What aircraft was involved and where did it happen?

The accident on 2011-09-02 involved a Bolkow 208C Junior, registration D-EGFU, at Peterborough Sibson Airfield, Cambridgeshire, GB.

What was the probable cause of the accident?

The accident was caused by the aircraft striking high-tension power transmission lines during approach, likely due to the pilot's unfamiliarity with the airfield's displaced thresholds and the lack of precise obstacle information in the flight guides used.

Fatal power line strike during approach at Sibson Airfield

A Bolkow 208C Junior crashed after striking high-tension power cables during its final approach to Peterborough Sibson Airfield, resulting in the death of the pilot.

What happened

On 2 September 2011, a Bolkow 208C Junior, registration D-EGFU, was conducting a private flight from Long Marston Airfield to Peterborough Sibson Airfield. During the final approach to Runway 24, the aircraft struck the uppermost cable of a high-tension power transmission line located approximately 0.5 nm from the displaced threshold. The impact caused the aircraft to fall vertically, hitting the ground in an inverted position. The pilot sustained fatal injuries, and the aircraft was destroyed.

At the time of the approach, a Cessna Caravan was taxiing for takeoff on the same runway. Witnesses noted that the D-EGFU appeared to be flying a normal attitude until the collision, but its approach path was closer to the runway than the departing aircraft had estimated.

The investigation

The AAIB examination of the wreckage found no evidence of mechanical or structural failure prior to the impact. The engine and flight controls were functional, and the propeller showed no signs of rotation at the moment of ground impact. Analysis of the wing structure revealed damage consistent with the cable cutting through the leading edge.

GPS data recovered from the aircraft showed the flight path included a climbing turn over Orton Waterville before descending onto the final approach. The investigation also reviewed airfield information sources, noting that the pilot was using an extract from a common airfield guide. This guide contained a 'Caution' regarding power lines but lacked specific details regarding their height or distance from the runway. Furthermore, the aircraft's approach targeted the start of the prepared runway surface rather than the displaced threshold, a choice potentially influenced by the unusual runway layout and the presence of the departing Caravan.

Findings

The pilot's unfamiliarity with the airfield and the unusual appearance of the runway, caused by significantly displaced thresholds, likely led to an approach path that intersected the power lines.
The aircraft struck high-tension transmission cables during the final approach.
Inconsistent or vague information in airfield guides regarding the specific location and height of the power lines contributed to the pilot's lack of awareness of the hazard.
The presence of a departing aircraft on the runway may have served as a distraction during the critical phase of the approach.
The lattice steel pylons supporting the lines were positioned such that they were difficult to see, leaving only the cables visible in the flight path.