History of the Flight
The aircraft, a Piper PA-28-161 Cherokee Warrior II registered G-BNOM, was landing on Runway 35 at Derby Airfield after a flight from Blackbushe. It was the pilot's second landing at this airfield. Weather conditions were good with calm wind, visibility of seven kilometres in haze, and scattered cloud at 4,500 feet. The aircraft weighed 993 kg at landing. Runway 35, a grass surface, had a declared Landing Distance Available (LDA) of 528 metres, the longest on the airfield.
The pilot contacted the airfield on Air/Ground radio and was advised of the active runway, circuit pattern, pressure setting, and wind conditions. Neither the pilot enquired about nor the operator offered information on the runway surface state, which was damp with remnants of overnight dew. The pilot flew the final approach at 75 kt with full flap and reduced power, but considered the speed 5 kt faster than appropriate. Two witnesses confirmed the aircraft appeared faster than normal on profile.
The aircraft touched down at 60 to 65 kt between one third and halfway into the runway. After touchdown, the pilot applied brakes but observed slower than expected deceleration, confirmed by witnesses. Despite maximum braking, it became clear the aircraft would run off the end and collide with a hedge and railway embankment. The pilot dismissed a touch-and-go due to trees and power cables in the climb-out path. As the aircraft approached the runway end, the pilot turned right 90 degrees to absorb impact on the left wing, preferring that to a head-on collision and providing better protection for the passenger. The left wing struck the bank at about 10 kt while moving sideways, causing the right wing to rise to 45 degrees before settling back on the landing gear. The pilot shut down the engine, and both occupants exited unhurt; no fire occurred.
Aircraft Examination
Post-accident inspection found no fault in the braking system. The throttle lever was in approximately the one-quarter open position, though it could have been moved when the aircraft was vacated. The fixed-pitch propeller blades had forward bends, indicating the engine was producing more than idle power at the time of impact. Throttle lever movement was unrestricted throughout its range.
Performance Considerations
The Airplane Flight Manual (AFM) for the Piper PA-28-161 gives a Landing Distance Required (LDR) of 492 metres under the day's conditions, assuming a dry runway and including a safety factor of 1.43 for private flights. However, for a wet grass runway, the CAA's General Aviation Safety Sense Leaflet 7B recommends an increased safety factor, resulting in an LDR of 591.5 metres, exceeding the available 528 metres LDA. The grass was damp with overnight dew, making the wet performance figure more appropriate.
The AFM specifies landing conditions: flaps 40 degrees fully extended, touchdown speed at stall, flaps retracted after touchdown, and maximum braking. The ground roll is approximately 50% of the total landing distance. The AFM also states final approach speed as 63 KIAS with flaps 40 degrees, and a touchdown speed of 42 KIAS for the aircraft's landing weight. The pilot's approach speed (75 kt) and touchdown speed (60-65 kt) exceeded these figures. Pooleys Flight Guide for Derby Airfield includes a caution for Runway 35 regarding power cables 100 feet above airfield level immediately north, and emphasizes the need for an early go-around decision on a missed approach.
Pilot's Conclusion
The pilot concluded that the accident resulted from his inexperience and his decision to continue the approach and landing rather than perform a go-around.