What happened
On April 10, 2019, a Cessna 172R, registration PT-WOW, was preparing for a flight training mission from Aeródromo Carlos Prates (SBPR) in Belo Horizonte, Brazil. The crew, consisting of a flight instructor and a student pilot, initially experienced excessive vibration during the takeoff roll. After consulting a mechanic, the instructor attempted a second takeoff roll to further investigate the vibration.
During this second attempt, the vibration recurred. The instructor decided to abort the takeoff; however, upon applying the brakes, the aircraft failed to decelerate effectively. In an attempt to stop the aircraft, the pilot performed a sharp turn (a "piggyback" or "power skid" maneuver), but the aircraft could not be stopped within the runway limits. The aircraft exited the runway and struck a masonry drainage ditch. The impact caused the left main landing gear and the nose gear to become trapped in the ditch, resulting in substantial damage to the landing gear, the lower fuselage, and the left horizontal stabilizer. Both occupants were unharmed.
The investigation
CENIPA investigators examined the maintenance history and the airport infrastructure. The investigation revealed that the aircraft had undergone an annual maintenance inspection just one day prior, which included the replacement of brake pads. While the maintenance manual for the Cessmina 172R requires a specific "bedding-in" procedure after pad replacement, no records were found to confirm this task had been completed. This lack of procedure execution may have contributed to the reduced braking effectiveness.
Furthermore, the investigation scrutinized the airport's taxiway safety. The drainage ditch, located within the taxiway safety area, was found to be non-compliant with Brazilian Civil Aviation Regulations (RBAC 154), which require such areas to be free of objects that could endanger aircraft. The investigation also noted that the airport operator's monitoring of the operational area failed to identify and mitigate the risk posed by the exposed ditch.
Findings
- The aircraft's brake pad replacement was not documented as having undergone the required bedding-in procedure.
- The pilot's decision to delay braking to minimize runway occupancy time may have contributed to the inability to stop.
- The drainage ditch at the end of runway 09 constituted a significant hazard as it was not properly covered or mitigated.
- Inadequate airport infrastructure supervision allowed a latent risk to remain in the operational area.