What happened
On July 14, 2006, a Tecnam P2002-JF, registration EC-JCQ, departed from Sabadell airport for Madrid-Cuatro Vientos following the installation of a new Rotax 912S2 engine. Shortly after takeoff, the pilot noted rising oil temperatures and vibrations, prompting a return to Sabadell. After a brief maintenance check and the replacement of a fuel system pipe, the aircraft departed again at 12:45.
Approximately thirty minutes into the second flight, the engine temperature rose to 120°C. As the pilot attempted to descend to mitigate the heat, the engine experienced power losses, a drop in RPM to 1,300, and a distinct metallic sound. The pilot declared an emergency to ACC Barcelona and performed an emergency landing at Borjas Blancas (Lleida). The two occupants escaped without injury, though the aircraft sustained minor damage to the nose gear.
The investigation
Investigators performed a full disassembly of the engine, which had only 45 hours of total operation since the new engine installation. The inspection revealed significant internal damage, including metallic particles in the magnetic plug, abrasion marks on the oil pump casing and crankshaft, and oxidation in the combustion chambers. Notably, the hydraulic tappet for the number one cylinder's exhaust valve was perforated, and the associated camshaft showed massive material loss.
Technical analysis by the manufacturer, Rotax, indicated that the perforation was caused by excessive friction and heat. This was attributed to a combination of excessive roughness on the hydraulic tappet's contact surface and the specific engine oil used during the manufacturing process. While Rotax implemented manufacturing improvements—including polishing tappet surfaces and enhancing quality controls—the investigation noted that existing service bulletins relied on reactive measures, such as checking magnetic plugs for metal shavings, which may not detect failures occurring rapidly within the first few flight hours.
Findings
- The engine failure was caused by the improper transmission of motion from the camshaft to the push rod due to a faulty hydraulic tappet.
- The primary cause of the component degradation was excessive friction and heat resulting from the roughness of the tappet contact surface and lubrication conditions.
- The hydraulic tappet for the number one cylinder failed to meet design hardness specifications and was physically perforated.
- The engine had only been in operation for 45 minutes since the new engine installation.
Safety action
Following the investigation, the CIAIAC issued a safety recommendation (REC 42/07) stating that EASA and Rotax should implement measures to guarantee the continued airworthiness of Rotax 912/914 engines using hydraulic tappets manufactured prior to the recent manufacturing improvements.