What happened
On April 21, 1997, a Socata TB20 Trinidad, registration F-GEVN, was conducting a flight training mission for air navigation technical personnel. The flight departed from Melun Villaroche and proceeded toward the Troyes Barbere and Saint-Dizier areas.
While approaching the Troyes Barberey aerodrome for landing on runway 36R, the pilot contacted the airfield information service (AFIS) to report being on long final. After receiving wind information indicating a 10-knot wind from 040° with gusts up to 19 knots, the pilot indicated an intention to fly a short final to account for the wind.
During the approach, the aircraft initially aligned with a four-lane road east of the airfield rather than the runway centerline. As the pilot attempted to maneuver the aircraft back toward the runway axis, the aircraft entered a loss of control. Witnesses observed the aircraft performing a sudden pitch-up and bank that increased until the aircraft was inverted and nose-down. Despite an apparent attempt by the pilot to recover the aircraft, the Socata TB20 struck the ground at a 20-degree nose-down attitude with its wings level, resulting in two fatalities and the destruction of the aircraft.
The investigation
The investigation focused on determining whether the pilot had suffered any loss of consciousness or physical impairment. Investigators examined several hypotheses, including potential intoxication from de-icing fluid or carbon monoxide (CO) poisoning.
Analysis of the radio communications showed the pilot's tone was clear, concise, and showed no signs of physical or mental distress. Toxicological examinations revealed CO levels in the blood of the occupants (0.163% and 0.070%) were too low to cause significant impairment, as symptoms typically do not appear until levels exceed 30%. Furthermore, no evidence was found of an exhaust leak that could have introduced significant amounts of CO into the cabin.
Findings
- The aircraft was in a landing configuration with the landing gear extended and flaps at 10 degrees.
- The aircraft was subjected to strong and turbulent winds during the final approach.
- The pilot's attempt to correct the initial misalignment with the runway axis, combined with the turbulent atmosphere and wind gusts, led to a stall during the turn.
- The engine was functioning normally and was still running at the time of impact.