Loss of control

Cessna U206F, VH-STL

Significant Factors

  1. Weather conditions at Horn Island aerodrome were less than visual meteorological conditions at the time of the occurrence.
  2. The pilot was not current for flight in IMC.
  3. The pilot lost control of the aircraft at an altitude from which recovery was not considered possible.



 

Summary

The pilot of a Cessna 206 (C206), departed from Badu Island, Qld at about 1210 Eastern Standard Time (EST) on a positioning flight to Horn Island, Qld in accordance with the visual flight rules (VFR). The aircraft had an estimated fuel endurance of 270 minutes. The pilot, who was the sole occupant, had been tasked to conduct a charter flight from Horn Island at 1330 with passengers who were reported as arriving on a scheduled flight from Cairns.

At about 1221 the pilot broadcast on the Torres Mandatory Broadcast Zone (MBZ) frequency that he was over Wednesday Island and tracking for a 3 NM final approach to runway 26 at Horn Island. A short time later he broadcast that he was holding until the weather over the runway cleared. At about 1238 the pilots of two aircraft in the Bamaga area reported hearing a MAYDAY broadcast from the pilot of the C206 on the MBZ frequency. The pilot did not describe the nature of the emergency. Further efforts by the pilots operating in the Bamaga area to contact the pilot of the C206 were unsuccessful and they advised air traffic services of the MAYDAY they had heard on the MBZ frequency.

An air and sea search was commenced. Later that day floating debris, identified as belonging to the C206, was located. The recovered items included the left main wheel and landing gear leg, the nose wheel and part of the nose gear landing leg and a seat. The following day divers located the aircraft approximately 3 NM east of Horn Island in 7 m of water but the pilot was not found.

The aircraft was recovered from the sea floor where it had been submerged for just over two days. It had been extensively damaged by impact forces. The nature of the recovery process resulted in further disruption of the wreckage. The outer left wing, left aileron and the engine cowls were not recovered. Salt-water corrosion had affected many of the aircraft components. The flaps were found in the retracted position and damage to the propeller blades was consistent with low engine power at the time of impact. Damage was consistent with the aircraft having struck the water at a moderate to high speed in a nose-down, left wing low attitude. The collision with the water was not survivable.

Examination of the damaged gyroscopic flight instruments did not reveal any indication of pre-impact malfunction. The vacuum pump was found in good condition and capable of normal operation. Although the aircraft was equipped with appropriate instrumentation for flight in instrument meteorological conditions (IMC) it was maintained to the VFR standard, as appropriate to the category of operation. Maintenance requirements were certified as having been performed and no evidence was found to indicate that the aircraft was other than serviceable prior to the flight. Analysis of recorded audio data determined that engine operation was normal during the pilot's radio transmissions.

The pilot was reported to have obtained a forecast from Airservices electronic briefing facility using the company computer terminal at Badu Island. That forecast predicted north-westerly stream weather characteristic of conditions normally experienced during the wet season in the Torres Strait area between October and April. The terminal area forecast for Horn Island, valid from 0600 to 1800, indicated light showers of rain and a visibility greater than 10 km. Throughout the forecast period, a temporary deterioration in conditions (up to 60 minutes) was forecast due to thunderstorms, with visibility reduced to 2000 m in rain and a cloud base of 800 ft. Approximately 40 minutes before he departed Badu Island, the pilot received a telephone call from the senior base pilot. The senior base pilot had flown from Badu Island to Horn Island that morning and advised him of the actual weather conditions he had encountered, including 20 minutes holding east of Horn Island while awaiting a rain shower to move from over the aerodrome.

Witnesses reported that the weather conditions at Horn Island aerodrome between 1230 and 1245 were less than visual meteorological conditions. Heavy rain had reduced visibility to less than 100 m. One witness reported seeing lightning to the north of the aerodrome. A Bureau of Meteorology assessment of weather conditions for the area east of Horn Island at the time of the occurrence indicated that the generally low overcast cloud contained embedded thunderstorm cells, with associated heavy rain and a cloud base less than 1,000 ft. The recorded rainfall intensity was heaviest between 1230 and 1300. Weather conditions at Horn Island at the time of the occurrence were described by witnesses as being the most severe seen that season.

The pilot held a Commercial Pilot (Aeroplane) Licence and a valid Class 1 medical certificate. He had obtained his commercial pilot licence in September 2000 and qualified for a command multi-engine instrument rating in April 2001. The pilot's logbook was not found. A compilation of flight time records showed that at the time of the occurrence the pilot had between 270 and 290 hours total flying experience that included approximately 45 hours on type. The company did not require the pilot to maintain IFR currency there was no evidence that the pilot had met recency requirements for instrument flight. The pilot was not reported to be suffering from any physiological condition that may have affected his capability as a pilot. He had been off duty for the two days prior to commencing duty on the morning of the accident.

In July 2001 the pilot moved to the Torres Strait area and gained some occasional flying experience with another operator. In November 2001 the pilot commenced employment with the operator he was working for at the time of the accident as a VFR charter pilot on C182 and C206 aircraft. On 19 November 2001, before commencing operational duties, the pilot had flown a familiarisation flight under supervision of the senior base pilot. On 27 November he had demonstrated proficiency on the C182 in normal and emergency procedures to an approved company check pilot. That flight of one and a half hours also incorporated a short area familiarisation. The pilot was then certified as competent to conduct company charter flights. On 1 December 2001 he flew the C206 while acting in-command under the supervision of the senior base pilot.

The flight was being conducted under the VFR, at an altitude that required the aircraft to remain clear of cloud, and with a minimum flight visibility of 5,000 m. The operator's operations manual instructed pilots to consider uplifting additional fuel for diverting or holding when the forecast indicated elements of weather below the minimum required for the flight. The pilot had departed with ample fuel reserves for holding or diverting. Company pilots reported that diversions and holding, due to rain showers and associated poor visibility, were not unusual during the wet season. The pilot had broadcast his intention to hold until weather conditions improved.

Although the pilot of the C206 had flown in IMC during his training he did not have any instrument flight recency and had very little exposure to tropical wet season weather conditions and its characteristic heavy rain shower activity.

The circumstances of the occurrence were consistent with a loss of control at low level and at an altitude from which recovery was not considered possible. Due to the limited information available to the investigation, the reason for the loss of control could not be determined. However, the circumstances were consistent with VFR flight into IMC.

Occurrence summary

Investigation number 200200035
Occurrence date 11/01/2002
Location 9 km E Horn Island, Aero.
State Queensland
Report release date 24/09/2002
Report status Final
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Loss of control
Occurrence class Accident
Highest injury level Fatal

Aircraft details

Manufacturer Cessna Aircraft Company
Model 206
Registration VH-STL
Serial number U20603389
Sector Piston
Operation type Charter
Departure point Badu Island, QLD
Destination Horn Island, QLD
Damage Destroyed

Messerschmitt BK117 B-2, VH-BKZ

Summary

The pilot of a BK117 helicopter reported that while in a gentle climb at about 4,600 feet during a post maintenance test flight, the helicopter suddenly pitched nose-up. The indicated airspeed decreased to zero and the helicopter then pitched nose-down to a slightly inverted attitude. After descending about 2,000 feet, the pilot regained control and landed safely.

