What happened
On September 21, 2023, a Diamond DA62, registration D-IRAY, departed Nancy - Essey airport for a cross-country flight to Germany. During the initial climb, at an altitude of approximately 700 feet, the pilot encountered an engine problem while performing a left-hand turn in the runway circuit. The pilot reported an engine issue via radio and subsequently declared a single-engine condition.
In an attempt to manage the failure, the pilot reduced power on both engines and eventually shut down the right-hand engine. While attempting an off-airfield emergency landing in a field near Seichamps, the aircraft encountered a gust of wind that caused a roll to the right. The pilot's attempt to correct the flight path led the aircraft into a hedge, causing the left wing to separate from the airframe. The pilot and one passenger sustained two injuries, and the aircraft was destroyed.
The investigation
The BEA examined the aircraft's engine control unit (EECU) data, which revealed that the right-hand engine's coolant temperature rose abnormally shortly after takeoff. Physical examination of the right-hand engine showed that the accessory belt had separated, and a belt tensioner pulley had moved out of its housing due to a deformed mounting bracket. Investigators also reviewed the pilot's actions regarding the engine failure management and the aircraft's flight path.
Findings
- The primary cause of the engine temperature warning was the separation of the right-hand engine accessory belt, likely caused by the ingress of a foreign object into the engine unit.
- The pilot's management of the failure involved large-amplitude and hasty inputs, potentially due to stress, which degraded the aircraft's performance.
- The pilot reduced power on both engines and reduced the right-hand engine to zero thrust without immediately feathering the propeller, creating significant asymmetric drag.
- The aircraft's yaw trim was not properly adjusted to compensate for the asymmetric thrust, making the aircraft more difficult to control during the emergency.