Accident Details
On the day of the accident, Northrepps Airfield had a single grass runway oriented 18/36, 1617 ft (493 m) long, with a down slope of 1.8% on Runway 18. The short grass was wet, and an aftercast indicated wind from approximately 210° at 10 to 13 kt. The pilot first approached Runway 18, touching down close to the threshold. After observing the slope ahead, he decided to go around and reposition for a landing on Runway 36 to take advantage of the up-slope. The pilot assessed that the braking effect of the wind would be insignificant compared to the uphill slope on Runway 36.
During the approach to Runway 18, the pilot noted a "shortened" and "non‑standard" windsock on a caravan near the threshold but did not rely on it for accurate wind strength. He did not recall seeing the airfield's other, larger windsock. The approach for a short field landing on Runway 36 was normal; the pilot closed the throttles just before the threshold. The aircraft touched down close to the threshold, and the pilot immediately retracted the flaps.
Sequence of Events
The pilot reported losing two-thirds of his touchdown speed by about the runway midpoint, with braking within expectations. He then stated that he "seemed to get to a point… when I realised that I was effectively getting no braking at all from the wheels and the uphill slope had petered away." He experienced a sensation similar to aquaplaning, with all braking authority seemingly lost. The aircraft continued along the runway, crossed the grassed overshoot area, ran over an earth bank beyond the runway end, and came to rest on a public road just north of the bank. The pilot shut down the aircraft, and all three occupants vacated without difficulty.
Probable Cause
The official investigation found that prior to the flight, the pilot did not use the aircraft flight manual to calculate his landing performance. Given the wind and surface conditions at Northrepps at the time, performance calculations indicated that a landing could only be made safely if both precise landing parameters and adequate braking were achieved. There was no evidence regarding the point of touchdown or associated speed; therefore, it was not possible to determine whether the failure to stop resulted from an imperfectly executed landing or a lack of braking effect on the short, wet grass.