What happened
On 7 October 2012, a Britten-Norman BN2A-26 Islander, registration VP-MON, was performing a commercial passenger flight from V C Bird International Airport in Antigua to Montserrat. Shortly after departing the airfield, the aircraft experienced a sudden yaw and roll to the right, followed by a rapid descent. The aircraft struck the ground within the airport perimeter, impacting the right wingtip first at a low forward speed. The impact caused the aircraft to cartwheel before coming to rest upright. The forward section of the fuselage was destroyed upon impact. The accident resulted in 3 fatalities (the pilot and two passengers) and 1 serious injury to a third passenger.
The investigation
The investigation examined the wreckage, witness accounts, and technical records to determine the cause of the engine failure. Investigators found that the right-hand engine was not producing power at the time of the crash. Analysis of the fuel system revealed significant quantities of water within the fuel supply for that engine. The investigation also noted that the aircraft had been parked during a period of heavy rainfall, during which approximately 40 mm of rain had fallen. Furthermore, the right-hand propeller was not in the feathered position at impact, and testing of the propeller control unit suggested that the pilot had made no attempt to feather the engine following the loss of power.
Findings
- The right-hand engine failed due to water contamination in the fuel system.
- The right-hand fuel filler cap was incompatible with the filler neck, allowing rainwater to enter the fuel tank while the aircraft was parked.
- The aircraft was not equipped with the modified fuel suction filter assembly (Mod NB/M/350), which provides better protection against water being drawn from the sump during takeoff.
- No water drain check was performed on the fuel system following the heavy rainfall prior to departure.
Safety action
Following the investigation, the European Aviation Safety Agency (EASA) issued an Airworthiness Directive requiring operators of Britten-Norman Islander and Trislander aircraft to verify that fuel caps are compatible with their respective filler necks and to conduct water contamination checks if necessary. Additionally, a Safety Recommendation was made to require that these aircraft be equipped with fuel suction filter assemblies designed to minimize the risk of water in the sumps reaching the engines.