Light aircraft forced to land on Wexford beach due to 'interruptions to fuel supply'

The 'forced' landing of light aircraft on a beach in Wexford more than three years ago was probably caused by interruptions to the fuel supply of both engines, investigators have concluded.

Two people, including the pilot, sustained serious injuries in the incident which happened close to Carnsore Point on September 23, 2021.

The incident was investigated by the Air Accident Investigation Unit at the Department of Transport and its final report has just been published.

According to the report, which runs to almost 60 pages, a group of researchers from University College Cork were on board the French–registered twin-engine aircraft at the time to survey and record sightings of various marine wildlife.

"On the day of the accident, the pilot and task specialists had planned to complete 16 pre-defined survey lines. The survey lines were completed after approximately four hours and 30 minutes of flying. The pilot then carried out an assessment of the fuel levels and advised the task specialists that it would be possible to complete two further survey lines whilst allowing enough fuel to return to Waterford Airport with fuel reserves intact," reads the report.

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The investigation established that during the final additional survey line, the right engine stopped suddenly and that the left engine began to lose power a short time later.

"The Pilot then routed directly towards land and elected to perform a forced landing on the beach. During the forced landing the nose of the aircraft impacted with the loose shale surface and decelerated rapidly, causing substantial structural damage to the forward cabin area," states the report which added that some parts of the debris were washed out to sea and were never recovered.

As part of the investigation, the fuel tanks were emptied and it was established they contained 74 litres of fuel which would have been enough to safely return to Waterford Airport.

Having spoken with those on board the plane, investigators established that the fuel gauges might not have been accurate, leading the pilot to believe he had more fuel in the tanks.

"One task specialist recalled that during the flight the pilot commented that they were ‘doing great’ with regards to fuel consumption. Prior to starting the final two survey lines, the Pilot believed that there was one hour and forty-five minutes of fuel left (just over one quarter of a tank on each side), however 20 minutes later (when the right engine symptoms started) the pilot recalled that the fuel level was between one quarter and half a tank. The Pilot then described how within a few minutes of the right engine stoppage, the indicated fuel level on the right tank dropped to zero."

AAIU inspectors state in their report that they found pre-existing damage to the fuel level transmitters, which they added could have resulted in false fuel gauge readings during the flight.

The report also makes reference to commentary from other pilots experienced in operating the same type of aircraft. Those pilots indicated that fuel supply interruptions were possible when flying in an uncoordinated manner with less than one quarter tank of fuel (as was the case in this instance).

"While it was not possible to be definitive about the mechanism by which the right engine stopped, the Investigation is of the opinion that the most likely cause was a fuel supply interruption. When the left engine appeared to be developing lower than expected power, the pilot manipulated the fuel selectors to crossfeed fuel from the right tank to the left engine which may have interrupted the fuel supply to the left engine, particularly given the anomalies identified with the crossfeed pipework" states the report.

Following the incident, the operator of the aircraft amended its standard operating procedures and instructed all pilots to have a minimum fuel quantity of 100 litres at all times for a high-risk flight.

Three safety recommendations have been made by the AAUI arising from their investigation.