Inspection of the helicopter systems by the company maintenance personnel could not find any reason for the sudden loss of control.

A Bureau of Meteorology area forecast, issued on the day of the incident, indicated severe turbulence below 10,000 feet. The forecast also included increasing westerly wind speeds ranging from 30 knots at 2,000 feet to 45 knots at 10,000 feet. The actual weather report for the area that the helicopter was operating in, indicated westerly wind speeds increasing from 35 knots at 2,000 feet to 50 knots at 7,000 feet. These conditions are conducive to mountain wave and rotor activity.

A rotor is a large air mass rotating about a substantially horizontal axis. It is generated in the lee of a mountain or sharp ridge in strong wind conditions.

The helicopter was operating on the lee side of a mountain range when the pilot experienced the rapid loss of control. It is probable that the helicopter encountered a rotor.

Occurrence summary

Investigation number 200003143
Occurrence date 17/07/2000
Location 9 km E Warragamba Dam, (VTC Check Point)
State New South Wales
Report release date 03/05/2001
Report status Final
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Loss of control
Occurrence class Accident
Highest injury level None

Aircraft details

Manufacturer Messerschmitt-Bolkow-Blohm
Model BK117
Registration VH-BKZ
Serial number 7213
Sector Helicopter
Operation type Aerial Work
Departure point Bankstown, NSW
Destination Bankstown, NSW
Damage Substantial

Cessna A185F, VH-TLO

Summary

The Cessna 185 (C185) aircraft had returned and landed at the departure aerodrome after completing a charter flight of approximately 90 minutes duration. The pilot reported that following a normal landing and after the tail wheel had been lowered to the runway, the aircraft nose commenced to yaw to the right. The pilot estimated that the aircraft was travelling at about 20 kts and despite applying full rudder and the use of differential braking it was not possible to regain directional control and the aircraft ground-looped. The left main gear-leg collapsed and the outboard portion of the left wing was substantially damaged when it struck the surface of the runway. The propeller also was damaged on contact with the runway. The pilot and three passengers were not injured and vacated the aircraft without assistance.

The pilot had been endorsed on the aircraft approximately one week before the accident. Although he had significant experience operating other tail-wheel equipped aircraft, he had logged only 18 hours on the C185. The majority of that experience had been accumulated while ferrying the aircraft from Moorabbin to Broome.

Following the accident, archived data from the Broome automatic weather station was retrieved from the Bureau of Meteorology. The data indicated that at the time of the accident a southerly wind was blowing with wind gusts recorded up to 11 kts. Analysis of the data indicated that the pilot could have encountered a right crosswind of up to 10 kts during the landing. That was within the aircraft manufacturer's demonstrated crosswind limit of 15 kts.

The aircraft centre of gravity was calculated to have been within published limits. However, it was close to the aft limit, thereby making directional control more difficult in the gusting crosswind conditions.

The weather conditions prevailing at the time of the accident would have made the aircraft more difficult to control, especially during the later stages of the landing roll as the aircraft slowed down and the rudder became less effective. Directional control at lower speeds becomes increasingly dependent on tail-wheel steering and the use of differential braking. The directional instability would have been further exacerbated with any sudden increase in crosswind component due to the gusty crosswind conditions.

Occurrence summary

Investigation number 200002700
Occurrence date 27/06/2000
Location Broome, Aero.
State Western Australia
Report release date 27/09/2001
Report status Final
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Loss of control
Occurrence class Accident
Highest injury level None

Aircraft details

Manufacturer Cessna Aircraft Company
Model 185
Registration VH-TLO
Serial number 18503658
Sector Piston
Operation type Charter
Departure point Broome, WA
Destination Broome, WA
Damage Substantial

Cessna 172R, VH-EWO

Summary

The pilot of the Cessna 172R had planned a private flight, with three friends, from Moorabbin via Williamstown, Laverton, Melton and Torquay before returning to Moorabbin. Before departure, the pilot arranged for the fuel load on the aircraft to be adjusted in order to ensure that the aircraft did not exceed its maximum allowable weight limit. The aircraft departed Moorabbin at about 1350 Eastern Summer Time.

Witnesses, including some with relevant aviation experience, reported seeing the aircraft conducting steep turns south of Melton township, north-east of Melton aerodrome, north of Gisborne and in the vicinity of the accident site. This information is consistent with photographs taken from the aircraft during the flight.

Radar information indicated that between 1432 and 1435, the aircraft was flown in a sequence of left turns through 360 degrees in the vicinity of the accident site. These turns were conducted at an altitude of between 1,900 ft and 2,300 ft above mean sea level (approximately 550 to 950 ft above ground level).

Witnesses reported that after completing two 360 degree left turns in the vicinity of the accident site, the aircraft headed north and adopted a nose-high attitude before entering a steep turn to the left. Most of the witnesses, including an experienced pilot, described seeing the aircraft's bank angle steepen as it passed a westerly heading and then the nose dropped such that the aircraft was heading approximately south in a near vertical, nose-down attitude. However, one witness described seeing the aircraft roll in a right-wing-over-left manoeuvre before it pitched nose-down.

One witness reported seeing the aircraft spiral to the ground however most witnesses saw it descend straight to the ground in a nose-down, near vertical attitude. Witness reports and wreckage evidence indicated that the aircraft impacted the ground heading approximately south and in a nose-down, right wing low attitude. The aircraft, which was destroyed by the impact, came to rest approximately 27 m from the initial impact point. There was no fire. The occupants received fatal injuries.

The wreckage was located in a paddock approximately 400 m north of the Gisborne-Kilmore Road, approximately half-way between Gisborne and Riddells Creek. The residence of one of the passengers was less than 1 km from the accident site. The elevation of the accident site was about 1,350 ft and Mount Macedon (3,284 ft) was 11 km to the north-north-west. The damage indicated that the engine was producing power and that the flaps were extended to approximately 10 degrees at the time of impact. The investigation did not identify any pre-existing defects that could have affected the operation of the aircraft.

Coordinated use of aileron, elevator and rudder controls will ensure that an aircraft maintains balanced flight. Discussions with the US Federal Aviation Authority (FAA) indicated that the Cessna 172 aircraft will exhibit mild stall characteristics if the aircraft stalls during balanced flight, and a pilot can regain control of the aircraft with a minimal loss of height. Most aircraft would require significantly more height above the ground to allow a pilot to recover control following a stall during unbalanced flight.

The Cessna Integrated Flight Training System Manual of Flight stated that a stall during a steep turn will result in a sharp nose and wing drop and that recovery actions must be prompt and precise.

