What happened
On June 4, 2011, a Cessna 172-RG, registration PR-VFE, was performing a private transport flight from Atibaia to Americana, Brazil. The flight included the pilot and three passengers. During the landing roll at Americana Aerodrome (SDAI), the pilot experienced a total loss of effectiveness in the left brake system approximately 300 meters from the runway threshold.
As the aircraft continued toward the opposite end of the runway at speed, the pilot shut down the engine and utilized differential braking to steer the aircraft off the runway via the right side. The aircraft sustained light damage to the engine mount, but all four occupants escaped without injury.
The investigation
CENIPA investigators examined the aircraft's braking system and the maintenance practices of the responsible repair station. The investigation revealed that the left brake pedal offered no resistance due to a hydraulic fluid leak occurring at the connection between the pressure tube and the assembly connector. A detailed analysis determined that the metal pressure tube had ruptured at the flange.
Investigators also reviewed the maintenance history and the technician's proficiency. During the inspection of the maintenance facility, several discrepancies were identified, including the use of uncalibrated measuring tools (a caliper lacking calibration stickers) and a lack of familiarity with the aircraft's service manuals. Furthermore, the inspection logs for the aircraft were found to be inadequately documented, lacking specific numerical values for critical measurements.
Findings
- Improper maintenance practices likely caused the pressure tube to weaken or rupture during reinstallation.
- The left brake disc showed advanced signs of pitting/craterization, despite being within thickness limits.
- The pilot was operating with an expired medical certificate and an expired technical rating.
- Maintenance oversight was inadequate, evidenced by the technician's inability to locate specific subsystems within the service manual.
- The aircraft's maintenance records were not up to date.
- The pilot failed to file a flight plan or notify the appropriate authorities regarding the flight.