistakenly selected take-off/go-around (TOGA) from the throttle controls instead of auto thrust disconnect, it had the effect of removing the flight director. This momentarily left the flight crew without a simple representation of pitch and bank angle guidance. With reduced visual cues due to the night-time conditions, rain and increasing crosswind on touchdown, the last 100 ft of the approach likely required the crew’s full attention to deal with the situation. Although the flight crew’s workload was undoubtedly higher than normal, the available evidence is not consistent with it being beyond the crew’s capabilities, and it is not possible to conclude that their elevated workload reduced their handling of the aircraft or their subsequent awareness of a nacelle strike.
Post-flight awareness of damage
The flight crew were aware that the landing had been non-standard and, after discussion with the captain, the FO obtained recorded data from the maintenance section of the on-board flight management computer. The FO’s interpretation of the data indicated that the landing had been conducted within normal parameters.
During the post-event investigation, the operator found that flight crew were not specifically instructed on how to interpret this data. Consequently, the FO did not understand the limitations in how the data was displayed, which led the flight crew to believe the landing was within acceptable limits, and alleviated any concerns they may have had with the landing. As a result, the flight crew did not alert the maintenance engineer of an increased likelihood of a hard landing or possible runway contact with the airframe.
Damage detection
Flight crew conduct an external inspection of the aircraft before every flight. As part of these inspections, the engines and surroundings are required to be examined. This includes an explicit requirement to inspect the underside of the nacelles for damage. This requirement was added to the operator’s procedures in 2011, adding to a previous requirement in 2005 to check that the engine exterior was not damaged.
At the time of the occurrence, however, the operator’s flight crew training package did not reflect the specific requirement to check for this damage. The captain conducted the planned return sector pre‑flight inspection at night, in heavy rain and wind. Although the environmental conditions were not optimal, the captain considered the inspection to be adequate. However, the flight did not proceed due to the weather and departed the next day, after an additional pre‑flight inspection, when conditions had eased. No flight crew inspections for the next four flights were effective in detecting the nacelle damage. Consistent with other occurrences investigated by the ATSB, this may have been influenced by an expectation that no damage was present. The operator has since amended its pilot training package to include the specific requirement to inspect the underside of the engine nacelles.
Additionally, a licensed engineer was required to conduct an external inspection before the first flight of a day and conduct a separate external inspection using a different inspection schedule before an aircraft conducted an extended range twin-engine operations (ETOPS) flight. Neither the daily external inspection, nor the ETOPS external inspection specifically required the underside of the nacelle to be visually inspected. Engineers were required to carry out a visual check of various components for ‘obvious signs of damage’. This included the inlet cowl outer surfaces and the abradable shroud.
While the lower surfaces of the nacelle were not specifically mentioned, the inspection requirements were broad in their requirements and not specific in their intent. This may have led to engineers not specifically inspecting under the engine nacelles. Since the occurrence, a specific requirement to inspect the nacelles’ underside has been added to engineers’ procedures.
A combination of rain, wind, and the position of the damage provided significant environmental challenges during the visual inspection.
Due to the positioning of the engines on a B737, the space between the underside of the nacelle and the ground is between 470 mm and 600 mm high, depending on the aircraft weight. While it is easy to inspect and access the sides of the nacelles, examining the underneath is more difficult. Tests by the operator showed that even when crouching down to view the underside of the nacelle from 2 m away, the area of damage was not visible. This meant anyone examining underneath the nacelle would have to be positioned close to the ground to obtain an adequate view of the area and any potential damage. No additional equipment, such as mirrors or waterproof clothing, were issued to flight crew to facilitate this level of inspection.
Sources and submissions
Sources of information
The sources of information during the investigation included:
the flight crew of VH-YIW
Virgin Australia Airlines Pty. Ltd.
the flight data recorder from VH-YIW
United States Joint Typhoon Warning Center
United States National Transportation Safety Board.
