What happened
On the evening of December 4, 2023, a Piper PA30, registration F-BPIR, was conducting an instrument flight rules (IFR) training mission from Toussus-le-Noble. The crew, consisting of a student pilot, an instructor, and one passenger, had previously completed a flight to Rouen-Vallée de Seine and was returning to Toussable-le-Noble. During the descent toward the approach fix, the aircraft's stall warning was triggered and remained active for several minutes.
At approximately 17:11 local time, while descending through 2,650 feet, both engines experienced an uncontrolled shutdown. The instructor took control of the aircraft and attempted to restart the right engine, but was unsuccessful. Unable to maintain altitude, the instructor performed a forced landing in an urban area near Villejuif. The aircraft struck a tree and a building before coming to a stop against a low wall. The pilot in training and the instructor sustained injuries, and the aircraft was destroyed.
The investigation
The BEA investigation focused on the sequence of fuel management and the aircraft's configuration prior to the engine failure. Investigators examined the aircraft's fuel system, which included main, auxiliary, and tip tanks. The investigation revealed that the engines had been starved of fuel.
Investigators also reviewed the training organization's (ATO) procedures, specifically their practice of simplifying fuel management to reduce pilot workload during multi-engine instrument training. The investigation looked into the preflight procedures, noting that the student pilot had performed several tasks from memory to save time due to a scheduled departure slot (CTOT). The investigation also examined the instructor's oversight and the adequacy of the ATO's checklists and risk assessments.
Findings
- The primary cause of the engine shutdown was the unpriming of the fuel system because the fuel tank selectors were left in the auxiliary (AUX) position.
- During the preflight draining of the tanks, the student pilot likely failed to return the selectors to the MAIN position. This error went undetected because the student was performing the checks from memory under time pressure, and the instructor did not verify the selector positions.
- The aircraft was operating on fuel from the AUX tanks without the crew's knowledge, as the ATO's standard practice was to use only MAIN tanks for such short flights.
- The ATO's simplified fuel management procedures and checklists reduced situational awareness and failed to provide a mechanism to detect a selection error during flight or during an engine failure.
- The instructor's decision to maintain a clean configuration (landing gear and flaps retracted) to maximize glide distance, combined with the lack of propeller feathering, contributed to the high sink rate during the final approach.