History of the Flight
On 30 September 2005, a Cessna 421C Golden Eagle, registration N421CA, was operating a private flight. The pilot first approached Runway 18 at Northrepps Airfield and touched down near the threshold, but elected to go around and reposition for a landing on Runway 36, which has an uphill slope. The approach to Runway 36 was normal; the pilot closed the throttles just before the threshold and retracted the flaps after touchdown. The pilot reported losing two-thirds of the touchdown speed by the runway midpoint, but then experienced a sensation similar to aquaplaning, with no braking effect. The aircraft continued past the runway end, crossed a grass overshoot area, traversed an earth bank, and came to rest on a public road. The three occupants exited without difficulty.
Runway 18/36 is a single grass strip 1,617 feet long with a 1.8% downslope on Runway 18 and an equivalent upslope on Runway 36. At the time of the accident, the grass was wet and the wind was from approximately 210° at 10 to 13 knots, resulting in a tailwind component for landing on Runway 36.
Pilot Background and Preparation
The pilot held a Private Pilot’s Licence and had 2,475 hours total flying experience, including 255 hours on type. He had purchased the aircraft two weeks before the accident and flown 17 hours since. He had not received any refresher training on the aircraft. Prior to the flight, he consulted a proprietary flight guide and spoke with the airfield operator, concluding that the operation into Northrepps was feasible. He did not consult the aircraft flight manual to determine landing distance or ground roll requirements, considering the grass and uphill slope sufficient to arrest the aircraft.
Performance Information
The aircraft flight manual provides landing distance data for a level, hard surface. For a weight of 6,000 lb, temperature +20°C, and sea level in still air, the landing distance is 2,070 feet with a ground roll of 500 feet. No allowance is given for runway slope. CAA Safety Sense Leaflet 7C suggests a 2% downslope increases landing distance by 10% and warns that wet grass may increase distances by up to 60%. Applying these factors to the runway and reported wind conditions, the calculated landing distance required for Runway 36 was approximately 3,879 feet, exceeding the available runway length.
Conclusion
The pilot did not use the aircraft flight manual to calculate landing performance before the flight. Given the wind and surface conditions, performance calculations indicated that a safe landing would require precise touchdown parameters and effective braking. The video evidence recorded by a member of the public did not show the touchdown zone, and there was no evidence of the touchdown speed. Consequently, it could not be determined whether the aircraft overran due to an imperfect landing or the lack of braking on the short, wet grass.