What happened
On July 25, 1999, a private Piper PA-28 Warrior, registration HB-PIB, was attempting a takeoff from Lausanne Airport. The pilot, accompanied by one passenger, was planning a leisure flight to Locarno. During the takeoff roll, the pilot observed the engine RPM at 2500 and the airspeed reaching approximately 55-60 knots.
As the aircraft reached the upward slope of the runway, the pilot believed the airspeed was insufficient for a safe departure. Consequently, the pilot aborted the takeoff and cut the engine power. Despite attempting to brake, the aircraft continued down the runway, crossed the end of the paved surface, and traveled across the grass area. The aircraft eventually descended a bank and came to a stop across a public road. While the aircraft sustained heavy damage, both occupants escaped the incident without injury.
The investigation
Investigators examined the mechanical condition of the Piper PA-28 Warrior, including the engine, instruments, and braking system. The engine was found to be in good working order, and inspections of the airspeed indicator and tachometer revealed only negligible deviations within tolerable limits. The aircraft's weight and balance were within prescribed limits, though the center of gravity was noted to be near the forward limit. Additionally, the elevator trim tab was set in a nose-down position.
Regarding the braking system, investigators found that the brake lines had been ruptured and the discs warped, but these damages were determined to have been caused by the impact with obstacles during the excursion rather than a pre-existing failure. The investigation also noted that the pilot had configured the flaps at 10 degrees, a setting not specifically recommended by the flight manual for these conditions.
Findings
- The pilot made an error in judgment by incorrectly assessing the aircraft's performance, believing the airspeed was too low for takeoff due to a headwind.
- The combination of a forward center of gravity and a nose-down trim setting likely created an increased requirement for back pressure, contributing to the pilot's perception that the aircraft was not accelerating adequately.
- The aircraft's excursion from the runway was primarily caused by insufficient braking following the aborted takeoff attempt.