What happened
On 28 March 2007, an Airborne Edge XT912-B/Streak III-B microlight, registration G-CEHH, was conducting a training flight at Plaistows Farm Airfield. The flight was being led by a qualified instructor, with a student pilot occupying the rear seat. The purpose of the session was to demonstrate an engine-off landing technique to the student.
During the flight, the aircraft climbed to approximately 2,000 feet before entering a glide descent as part of a left-hand circuit for Runway 3-3. While performing a series of S-turns, the aircraft drifted east of the extended runway centreline and onto a right base leg. During this phase, the aircraft's left wing struck the upper branches of a tree located roughly 200 metres from the runway threshold. The impact caused significant structural damage to the wing and rendered the aircraft unstable. The aircraft subsequently fell to the ground approximately 80 metres from the tree. The impact resulted in one fatality and one serious injury.
The investigation
Investigators examined the aircraft's mechanical condition and the circumstances of the flight. Engineering checks of the Rotax 912 engine and fuel systems showed no evidence of mechanical failure or fuel contamination. Evidence suggested the engine was not running at the time of the ground impact, though the ignition switches were in the on position.
The investigation also considered whether a visual illusion caused the pilot to misjudge the tree's position. While the tree's upper branches might have appeared to blend with distant woodland, testing via helicopter and photography was inconclusive. Furthermore, the investigation looked into the suitability of the airfield for engine-off training, noting that the small size of Plaistows Farm Airfield increases the risk of a misjudged approach.
Findings
- The instructor's blood alcohol level was 137 mg/100 ml, significantly exceeding the UK flying limit of 20 mg/100 ml.
- The high level of alcohol in the instructor's system likely caused serious impairment of judgement.
- The execution of S-turns during the engine-off approach caused the aircraft to fly at a low altitude toward the tree, which was not the primary focus of the crew's attention.
- The impact with the tree's branches caused the left wing to collapse, leading to the subsequent crash.