What happened
On September 28, 2016, a Cessna 152, registration I-ECSO, was conducting a VFR navigation training flight from Rome Urbe airport. The flight was intended to be a closed circuit via Perugia. While cruising at approximately 3,000 feet near the Passo Corese waypoint, the aircraft experienced a gradual loss of engine RPM, followed by a complete engine failure.
The instructor took control of the aircraft and attempted to identify a suitable landing site. During the descent, the engine briefly restarted, which caused a sudden increase in airspeed and altitude, disrupting the approach path. The instructor ultimately performed a controlled impact into a wooded area near Ornaro, intentionally striking a tree to mitigate the force of the impact. Both the instructor and the student sustained injuries during the crash, which destroyed the aircraft.
The investigation
The ANSV examined the wreckage, the engine, and the flight crew's actions. Technical analysis of the Lycoming O-235-L2C engine revealed no pre-existing mechanical failures or defects that would have caused an immediate engine shutdown, though some wear was noted on the camshaft and tappets. The investigation also reviewed meteorological data, which indicated that while conditions were generally suitable for VFR flight, the possibility of carburetor icing could not be ruled out.
Investigators also reviewed the cockpit configuration following the impact. The fuel shut-off valve was found in the 'ON' position and the mixture was set to 'FULL RICH,' which deviated from the emergency procedures recommended in the Cessna 152 flight manual for an engine failure or emergency landing.
Findings
- The exact cause of the engine failure could not be determined with certainty.
- The flight crew did not strictly follow the engine failure restart procedures, specifically failing to activate the carburetor heat when the power loss was first detected.
- The aircraft's configuration at impact (mixture and fuel shut-off settings) was inconsistent with the emergency landing protocols outlined in the flight manual.
- Environmental conditions at the time of the event were potentially conducive to carburetor icing.