What happened
On September 3, 2004, a privately operated Commander Aerocommander 114, registration OO-TST, was conducting a cross-country flight from Antwerp, Belgium, to Calais, France. The flight plan originally included a stop in Ursel, Belgium, but the pilot decided to proceed directly to Calais to avoid heavy traffic in the Ursel circuit.
Approximately 25 minutes into the flight, while passing the "E" point of the Calais control zone at 1,500 feet, the Lycoming IO 540 engine began to sputter and subsequently failed. The pilot attempted to switch fuel tanks and restart the engine, but was unsuccessful. After notifying Calais tower of the engine failure and the intention to perform an emergency landing, the pilot identified a small paved strip and attempted to land. Upon touchdown, the pilot realized the strip was actually a model aircraft runway. The aircraft veered longitudinally off the runway and was brought to a halt by a safety barrier bordering a nearby road. The aircraft sustained heavy damage.
The investigation
The investigation focused on the cause of the engine failure and the pilot's pre-flight preparations. Investigators examined the aircraft's fuel tanks, which were found to be empty. A review of the aircraft's logbook revealed that the last significant refueling had occurred on August 22, 2004.
Crucially, the investigation scrutinized the pilot's method for calculating remaining flight endurance. The pilot had relied on a calculation derived from the logbook entries to estimate available fuel. It was discovered that the pilot had incorrectly read the logbook entries, using a timestamp from a previous entry rather than the most recent hour meter reading. Furthermore, the investigation noted that the hour meter readings used for such calculations are unreliable for precise endurance estimates because the rate of accumulation varies with engine RPM.