Accident Overview
The aircraft, identified as G-TWIG, was completing its fifth sector of the day when the incident occurred. Shortly after initiating a descent toward Inverness, the aircraft's rate of descent became unsteady, and it began a left turn. According to the investigation, the aircraft struck the ground in a steep, left, spiral dive.
Wreckage and Impact
The wreckage exhibited extreme fragmentation, indicating a high impact speed, estimated at around 350 knots. Investigators examined the possibility of major airframe or powerplant failures but found no evidence to support such conclusions.
Investigation Findings
Despite a thorough investigation, there was insufficient evidence to determine why the aircraft suddenly deviated from controlled flight. Additionally, no evidence was found consistent with any attempt by the crew to recover from the dive. The investigation reiterated two safety recommendations previously made to the European Aviation Safety Agency (EASA) concerning flight recorders.
Official Probable Cause
According to the official report, during a gentle descent from flight level 95 to flight level 75 in instrument meteorological conditions, G-TWIG rapidly entered a dramatic and sustained maneuver from what initially appeared to be controlled flight at normal descent speed. Due to insufficient evidence, the cause or causal factors for this rapid deviation from controlled flight could not be identified.