The pilot held a private pilot licence and was endorsed on the aircraft type. He had completed spin recovery training, however the training was conducted in a different aircraft type. The pilot had accrued approximately 68 hours total flying experience. The post-mortem and toxicological examination did not identify any pre-existing conditions that could have affected the pilot's ability to fly the aircraft.

At the time of the accident the prevailing weather conditions were fine with scattered high level cloud. The Kilmore Gap automatic weather observation taken at 1430 indicated that the wind was 340 degrees at 19 kts gusting to 27 kts. The observation taken at Melbourne's Tullamarine airport at 1431 indicated that the wind was 360 degrees at 15 kts gusting to 27 kts and that the temperature was 33 degrees Celcius. During strong, gusting wind conditions such as existed at the time of the accident, hills and mountains can induce severe turbulence and downdraughts.

The aircraft was probably operating in turbulent conditions at the time of the accident, given the location of Mount Macedon upwind of the accident site. The manoeuvre described by witnesses was consistent with the aircraft stalling during the steep left turn. It is likely that the aircraft's reduced performance in the ambient temperature and the gusty and turbulent conditions contributed to the stall. In addition, the turbulent conditions would have made it very difficult for the pilot to maintain the aircraft in balanced flight during the sequence of steep turns. The loss of control following the stall and the pilot's failure to recover control in the height available was consistent with the stall occurring during unbalanced flight.

Occurrence summary

Investigation number 199905698
Occurrence date 01/12/1999
Location 6 km NE Gisborne
State Victoria
Report release date 05/04/2000
Report status Final
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Loss of control
Occurrence class Accident
Highest injury level Fatal

Aircraft details

Manufacturer Cessna Aircraft Company
Model 172
Registration VH-EWO
Serial number 17280172
Sector Piston
Operation type Private
Departure point Moorabbin, VIC
Destination Moorabbin, VIC
Damage Destroyed

Cessna U206G, VH-EOY, Wrotham Park Aerodrome, Queensland, on 20 October 1999

Summary

The pilot of a Cessna 206 aircraft, and two passengers, were returning to Weipa from Rockhampton.

They departed Rockhampton at about 1130 Eastern Standard Time on the day before the accident, and landed to refuel at Charters Towers. Witnesses reported that the pilot seemed to be in a hurry and had stated his intention to fly to Weipa that day.

The pilot subsequently encountered severe smoke haze during the flight. Reduced visibility in the smoke haze made visual navigation difficult. Shortly before last light, the pilot saw an airstrip at the pastoral property "Wrotham Park" and landed the aircraft. The pilot believed he had landed at "Bellvue" until he was informed of the correct location. The manager of "Wrotham Park" provided food and overnight accommodation for the pilot and passengers.

At first light the following morning, the pilot taxied the aircraft for take-off from runway 24. While the aircraft was taxiing, the station manager noticed that a bag belonging to one of the aircraft occupants had been left behind. He drove out to the aircraft and handed the bag to the pilot, who had left the aircraft to collect it. Soon after, the pilot began the take-off.

The aircraft was heard to take-off, followed by the sound of impact.

Examination of the wreckage and assessment of the flight path and impact sequence determined that shortly after lift-off the aircraft yawed and rolled to the left, and began to descend. The leading edge of the left wing struck a powerline 8 m above the ground and about 100 m south-east of the runway centreline. The aircraft then cartwheeled through the top of a building, and its right side struck the ground while travelling slowly rearwards. It came to rest on its right side, about 5 m from the building and about 130 m south-east of the runway centreline. The passengers, who occupied the right seats of rows one and two, were seriously injured. The pilot was fatally injured.

One of the passengers later recalled hearing the stall warning activate shortly after lift-off.

The right wing had been severed and the windscreen shattered; however, the cockpit and cabin were almost intact. The wreckage examination did not reveal any pre-impact technical defect that may have contributed to the accident. Tests on fuel removed from the aircraft tanks found it to be free of the contaminant ethylene diamine.

Rescuers reported that the pilot was not restrained by a seat belt when they arrived at the accident site.

Civil Aviation Safety Authority records indicated the pilot's medical certificate was current. The autopsy and toxicology analysis on the pilot did not reveal any pre-existing medical condition that may have contributed to the accident.

The airfield at Wrotham Park was unlicensed. The field was 500 ft above mean sea level, and consisted of a single runway, 915 m in length, designated 06/24. The surface was gravel and was in good condition at the time of the accident. There were no obstructions affecting the approach or departure flight paths in either direction.

The Bureau of Meteorology assessed the weather conditions at the time of the accident as fine with a light breeze of less than 5 kts from the north-north-east. Visibility was assessed as good but with a small chance of patches of fog. Visibility in fog, if present, was assessed as approximately 500 m.

The pilot had flown about 22 hours in the aircraft, having purchased it 6 weeks before the accident. He had no prior experience on the aircraft type. The runway at Wrotham Park was both the shortest, and the first gravel runway the pilot had used in this aircraft. The pilot apparently did not fasten his seatbelt after collecting the bag, indicating that he may have been under some stress, possibly because he was concerned about the delay in his return to Weipa.

Why the pilot lost control of the aircraft during the take-off could not be determined.

Occurrence summary

Investigation number 199904898
Occurrence date 20/10/1999
Location Wrotham Park, Aero.
State Queensland
Report release date 19/09/2000
Report status Final
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Loss of control
Occurrence class Accident
Highest injury level Fatal

Aircraft details

Manufacturer Cessna Aircraft Company
Model 206
Registration VH-EOY
Serial number U20605933
Sector Piston
Operation type Business
Departure point Wrotham Park, QLD
Destination Weipa, QLD
Damage Destroyed

Britten Norman Ltd BN-2A-26, VH-XFF

Safety Action

As a result of this occurrence, the Australian Transport Safety Bureau (formerly BASI) is investigating a possible safety deficiency 19990038 that relates to the security of airfields in the Torres Strait against public access.

Any safety output issued as a result of the analysis of safety deficiency 19990038 will be published in the Bureau's Quarterly Safety Deficiency Report.

Significant Factors

  1. The pilot initiated a go-around from final approach because of a vehicle on the airstrip.
  2. The left propeller showed little evidence of rotation damage. The reason for a possible loss of left engine power could not be determined.
  3. For reasons that could not be established, the pilot lost control of the aircraft at a low height.

Analysis

The flight

The flight apparently proceeded normally until late final approach when the pilot initiated a go-around because of a vehicle on the airstrip. There were clear indications from the wreckage examination that the aircraft was rolling and yawing left at impact. The status of the left engine at impact logically supported such aircraft behaviour. While the witness description of the aircraft initially veering left also supported this conclusion, the report that the aircraft rolled right immediately before impact did not. In the asymmetric power and low speed situation that existed, it was most unlikely that the aircraft could have rolled right. On balance, therefore, the direction of roll as recalled by the witnesses was incorrect.

