What happened
On the night of 3 November 2013, a Pilatus Britten-Norman BN2B-21 Islander, registration G-CIAS, was deployed on an urgent private search and rescue mission near the Channel Islands. The flight was tasked with locating two fishermen reported to be in distress near Les Écrutous. The mission was conducted under extremely challenging conditions, characterized by heavy rain, low cloud, turbulence, and strong winds.
Shortly after takeoff, the pilot noticed a change in the engine note. While attempting to troubleshoot the issue, the right-hand engine lost power. As the pilot diverted the aircraft toward Jersey Airport, the left-hand engine also ceased producing power. Despite the lack of visibility and the loss of both engines, the pilot managed to navigate toward the coast and execute a forced landing near Devil’s Hole. The aircraft struck a hedge and came to rest against a tree, causing significant damage to the airframe, including the wing and landing gear. There were no injuries among the pilot and the 41 passengers on board.
The investigation
The AAIB investigation focused on the cause of the dual engine failure and the operational procedures of the volunteer organization. Investigators examined the aircraft's fuel system, finding that the fuel tank selector switches were set to the tip tanks. While the main tanks were nearly full, the tip tanks were empty.
Technical analysis revealed that the engines had been fed by the tip tanks, which had been exhausted during the flight. The investigation also looked into the pilot's pre-flight routines, noting that the pilot relied on memory rather than written checklists and had not physically verified the fuel levels in the tip tanks. Furthermore, the investigation reviewed the cockpit layout, noting that the switches for the tip tanks were small and located away from the primary fuel gauges, and that the indicator lights dimmed when those tanks were in use, which could obscure information.
Findings
- The primary cause of the engine failures was fuel exhaustion caused by the engines being supplied from the tip tanks rather than the main tanks.
- The fuel system was configured to use the tip tanks following a previous training flight, a setting that went unnoticed during pre-flight preparations.
- The pilot's high workload due to severe weather and the urgency of the search mission likely hindered the detection of the fuel issue.
- The operator's procedures lacked robust checklists, and the pilot did not perform a physical dipstick check of the fuel quantities.
- The cockpit design contributed to the error, as the tip tank selectors were difficult to monitor and the indicator lights were not clearly positioned.