Loss of control

On 18 August 2011, an Aérospatiale Industries AS355F2 helicopter, registered VH-NTV, was operating in an area east of Lake Eyre, South Australia (SA). On board were the pilot and two passengers. The helicopter landed on an island in the Cooper Creek inlet, about 145 km north of Marree, SA, at about 1715 Central Standard Time.

At about 1900, the helicopter departed the island, and soon after take-off it collided with terrain. The pilot and the two passengers were fatally injured, and the helicopter was destroyed by the impact forces and a fuel-fed fire.

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Updated 19 July 2013

The Australian Transport Safety Bureau (ATSB) received the results of the flight simulations and modelling that were previously advised as being conducted by external specialists in June 2012. The ATSB is now finalising its draft report, which will be sent to directly involved parties and other parties with an interest in July/August 2013. Feedback from those parties on the factual accuracy of the draft report over the 28-day DIP period will be considered for inclusion in the final report, which is anticipated to be released to the public in September/October 2013. 

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Updated 9 July 2013

The Australian Transport Safety Bureau (ATSB) received the results of simulations and modelling conducted by external specialists in June 2012. The ATSB is now finalising its draft report, which will be sent to directly involved parties and other parties with an interest in July/August 2013. The final report will be publicly released in September/October 2013.

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Update 26 November 2012

The Global Positioning System (GPS) data that was recovered from the accident site indicates that the helicopter took off normally, before being established on a heading of 035 °M at 1,500 ft above mean sea level (AMSL). After maintaining 1,500 ft for 17 seconds, the helicopter commenced a gradual turn to the right and started to descend. The descending right turn continued for about 35 seconds until the last GPS plot at an altitude of about 728 ft, or about 725 ft above the elevation of the accident site. The location of the accident site was consistent with a continuation of the recorded flight path.

The Australian Transport Safety Bureau (ATSB) is examining various scenarios to explain the helicopter’s flight path, including spatial disorientation and pilot incapacitation. As part of these activities, the ATSB has arranged for simulations to be conducted of the flight by external agencies. Given the time required to conduct and analyse these simulations, the final report is now not expected to be released until the first quarter of 2013.

Although the reasons for the flight path have not yet been determined, the ATSB is concerned about the conduct of visual flight rules (VFR) flights in dark night conditions – that is, conditions with minimal celestial illumination, terrestrial lighting cues or visible horizon. The ATSB is reviewing the regulatory requirements and guidance for the conduct of night VFR flights, and the training and ongoing assessment of pilot skills to conduct such flights. The ATSB is also preparing an ‘Avoidable Accidents’ educational report focussing on night VFR accidents. 

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

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Update 15 August 2012

Since the Preliminary Report was issued on 16 September 2011, the ATSB investigation has:

• examined the helicopter's maintenance and airworthiness records
• examined the helicopter's engines, instruments and other recovered components
• tested fuel samples from the drums that were used to refuel the helicopter
• recovered and analysed data from a GPS device on board the helicopter
• reviewed the pilot's experience and medical status
• analysed witness statements and conducted further witness interviews as required. 

The download and analysis of the GPS data required an extensive period of time, as well as input from overseas investigation agencies.
 
Overall, the analysis of the circumstances of the accident has been difficult due to the limited evidence available.
 
The ATSB has completed its data collection activities and is preparing its draft final report, which will be issued to Directly Involved Parties for their comments.

On 30 April 2011, the owner-pilot of a Robinson Helicopter Co. R44 helicopter, registered VH-ETT, was conducting a local flight from a private property located near Kilmore Gap, Victoria. During low-level manoeuvring at low speed around a dam, the pilot lost directional control and landed heavily in the water. The helicopter was seriously damaged; the pilot and passenger sustained minor injuries.

The investigation found that the helicopter was probably serviceable, and that the loss of directional control was likely to be a result of a loss of tail rotor effectiveness.

The emergency locator transmitter (ELT) activated on impact and prompted an effective search and rescue (SAR) response through a broadcast on the 121.5 MHz frequency. However, the 406 MHz transmission that was monitored by the SAR agency did not trigger an alert or provide identification information. As a result, there was no assurance of an immediate and effective response from the SAR agency.

The investigation found that the ELT could be programmed with identification information either directly or (if fitted) by input from a component (dongle) in the ELT wiring connector. In this occurrence, the ELT had been inadvertently reprogrammed with incorrect information from the dongle.

A minor safety issue was identified in that there were only subtle cues to distinguish programmable dongles from the standard-type wiring connector. There was also variability in the conduct of post-installation ELT testing.

