What happened
On 19 January 2020, a DIAMOND DA20-A1, registration EC-JLN, was conducting a private flight from El Berriel Aerodrome to La Gomera Airport. The flight, intended to build experience for two pilots undergoing advanced training, also included planned maneuvers at Tenerife North Airport.
While flying over the sea north of the Gran Canaria coastline, the pilot reported low oil pressure and smoke in the cabin. Shortly thereafter, the engine failed completely. The pilot was forced to perform an emergency sea landing in front of El Altillo beach. The two occupants successfully evacuated the aircraft and swam to the shore, where they were assisted by bystanders.
Although the aircraft did not suffer significant damage during the initial ditching, it was subsequently pushed by waves and currents into rocks, damaging both wings. The aircraft also sustained widespread damage from seawater corrosion.
The investigation
The investigation focused on the cause of the engine failure and the discrepancy in the oil-level check procedures. Investigators examined the engine's lubrication system and found that the connecting rod of cylinder no. 1 had broken near its attachment to the crankshaft, showing signs of excessive stretching and deformation.
Analysis of the engine revealed that the lubrication system contained approximately one liter of oil mixed with seawater. While the rest of the engine appeared well-lubricated, the front and center crankshaft bearings showed significant wear and evidence of high-temperature exposure.
Furthermore, the investigation examined the aircraft's technical logbook and maintenance records. It was noted that the oil-level check procedure outlined in the aircraft's flight manual was insufficient, as it only required checking the dipstick mark without the specific pre-check actions—such as manually turning the propeller—recommended by the engine manufacturer, Rotax.
Findings
- The primary cause of the accident was insufficient lubrication of the connecting rod in cylinder no. 1, which led to the in-flight engine failure.
- A contributing factor was the deficient oil-level verification procedure used by the personnel operating the aircraft, which failed to detect the low oil level.
- The aircraft flight manual's oil-level check instructions differed significantly from the more detailed procedure required by the engine manufacturer.