What happened
On December 3, 2017, at 19:25 UTC, a Beechcraft M35, registration PP-VIT, was performing a local scenic flight departing from the Telêmaco Borba Aerodrome (SSVL) in Paraná, Brazil. The aircraft was occupied by a pilot and one passenger.
During the initial climb, after passing 500 feet, the engine ceased operation while the pilot was executing a left turn. The pilot attempted to restart the engine by switching fuel tanks, which resulted in the engine running for only a few seconds before failing again. Unable to return to the runway, the pilot performed an emergency landing in a nearby clearing. The impact caused substantial damage to the aircraft, and both the pilot and the passenger sustained serious injuries.
The investigation
CENIPA investigators focused on identifying the cause of the engine failure. The engine was removed and tested by a certified maintenance organization under the supervision of SERIPA V and IAE technicians. During bench testing, investigators discovered a fuel leak on the fuel metering unit near the mixture control lever.
Upon disassembly of the fuel metering unit, the investigation revealed that a sealing ring had become dried and brittle, failing to prevent air from entering the fuel system. This air ingress was identified as a potential cause for the engine flameout.
Records indicated that while the component had not reached its hourly overhaul limit, it had exceeded its calendar life limit. The unit's last overhaul occurred in December 2002, meaning the 12-year time-in-service limit had expired in December 2014. No records were found to confirm that an operational evaluation had been performed to justify extending the component's service beyond the manufacturer's recommended calendar limit.
Findings
- The engine failure occurred during the climb phase of flight.
- The fuel metering unit exhibited a leak due to a dried-out sealing ring.
- The component's overhaul was overdue based on the manufacturer's recommended 12-year calendar limit.
- The lack of a documented operational assessment to justify the use of an expired component prevented the identification of the degraded seal.