What happened
On the morning of January 7, 2011, a Beech 200, registration F-GMPO, departed from Montpellier Aerodrome for an IFR flight to Albert Bray. During the initial climb, the flight crew noticed the left horizon instrument became unusable. The pilot flying, who was the co-pilot, observed amber lights indicating generator issues, but attempts to reset the generators were unsuccessful. The commander then decided to abort the flight.
As the crew began the landing gear extension sequence, the aircraft suffered a total electrical failure. The cockpit lighting became extremely dim, making instrument readings difficult. While attempting an emergency landing, the crew was uncertain if the gear was properly locked, as the co-pilot was still manually completing the emergency extension sequence. Due to the deteriorating weather and low visibility, the commander proceeded to land on runway 31 right. During the landing roll, the main landing gear collapsed, causing the fuselage to make contact with the ground before the aircraft came to a halt.
The investigation
The investigation focused on the cause of the generator disconnection and the subsequent electrical failure. Investigators examined the cockpit switch configuration, noting that the ENG AUTO IGNITION switches and the IGNITION AND ENGINE START switches are visually similar and located in close proximity. Tests performed on the aircraft's voltage regulators, battery, and generators showed no mechanical or electrical malfunctions in the components themselves.
Findings
- The crew mistakenly moved the IGNITION AND ENGINE START switches to the ON position while intending to adjust the auto-ignition settings before takeoff.
- This error automatically disconnected both generators, a condition the crew failed to detect immediately despite the activation of the Master Caution light.
- Because the engine start switches remained in the ON position, the crew's attempts to reset the generators were ineffective.
- The total electrical failure occurred during the normal landing gear extension sequence.
- The emergency landing gear extension procedure was left incomplete due to the high-stress environment and limited time available during the approach.
- The physical similarity and close proximity of the two different switch types served as a significant contributing factor.
Safety action
- The BEA has issued recommendation FRAN-2012-012 to EASA and the FAA, requesting that the manufacturer modify the ergonomics of the ENG AUTO IGNITION and IGNITION AND ENGINE START switches on Beech 200 aircraft to prevent future crew confusion.