In response, on 6 June 2011, the Civil Aviation Safety Authority (CASA) published Airworthiness Bulletin 25-018 to alert maintenance organisations to the risk of programming dongles transferring potentially invalid details to the memory of ELTs. CASA advised that an article in Flight Safety Australia would also highlight the issue.

The helicopter manufacturer advised that they were introducing measures to increase awareness of programming dongles in their new helicopters.

What happened

On 28 July 2011, at around 1615 Central Standard Time, a Robinson R44 Raven II helicopter, registered VH-ZWC, departed Darwin Airport on a charter flight to Bamurru Plains, Northern Territory. Approximately 30 minutes into the flight, the aircraft lost main rotor drive and the pilot conducted an autorotative descent and landing. There were no reported injuries.

What the ATSB found

The ATSB’s investigation found that the loss of main rotor drive was associated with corrosion and subsequent fatigue failure of the main rotor gearbox gear carrier, as a result of water present in the main rotor gearbox.

What has been done as a result

The helicopter manufacturer has modified the design of the gear carrier to incorporate a metallic cadmium surface plating to improve the corrosion resistance of the assembly.

In May 2012, the Civil Aviation Safety Authority (CASA) released Airworthiness Bulletin 63-008, to raise awareness among operators and maintenance providers of Robinson R44 helicopters of the hazards associated with gearbox internal corrosion due to water ingress. The bulletin made several recommendations aimed at reducing the associated risks.

Safety message

Operators and maintainers of Robinson R44 helicopters are alerted to the potential for the ingress of water into the main rotor gearbox, and for the subsequent corrosion and possible fatigue cracking of componentry, which could lead to a loss of main rotor drive while in flight. Responsible persons are referred to the recommendations contained within CASA AWB 63-008, which are aimed at limiting the likelihood of water ingress and provide guidance on remedial action should water ingress be suspected.

On 3 June 2011, a Kawasaki Heavy Industries 369HS helicopter, registered VH-XAA, collided with terrain 42 km west-south-west of Canberra Airport, New South Wales. The helicopter sustained serious damage and both occupants received injuries.

Earlier that day the helicopter had departed from a private helicopter landing site about 22 km north-west of Canberra Airport for defence aircrew currency training in the Brindabella Ranges, New South Wales. Pre-departure checks had been normal, and the weather was clear.

After identifying a suitable landing site in the Ranges, the pilot reported that he brought the helicopter into a high hover of about 50 -70 ft above ground level (AGL). He assessed that an adequate power margin existed prior to commencing a right tail rotor pedal turn through about 180° to position for landing. Approaching the required position, the pilot applied left tail rotor pedal to stop the turn, however, the helicopter continued to turn to the right. The pilot assessed that he had lost tail rotor effectiveness and commenced recovery actions, but this was hampered by the proximity of nearby trees. The helicopter continued the right yaw through a number of 360º turns while slowly descending. At about 30 ft AGL, the pilot assessed that collision with the trees was imminent and decided to conduct an emergency landing in the clearing below. The helicopter descended rapidly towards terrain and landed heavily in a level attitude, striking a large log. After rapidly rolling through trees then down a bank the helicopter came to rest in a creek bed.

Both occupants exited the helicopter and activated the portable emergency locator beacon. They were later airlifted out by a rescue helicopter.

On 16 January 2011, at about 1800 Eastern Standard Time, a De Havilland Aircraft DH-82A (Tiger Moth) aircraft, registered VH-WHW (WHW), departed Toowoomba, Queensland on a private local flight.

On board was the pilot in command (PIC) and a flying instructor from the local Aero Club. The PIC conducted a pre-flight inspection, which included a check of the fuel, oil and control cables. He determined that WHW was serviceable and had sufficient fuel for the flight. There were no loose items in the aircraft's storage locker or in the cockpit.

About 15 minutes after take-off, the flying instructor, who was acting as the handling pilot at the time, initiated a left turn to return to the airport. The PIC recalled that, during the turn, WHW suddenly pitched down followed by a second, even more severe, pitch down motion. Both the PIC and the handling pilot recalled that the control stick did not move when WHW pitched down.

In response to the sudden and uncommanded nose down motion, both pilots attempted to raise the nose by applying back pressure on the control stick. Their actions had no effect and WHW continued to pitch nose down until the aircraft became inverted.

The aircraft was about 100 ft above the trees and inverted when it began to climb. Both pilots felt significant g-force followed by the collision with the trees.

The aircraft came to rest upside down on the side of Mount Davidson in bushland. Both occupants sustained serious injuries.

On 13 May 2011, at 1606 Eastern Standard Time, an Aérospatiale Eurocopter AS 350B3 helicopter, registered VH-XXW, impacted terrain at Bankstown Airport, New South Wales. As the result of the post-impact fire, the helicopter sustained serious damage.

