What happened
On the morning of 12 November 1996, a Piper Cherokee Six, registration G-ILTS, attempted to depart from Warren's airstrip near Gorey, Co Wexford. During the takeoff roll, the aircraft struggled to gain sufficient speed and bounced twice on the grass surface. As the aircraft approached the end of the runway, the main undercarriage struck a barbed wire boundary fence, breaking wooden poles in the process.
Following the impact, the aircraft maintained a high nose-up attitude for approximately 300 metres. The pilot subsequently executed an emergency landing in an adjacent cultivated field. The impact with the ground was heavy, causing the main undercarriage to detach and resulting in significant damage to the aircraft's underside. All five persons on board evacuated the aircraft safely and without injury.
The investigation
The investigation examined the aircraft's performance capabilities, the runway conditions, and the pilot's preparations. Investigators found that the usable runway length was approximately 450 metres, significantly shorter than the 505-metre total length of the strip. The runway surface was noted to be soft with lush grass and morning dew, and the takeoff involved an uphill gradient.
Technical examination of the aircraft revealed a missing spacer in the port wheel assembly, which caused the wheel to wobble and may have contributed to a leftward veer during the takeoff run. While the pilot reported an unfamiliar engine sound, investigators found no significant engine malfunction that would have directly caused the accident. Furthermore, no formal weight and balance calculations had been performed prior to departure, making it impossible to confirm the exact load, though it was suspected the aircraft may have been at or above its maximum allowable takeoff weight.
Findings
- The aircraft failed to reach a safe flying speed within the available runway length due to reduced accelerative performance.
- This lack of performance was caused by the combined impact of the aircraft potentially being at or above its maximum takeoff weight, the uphill gradient, and the soft, damp grass surface.
- The pilot did not perform weight and balance calculations to ensure an adequate safety margin for the marginal airstrip.
- The pilot did not fully account for how the runway gradient and surface conditions would affect the aircraft's takeoff distance.
Safety action
- Pilots of general aviation aircraft should be reminded of the necessity of calculating aircraft weight and center of gravity to ensure adequate performance for intended flights.
- Performance calculations should explicitly include factors such as wind conditions, runway gradient, and surface conditions to maintain appropriate safety margins.