What happened
On June 20, 2011, a Cessna 150E, registration PT-BXF, was conducting a flight training mission in the Salvador terminal area (TMA-SV), Brazil. The flight, operated by CFA Cursos Ltda., was carrying an instructor and a student pilot. During the flight, while attempting to demonstrate a maneuver, the instructor noticed that the rudder was no longer responding to flight controls. The instructor immediately initiated a return to the origin airport, Aeródromo Internacional Deputado Luís Eduardo Magalhães (SBSV), where the aircraft landed successfully. There were no injuries to the two occupants and no damage to the aircraft.
The investigation
CENIPA investigators examined the aircraft's flight control components and maintenance history. Upon inspection, investigators found an AN3-7 fastening bolt, which secures the upper part of the rudder to the vertical stabilizer, had become loose and was found inside the rudder assembly.
While recent maintenance records indicated that 50 and 100-hour inspections had been performed by the maintenance organization (TBA) in May 2011, investigators noted that both the bolt and its attachment point were covered in grease. This was inconsistent with the manufacturer's lubrication manual, which specified the use of general-purpose oil (MIL-L-7870 OGP). Furthermore, the investigation revealed that the aircraft's logbooks were being held by the maintenance organization rather than the operator, preventing the operator from accurately tracking flight hours since the last inspections.
Findings
- Inadequate maintenance practices, as evidenced by the use of an incorrect lubricant (grease instead of specified oil) on critical rudder components.
- Deficiencies in management supervision, specifically regarding the lack of oversight of maintenance activities and the failure to maintain updated aircraft records at the operator's facility.
- The flight crew was properly qualified and the aircraft was airworthy and within weight limits at the time of departure.