Whether the vehicle entered the airstrip during the latter stage of the aircraft's approach, or whether it was on the airstrip and the pilot expected it to move, was not determined. However, the position of the wing flaps at impact suggested that the pilot had selected full flap, and that the flaps subsequently did not move from this position. This implied that the pilot had been committed to land and that the aircraft speed was at, or less than, 65 kts.

Under normal circumstances, a go-around with both engines operating would have been a relatively basic procedure for the pilot to conduct. Because there was no apparent earlier action or radio call, it is unlikely that the pilot was aware of an asymmetric engine condition until the go-around was initiated. When the asymmetric power condition arose, the pilot's task was complicated by a number of aspects:

  1. the aircraft was at low level, and probably low speed, when the go-around was initiated. This would have provided minimal opportunity for the pilot to lower the nose of the aircraft to increase airspeed and hence aircraft controllability;
  2. depending on the exact position of the aircraft when the go-around was initiated, the pilot may have had to manoeuvre away from the sand dune and coconut palms on the southern side of the strip;
  3. the pilot had to deal with the control forces associated with the asymmetric power condition, in addition to those associated with the engine power increase;
  4. to retract the flaps to the take-off position, feather the left propeller, and adjust the elevator and rudder trims would have required the pilot to fly the aircraft with her left hand while conducting these other tasks with her right hand. Completion of these tasks may have been difficult, if not impossible, in that control of the aircraft may have required the pilot to use two hands on the control yoke to overcome the out-of-trim forces;
  5. the pilot's stature, seating position as altered by the cushions she normally used, and the position to which the rudder pedals had been adjusted, may have affected her ability to manipulate the aircraft controls to the extent necessary to maintain control of the aircraft;
  6. at a speed of 60 kts, the aircraft would have taken about 7 seconds to travel from overhead the witnesses at the eastern end of the island direct to the impact position. While the actual aircraft track was not established, this timeframe was probably indicative of the period available for the pilot to recognise the situation, evaluate available options, decide what action should be taken, and initiate that action; and
  7. the north-westerly wind would have exacerbated any tendency for the aircraft to drift left as a result of the asymmetric power situation.

These influences would have placed the pilot under an extreme combination of workload and stress and may have affected her decision-making and flying ability.

An alternative course of action available to the pilot was to overfly the vehicle and land the aircraft on the remaining section of strip. Another was to reduce power on the right engine and conduct an emergency landing on the tidal flat area. However, without accurate information concerning the position and altitude of the aircraft when the go-around was initiated, no positive conclusions could be drawn concerning these options.

Wreckage examination

The pre-impact position of the carburettor heat controls for both engines could not be positively determined. It is possible for ice to have formed in one carburettor and not the other. If ice was present in the left engine carburettor during the approach, it was unlikely to have been evident to the pilot because the engine was probably operating at low power. Such a condition could have caused the engine to fail to respond at the commencement of the go-around. Because of the saltwater corrosion damage, it was not possible to assess the pre-accident condition of the carburettor. It is also possible that aggressive throttle operation by the pilot at the commencement of the go-around could have affected normal engine operation. In summary, there was insufficient evidence to reach a positive conclusion concerning the operation of the left engine.

Examination of the aircraft wreckage did not reveal any evidence to link the circumstances of the accident with the defects listed in ASR 111642, or those subsequently rectified on 2 January 1999. Further, no evidence was found of any aircraft unserviceability being reported and/or recorded between 2 January and the accident flight.

Factual Information

History of the flight

Uzu Air conducted passenger and freight operations between Horn Island and the island communities in the Torres Strait. It operated single-engine Cessna models 206 and 208 aircraft, and twin-engine Britten Norman Islander aircraft.

On the morning of the accident, the pilot flew a company Cessna 206 aircraft from Horn Island to Yam, Coconut, and Badu Islands, and then returned to Horn Island. The total flight time was about 93 minutes.

The pilot's schedule during the afternoon was to fly from Horn Island to Coconut, Yam, York, and Coconut Islands and then back to Horn Island, departing at 1330 eastern standard time. The flight was to be conducted in Islander, VH-XFF. Three passengers and about 130 kg freight were to be carried on the Horn Island - Coconut Island sector. Another company pilot had completed three flights in XFF earlier in the day for a total of 1.9 hours. He reported that the aircraft operated normally.

Witnesses at Horn Island reported that the preparation for the flight, and the subsequent departure of the aircraft at 1350, proceeded normally. The pilot of another company aircraft heard the pilot of XFF report 15 NM SW of Coconut Island at 3,500 ft. A few minutes later, the pilot reported downwind for runway 27 at Coconut Island. Both transmissions sounded normal.

Three members of the Coconut Island community reported that, at about 1410, they were on the beach at the eastern extremity of the island, about 250 m from the runway threshold and close to the extended runway centreline. Their recollections of the progress of the aircraft in the Coconut Island circuit are as follows: the aircraft joined the downwind leg and flew a left circuit for runway 27; the aircraft appeared to fly a normal approach until it passed over their position at an altitude of 200-300 ft; and it then veered left and commenced a shallow climb before suddenly rolling right and descending steeply onto a tidal flat, about 30 m seaward from the high-water mark, and about 200 m from their position.

Injuries to persons

InjuriesFatalSeriousMinorNoneTotal
Crew1---1
Passenger21--3
Ground-----
Total31--4

Damage to aircraft

Severe disruption to the outer right wing and nose sections occurred as a result of impact forces. Less significant damage occurred to the outer left wing leading edge. The fuselage fractured just aft of the wing trailing edge. The wing attachment points failed, allowing the wing to rotate forward and partially crush the cockpit/forward cabin area. There was a compression fracture of the upper surface of the left horizontal stabiliser near the inboard end. The outboard end of the left stabiliser had been bent upwards by ground impact.

Other damage

There was no other damage.

Personnel

  • Pilot
     

    Age:27
    Licence category:Commercial
    Medical certificate:Class 1 (valid to 27 June 1999)
    Instrument rating:Command Multi Engine
    Total flying hours:2,540
    Total on type:197
    Total last 90 days:205
    Total last 24 hours:2
    Last flight check:12 November 1998

     

     
  • Flying experience and qualifications
    The pilot began flying in 1990 and gained a Private Pilot (Aeroplane) Licence on 21 March 1991. She was issued with a Commercial Pilot Licence on 18 August 1994 and gained a Command Multi-engine Instrument Rating on 21 October 1996. On 1 February 1995, the pilot qualified as a Grade 3 Fixed Wing flying instructor, and gained a Grade 1 instructor rating on 25 September 1997. She was issued with a multi-engine training approval on 30 March 1998.

    As well as being qualified to fly Islander aircraft, the pilot held endorsements on a number of other twin-engine aircraft, including Aero Commander, Beechcraft Baron, Cessna 310, Piper's Navajo, Seneca, and Seminole.

