On Sunday 31 December 2017 a De Havilland DHC-2 Beaver seaplane, operated by Sydney Seaplanes, crashed near Sydney sadly killing the pilot and the 5 passengers.
The reports so far on this tragic accident indicate that the aircraft had taken off and was climbing, then nosedived into the River Hawkesbury, north of Sydney. Despite brave rescue efforts of nearby boaters, the aircraft sank rapidly after impact with all on board.
The Australian Transport and Safety Bureau (ATSB) are investigating the crash, which will include detailed examination of the wreckage which was recovered from a depth of 40ft in the river.
The passengers in the aircraft were Richard Cousins, the CEO of British food services company Compass Group, his fiancée Emma Bowden, her daughter Heather and Mr Cousins sons William and Edward. The family were returning to Rose Bay on Sydney harbour after lunch at the exclusive waterside Cottage Point Inn restaurant.
The 1960s single-engine DHC-2 Beaver aircraft was previously involved in a crash in 1996 - officials have said that this will form part of their wide-ranging investigation. In addition, the same model of aircraft crashed in Canada in 2015 killing another UK family. For this 2015 accident, the Transportation Safety Board of Canada determined that the DHC-2 Beaver crashed after experiencing an aerodynamic stall during a steep turn. The report by the Canadian investigators also identified 31 deaths in 9 separate fatal accidents and 3 non-fatal accidents involving the DHC-2 that were caused by aerodynamic stalls. As a result of these findings, the Canadian investigators required that all commercial DHC-2 aircraft in Canada be fitted with a stall warning system that would provide the pilot with an alarm when the aircraft approaches an aerodynamic wing stall.
Jim Morris, a former RAF pilot and specialist aviation lawyer who is Head of Aviation at Ashfords, commented: "This tragic accident is very concerning as reports indicate that the weather was good and the pilot was very experienced, yet the seaplane appears to have suffered a problem that caused a catastrophic loss of control.
"Factors that will be considered by the air accident investigators will include whether there was an engine problem / failure, whether there was a structural failure or problem with the flying controls, the wing flap configuration, whether the aircraft suffered a wing stall and whether a stall warning system had been fitted to the aircraft.
"Given the previous DHC-2 accidents caused by wing stalls and the Canadian investigation conclusions on the DCH-2 crash in 2015, the possibility of a wing stall causing the crash could be a key aspect of the investigation.
"A wing stall occurs when the air flow starts to separate from the top of the wing, causing rapid loss of lift and height if not corrected promptly by the pilot. A number of factors can cause a wing stall, such as flying too slowly or increasing the load on the wings beyond the lift available from the airflow speed, such as a sharp turn.
"Due to the large loss of height that can result from a wing stall, pilots are taught to recognise when an aircraft is about to enter such a stall, which normally involves vibration in the airframe and flying controls (due to aerodynamic buffeting), and how to quickly recover from the stall. However, if an approaching wing stall is not promptly recognised by the pilot, the full wing stall can rapidly develop causing rapid loss of height and a possible wing drop causing a nose down spiral.
"As identified in the Canadian accident investigation of the 2015 crash, for the DHC-2 Beaver there is concern that the DHC-2's aerodynamic pre-stall buffeting does not provide pilots with adequate warning of an impending wing stall and in particular situations, such as during a steep turn with power applied, there may be few or no signs of an impending wing stall, with the flight path then rapidly changing from horizontal to vertical.
"For an aircraft at low altitude flight, such as the Sydney seaplane shortly after take-off, a stall with wing drop would mean that the pilot would not be able to regain control of the aircraft before impact with the water.
"It is to be hoped that the Australian air accident investigators can promptly identify what caused the loss of control so that lessons can be learned and appropriate safety measures implemented for future DHC-2 Beaver operations."