Accident to the Socata TBM700N registered N850GC on 08/08/2013 at Vertaizon (Puy-de-Dôme)

Investigation progression Closed
Progress: 100%

Cat. 2 investigation report: simplified-format report, adapted to the circumstances of the occurrence and the investigation stakes.

The pilot, who was accompanied by two passengers, took off from Toussus‑le‑Noble bound for Clermont-Ferrand Auvergne for a private flight on an IFR flight plan. Cruise was conducted at FL 230.

The path constructed from the radar data suggests that the autopilot was engaged. When the pilot established radio contact with the Clermont-Ferrand approach controller, the controller asked him to descend to FL 90, direct to RIMOR IAF under the ILS Z procedure for runway 26 in use. The pilot did not read back. When the controller contacted him again to find out if he had heard the instruction, the pilot read back with a flight level error. The controller corrected him, instructed him to descend to 6,000 feet and cleared him for the ILS Z approach to runway 26. The meteorological conditions at the time of the approach were IMC.

Ten minutes later, at a distance of 12 NM from CF, the pilot announced that he was established on the localizer for runway 26. The approach controller transferred him to the tower controller. Thirty seconds later, the pilot advised the tower controller that he was established on the localizer for runway 26, 10 NM from CF. The tower controller then cleared him to land on runway 26.

The aeroplane remained in level flight at 4,000 feet beyond the final approach point (FAP) located 9.1 NM from CF. The pilot probably disconnected the autopilot and attempted to rectify the glide slope from above at around 1 NM after the FAP. About two minutes later, the tower controller noticed a lateral deviation to the right of the runway centreline and contacted the pilot. The pilot informed him that he wished to "go around and go back to resume the approach" and announced that "his autopilot had malfunctioned".

As the pilot was not following the published missed approach procedure, the controller suggested that he climb to the 6,000-foot safety altitude in the direction of the TIS VOR by making a right turn. The pilot read back, but first returned to the runway centreline in level flight at 4,000 ft. The controller then repeated his instruction to re-join the TIS VOR. The pilot replied that he was going to “programme” this point and then turned several times to the right and then to the left, first descending and then climbing. During this phase, the controller provided heading instructions to re-join the TIS VOR. The pilot read back with delays and sometimes with errors. The controller realised this and therefore limited his instructions to a climb to 6,000 ft. The aeroplane then started to climb to about 5,500 ft and then descended at a significant vertical speed south of the runway centreline. Witnesses saw the aeroplane collide with the ground on a steep slope with a wings-level attitude.

The path and readbacks show that the pilot lost situational awareness. The reduction in airspeed following the last climb caused him to lose control of the aeroplane, which collided with the ground. The entire approach was flown without any external references.

Publications and press releases