What happened
On May 15, 2006, a Beechcraft C90, registration PT-OJU, departed from Campo de Marte Airport (SBMT) bound for Ribeirão Preto (SBRP). The aircraft was carrying one pilot and seven passengers. During the initial climb phase, the pilot heard a loud noise from the left engine, followed by a significant loss of power and airspeed.
In response to the engine failure, the pilot feathered the propeller and shut down the affected engine. After coordinating with air traffic control, the pilot diverted to Bragan and proceeded to perform an emergency landing at Bragança Paulista Airport (SBBP). During the landing sequence, the aircraft failed to stop within the runway limits, overshooting the end of the pavement and descending into an embankment at the extension of runway 16. The aircraft sustained severe damage, though all eight occupants (the pilot and seven passengers) escaped without injury.
The investigation
CENIPA investigators examined the engine components and maintenance records. Metallographic analysis of the left engine's turbine blades revealed that the failure was likely caused by material fatigue, which was exacerbated by corrosion and overheating. The investigation also noted discrepancies in the aircraft's maintenance logs, specifically a missing engine logbook and a gap of approximately 489 flight hours that could not be accounted for through verified records.
Investigators also analyzed the landing performance. Tire marks on the runway indicated heavy braking, suggesting the pilot may have utilized an approach with an improper glide slope or excessive speed, leading to a long landing that exceeded the available runway length.
Findings
- The primary cause of the engine failure was the fracture of a turbine blade due to fatigue, influenced by corrosion and overheating.
- Inadequate maintenance supervision may have prevented the timely detection of the progressing fatigue and corrosion.
- A lack of managerial oversight resulted in incomplete maintenance records and unverified engine flight hours.
- The pilot's approach parameters—specifically regarding airspeed and altitude—likely contributed to a long landing and subsequent runway excursion.