References
Battelle Memorial Institute 1998, An overview of the scientific literature concerning fatigue, sleep,and the circadian cycle, Report prepared for the Office of the Chief Scientific and Technical Advisor for Human Factors, United States Federal Aviation Administration.
Dawson D & McCulloch K 2005, ‘Managing fatigue: It’s about sleep’, Sleep Medicine Reviews, vol. 9, pp. 365–380.
Harrison H & Horne JA 2000, ‘The impact of sleep deprivation on decision making: A review’, Journal of Experimental Psychology, vol. 6, pp. 236–249.
Staal MA 2004, Stress, cognition, and human performance: A literature review and conceptual framework, National Aeronautics and Space Administration Technical Memorandum NASA/TM‑2004-212824.
Thomas MJW & Ferguson SA 2010, ‘Prior sleep, prior wake, and crew performance during normal flight operations’, Aviation, Space, and Environmental Medicine, vol. 81, pp. 665–670.
Wickens CD & Hollands JG, 2000, Engineering psychology and human performance, 3rd edition,
Prentice-Hall International Upper Saddle River, NJ.
Williamson A, Lombardi DA, Folkard S, Stutts J, Courtney TK & Connor JL 2011, ‘The link between fatigue and safety’, Accident Analysis and Prevention, vol. 43, pp. 498–515.
Submissions
Under Part 4, Division 2 (Investigation Reports), Section 26 of the Transport Safety Investigation Act 2003 (the Act), the Australian Transport Safety Bureau (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 flight crew, Virgin Australia Airlines Pty. Ltd. and the Civil Aviation Safety Authority.
Submissions were received from Virgin Australia Airlines Pty Ltd. The submissions were reviewed and, where considered appropriate, the text of the report was amended accordingly.
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
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.
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On 11 May 2016, an Airbus A320-232, registered VH-VGF (VGF) and operated by Jetstar Airways Pty Ltd was taking off on runway 27 at Melbourne Airport, Victoria. The flight crew consisted of a training captain in the left seat, a cadet pilot in the right seat and a safety pilot, who was also the first officer, in the jump-seat. This was the cadet pilot’s first take-off as pilot flying. During rotation, the tail of the aircraft contacted the runway surface.
After take-off, the cadet pilot realised that the pitch rate during rotation was higher than normal and discussed this with the captain. During the climb, the cabin crew discussed hearing an unusual noise during the take-off rotation with the captain. Due to the higher-than-normal rotation rate and the noise heard by the cabin crew, the captain elected to stop the climb and return to Melbourne. The first officer swapped seats with the cadet pilot and the aircraft landed uneventfully on runway 27.
What the ATSB found
The ATSB found that during rotation, the cadet pilot applied a larger than normal sidestick pitch input resulting in a higher-than-normal pitch rate. The tail of the aircraft contacted the runway surface resulting in damage to the auxiliary power unit (APU) diverter and APU drain mast. While airborne, the crew did not specifically advise air traffic control (ATC) of the possibility that a tail strike had occurred during take-off.
What's been done as a result
The cadet pilot undertook additional training and assessment before returning to flight duties. Soon after the event, the operator circulated a newsletter to their A320 flight crew highlighting the need to inform ATC of a suspected tail strike or any potential failure resulting in damage/debris.
Safety message
Good communication from the cabin crew alerted the flight crew that a tail strike may have occurred. The climb was stopped and a timely decision to return to Melbourne was taken which minimised the potential risk from damage caused by a tail strike.
It is important to notify ATC of a possible tail strike as soon as operationally suitable. When a potential tail strike has been reported, ATC restricts operations on the affected runway and arranges that a runway inspection is carried out to identify any runway damage or aircraft debris.
The occurrence
At 1449 Eastern Standard Time on 11 May 2016, an Airbus A320-232, registered VH-VGF (VGF) and operated by Jetstar Airways Pty Ltd was taking off on runway 27 at Melbourne Airport, Victoria for a planned flight to Hobart, Tasmania. The flight crew consisted of a training captain in the left seat, a cadet pilot in the right seat and a safety pilot, who was also the first officer (FO), in the jump-seat. This was the first take-off as pilot flying[1] (PF) for the cadet pilot.