    The pilot completed her endorsement on the Islander on 10 September 1998 and a proficiency check on 16 September 1998. The endorsement and check reports indicated that the pilot operated the aircraft at a high standard, and was disciplined and thorough with checks and procedures. No significant deficiencies were recorded. The training included asymmetric handling sequences, one of which was a simulated single-engine go-around from final approach with the wing flaps at the take-off position.

    The pilot completed airfield checks at a number of airstrips in the Torres Strait, including Coconut Island, on 12 November 1998.

  • Seven-day history
    The following summary of the pilot's flight and duty times was taken from company records:

    DateDuty hoursFlight time (hours)
    9 January0630-18004.1
    10 Januaryday offnil
    11 January1200-1800nil
    12 January0700-18004.8
    13 Januaryreservenil
    14 January0700-18307.3
    15 Januaryday offnil

    Associates of the pilot reported that she appeared in good health on the morning of the accident.

  • Seat cushions
    The pilot was approximately 157 cm tall. The operator reported that the pilot used two foam-rubber cushions (one on the seat and the other against the seat back) to adjust her seating position to enable her to achieve full movement of the cockpit controls. The seat cushions normally used by the pilot were not found. No person was found who could recall the pilot taking the cushions to the aircraft before the flight. However, the cushions were not at the company office where they were usually stored when not in use. Assuming they were on the aircraft, it is likely that they were lost as a result of the post-accident tidal and/or wind action.

Aircraft information

  • Significant particulars
     

    Registration:VH-XFF
    Manufacturer:Britten Norman Pty Ltd
    Model:BN2A-26 Islander
    Serial number:C763
    Country of manufacture:United Kingdom
    Engines:Lycoming O-540-E4C5
  • Certificate of airworthiness
     

    Number:CS/34
    Issued:18 December 1989
    Category of operation:Normal
  • Certificate of registration
     

    Holder:Uzu Air Pty Ltd
    Number:CNS/00034/04
    Issued:6 January 1994
  • Maintenance release
     

    Number:285070
    Issued:5 December 1998
    Valid to:5 December 1999
    Total airframe hours:16,775.3 hrs
  • Weight and balance
    The aircraft weight at the time of the occurrence was about 2,759 kg. The maximum allowable take-off weight was 2,994 kg. The centre of gravity was within limits.
  • Maintenance history
    An examination of the maintenance history of XFF revealed that the aircraft had been inspected on 6 November 1998 by an airworthiness officer from the Civil Aviation Safety Authority. As a result of the inspection, Aircraft Survey Report (ASR)111642 was issued to the maintenance organisation. The report listed five Code B and one Code C defects. Persuant to Civil Aviation Regulation 38(1) the maintenance organisation was required to assess and rectify Code B defects as necessary. CASA form ASSP 604 states that "An endorsement of the maintenance release in accordance with Civil Aviation Regulation 50 may be required". Yes and no boxes, on the Aircraft Survey Report (ASR)111642 dated 6 November 1998, to indicate whether maintenance release endorsement was required, were not entered. Code C defects constitute "a contravention of requirements imposed under the Civil Aviation Regulations" and were required to be assessed and rectified as necessary.

    The defects were:

    • an oil leak in the left engine - Code B;
    • the left landing gear torque links were worn at the pivot points - Code B;
    • cracks in the left landing gear cowling - Code B;
    • surface corrosion on the underside of the left wingtip - Code B;
    • a broken bonding wire on the right flap - Code B; and
    • there was no load limitation placard on the rear baggage door - Code C.

    The aircraft logbook recorded that the last Schedule 5 (100 hourly) maintenance on the aircraft was completed on 5 December 1998. There was no record that the defects notified in ASR 111642 had been rectified during the maintenance. The engineering manager had certified an entry in the logbook regarding the inspection. It stated that there were no defects noted during the maintenance. The aircraft was flown the following day.

    An entry in the aircraft logbook dated 02 January 1999 listed the following maintenance actions:

    • An oil leak from the left engine was rectified by the removal of the engine sump, replacement of the sump gasket and re-fitment of the sump assembly.
    • Surface corrosion on the left-wing tip was repaired.
    • Stop drilling was conducted to control cracks in the left main landing gear leg fairing.
    • A left engine cowl latch was replaced.
    • Both left and right magnetos on the left engine were replaced with overhauled units. This was done for convenience as the replaced units were approaching the end of their in-service lives.
    • The left engine lower mounts were replaced.
    • The engine dual tachometer (RPM) instrument was repaired and refitted to the aircraft.
    • Support brackets were fitted to the left engine exhaust.
    • Bonding wire on the right-hand flap was replaced.
    • The right engine starter was lubricated.
    • Engine intake ducting to the left engine was replaced because of oil contamination.

    There was no record of any maintenance being conducted on the left landing gear torque links.

    At the time the maintenance was carried out, the aircraft had completed 19.6 flying hours since the issue of the maintenance release on 5 December 1998. The aircraft then completed a further 43.9 flying hours before the commencement of the accident flight. There was no record of any maintenance action being undertaken during this intervening period relating the rectification actions or any other matter.

Meteorological information

The Bureau of Meteorology advised that the probable weather at Coconut Island around the time of the accident was as follows:

  • Isolated to scattered showers, and isolated thunderstorms;
  • North-westerly wind at about 15 kts;
  • Generally good visibility but reducing in precipitation; and
  • Broken cumulus cloud with a base at 2,000 ft, with broken higher layers.

At 1400, the automatic weather station at Coconut Island recorded an ambient temperature of 30 degrees Celsius, a dew point of 25 degrees Celsius, and an atmospheric pressure of 1007 hectopascals. Witnesses at the island reported that the weather was fine at the time of the accident, with the wind gusting from the northwest.

Aids to navigation

Not relevant

Communications

The pilot was communicating on the area frequency of 120.3 MHz during the flight. The pilot of another aircraft heard transmissions from the pilot of the Islander on that frequency.

Aerodrome information

Coconut Island is about 110 km NE of Thursday Island. The island is composed of coral sand and is predominantly flat. It extends east-west for about 1.75 km, and is less than 0.5 km across, north-south, at its widest part. The airstrip occupies the eastern portion of the island and is aligned east-west. It is 880 m long, 60 m wide and composed of grassed coral sand. On the southern side of the strip, and extending for most of its length, is a sand dune approximately 5 m high with coconut palms growing on it.

The threshold for runway 27 is about 350 m from the eastern extremity of the island. At the time of the accident, the local refuse tip was situated between the end of the strip and the eastern extremity of the island, and north of the extended centreline of the runway. A dirt road linked the community living area and the refuse tip. The road followed the southern side of the strip to the eastern end before turning north towards the refuse tip area.

Flight recorders

The aircraft was not equipped with flight data or cockpit voice recorders, nor was such equipment required by regulation.

Wreckage examination

The wreckage was subjected to tidal saltwater immersion for 3 days before it was examined.

