What happened
On May 28, 2012, a Diamond DA 42 Twin Star departed from Schwerin-Parchim Airport for an IFR flight to Basel, Switzerland. Shortly after takeoff from runway 24, the pilot reported an engine failure on the right engine. Radar data indicated that the aircraft was approximately one nautical mile west of the runway end at an altitude of 650 feet when the failure occurred.
The pilot requested permission to land on runway 06, but while executing a right-hand turn toward the airfield, the aircraft' and altitude steadily decreased. The aircraft was observed by witnesses flying in a right turn with low bank angle over the airfield before impacting a field south of the airport. The impact caused the aircraft to overturn, resulting in two fatalities and two serious injuries to the occupants. The aircraft was destroyed, and damage was also sustained to ground property.
The investigation
The BFU investigation focused on the mechanical state of the right engine and the pilot's emergency response. Examination of the right engine revealed that a significant amount of fibrous material was present in the gearbox housing, and the friction disc was almost entirely worn with visible cracks. FADEC data showed a steady increase in engine overspeed on the right engine, reaching 4,517 rpm, rather than the standard 3,887 rpm.
Investigators also examined the propeller, finding it was in the start lock position with a blade angle of 14.1 degrees. This meant the propeller was not in the feathered position, which significantly increased drag and hindered the aircraft's ability to maintain altitude. The investigation also reviewed the pilot's recent training and experience, noting that while he held a multi-engine rating, he had only 45 hours of experience on this specific aircraft type and had recently completed his multi-engine training in 2011.
Findings
- The primary cause of the accident was an engine overspeed on the right engine during climb, caused by a contaminated clutch.
- The pilot failed to follow established emergency procedures, specifically failing to shut down the right engine to bring the propeller into the feathered position.
- The pilot did not execute a structured emergency response and failed to initiate an emergency landing in the clear, unobstructed fields available near the airport, instead attempting to return to the airfield.
- Contributing factors included the pilot's limited experience with the Diamond DA 42 Twin Star and the failure of a previous maintenance inspection to detect the technical defect in the engine.
Safety action
Following the investigation, EASA issued Airworthiness Directive No. 2012-0116, which mandated a modification to the FADEC software for Engine Fuel & Control systems.