After take-off, the cadet pilot realised that the pitch rate during rotation was higher than normal and discussed this with the captain. Later, during the climb, the cabin crew alerted the captain to unusual noises during rotation. As a result, the captain elected to stop the climb and return to Melbourne. The first officer also swapped seats with the cadet pilot.
The aircraft descended and landed uneventfully on runway 27. During the flight, no faults were annunciated to the crew.
After landing, engineers inspected the aircraft. Damage to the auxiliary power unit (APU) diverter (air inlet) and APU drain mast was evident. This damage was consistent with the aircraft tail contacting the runway surface during rotation.
Flight crew information
The cadet pilot had completed training leading to a Commercial Pilot’s Licence (CPL) and a multi-engine command instrument rating and had completed the theory examinations for an Air Transport Pilot (Aeroplane) Licence (ATPL). An A320 type rating was gained after ground school and simulator sessions were successfully completed. The simulator component consisted of ten 2-hour sessions.
The flight was scheduled as a training flight with the cadet pilot conducting his fifth sector of line training and the first sector of the current shift. There was also an FO in the jump seat acting as a safety pilot. The four previous sectors had been flown with the cadet pilot as pilot monitoring (PM). This was the first flight for the cadet pilot as PF.
The training captain was suitably qualified and experienced.
Aircraft information
Pitch control
The A320 is a ‘fly-by-wire’ aircraft, that is, there was no direct mechanical link between most of the flight crew’s controls and the flight control surfaces. Flight control computers send movement commands via electrical signals to hydraulic actuators that are connected to the control surfaces.
The controls include the sidestick controllers (or sidesticks) to manoeuvre the aircraft in pitch and roll. During manual flight, such as take-off, the flight crew make pitch control inputs using their sidesticks. Both the captain’s and first officer’s sidesticks move independently and there is no mechanical link between them. The range of movement of the sidestick in pitch is ± 16°.
Rotation technique
The following extracts are from the operator’s Flight Crew Training Manual:
On a normal take-off, to counteract the pitch up moment during thrust application, the PF should apply half forward (full forward in cross wind case) sidestick at the start of the take-off roll until reaching 80 kts. At this point, the input should be gradually reduced to be zero by 100 kts.
During the take-off roll and the rotation, the pilot flying scans rapidly the outside references and the primary flight display (PFD). Until airborne, or at least until visual cues are lost, this scanning depends on visibility conditions (the better the visibility, the higher the priority given to outside references). Once airborne, the PF must then control the pitch attitude on the PFD using the flight director (FD) bars in speed reference system (SRS)[2] mode which is then valid.
Initiate the rotation with a smooth positive backward sidestick input (typically 1/3 to 1/2 backstick). Avoid aggressive and sharp inputs. The initial rotation rate is about 3 deg/sec. If the established pitch rate is not satisfactory, the pilot must make smooth corrections on the stick. He must avoid rapid and large corrections, which cause sharp reaction in pitch from the aircraft.
Pitch limitation
The manufacturer advised that, with the main gear oleo[3] fully compressed and wings level, the pitch attitude that will result in ground contact for the A320 is 11.7°. With the main gear oleo fully extended, the pitch attitude that will result in ground contact is 13.5°.
Take-off configuration
Data from the flight recorders showed:
gross weight was 64.7 tonnes
take-off flap setting was Config 1+F[4] (slats/flaps 18°/10°)
trim setting was +1.4 units consistent with a centre of gravity (CG) of 34.4 per cent
The flap setting, trim setting and take-off speeds used agreed with those calculated by the aircraft manufacturer.
Flight recorders
The ATSB downloaded and analysed both the cockpit voice recorder (CVR) and the flight data recorder (FDR).
CVR
Crew interviews and CVR information showed that:
All the required briefings and checklists were performed.
The PM noticed approximately 6 medium-sized birds flying from left to right as the aircraft was reaching V1.