  • Airframe
    An examination of the airframe did not reveal any fault that might have contributed to the accident. All flying controls were capable of normal operation prior to impact. The wing flaps were in the full-down position at impact. The right-wing fuel tank had been ruptured by the impact, while the left-wing tank was intact. A significant quantity of fuel remained in the left tank.
  • Cabin
    The pilot's seat was mounted on a frame attached to the cabin floor. The seat could be adjusted fore and aft on the frame, but there was no vertical adjustment. During the impact, the frame partially collapsed down and towards the right. The seat was locked in the full-forward position. The pilot's lap-sash harness assembly remained intact during the impact.

    The rudder pedals were adjustable fore-aft into a locked position as selected by the pilot. The rudder pedals on the left side of the cockpit were locked one notch forward of the rearmost position. Damage indicated that the pedals were locked in that position at impact.

    The cabin was fitted with four bench-type passenger seats, each capable of seating two persons. The seat frames were secured to the floor. Two lap safety harnesses were attached to each seat frame.

    At the initial examination of the wreckage, there were no passenger seats in the cabin. All seats had been removed from the cabin during the rescue activities. One seat, found above the high-water mark, was recovered for examination. The remaining seats were not found and probably disappeared as a result of tidal action.

    Those involved in the initial response following the accident indicated that one seat remained attached to the cabin floor and was levered free with a crowbar. The remaining seats were loose, apparently after becoming detached during the impact sequence. Examination of the seat attachment points indicated that the first, second and third row seat frames had failed due to impact induced stresses. There was significant bending forward and to the right. Examination of the seat found above the high-water mark indicated that it was the rear seat that had been levered from the floor during the rescue activities.

    Apart from the two safety harnesses attached to the rear seat, only one-half of one other passenger harness was recovered. A section of a broken seat attachment bracket remained attached to the harness. The original location of the harness piece could not be determined.

  • Engines and propellers
    Both engines and propellers were recovered from the accident site and examined. Disruption of the airframe prevented determination of the position of the engine controls at impact.

    The right propeller exhibited signs of severe tip curl and leading-edge abrasion, consistent with the engine developing high power at impact. Examination of the engine did not reveal any condition likely to have prevented normal engine operation. Salt-water corrosion damage prevented a detailed examination of the carburettor.

    The left propeller showed little evidence of rotational damage. The propeller had not been feathered. Laboratory examination of a failure of the left engine mixture control rod confirmed that the failure occurred at impact as a result of impact induced stresses. Examination of the engine did not reveal any condition likely to have prevented normal operation. After sand and other internal debris were removed, the magnetos were bench run for more than 30 minutes. They functioned normally during that period. The condition of the carburettor prevented confirmation of its serviceability at impact.

  • Carburettor heat system
    The left and right carburettor heat control levers were mounted on the lower quadrant of the cockpit centre pedestal. Both levers had been bent flat against the pedestal face, and were in the OFF position.

    The carburettor air intake system of each engine had been destroyed during the impact sequence. Neither the pre-impact position of the normal/alternate air doors, nor the condition of the hot air flexible hose, could be determined.

Impact information

Consideration of the wing and nose section crush lines, along with the nature of damage to the fuselage and horizontal stabiliser, indicated that the aircraft was yawing and rolling left at impact. The pitch attitude at impact was 40-50 degrees nose-down. The right wing struck the ground first and bore the principal impact. The nose section, and then the left wing outboard leading edge struck the ground. Because of tidal activity, no ground impact marks were evident. The aircraft speed at impact could not be determined.

Medical and pathological information

The Bureau had not received the medical and pathological information at the time of the release of this report.

Fire

There was no fire.

Survival aspects

The deformation of the nose section and the forward/downward rotation of the wing significantly reduced the occupiable cockpit space. This, along with the impact forces, meant that the chances of survival for the pilot were low.

The surviving passenger indicated that she occupied the seat row immediately behind the pilot. The other two passengers occupied the second and third rows. The failure of the seat-to-floor attachments of the occupied seats in the aircraft cabin indicated that deceleration forces experienced in this area were high, thereby reducing survivability.

Aircraft operation

  • Emergency operating procedures
    Section 4 of the Owner's Handbook for the aircraft type addresses emergency operating procedures. Relevant extracts from the section include the following:

    "Warning ...
    It is essential to raise the flaps to the fully up position to achieve the optimum climb gradient."

    "Critical engine
    Failure of the left engine has the most adverse effect on the handling and performance of the aircraft."

    "Landing with one engine inoperative
    Make an initial approach to approximately 65 kt (75 m.p.h.) IAS with the flaps selected to TAKE-OFF (25 deg). When committed for landing, select FLAPS DOWN (56 deg) and reduce speed over the threshold to a value compatible with the information scheduled in Sect. 6 and touchdown normally."

    Section 3, Operating Instructions, of the Owner's Handbook, included the following information:

    "Touch down
    Initial approach should be made at 65 kts (75 m.p.h.) IAS with flaps at TAKE-OFF (25 deg). After selection of FLAPS DOWN (56 deg) the speed may be progressively reduced to the appropriate threshold speed quoted in Section 6. After touch down allow the nose wheel to sink gently and apply the brakes as required."

    "Baulked landing
    Apply full power smoothly to the engines and be prepared to deal with a nose-up change in trim which can require a strong stick force, especially if the airspeed is low. Establish a positive climb away, select flaps to T.O., trim the aeroplane and accelerate to 61 kts (70 m.p.h.). Select flaps UP at a height above 200 feet and climb out at 65 kts (75 m.p.h.) IAS."

  • Carburettor icing
    Section 3, Operating Instructions, of the Owner's Handbook, included the following information:

    "260 H.P. ISLANDER

    Use of carburettor heat
    Carburettor icing can occur, unexpectedly, in various combinations of atmospheric conditions. On damp, cloudy or foggy days, regardless of the outside temperature, keep a sharp watch for power loss, indicated by a decrease in manifold pressure. When this is seen, apply full carburettor heat for 30 seconds; this action will cause a further slight drop in manifold pressure. Return the heat control levers to OFF and note that selected engine power is restored. Do not keep heat selected FULL for long periods or excessive power loss will result, with very little indication from the manifold pressure indicator. During normal flight operations the carburettor heat control levers should be left in the OFF position."

    Section 3 also included, in the "Airfield Approach" checklist, the following comment on carburettor heat:

    "Intermittent use may be advisable to ensure responsive engines if a baulked landing is likely and ambient conditions are such that ice formation could occur."

    The temperature information supplied by the Bureau of Meteorology for Coconut Island around the time of the accident indicated that the atmospheric conditions were conducive to light carburettor ice forming at cruise or descent engine power settings.

    The company chief pilot knew of no instance of carburettor icing in Islander aircraft operating in the Torres Strait. The normal practice was that company pilots did not use carburettor heat during flights in the area. Similar comment was received from other organisations and pilots with extensive experience in operating Islander aircraft in the Torres Strait area.

