Published: 1 March 2017
History of the flight
On 10 January 2017, at about 1030 Eastern Standard Time, a Cessna Aircraft Company 172M, registered VH-WTQ (WTQ), departed Agnes Water Airstrip on a charter service to a beach‑landing location about 12 NM (22 km) to the north-west near Middle Island, Queensland. On board were a pilot and three passengers (Figure 1).
The pilot reported that at about 1038, while conducting a low-altitude inspection of the beach‑landing site, the aircraft sustained a sudden loss of engine power. With limited time to respond to the power loss, and in an effort to avoid landing in the water, the pilot elected to turn back and land on the beach. The pilot reported considering this the safest option.
Source: Google earth, modified by the ATSB
Two witnesses who observed the accident sequence indicated that the aircraft was flying parallel to the beach before turning left at an increasingly steep bank angle. The left wingtip struck the ground and then the nose, before the aircraft came to rest about 5 m past the nose impact point. One of the rear-seat passengers was fatally injured and the other three occupants sustained serious injuries. The aircraft was destroyed (Figure 2).
The pilot of another aircraft that was also operating a charter service to the same location, and was about 2 NM (4 km) behind WTQ, reported not seeing the accident sequence. When the pilot of the other aircraft observed the wreckage of WTQ during a flypast of the accident site, they immediately radioed air traffic services to advise that there had been an accident. The pilot landed the aircraft on the beach and, in conjunction with witnesses already at the scene, provided emergency assistance.
Site and wreckage
Inspection of the site and wreckage identified:
- that the aircraft impacted terrain in a left wing-low, steep nose-down attitude
- that the aircraft was facing the opposite direction to the initial impact
- no sign of rotational damage to the propeller
- all of the aircraft components and flight control surfaces
- continuity of the flight control systems
- that the flaps were in the ‘up’ position when the aircraft impacted the ground.
Several aircraft components, including the engine and a Garmin 296 Global Positioning System (GPS) unit, were removed from the accident site for further examination by the ATSB.
Data from the recovered GPS unit was successfully downloaded by the ATSB. This data included recorded values of time, latitude, longitude and altitude about every 10 seconds throughout the accident flight. Using the data, the aircraft’s flight path from Agnes Water to the accident site was overlayed on Google earth (Figure 3).
Source: Google earth, modified by the ATSB
A review of the Airservices Australia recorded radar data showed a number of secondary radar returns that were confirmed to be from WTQ. The radar data provided track and altitude information from 1032 until 1038, at which time the radar return was lost.
The Queensland Police Service downloaded data from a mobile phone that was located on the accident site. This data was provided to the ATSB and included a video file of the entire flight and accident sequence. The video was taken by the passenger who occupied the front-right seat.
Recovered flight video
Preliminary analysis of the recovered flight video indicated:
- a normal take-off and climb to a cruise altitude of about 1,500 ft
- at about 4 minutes flight time, the pilot conducted a series of manoeuvres including steep turns, steep climbs and descents, manoeuvres that were consistent with negative g and yawing the aircraft left and right
- after about 6 minutes flight time, and after a second series of yawing and other manoeuvres that were consistent with negative g, the engine power momentarily reduced before recovering
- a descent down to about 100 ft and flight parallel to the beach over water, consistent with the conduct of a beach-landing site inspection
- at about 7 minutes flight time, the engine sustained a sudden power loss and subsequently the:
- pilot turned the aircraft to the right momentarily before raising the nose and initiating a left turn with an initial bank angle of about 45°
- bank angle increased and the airspeed decreased to a point where the aircraft’s stall warning horn sounded for about 3 seconds
- aircraft rolled left and pitched nose down before impacting terrain.
Pilot actions following engine power loss
The circumstances of this accident are still being investigated. However, the ATSB reminds pilots that the risk of injury following a complete or partial engine power loss can be significantly reduced by using strategies such as:
- undertaking pre-flight decision making and planning for emergencies and abnormal situations for a particular landing area
- taking positive action and maintaining aircraft control, either when turning back to the landing area or conducting a forced landing, while being aware of the variables affecting the success of the forced landing such as any flare energy and the aircraft’s height and stall speed.
The investigation is continuing and will include examination of the:
- GPS, video and radar data
- recovered engine and engine components
- pilot information
- aircraft, operator, and maintenance documentation and procedures
- aircraft weight and balance.
The information contained in this web update is released in accordance with section 25 of the Transport Safety Investigation Act 2003 and is derived from the initial investigation of the occurrence. Readers are cautioned that new evidence will become available as the investigation progresses that will enhance the ATSB's understanding of the accident as outlined in this web update. As such, no analysis or findings are included in this update.
- Eastern Standard Time (EST): Coordinated Universal Time (UTC) + 10 hours.
- Secondary surveillance radar relies on an aircraft’s operational transponder transmitting a data signal in response to being interrogated by an air traffic service radar or another receiver (for example, another aircraft’s Traffic Alert and Collision Avoidance System). The amount of information transmitted in the data signal is dependent on the type of transponder in the aircraft. This can range from the aircraft’s altitude (Mode C) to the identification of the flight and the pilotselected cruising level (Mode S).
- G load: the nominal value for acceleration. In flight, g load represents the combined effects of flight manoeuvring loads and turbulence and can have a positive or negative value.
- Yawing: the motion of an aircraft about its vertical or normal axis.