The calls of ‘V1’ and ‘rotate’ were made at the appropriate time.
The rotation was significantly faster than usual. The rotation was stopped at approximately +16° and a normal climb was flown with a standard acceleration, and cleanup was conducted normally.
There were no abnormal indications, and the pilots didn’t hear or feel anything unusual during the climb.
During climb, the cabin manager (CM) called the flight deck and informed the captain that the two cabin crew seated in the rear of the cabin had felt that the take-off was different from usual and thought something had moved or made a noise/vibration.
The captain immediately called the rear galley to gather more information first hand. The cabin crew advised that they had felt that the aircraft tilted more rapidly or to a different angle than was usual. They also advised that they heard and felt some kind of movement in the rear of the aircraft. The cabin crew thought the noise was something in the cargo hold and there was a sliding or thump type of noise/vibration in the underfloor or rear galley area. The cabin crew also said that it may have been the sound of the aircraft tail possibly contacting the runway.
With this information and the knowledge of the higher rotation rate at take-off, the captain decided that the safest course of action would be to cease the climb and to return to Melbourne for a precautionary engineering inspection. The climb was stopped while the aircraft systems were checked but there were no abnormal indications. The captain took control and was PF for the approach and landing at Melbourne.
The captain advised air traffic control (ATC) that the flight would need to return to Melbourne due to an ‘engineering issue’ and that ‘ops were normal’. The cadet pilot and safety pilot changed seats and the safety pilot became the PM for the return to Melbourne.
After landing, an engineering inspection confirmed that a tail strike had occurred. The captain then advised ATC that a tail strike had occurred.
FDR
Key parameters from the FDR were analysed and are shown in Figure 1.
The aircraft taxied onto runway 27 and the take-off commenced at 1448. The sidestick data shows that the pilot in the right seat (cadet) was the PF. At approximately 40 kt, a nose-down sidestick input was made and this input remained until the aircraft had accelerated to 100 kt. The sidestick pitch input was then neutral until approximately 140 kt when a nose-up input commenced. The nose-up input reached a maximum value of 12.5° or 78 per cent of a full-scale input. The aircraft rotated with a pitch rate of about 9 deg/sec reaching a maximum pitch attitude of 16°. The sidestick input was then reduced and the aircraft’s pitch attitude correspondingly reduced.
The aircraft climbed and levelled at FL226 at 1458. The aircraft returned to Melbourne and landed on runway 27 at 1523. The pilot in the left seat was the PF for the landing.
Figure 1: FDR plot of key parameters
Source: ATSB
Weight and balance
There was no evidence of any anomalies with the aircraft weight and balance. The recorded trim setting for the horizontal stabiliser (+1.4 units nose-down) was in accordance with the centre of gravity documented on the loadsheet. Post-flight checks did not reveal any evidence of cargo load-shifting.
Runway inspection
During take-off, as the aircraft became airborne, the captain and safety pilot observed that the aircraft had flown through ‘about 6 birds or so’. The cadet pilot reported not noticing the birds.
After take-off, the captain advised ATC about the birds but ‘didn’t think that they had hit any’. Later, ATC advised the crew that nothing had been found on the runway. While airborne, the captain did not advise ATC of a possible tail strike as he considered that it was unlikely to have occurred.
After landing, an engineering inspection confirmed that a tail strike had occurred, and the captain then passed on that information to ATC.
Airservices Australia advised that when a bird strike is reported to ATC, a runway inspection is initiated which specifically looks for bird carcasses or any evidence that a bird strike occurred. Arriving and departing aircraft are given the option of continuing their approach or departure, or delaying until the inspection is complete.
When a potential tail strike has been reported, ATC restricts operations on the affected runway, and arranges for a runway inspection to be carried out which looks for runway damage and aircraft debris.
Aircraft inspection
After landing, engineers inspected the tail of the aircraft (Figure 2). Damage to the APU diverter (air inlet) and APU drain mast was evident (Figure 3). This damage was consistent with the aircraft tail contacting the runway surface.