The owner-pilot had earlier completed an 'air transit' at about 15-20 ft above ground level (AGL), from outside a hangar, to a grassed area south-west of the main helipad.

While stationary in a hover, with a recorded 15 kt wind onto the right front of the helicopter, and at about 10 ft AGL, the pilot decided to land on the grass. When the helicopter was about 2 ft AGL, the pilot stated that it suddenly rotated to the left in an anticlockwise direction. The pilot was unable to correct the anticlockwise yaw with progressive right pedal input. The pilot then raised the collective lever and climbed to about 10 ft AGL, completing about three to four, 360 º rotations.

At the same time, the pilot noticed the helicopter drifting towards a chain-wire fence adjacent to a freight building. During the uncontrolled anticlockwise yaw, the pilot reported that there were no visual or aural warnings. While still rotating, the pilot decided to conduct a forced landing and slowly lowered the collective lever. The helicopter contacted the ground, rolled onto its right side and was seriously damaged from the post-impact fuel fed fire. The pilot sustained minor injuries.

Preliminary report released 18 March 2011

On 4 February 2011, a Robinson Helicopter Company R44 Astro helicopter (R44), registered VH‑HFH, was conducting circuit operations at Cessnock Aerodrome, New South Wales. On board the helicopter were an instructor, a pilot undergoing a helicopter flight review and a passenger.

Following the completion of a sequence involving the simulated failure of the helicopter's hydraulic‑boost system, the instructor assessed that the hydraulic system had actually failed. He elected to reposition the helicopter on the aerodrome to facilitate further examination. Upon becoming airborne, control of the helicopter was lost, and it collided with the runway and, shortly after, there was a fire. The pilot managed to exit the helicopter; however, the instructor and passenger were fatally injured.

Examination of the wreckage identified that a bolt securing part of the flight control system had detached. Although the circumstances of the accident are still under investigation, the Australian Transport Safety Bureau has, in the interest of transport safety, issued a Safety Advisory Notice suggesting that operators of hydraulic system-equipped R44 helicopters, and organisations performing inspection, testing, maintenance and repair activities on the flight controls of those helicopters, inspect and confirm the security of the aircraft's hydraulic-boost servos.

After a number of dual circuits, the pilot was authorized to carry out solo circuits with touch and go landings. After the first touchdown the pilot applied full power then selected the flap to 10 degrees. The aircraft entered a rapid turn to the left, and the pilot abandoned the take-off. The aircraft slid sideways off the strip and the nosewheel was broken off. The pilot was carrying out her first solo period of touch and go landings. After applying full power she noticed that the aircraft was accelerating more quickly than when she had been under dual instruction. The pilot had previously required forward pressure on the control column while retrimming the aircraft. On this occasion she had not had time to retrim and the investigation revealed that the aircraft had been "wheelbarrowing" on the nosewheel when directional control was lost.

The pilot had hired the aircraft in order to maintain currency on the type. After an uneventful flight in the training area he returned to the circuit and carried out a normal approach. However, shortly after touchdown the aircraft swerved to the left and the pilot was unable to regain directional control. The aircraft ran off the side of the runway and the nosegear collapsed. It was discovered that the elevator trim had been set almost fully nose down, and the rudder trim was set almost fully nose left at the time of the accident. The nosewheel had contacted the runway at about the same time as the mainwheels, and it was likely that the subsequent loss of control was the result of the aircraft "wheel-barrowing" on the nosewheel. The pilot, who had only limited experience on the type, had believed that the aircraft had been correctly trimmed prior to touchdown.

The pilot, who was also the holder of a Private Pilot Licence, was conducting his first gliding flight for the day. The glider was aero-towed to 1100 feet above the aerodrome, but only weak lift was encountered in the area. The pilot elected to return for landing and commenced a normal circuit. On the downwind leg strong sink was encountered and the base turn was conducted at about 300 feet above the ground. Indicated airspeed at the time was reported to be about 55 knots. The pilot subsequently advised that the roll into the turn was normal, but he was unable to level the wings again, even with full opposite aileron. The aircraft continued descending in a wing-low attitude and struck the ground about 250 metres before the threshold of the strip. Investigation revealed no evidence of any pre-impact defect or malfunction of the controls, and atmospheric conditions at the time were reported as being stable. When the sink was encountered on the downwind leg, the pilot had modified his circuit by flying closer to the strip. As a result, the angle of bank required for the base turn was steeper than normal. It was considered probable that the aircraft had stalled during this turn onto base, with insufficient height remaining to allow the pilot to recover control.