What happened
On August 31, 2012, a Robin RH 200/120-B, registration EC-HMF, departed from Sabadell Airport for a local flight. The aircraft was operated by Aeroclub de Barcelona-Sabadell and carried a pilot and one passenger.
As the aircraft began its takeoff roll on runway 13, the engine revolutions dropped abruptly from 2,400 rpm to 2,050 rpm. Although the passenger noted the drop in engine speed, the pilot continued the takeoff. The aircraft became airborne before the midpoint of the runway, but the engine failed to reach the power required to maintain a safe climb.
While flying at a low altitude along the Ripoll river, the pilot attempted to return to the aerodrome. However, due to the low altitude and the presence of high-voltage power lines to the right, the pilot was unable to execute a safe turn. The aircraft eventually struck several trees in a wooded area near Castellar del Vallés at approximately 840 ft. The aircraft was destroyed, but both occupants escaped without injury.
The investigation
The CIAIAC investigation utilized onboard video footage, radar tracks, and radio communications to reconstruct the flight. The video evidence revealed that the pilot did not follow the engine test procedures established in the flight manual.
An inspection of the Lycoming O-2/35-L2A engine revealed that cylinder number one had failed. Investigators found that the cylinder was burned and showed no compression, likely due to extreme temperatures. The presence of oil in the intake manifolds and the appearance of the spark plugs suggested the engine had been operating with overly lean mixtures, which led to oil accumulation and the eventual failure of the cylinder.
Furthermore, the investigation identified a discrepancy in the cockpit instrumentation: the green arc on the tachometer did not match the operating range specified in the aircraft's flight manual. This discrepancy likely contributed to the pilot's failure to recognize the severity of the power loss during the takeoff roll.
Findings
- The primary cause of the accident was the pilot's failure to identify the engine failure during the takeoff roll and the subsequent failure to abort the takeoff.
- The engine failure was caused by the loss of cylinder number one due to excessive heat and oil accumulation.
- The pilot's limited experience in this specific aircraft type, combined with frequent flying in a wide variety of different aircraft models, acted as a contributing factor to the erroneous decision-making.
- The tachometer markings on EC-HMF did not align with the official flight manual specifications, complicating the monitoring of engine performance.
Safety action
- REC 86/12: It is recommended that Aeroclub Barcelona-Sabadell inspect its fleet to identify any aircraft where tachometer markings do not match the flight manual and ensure that compliant instruments are installed.