What happened
On April 11, 2018, an Aero Boero AB-115, registration PP-GFK, was performing a series of touch-and-go landings for a Commercial Pilot License training program at the Eldorado do Sul Aeroclube (SIXE) in Rio Grande do Sul, Brazil. The flight involved a student pilot and an instructor.
During the sixth landing attempt, the student pilot executed a flare that was too high, causing the aircraft to stall and strike the runway forcefully. As the aircraft impacted the ground, the right main landing gear axle failed. This loss of structural integrity caused the aircraft to lose control on the ground, leading to the left wing and propeller striking the runway. The aircraft sustained substantial damage, including damage to the engine, propeller, and left wing.
The investigation
CENIPA investigators examined the aircraft's maintenance records and the physical components of the landing gear. Laboratory analysis of the fractured right main landing gear axle revealed that the failure was caused by an overload during the hard landing. However, the investigation also identified that the fracture was facilitated by corrosion pits that acted as stress concentrators, as well as poor-quality welding that had rendered the material brittle.
The investigation also reviewed the flight training records at the aeroclube. It was noted that there was a lack of standardization in how instructors completed flight evaluation forms, with discrepancies between maneuver comments and assigned grades. Furthermore, the investigation found that the instructor's intervention during the critical phase of the landing was delayed, allowing the student's error to reach an irreversible state.
Findings
- The primary cause of the axle failure was the overload resulting from a hard landing.
- Existing corrosion pits and low-quality welding on the landing gear component significantly reduced its impact resistance.
- A lack of a rigorous maintenance program for this specific component allowed corrosion to develop.
- The instructor's delayed reaction to the student's improper flare contributed to the severity of the impact.
- Inconsistencies in flight training documentation and a lack of standardized instructor grading were identified within the flight school's administrative processes.