What happened
On 21 September 2008, a Reims Cessna F152, registration G-BLZE, was involved in an accident during a private cross-country flight at Farway Common Airfield in Devon. After completing successful landings at Manston and Bembridge, the pilot and passenger arrived at the unlicensed airfield. Following a period on the ground, the pilot decided to depart from Runway 10.
During the takeoff roll, the aircraft accelerated to approximately 40 to 45 KIAS. Fearing that the aircraft would not reach the necessary 50 KIAS rotation speed to safely clear obstacles, the pilot elected to abort the takeoff. During the deceleration phase, the aircraft failed to stop before striking a hedge at the end of the runway. The impact caused damage to the nose and right wing, and the right wing fuel tank began to leak, though no fire occurred. There were no injuries to the two occupants.
The investigation
The AAIB investigation examined the aircraft's performance capabilities and the runway conditions. The pilot noted that the aircraft had required significant power to taxi off the runway after a previous landing, leading to a suspicion that a brake might have been partially seized. The pilot also considered that the 5 to 6 cm long grass might have impeded acceleration.
Investigators analyzed the takeoff distances for the specific weight and atmospheric conditions. While the manufacturer's data suggested a safe takeoff was possible on the available 550 m runway, the investigation looked at more conservative safety margins recommended by the CAA. These margins account for the increased ground roll and takeoff distance required when operating on grass surfaces.
Findings
- The aircraft's acceleration ceased at approximately 45 KIAS, preventing the pilot from reaching the required rotation speed.
- Insufficient runway remaining was available to safely stop the aircraft once the decision to abort was made.
- The 2.5% downslope of the runway likely increased the required braking distance.
- A partially stuck brake may have contributed to the lack of acceleration, though this could not be definitively confirmed.
- The use of a more conservative safety factor for grass operations might have indicated that a safe takeoff was not achievable.