What happened
On August 31, 2013, a Cessna C-525, registration PT-FJA, was performing a scheduled flight from Goiânia (SBGO) to Congonhas (SBSP) with two pilots and six passengers on board. Approximately nine minutes into the flight, while climbing through FL190, the crew received a low oil pressure warning for the right engine. The pilots immediately reduced power to the right engine and coordinated a return to the departure airport.
During the turn for the return approach, the crew received a second low oil pressure warning, this time for the left engine. The crew declared an emergency and requested priority landing for runway 32 at SBGO. The aircraft landed safely without damage, and all eight occupants remained uninjured.
The investigation
CENIPA's investigation focused on the maintenance performed on the aircraft prior to the flight. The investigation established that on the evening of August 30, 2013, a mechanic performed maintenance on the starter generators of both engines. This work was completed late at night after a long shift, and although an oil leak was noted during ground engine runs, the aircraft was approved for service without the required test flight.
Investigators found that the maintenance performed—specifically involving the replacement of a carbon seal—was outside the scope of the maintenance company's authorized capabilities. Furthermore, the maintenance was performed in a manner inconsistent with the manufacturer's manual, and the necessary post-maintenance test flight was bypassed due to time constraints and pressure to return the aircraft to service.
Findings
- Improper maintenance execution: The mechanic performed maintenance tasks that were not authorized under the company's specific addendum and failed to follow the manufacturer's maintenance manual.
- Maintenance fatigue and pressure: The mechanic was working under significant mental fatigue after a 13-hour shift and felt pressure to complete the task due to the importance of the client and the operator's expectations.
- Organizational failures: The maintenance company failed to communicate the necessity of a test flight to the operator, and the engineering oversight failed to identify that the maintenance was being performed incorrectly.
- Inadequate management oversight: The operator's delay in authorizing the purchase of necessary parts created a sense of urgency that contributed to the decision to rush the maintenance process.