What happened
On March 21, 2012, a Diamond DA-40D aircraft, registration PH-XJB, was conducting a private flight from Lelystad Airport. While cruising at 1,000 feet with one pilot and one passenger, the occupants heard a loud bang, immediately followed by a total loss of engine power. The pilot reported no prior warning signs, such as unusual vibrations or noise, before the failure occurred.
Following the failure, a rattling sound was heard from the engine compartment. The pilot initiated emergency procedures, including transmitting distress signals and preparing for an emergency landing in a nearby field near Hollandse Brug. During the approach, the pilot attempted to restart the engine by toggling the engine master switch, but deactivated it again after detecting the smell of burning. The aircraft landed in a field at approximately 70 knots. Both occupants exited the aircraft uninjured, though the engine compartment was heavily coated in oil.
The investigation
Investigators examined the engine and found significant structural damage. Two holes had been punched through the engine casing; one allowed the crankshaft to be visible, while the other was caused by a connecting rod protruding outward.
Detailed disassembly of the TAE 125-01 diesel engine revealed that the upper half of the connecting rod bearing for cylinder number 3 was missing. The connecting rod itself was slightly bent. While the engine manufacturer suggested that debris from a fire-resistant protective sleeve—consisting of red rubber particles and non-metallic fibers—had entered the combustion chamber and caused the piston to seize, the investigation could not definitively confirm this sequence. The presence of these fibers could have been a result of the mechanical failure rather than the cause.
Findings
- The engine failure was likely caused by an undetermined failure mechanism of the connecting rod bearing in cylinder number 3.
- The failure of the bearing allowed the connecting rod to move freely, leading it to strike and penetrate the engine crankcase.
- FADEC data showed no engine parameter exceedances prior to the failure, and all recorded warnings occurred after the engine had already malfunctioned.
- The investigation noted that this incident is part of a pattern of similar failures in TAE 1215-01 engines, including documented cases in Norway and Germany involving similar damage to cylinder number 3.