What happened
On 7 October 2012, a Britten-Norman BN2A-26 Islander, registration VP-MON, was conducting a commercial passenger flight from V C Bird International Airport in Antigua to Montserrat. Before the flight, the airport had experienced heavy rain showers, with approximately 40 mm of rainfall recorded.
Shortly after takeoff, the aircraft experienced a sudden yaw and roll to the right, descending rapidly and losing control. The aircraft impacted the ground within the airport perimeter, striking the ground with the right wingtip first. The impact destroyed the forward fuselage, while the rear of the aircraft remained relatively intact. The accident resulted in three fatalities (the pilot and two passengers) and one serious injury to a third passenger.
The investigation
The investigation examined the wreckage and technical records to determine the cause of the engine failure. Investigators found that the right-hand engine was not producing power at the moment of impact. Analysis of the fuel system revealed that significant quantities of water were present in the fuel supply feeding the right-hand engine.
Further examination of the fuel filler cap showed that the design was incompatible with the filler neck, which allowed rainwater to enter the fuel tank while the aircraft was parked. Additionally, the investigation looked into the fuel suction filter assembly. It was noted that the aircraft was not equipped with the modified filter design (Mod NB/M/350) intended to protect against water accumulation in the sump.
Findings
- The right-hand engine failed due to water contamination in the fuel system.
- The fuel filler cap design allowed water to enter the tank during recent heavy rainfall.
- The aircraft's fuel suction filter was the pre-modification type, which is less tolerant of water collecting in the sump during the takeoff rotation.
- The propeller on the failing engine was not in the feathered position, meaning no attempt was made to execute engine-out procedures.
Safety action
- Safety Recommendation 2013-014: It is recommended that the European Aviation Safety Agency (EASA) takes action to ensure Britten-Norman Islander aircraft are equipped with fuel suction filter assemblies that minimize the risk of water in the tank sumps being fed to the engines.