Lake, Sea, Ocean, River

The ingestion of large birds into each engine, which resulted in an almost total loss of thrust in both engines and the subsequent ditching on the Hudson River. Contributing to the fuselage damage and resulting unavailability of the aft slide/rafts were:
-the Federal Aviation Administration’s approval of ditching certification without determining whether pilots could attain the ditching parameters without engine thrust,
-the lack of industry flight crew training and guidance on ditching techniques,
-the captain’s resulting difficulty maintaining his intended airspeed on final approach due to the task saturation resulting from the emergency situation.
Contributing to the survivability of the accident was:
-the decision-making of the flight crew members and their crew resource management during the accident sequence,
-the fortuitous use of an airplane that was equipped for an extended overwater flight, including the availability of the forward slide/rafts, even though it was not required to be so equipped
-the performance of the cabin crew members while expediting the evacuation of the airplane,
-the proximity of the emergency responders to the accident site and their immediate and appropriate response to the accident.

Controlled flight into terrain after the crew descended too low on final approach.
The following contributing factors were identified:
- Limited visibility due to the night and low clouds,
- The approach was completed with a tailwind component,
- The approach was started about an hour after sunset,
- The copilote was inexperienced.

The accident was caused by the loss of control of the airplane by the crew following the improvised demonstration of the functioning of the angle of attack protections, while the blockage of the angle of attack sensors made it impossible for these protections to trigger. The crew was not aware of the blockage of the angle of attack sensors. They did not take into account the speeds mentioned in the program of checks available to them and consequently did not stop the demonstration before the stall.
The following factors contributed to the accident:
• The decision to carry out the demonstration at a low height
• The crew’s management, during the thrust increase, of the strong increase in the longitudinal pitch, the crew not having identified the pitch-up stop position of the horizontal stabilizer nor acted on the trim wheel to correct it, nor reduced engine thrust
• The crew having to manage the conduct of the flight, follow the program of in-flight checks, adapted during the flight, and the preparation of the following stage, which greatly increased the workload and led the crew to improvise according to the constraints encountered
• The decision to use a flight program developed for crews trained for test flights, which led the crew to undertake checks without knowing their aim
• The absence of a regulatory framework in relation to non-revenue flights in the areas of air traffic management, of operations and of operational aspects
• The absence of consistency in the rinsing task in the airplane cleaning procedure, and in particular the absence of protection of the AOA sensors, during rinsing with water of the airplane three days before the flight. This led to the blockage of the AOA sensors through freezing of the water that was able to penetrate inside the sensor bodies.
The following factors also probably contributed to the accident:
• Inadequate coordination between an atypical team composed of three airline pilots in the cockpit
• The fatigue that may have reduced the crew’s awareness of the various items of information relating to the state of the systems.

Following a review of the available evidence covering:
• Witness information,
• The pilot's fatigue and health,
• The airworthiness of the aircraft,
• Aircraft fuel,
• The weather affecting the flight, and
• The aircraft’s loading and weight and balance,
The investigation was unable to identify any factors that may have contributed to the accident. From the evidence available, the following findings are made with respect to the missing aircraft at Buckingham Bay, Northern Territory on 16 October 2008 involving Gippsland Aeronautics GA8 Airvan aircraft, registered VH-WRT. They should not be read as apportioning blame or liability to any organisation or individual. No contributing safety factors were identified.
Other safety factors:
• The main vertical net and the throwover net were not used to restrain the cargo.
• The full jerry cans were not secured in the aircraft cabin.
• At the time of departure, the aircraft’s centre of gravity (c.g) was probably to the rear of the permitted c.g limit that was published in the Aircraft Flight Manual.
• There was no record that the pilot lodged a flight notification for the flight with Airservices Australia.

Engine failure for unknown reasons.

Failure of the left engine on final due to fuel exhaustion. It remained a total of 3 gallons of fuel in the left fuel tank and 23 gallons in the right main tank.