Summary
On 24 October 2013, a Piper PA-34-200 Seneca, registration G-BASM, overran Runway 06 at Denham Aerodrome in Buckinghamshire. The aircraft, which had just completed a flight from Andrewsfield Aerodrome in Essex, continued through a perimeter fence, across a public road, and came to rest in a grass field. The pilot was not injured and vacated the aircraft without assistance. The aircraft sustained substantial damage.
History of the Flight
The aircraft had undergone annual maintenance at Andrewsfield Aerodrome. Following maintenance, the engines were ground run for approximately two hours, and again for 15 to 20 minutes a week later. The pilot, who held a Private Pilot’s Licence and had 1,216 hours total flying experience (535 on type), had not flown for over three months. He arrived to collect the aircraft for a 20-minute flight back to Denham, where it was usually kept.
Before departure, the pilot refuelled the aircraft with 230 litres (60 USG) of fuel and performed a water drain check. The flight to Denham was uneventful. Weather on arrival was fine, with surface wind from 120° to 160° at 4 to 8 knots. The pilot joined the circuit on a base leg for Runway 06 but was asked by the Air Ground (A/G) operator to go around because of proximity to another aircraft.
During the go-around, both engines began to run roughly and the pilot was unable to maintain height. He turned onto crosswind leg early and broadcast that he had two rough-running engines. The A/G operator acknowledged and notified the aerodrome Rescue and Fire Fighting Service. The pilot adjusted the throttle, mixture, and carburettor heat but saw no improvement. He turned onto final approach at about 350 ft aal, maintaining a higher-than-usual airspeed of 85 to 90 knots.
The A/G operator observed the aircraft low on final. As it floated down the runway, the pilot decided against another go-around due to concern about insufficient power. He estimated touchdown about halfway along the 775-metre asphalt runway (landing distance available 706 m). Despite heavy braking, the aircraft departed the paved surface, crossed a fence and road, and stopped in a field.
Discussion
The pilot assessed that he had landed at too high a speed and also considered that fuel contamination might have caused the rough-running engines. However, he had experienced no engine problems during the en-route portion of the flight. The Landing Ground Roll for a PA-34-200 at maximum weight in standard conditions with nil wind is approximately 427 m (1,400 ft).
No overhead circuit joining procedure exists at Denham; inbound aircraft must establish radio contact and join an extended base leg. Runway 06 has abbreviated Precision Approach Path Indicators (APAPI) set at 4.5°.
Probable Cause
The source does not provide an official probable cause. The pilot's own assessment attributed the accident to landing at excessive speed and possible fuel contamination, but these are not stated as a formal cause.
Damage
The aircraft sustained substantial damage. The pilot was uninjured and dismantled the aircraft to recover it from the field.