Figure 2: General location of damage
Source: Victor Pody annotated by ATSB
Figure 3: Damage to aircraft tail section (circled). Note: access doors are open for inspection
Source: Operator annotated by ATSB
Weather
Weather information was obtained from the Bureau of Meteorology. Visibility was 10 km or more with a few clouds at 3,000 ft. The automatic terminal information service (ATIS) wind was 300/16[7] with a maximum crosswind of 16 kt.
The operator has a crosswind limitation of 10 kt for cadet pilots. The captain observed the crosswind component using the windsock, while lining up for take-off, and assessed it as a maximum of 10 kt.
There were four anemometers at Melbourne airport which log minimum, maximum and average wind information over a one-minute period. The closest anemometer to the point of rotation was the northern anemometer. The one-minute values were:
For runway 27, a wind of 334 degrees at 11 kt equated to a crosswind from the right of 10 kt.
Other events
The ATSB occurrence database was searched for ground strike events for all aircraft types from 1980 onwards. Fifty-one events were found, 22 occurring on take-off, 26 on landing and the phase of flight was unknown for 3 occurrences. The aircraft type represented most frequently was the B767-300 (13 occurrences) noting that the B767-300 is equipped with a tail skid. There were no other reported occurrences involving an A320 and none involving an A321.
The possibility of a tail strike led the captain to decide to return the aircraft to Melbourne for a precautionary engineering inspection. This analysis will examine the actions of the flight crew and any operational issues that had the potential to affect the flight or other flights.
Rotation
The rotation was initiated at the correct speed and there was no evidence of any anomalies with the aircraft weight and balance, trim setting or any aircraft system.
During rotation, the cadet pilot applied a larger than normal pitch input (3/4 backstick versus the recommended 1/2 to 2/3 of backstick travel) resulting in an excessive pitch rate during rotation (9 deg/sec versus a target of 3 deg/sec).
Following the incident, the cadet pilot undertook additional training and assessment before returning to flight duties.
Risk controls
Pitch monitoring
The independent nature of the sidesticks meant that the training captain could not directly monitor the cadet pilot’s sidestick input. The resultant pitch rate that occurred during the take-off could be monitored and was observed by the captain as being faster than normal. Despite this, the entire rotation period was brief and there was little time for the Captain to respond to an inappropriate pitch input.
Flight data analysis program
The operator routinely monitors flight data through a flight data analysis program. Pitch attitude and pitch rates recorded during rotation are monitored to identify exceedances and operational trends. If an adverse trend is detected then corrective action can be taken (for example through a change to the training syllabus or advice to crew through a newsletter) and the effects of the change(s) monitored.
Runway inspection
Debris poses a hazard to aircraft taking off and landing and ATC should be advised as soon as operationally suitable if a tail strike is suspected. When a possible tail strike has been reported, ATC restricts operations on the affected runway and arranges for a runway inspection to be carried out which looks for runway damage as well as aircraft debris. Metallic debris poses a particular hazard to aircraft tyres.
As well, if debris is identified then this would confirm to the crew while airborne that a tail strike had occurred.
In this case, the pilot advised ATC that they were returning due to an engineering issue, but did not mention that they may have had a tail strike during take-off.
Following this incident, the operator circulated a newsletter to their A320 flight crew highlighting the need to inform ATC of a suspected tail strike or any failure resulting in damage/debris.
Findings
From the evidence available, the following findings are made with respect to the tail strike during take-off involving Airbus A320 VH-VGF at Melbourne Airport, Victoria on 11 May 2016. These findings should not be read as apportioning blame or liability to any particular organisation or individual.
Contributing factor
The cadet pilot applied a larger than normal sidestick pitch input to initiate rotation. This resulted in a high rotation rate during the take-off and the aircraft’s tail contacted the runway.
Other factor
The potential tail strike was not adequately communicated to Melbourne air traffic control. This delayed checking the runway for aircraft debris.
