What happened
On November 13, 2021, a Piper Aircraft PA-28-140 Cherokee, registration PT-IZS, was conducting a flight training mission from São Paulo (SBMT) to Atibaia (SDTB). The flight, operated by Aeroclube de São Paulo, carried an instructor and a student pilot performing 360-degree approach maneuvers.
During the landing phase at Atibaia, the crew noted they were above the ideal glide slope on final approach. Upon touchdown, the aircraft entered a porpoising condition. In an attempt to recover, the aircraft drifted to the right, causing the right main landing gear to collide with a runway edge marker. The impact caused the landing gear to collapse and the aircraft to skid across the runway, resulting in substantial damage to the aircraft. Both occupants were uninjured.
The investigation
CENIPA investigators examined the aircraft's maintenance history, finding that all inspections were up to date and no mechanical anomalies were present. The investigation focused on the flight dynamics and the airfield infrastructure.
Investigators noted that the instructor was actively participating in the flight decisions rather than acting solely as an observer, as prescribed for certain solo-training missions. The investigation also highlighted that the runway marker struck by the aircraft was not sufficiently frangible, a finding consistent with a previous accident at the same airfield in 2019. Furthermore, the investigation reviewed the flight school's training program and its risk assessment regarding operations at Atibaia, which has a known history of runway excursions.
Findings
- The primary cause of the landing gear failure was the collision with a non-frangible runway marker.
- The student pilot's failure to maintain a stabilized approach led to a porpoising motion.
- The instructor's intervention to execute a go-around occurred too late to prevent the loss of directional control.
- Crosswind components were near the operational limits established by the flight school's manual.
- The airfield infrastructure contributed to the severity of the damage due to the inadequate design of the edge markers.
- There was a lack of adequate risk assessment by the flight school regarding operations at this specific aerodrome.