What happened
On 4 October 2003, a Piper PA-34-220T Seneca III, registration G-LENY, was conducting a passenger flight from Oxford to Toussus le Noble, France. Approximately one hour into the flight, while traversing the English Channel, the right-hand engine began running roughly and lost power. The pilot observed that the fuel pressure for the right engine had dropped to zero and the right-hand tank gauge indicated an empty state, while the left tank showed approximately 10 Gall US remaining.
In response to the engine failure, the pilot shut down and feathered the right engine and diverted to Dieppe. The aircraft performed a safe single-engine landing at the airfield. Following the landing, the crew performed engine runs and power checks, which confirmed that the issue was caused by fuel starvation rather than a mechanical malfunction. After refuelling and receiving maintenance clearance, the flight was able to continue to its destination.
The investigation
The investigation established that although the pilot had calculated the necessary fuel for the flight and sent a fax request to a refueling organisation the previous evening, the request was never received because the recipient's fax machine had run out of toner. Consequently, the aircraft was not replenished as planned.
During the pre-flight inspection, the pilot performed a visual check of the fuel tanks. Although no fuel was visible, the pilot was not alarmed because the expected fuel load was only about 75% of the total capacity. Furthermore, the pilot noted a discrepancy between the fuel gauges and the expected levels but dismissed the readings due to a personal distrust of the accuracy of light aircraft fuel gauges. It was also discovered that a significant fuel imbalance had developed over the previous 11 hours of flight time, as the right-hand engine was consuming fuel at a higher rate than the left, a fact that had gone uncorrected by previous crews.
Findings
- The primary cause of the incident was insufficient fuel onboard due to the failed delivery of the refueling request.
- The pilot's failure to recognize the low fuel levels was due to a mistaken belief that the aircraft's fuel gauges were unreliable.
- The lack of visible fuel during the pre-flight check did not trigger concern because the pilot expected a partial load.
- A cumulative fuel imbalance between the two tanks had developed over several hours of operation, which contributed to the right engine running out of fuel first.
Safety action
- The operator reviewed company procedures regarding refueling and in-flight fuel management.
- The pilot received additional training.
- The refueling organisation implemented a new procedure to indicate the specific amount of fuel loaded into each tank on the fuel order form.