What happened
On March 23, 2017, a Cessna C152, registration OB-2093, was conducting a local instrument flight training mission from Pucallpa International Airport in Peru. The crew, consisting of a flight instructor and a student pilot, was operating under Visual Flight Rules (VFR) when, at approximately 14:51 local time, the engine experienced a sudden loss of power and subsequently shut down. The aircraft was at an altitude of 3,200 feet, approximately 6 nautical miles from the airport.
The crew declared an emergency and attempted to restart the engine in flight, but the efforts were unsuccessful. The instructor took control of the aircraft and identified an irregular agricultural field for an emergency landing. While the initial touchdown at approximately 1,000 feet was normal, the aircraft traveled roughly 100 meters before the nose gear sank into a hole in the uneven terrain. This caused the aircraft to nose over (capsize). The crew escaped the aircraft without injuries, and no fire occurred, though the aircraft sustained significant damage to the propeller, engine, and wings.
The investigation
The investigation conducted by the CIAA established that the aircraft and its components were airworthy and that maintenance was up to date. The engine had recently undergone an overhaul and was well within its operational limits. The investigation focused on the sequence of events leading to the engine failure and the subsequent impact with the ground.
Findings
- The primary cause of the engine failure was carburetor icing, which led to the uncommanded loss of power and engine shutdown.
- The weather conditions were conducive to the formation of ice in the carburetor.
- The crew failed to activate the carburetor heat, a procedure specified in the manufacturer's flight manual for use during periods of high humidity or as a preventative measure.
- There was a failure to correctly interpret the meteorological forecast (METAR), which contained indicators of conditions favorable for ice formation in the induction system.
- The irregular terrain of the landing site contributed to the nose gear collapse and the subsequent overturning of the aircraft.