Sources and submissions
Sources of information
The sources of information during the investigation included:
crew interviews
operator’s report
maintenance documents
Bureau of Meteorology weather reports and observations
flight recorders (FDR and CVR).
Submissions
Under Part 4, Division 2 (Investigation Reports), Section 26 of the Transport Safety Investigation Act 2003 (the Act), the Australian Transport Safety Bureau (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 Jetstar, the captain, the cadet pilot, Airbus, Airservices Australia and the Civil Aviation Safety Authority.
Submissions were received from the captain, Airservices Australia and the Civil Aviation Safety Authority. 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
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.
On 22 April 2016, an instructor and student were conducting flight training in a Robinson R22 helicopter, registered VH-MFH (MFH), at Ballina Byron Gateway (Ballina) Airport, New South Wales (NSW). The lesson involved practising transitioning from hovering to forward flight.
On the same morning, the pilot of a Lancair aeroplane, registered VH-XCG (XCG), was conducting a private flight under the instrument flight rules (IFR),[1] from Wedderburn Airport, NSW, to Ballina Airport, with one passenger on board.
At about 1006 Eastern Standard Time (EST), the instructor of MFH broadcast on the Ballina common traffic advisory frequency (CTAF) that they were established on runway 24 and would be conducting low-level operations on the runway for the next 15 minutes.
At about the same time, XCG was approaching Ballina via an area navigation (RNAV) approach to runway 24. The pilot reported that their attention was focused on the newly installed electronic instrumentation and associated navigation system. When the aircraft was descending through about 500 ft on final approach, the pilot sighted a helicopter (MFH) ahead on the runway threshold, and realised they had omitted to select the CTAF and to broadcast an inbound call.
At about 1012, MFH was stationary on the threshold of runway 24, facing along the runway to the south-west. The instructor of MFH communicated with the pilot of another helicopter operating at the aerodrome to arrange mutual separation. Soon after, the pilot of the other helicopter broadcast ‘the plane coming in on runway 24, your intentions?’ There was no response to this transmission.
That call alerted the instructor of MFH to the aeroplane approaching runway 24 (XCG). The instructor looked out of the helicopter door, and sighted XCG, which was behind them on final approach to runway 24, and estimated the aircraft to be about 200 to 500 m away. The instructor immediately took control of the helicopter from the student and vacated the runway to the grassed area north of the runway.
After initially sighting MFH on the runway, the pilot of XCG considered conducting a go-around, but then observed MFH lift off and move to the grass area north of the runway. The pilot of XCG elected to continue the approach, and landed on runway 24.
Safety message
The ATSB SafetyWatch highlights the broad safety concerns that come out of our investigation findings and from the occurrence data reported to us by industry. One of the safety concerns is safety around non-towered aerodromes.
Pilots are encouraged to prioritise their attention carefully and appropriately as they near non-towered aerodromes. An effective lookout for other aircraft, supported by communication with traffic in the vicinity, should be a high priority.
The ATSB report Limitations of the See-and-Avoid Principle outlines the major factors that limit the effectiveness of un-alerted see-and-avoid. Insufficient communication between pilots operating in the same area is the most common cause of safety incidents near non-controlled aerodromes.
Most occurrences reported to the ATSB at non-towered aerodromes involve conflicts between aircraft, or between aircraft and ground vehicles. In particular, active runways should be approached with caution. The ATSB publication A pilot’s guide to staying safe in the vicinity of non-towered aerodromes, stated that a large number of the conflicts between aircraft involved:
ineffective communication between pilots operating in close proximity
the incorrect assessment of other aircraft’s positions and intentions
relying on the radio as a substitute for an effective visual lookout
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 potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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] Instrument flight rules permit an aircraft to operate in instrument meteorological conditions (IMC), which have much lower weather minimums than visual flight rules. Procedures and training are significantly more complex as a pilot must demonstrate competency in IMC conditions, while controlling the aircraft solely by reference to instruments. IFR-capable aircraft have greater equipment and maintenance requirements.
