Aviation safety investigations & reports

Loss of control and collision with water involving Eurocopter EC120B, VH-WII, Hardy Reef, Whitsundays, Queensland, on 21 March 2018

Investigation number:
AO-2018-026
Status: Completed
Investigation completed
Phase: Final report: Dissemination Read more information on this investigation phase

Final report

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What happened

On 21 March 2018, a Eurocopter EC120B helicopter, registered VH-WII and operated by Whitsunday Air Services, departed Hamilton Island Airport, Queensland on a charter flight to Hardy Reef. On board were the pilot and four passengers.

The pilot conducted the approach to the pontoon landing site at Hardy Reef into wind. During the approach, the pilot slowed the helicopter to allow birds to disperse. The pilot was then planning to yaw the helicopter left into the intended landing position, and there was about 20 kt crosswind from the right of the intended position.

When the helicopter was yawing left into position, just over the pontoon, the pilot noticed a message illuminate on the helicopter’s vehicle engine multifunction display (VEMD), and elected to conduct a go-around. During the go-around, after the helicopter climbed to about 30–40 ft, there was a sudden and rapid yaw to the left. In response to the unanticipated rapid yaw, the pilot lowered the collective but was unable to recover the situation.

In the limited time available after the unsuccessful action to recover from the rapid left yaw, the pilot did not deploy the helicopter’s floats and conduct a controlled ditching. The helicopter collided with the water in a near-level attitude, with forward momentum and front-right corner first. Almost immediately, the helicopter rolled to the right and started rapidly filling with water. The pilot and two of the three rear seat passengers evacuated from the helicopter with minor injuries. Although the impact forces were survivable, the other two passengers were unconscious following the impact and did not survive the accident.

The helicopter sank and, associated with unfavourable weather conditions in the days following the accident, subsequent searches were unable to locate and recover the helicopter.

What the ATSB found

Although none of the possible VEMD messages required immediate action by the pilot, the pilot considered a go-around to be the best option given the circumstances at the time.  

During the go-around, the helicopter continued yawing slowly to the left, and the pilot very likely did not apply sufficient right pedal input to correct the developing yaw and conduct the go-around into wind. The helicopter then continued yawing left, towards a downwind position, until the sudden and rapid yaw to the left occurred. In response to the rapid yaw, it is very likely that the pilot did not immediately apply full and sustained right pedal input.

The operator complied with the regulatory requirements for training and experience of pilots on new helicopter types. However, the ATSB found the operator had limited processes in place to ensure that pilots with minimal time and experience on a new and technically different helicopter type had the opportunity to effectively consolidate their skills on the type required for conducting the operator's normal operations to pontoons. In this case, the pilot of the accident flight had 11.0 hours experience in command on the EC120B helicopter type, and had conducted 16.1 hours in another and technically different helicopter type during the period of acquiring their EC120B experience. Associated with this limited consolidation on the EC120B, it is likely that the pilot was experiencing a high workload during the final approach and a very high workload during the subsequent go-around.

In addition to limited consolidation of skills on type, the ATSB found that the safety margin associated with landing the helicopter on the pontoon at Hardy Reef was reduced due to a combination of factors, each of which individually was within relevant requirements or limits. These factors included the helicopter being close to the maximum all-up weight, the helicopter’s engine power output being close to the lowest allowable limit, the need to use high power to make a slow approach in order to disperse birds from the pontoon, and the routine approach and landing position on the pontoon requiring the pilot to turn left into a right crosswind (in a helicopter with a clockwise-rotating main rotor system).

The ATSB also identified that the passengers were not provided with sufficient instructions on how to operate the emergency exits and the passenger seated next to the rear left sliding door (emergency exit) was unable to locate the exit operating handle during the emergency, and as a result the evacuation of passengers was delayed until another passenger was able to open the exit. The nature of the handle’s design was such that its purpose was not readily apparent, and the placard providing instructions for opening the sliding door did not specify all the actions required to successfully open the door.

The investigation also identified safety factors associated with the operator’s use of passenger-volunteered weights for weight and balance calculations, the operator’s system for identifying and briefing passengers with reduced mobility, bird hazard management at the pontoons, and passenger control at the pontoons.

What has been done as a result

In July 2019, the helicopter manufacturer released a safety information notice about unanticipated left yaw in helicopters with a clockwise-rotating main rotor system. The notice provided detailed advice regarding the circumstances where unanticipated yaw can occur and the importance of applying full opposite right pedal if it occurs. The notice also stated that, for helicopters with a clockwise-rotating main rotor system, to prefer (as much as possible) yaw manoeuvres to the right, especially in performance-limited conditions.

Following the accident, the operator implemented several additional processes for pilots transferring to new helicopter types and for operations at pontoons. This included pilots conducting only into-wind operations at pontoons until they had obtained 20 hours on type. The operator also introduced a safety management system (SMS), revised processes for obtaining accurate passenger weights, and introduced training for pilots in how to avoid birds and how to inspect blades following a birdstrike.

In addition, the operator revised their pre-flight safety briefing video and passenger-briefing cards to include all types of seatbelts and instructions on how to operate all emergency exits and address other matters. The Civil Aviation Safety Authority (CASA) revised its passenger safety briefing guidance, which now contains information specific to helicopter operators. The Civil Aviation Safety Regulation (CASR) Part 133 Manual of Standards applicable to helicopter operators also requires that passengers seated in an emergency exit row are briefed about what to do when an exit is required to be used. In addition, all passengers must be verbally briefed on the location of exits and the brace position. 