  • Aircraft wing flap operation
    The Owner's Handbook, Section 2, titled Design Information, under the sub-heading Flight Controls, contained the following information:

    "Electrically operated single-slotted flaps are fitted. An actuator on the wing rear spar operates the flaps through a system of push-pull rods. A selector switch on the pilot's console controls the actuator and a flap position indicator is situated on the cabin roof instrument panel. The flap control selector switch is a spring-loaded centre OFF unit and is wired to the actuator through a system of relays. Moving the switch to the DOWN position will only move the flaps 25 degrees to a TAKE-OFF setting and when this setting has been reached a second downward switch movement will be required to set the flaps to DOWN. Similarly, when raising the flaps, the first switch movement will only raise them to the TAKE-OFF setting and a second switch movement is necessary to completely raise the flaps."

    Pilots who had flown the aircraft indicated that the flap selector switch had to be held up or down against the spring, for a short time, before flap movement commenced.

Aircraft single-engine climb performance

Section 1 of the Owner's Handbook for the aircraft stated that the minimum control speed (single engine) was 39 kts. It applied when the flaps were up and the propeller on the inoperative engine was feathered.

Section 6 of the Owner's Handbook contained aircraft performance data, including single engine rate of climb data at 65 kts with the flaps up. The data indicated that, at an aircraft weight of 2,727 kg, an ambient temperature of 30 degrees Celsius, and at sea level, the rate of climb the aircraft was capable of achieving with one engine inoperative was about 160 ft/min.

The aircraft manufacturer advised that there were no actual performance figures available for the BN-2A-26 Islander aircraft with one engine inoperative, propeller unfeathered, and flaps down. However, there were unofficial climb figures for a BN-2B-26 variant of the Islander, with flaps up, and an unfeathered propeller. These were measured under test conditions at 65 kts airspeed and indicated that there was a decrement of between 70 and 90 ft/min (depending on the unfeathered propeller RPM) below the scheduled one-engine inoperative performance figures. The manufacturer also advised that aircraft performance with both engines operating was reduced by approximately 40 per cent when the flaps were selected from up to down, although this data could not be applied directly to flight with one engine inoperative. Go-around tests with one engine inoperative and flaps down had not been conducted.

Pilots experienced on the aircraft type, reported that the performance of the aircraft with flaps down and one propeller not feathered was unlikely to allow a successful go-around to be conducted.

Other information

  • Information from surviving passenger
    Approximately 6 months after the accident, the surviving passenger provided the following information concerning the flight.
    1. She was seated in the row behind the pilot.
    2. One of the other passengers was in the second row, while the third passenger was in the third row.
    3. Her safety harness remained secured throughout the flight.
    4. There was no unusual event during the flight: the engines sounded normal.
    5. When the aircraft was on approach to Coconut Island, the pilot said that they could not land because there was a truck on the airstrip.
    6. The passenger saw a vehicle on the strip. It was stationary, and near the eastern end of the strip.
    7. The pilot was cross and said that there was no driver in the vehicle.
  • Other information from witnesses at Coconut Island
    At the time of the accident, an aircraft operated by another company was parked at the western end of the airstrip. Two pilots were loading a consignment of crayfish onto the aircraft. Neither saw or heard XFF arrive in the circuit or fly the approach, nor could they recall if a vehicle had been on the strip around the time the aircraft was on approach. They indicated that their loading activities, along with the existing wind conditions, would have greatly reduced the likelihood of them hearing sounds from the eastern end of the airstrip. They were not aware of the accident until one of the island residents who witnessed the accident from the eastern end of the island raised the alarm. They proceeded to the accident site and, along with some of the island residents, provided assistance to the victims as far as they were able. One of the island residents advised the Thursday Island Police of the accident. They arranged for a medical team and police to be flown to the island in two helicopters. They arrived at the island between one and one and one-half hours after the accident.

    None of the three island residents who witnessed the accident reported seeing a vehicle on the airstrip when the aircraft was on final approach.

  • Information from other company pilots
    Other pilots working for the operator indicated that island airstrips within the Torres Strait area were generally free of obstacles for their operations. There had been occasions, however, when vehicles, persons, or animals on the airstrip had caused pilots to go-around from a landing approach, requiring them to make a second approach.

    There were no radio links between aircraft and persons at the island airstrips. Local populations relied on hearing and/or seeing aircraft arriving to become aware of their presence. Depending on the weather and wind conditions, pilots did not always overfly airstrips before joining the circuit but often joined the downwind leg before completing a base leg and landing off final approach.

  • Birdlife on the airstrip
    In the period during which the accident occurred, there were large numbers of migratory birds on Coconut Island. Many hundreds were seen occupying the grassed runway area. The birds were small and difficult to see in the ankle-high grass. When approached by a vehicle, they generally remained on the ground until the vehicle was closer than 20-30 m. When they did fly, it was as a flock.

    The opinion of company pilots was that the birds were not sufficiently large to constitute a significant safety hazard to aircraft operations. They believed that the pilot would not have discontinued the approach because of bird activity given their small size, and given that an aircraft would normally have been almost at the point of touchdown before the birds would begin to fly. However, there was no evidence that the aircraft had struck a bird.

Occurrence summary

Investigation number 199900220
Occurrence date 16/01/1999
Location Coconut Island, (ALA)
State Queensland
Report release date 16/12/1999
Report status Final
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Loss of control
Occurrence class Accident
Highest injury level Fatal

Aircraft details

Manufacturer Pilatus Britten-Norman Ltd
Model BN2
Registration VH-XFF
Serial number 763
Sector Piston
Operation type Charter
Departure point Horn Island, QLD
Destination Coconut Island, QLD
Damage Destroyed

Saab SF-340A, VH-LPI

Summary

On 11 November 1998, VH-LPI, a Saab 340A turbo-propeller aircraft was enroute between Albury, NSW and Melbourne, Victoria on a scheduled public transport service. The aircraft was operating in instrument meteorological conditions and had accumulated a deposit of ice on the wings and windscreen wipers. The crew interpreted this ice deposit as being less than that required for them to activate the de-ice systems on the wing leading edges, in accordance with the aircraft flight manual procedures. As the aircraft approached Melbourne the crew were instructed to enter a holding pattern at Eildon Weir. The crew acknowledged this instruction and reduced power in order to slow the aircraft to the holding pattern airspeed. The crew subsequently allowed the airspeed to fall below the target speed of 154 knots, and despite remedial action, did not regain the target speed.

Shortly after the aircraft entered the holding pattern it suffered an aerodynamic stall and rolled approximately 126 degrees to the left and pitched nose down to approximately 35 degrees. The crew regained control after approximately 10 seconds. The aircraft lost 2,300 ft of altitude. The crew was not provided with a stall warning prior to the stall.

The investigation found that despite being certified to all required certification standards at the time, the Saab 340 aircraft can suffer from an aerodynamic stall whilst operating in icing conditions without the required warnings being provided to flight crew. This problem had been highlighted when the aircraft was introduced to operations in Canada and as a result a modified stall warning system was mandated for aircraft operated in Canada. This modification was not fitted to other Saab 340 aircraft worldwide.

