Unintended engine power surge leads to runway excursion and collision

Casualties unknown • Conséquences et dommages, FR

A Socata TB9 aircraft was destroyed after an unexpected engine power surge during startup caused the aircraft to veer off the runway and strike a perimeter fence.

What happened

On May 27, 2013, at 11:45 local time, a Socata TB9, registration F-GKVV, was undergoing engine startup at the Lille-Lesquin aerodrome. While parked, the pilot had adjusted their seating position using cushions rather than adjusting the seat itself. Following standard procedures, the pilot applied the parking brake and performed five throttle injections to prime the cold engine before returning the throttle to idle.

During the start sequence, the pilot perceived insufficient power and advanced the throttle. This caused the engine to deliver full power, resulting in an unintended forward movement of the aircraft. Although the pilot attempted to re-apply the parking brake and return the throttle to idle, these actions failed to stop the movement. The aircraft proceeded toward runway 20, veered left, and exited the paved surface. The right wing struck the aerodrome's perimeter fence, causing the aircraft to pivot and collide with the structure. The aircraft was destroyed in the accident.

The investigation

The BEA examined the aircraft's power controls and braking systems, finding no mechanical anomalies. Investigators noted that the pilot's seat was positioned at the furthest rear setting. The pilot, who held a PPL(A) and had 140 total flight hours, had only 12 hours of experience on the Socata TB9 and had not flown this specific model for 11 months. Prior to the accident, the pilot had been flying exclusively on a different type, the WT9 Dynamic.

Technical comparisons between the Socata TB9 and the WT9 Dynamic revealed significant differences in braking systems and seat configurations. The investigation also looked into the flight club's operations, finding that the club's manual required recent experience (within four months) to operate the TB9. However, the club's reservation software did not enforce this, and the requirement had not been effectively communicated to the pilots.

Findings

The accident was likely caused by inadequate engine startup procedures and an inappropriate pilot response to interrupt the taxiing.

Contributing factors included:

  • The pilot's limited experience on the Socata TB9.
  • Improper seat positioning due to the use of cushions, which affected the pilot's ability to operate the brakes effectively.
  • Inadequate communication from the flight club regarding aircraft usage requirements.

Safety action

Following the investigation, the flight club implemented several measures, including:

  • Informing pilots of the specific recent experience requirements for different aircraft types.
  • Enforcing these experience rules during the aircraft key release process.
  • Conducting instructor meetings to improve safety briefings regarding engine startup and taxiing procedures.

Probable cause

The accident resulted from an unintended surge in engine power during startup, compounded by the pilot's insufficient experience on the specific aircraft type and an improper seating arrangement that hindered effective braking.

Frequently asked questions

What happened in the 2013-05-27 Socata TB9 accident near Conséquences et dommages, FR?

A Socata TB9 aircraft was destroyed after an unexpected engine power surge during startup caused the aircraft to veer off the runway and strike a perimeter fence.

What aircraft was involved and where did it happen?

The accident on 2013-05-27 involved a Socata TB9, registration F-GKVV, at Conséquences et dommages, FR.

What was the probable cause of the accident?

The accident resulted from an unintended surge in engine power during startup, compounded by the pilot's insufficient experience on the specific aircraft type and an improper seating arrangement that hindered effective braking.

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