Safety message

This accident and many other previous accidents demonstrate the importance of pilots having experience in the helicopter type when faced with unfamiliar situations in performance-limited conditions. Operators, as part of their safety management processes, should consider skill consolidation during and following the in command under supervision (ICUS) phase and provide as much consolidation as possible to reduce the risk of transitioning to a new aircraft type. This is particularly relevant for types with significant differences to those a pilot has previously flown and for operations with reduced safety margins.

Operators are also encouraged to build safety margins into their operations, to minimise the risk of performance-limited conditions during critical phases of flight, and provide pilots the best opportunity to succeed.

Industry understanding of yaw control problems in helicopters is always developing. Pilots and operators should identify and avoid situations that present potential for loss of yaw control in their helicopter type. This could include planning approaches that can be rejected by turning with the torque of the helicopter (for example, if crosswind turns are required when landing, conduct turns to the right in a helicopter with a clockwise-rotating main rotor system).

In the event of a loss of yaw control at low height and airspeed, pilots need to follow the immediate actions specified by the relevant helicopter manufacturer (which typically include immediately applying full opposite pedal input).

For helicopter flights over water, given the risk of inversion, capsize and disorientation following a ditching, it is imperative that passenger safety briefings include how to operate the passenger’s seatbelt and the location and operation of the emergency exits. In addition, for operators and pilots of EC120B aircraft, passengers in the rear of the helicopter should be specifically briefed about the location of the operating handle and the three actions required to open the rear left sliding exit: pull the handle up, push the door out, and slide the door back.

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The occurrence

Context

Safety analysis

Findings

Safety issues and actions

Sources and submissions

Appendix A – Analysis of photographs taken during flight

Appendix B – Airbus Helicopters Safety Information Notice

Appendix C – Unanticipated yaw occurrences

Glossary

Safety Issues

Go to AO-2018-026-SI-01 - Go to AO-2018-026-SI-02 - Go to AO-2018-026-SI-03 - Go to AO-2018-026-SI-04 - Go to AO-2018-026-SI-05 - Go to AO-2018-026-SI-06 - Go to AO-2018-026-SI-07 -

Operator consolidation processes for flight crew

Although the operator complied with the regulatory requirements for training and experience of pilots, it had limited processes in place to ensure pilots with minimal time and experience on a new and technically different helicopter type had the opportunity to effectively consolidate their skills on the type required for conducting the operator's normal operations to pontoons.

Safety issue details
Issue number: AO-2018-026-SI-01
Status: Closed – Adequately addressed

Requirements for verbally briefing passengers on emergency exits

There was no requirement for operators of passenger transport flights in aircraft with six or less seats to provide passengers with a verbal briefing, or written briefing material, on the method for operating the emergency exits.

Safety issue details
Issue number: AO-2018-026-SI-02
Status: Closed – Adequately addressed

Design of the EC120B rear left emergency exit

Due to multiple factors, the design of the rear left sliding door (emergency exit) on the EC120B helicopter was not simple and obvious to use unless the occupant was provided with specific instructions about how to operate the exit. In particular:

  • the door required three actions to open (pull handle up, push door out, slide door back), and the second action was not indicated in either the design of the handle or the placard next to the handle
  • the design of the inside handle was such that its purpose may not have been readily apparent to many users.
Safety issue details
Issue number: AO-2018-026-SI-03
Status: Open – Safety action pending

Passengers with reduced mobility

The operator’s system used to identify passengers with reduced mobility and/or required additional safety briefing information relied on passengers self-reporting a problem.

Safety issue details
Issue number: AO-2018-026-SI-04
Status: Closed – Partially addressed

Operator helicopter loading practices

Although the operator had calibrated scales available for use at two of their check-in locations, they were not routinely used to ascertain actual passenger and/or baggage weights. Instead, the operator's personnel relied on passengers’ volunteered weights (without an additional allowance) and only weighed passengers when the volunteered weights were perceived to be inaccurate.

Safety issue details
Issue number: AO-2018-026-SI-05
Status: Closed – Adequately addressed

Operator management of birdstrikes

There was often a significant number of birds located on the pontoons at Hardy Reef used by the operator. However, the operator did not have a process to systematically manage the risk of birdstrike. For example:

  • The operator had not conducted a formal risk assessment of the bird hazard at the pontoons.
  • The operator did not record birdstrike occurrences, which reduced its ability to accurately assess the ongoing hazard associated with birdstrikes at the pontoons. Birdstrike occurrences were also not notified to the ATSB (as required).
  • The operator did not provide guidance or appropriate equipment to enable pilots to effectively conduct visual inspections following an actual or suspected birdstrike at the pontoons.
Safety issue details
Issue number: AO-2018-026-SI-06
Status: Closed – Partially addressed

Pilots leaving the controls of the helicopter

It was common practice for the operator’s pilots to leave the controls of their helicopter, while the rotors were turning and the friction locks applied, to escort passengers to and from the helicopter.

Safety issue details
Issue number: AO-2018-026-SI-07
Status: Closed – Partially addressed
General details
Date: 21 March 2018   Investigation status: Completed  
Time: 15:37 AEST   Investigation level: Systemic - click for an explanation of investigation levels  
Location   (show map): Hardy Reef pontoon, 72 km north‑north‑east of Hamilton Island, Whitsundays   Investigation phase: Final report: Dissemination  
State: Queensland   Occurrence type: Collision with terrain  
Release date: 16 June 2021   Occurrence category: Accident  
Report status: Final   Highest injury level: Fatal  

Aircraft details

Aircraft details
Aircraft manufacturer Eurocopter  
Aircraft model EC120B  
Aircraft registration VH-WII  
Serial number 1603  
Operator Whitsunday Air Services  
Type of operation Charter  
Sector Helicopter  
Damage to aircraft Destroyed  
Departure point Hamilton Island, Qld  
Destination Hardy Reef, Qld  
Last update 16 June 2021