The investigation also found a number of other occurrences involving Saab 340 aircraft where little or no stall warning had been provided to the crew while operating in icing conditions. Deficiencies were found in the operator's manuals, procedures and training.

During the course of the investigation, a number of recommendations were made in 1998 and 1999 concerning flight in icing conditions and modifications to the Saab 340 stall warning system. The completion of the investigation and finalisation of the report were the result of extensive consultation with the aircraft manufacturer and certification authorities.

Occurrence summary

Investigation number 199805068
Occurrence date 11/11/1998
Location Eildon Weir
State Victoria
Report release date 15/05/2001
Report status Final
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Loss of control
Occurrence class Incident
Highest injury level Minor

Aircraft details

Manufacturer Saab Aircraft Co.
Model 340
Registration VH-LPI
Serial number 340A-151
Sector Turboprop
Operation type Air Transport Low Capacity
Departure point Albury, NSW
Destination Melbourne, VIC
Damage Nil

Air Tractor AT-502, VH-SNA, near Rocky Gully, Western Australia, on 14 August 1998

Summary

The Air Tractor was being used to conduct aerial reconnaissance of a forestry area prior to spraying the trees. The north-easterly wind was gusting from about 15 kts and there was 8 OCTAS of low cloud with passing rain showers. The horizon was often obscured. The pilot reported that he encountered some turbulence during the flight.

On completion of the reconnaissance flight, the pilot decided to land towards the east-south-east. He reported that late in the landing approach, with full flap selected the aircraft unexpectedly rolled left. He was unable to correct the roll before the left landing gear struck the perimeter fence. The aircraft veered left, and its left wing struck the chemical loader that was parked near the edge of the airstrip. The aircraft then cartwheeled before coming to rest inverted. The pilot and bystanders were unhurt, but the aircraft was destroyed.

No deficiencies could be found with the aircraft that may have contributed to the accident.

Occurrence summary

Investigation number 199803258
Occurrence date 14/08/1998
Location 19 km E Rocky Gully
State Western Australia
Report release date 04/08/1999
Report status Final
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Loss of control
Occurrence class Accident
Highest injury level None

Aircraft details

Manufacturer Air Tractor Inc
Model AT502
Registration VH-SNA
Sector Turboprop
Operation type Aerial Work
Departure point Rocky Gully, WA
Destination Rocky Gully, WA
Damage Destroyed

Cessna A185E, VH-HTS

Summary

On Sunday, 26 July 1998, at about 1324 EST, a Cessna A185E floatplane, VH-HTS, crashed onto a ridge forming the southern shore of Calabash Bay NSW. The accident occurred during a go-around manoeuvre following an unsuccessful landing approach to the Berowra water alighting area. At the time of the accident the Calabash Bay area was affected by strong winds, widespread rain and showers, low cloud, and reduced visibility. The aircraft was operated by South Pacific Seaplanes and was undertaking a charter flight from Palm Beach to Berowra. All five occupants, including the pilot, suffered fatal injuries. The aircraft was destroyed by impact forces.

The investigation found that the circumstances of the accident were consistent with uncontrolled flight into terrain. The decision by the pilot to carry out a go-around into a confined area surrounded by steep-sided terrain was the culminating factor in a combination of local factors, organisational deficiencies and inadequate safety defences. Local factors included poor weather conditions, a lack of formal procedures to provide safe methods of operation, and commercial pressures. Organisational deficiencies were identified within South Pacific Seaplanes concerning the management and conduct of charter operations carried out by that company, and in the safety regulation of those operations by the Civil Aviation Safety Authority.

During the investigation a number of safety deficiencies were identified. Safety actions to address those deficiencies are currently being formulated by the Bureau of Air Safety Investigation. A description of those deficiencies, and corresponding safety actions, will be summarised in section 4 of the final report.

Occurrence summary

Investigation number 199802830
Occurrence date 26/07/1998
Location Calabash Bay
State New South Wales
Report release date 25/02/1999
Report status Final
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Loss of control
Occurrence class Accident
Highest injury level Fatal

Aircraft details

Manufacturer Cessna Aircraft Company
Model 185
Registration VH-HTS
Serial number 18501835
Sector Piston
Operation type Charter
Departure point Palm Beach, NSW
Destination Berowra Waters, NSW
Damage Nil

Bell 206B (III), VH-WCF, 204 km north-north-east of Geraldton, Western Australia

Summary

The helicopter was landed on an uneven 2 to 3 degree slope to offload two surveyors and their equipment. The forward sections of the skids were in firm contact with the ground, but because of the uneven surface the rear of the left skid was not in firm contact. After landing, the pilot lowered the collective and moved the cyclic control to confirm the helicopter was firmly seated on the ground before he allowed the passengers to disembark. The engine was running and the rotor was turning at 100% of operating RPM. There was a gusty 15-20 kt wind from 30 degrees to the right of the nose.

The rear seat passenger disembarked from the left (downhill) side, unloaded his equipment, and moved away from the helicopter towards the front as briefed. The front seat passenger disembarked from the left side, unloaded his equipment, climbed back on to the left skid, and reached into the cockpit through the door. The pilot said that he had been observing the site to his right to ensure it was clear, and when he looked back towards the front he realised the right skid was just off the ground. The pilot said he noticed a cool strong wind coming through his open window when the helicopter started to roll. He moved the cyclic control to the right but this had no effect. The pilot said he then pulled in collective but the helicopter continued to roll to the left and the left skid did not leave the ground. He then noticed the passenger on the top step on the left side. The pilot said he yelled at the passenger who immediately jumped off the step, closed the door and faced the helicopter with his arms outstretched. The helicopter continued to roll to the left and the passenger ran away directly to the left of the helicopter. As the weight came off the skids, the helicopter began to slide sideways down the slope. The slide was stopped, half a metre later by a partially buried stump and the helicopter rolled over. The pilot was unable to recover control before the rotor blades made contact with the passenger and the ground. The passenger was struck by at least one main rotor blade and was fatally injured.

It is probable that the helicopter very rapidly entered a condition known as dynamic rollover, where the only possible recovery action was to fully lower the collective. However, it is unlikely that the pilot had sufficient time to recognise the developing the situation and to take the appropriate action before the rollover became unrecoverable.

Occurrence summary

Investigation number 199703335
Occurrence date 12/10/1997
Location 204 km north-north-east of Geraldton
State Western Australia
Report release date 25/02/1998
Report status Final
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Loss of control
Occurrence class Accident
Highest injury level Fatal

Aircraft details

Manufacturer Bell Helicopter Co
Model 206
Registration VH-WCF
Serial number 3134
Sector Helicopter
Operation type Charter
Departure point 108 NM NNE Geraldton WA
Destination 110 NM NNE Geraldton WA
Damage Substantial