At about 0725 Eastern Standard Time (EST) on the morning of 24 April 2016, the pilot of a Kavanagh Balloons B-400, registered VH-WNV (WNV), prepared to land at Rothbury near Cessnock, New South Wales (Figure 1). On board the scenic flight were the pilot and 16 passengers. The balloon was one of a number of balloons conducting a similar scenic flight that morning.
The pilot had selected a landing site, and informed the ground crew by radio, but the light wind carried WNV, and the other balloons in the group, a little further past this site. The pilot in WNV (and the other balloon pilots) then selected a nearby paddock for landing, and updated the ground crew accordingly. The pilot lined the balloon up to land, but then noticed a small dam along the intended landing path. The pilot manoeuvred the balloon over the dam before turning off the burners, and making a gentle landing.
Figure 1: VH-WNV landing area (green circle)
Source: Airservices Australia: Extract of Sydney World Aeronautical Chart, annotated by ATSB
The manoeuvring over the dam resulted in the balloon being a little closer to the tree line than ideal (Figure 2). Mindful that the ground crew had to pack up the 400,000 cubic foot balloon once the passengers has disembarked, the pilot advised them that they would move the balloon back about 10m further from the trees. To assist with this process, and make the balloon more buoyant, the pilot checked the neck of balloon was still sufficiently open, and then turned on the pilot light of one of the two burners.
Moments later, the pilot again checked the neck of the balloon and noticed the gentle wind had blown part of the deflating balloon back on itself and there was black smoke emanating from this area. The pilot then observed that some of the fabric had melted and had begun to drip onto the occupants of the basket. The pilot quickly re-directed the ground crew from the task of pulling the top of the balloon down, to assisting the passengers disembark and move away to a safe area.
To avoid any potential of the balloon becoming aloft during the disembarkation process, the pilot pulled the smart vent[1] to rapidly release air. The pilot reported it was difficult to assess the extent of the fire from the basket, but they were aware that the balloon envelope ‘sliding’ on itself was adding more fabric as ‘fuel’ to the fire.
The balloon envelope deflated and landed next to the basket. The pilot (still on board) and the ground crew, after ensuring the passengers were safe, discharged fire extinguishers. Within a few minutes, the crew were able to spread the balloon envelope out and extinguish the fire.
During the emergency disembarkation, two of the passengers received minor burn injuries. The lower section of balloon envelope was substantially damaged.
Figure 2: Kavanagh Balloons B-400, VH-WNV at Rothbury
Source: Pilot
Pilot comments
The pilot had logged over 1,330 flying hours, with about 350 hours on the Kavanagh Balloons B‑400.
In hindsight, the pilot advised that the decision to move the balloon back 10 m to assist the ground crew with the collapse and pack-up of such a large balloon was not the correct one. Other balloons landing nearby did not attempt to move their balloons away from the tree line.
Safety message
This occurrence highlights how quickly events may change. The simple decision by an experienced pilot to move the balloon back 10 m from the tree line to assist the ground crew inadvertently led to a fire.
The Federal Aviation Administrations’ (FAA) comprehensive Balloon Flying Handbook (2008) covers all aspects of balloon flying including aeronautical decision-making. Aeronautical decision-making is a systematic approach to the mental process used by pilots to determine the best course of action in response to a given set of circumstances. It builds on the foundation of conventional decision-making but enhances the process to decrease the probability of pilot error.
As almost all ballooning operations are conducted as single-pilot operations, ballooning uses a variant of crew resource management, known as single-pilot resource management. This integrates:
human resources
situational awareness
decision-making process
risk management
training.
One way in which the risk management decision path can be framed is through the perceive-process-perform model, which offers a structured way to manage risk.
– consequences posed by each hazard – alternatives that eliminate hazards – reality (avoid wishful thinking) – external factors (‘get-home-itus’).
Perform risk management:
– transfer – can someone be consulted? – eliminate – can hazards be removed – accept – do benefits outweigh risk? – mitigate – can the risk be reduced?
Other decision-making models are also covered in the manual.
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 potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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.
