What happened
On January 10, 2018, at approximately 15:40 UTC, a Cessna A188B, registration PR-NAS, was conducting a local visual flight for touch-and-go training at Aeródromo de Safra (SSFC) in Dom Pedrito, Rio Grande do Sul. During the fourth landing of the flight, the left landing gear leg failed. This caused the aircraft to yaw to the left and come to a stop on the runway.
The aircraft sustained substantial damage to its propeller, engine, landing gear, and spraying equipment. The pilot was uninjured during the occurrence.
The investigation
CENIPA's investigation revealed significant irregularities regarding both the aircraft's maintenance and the operator's response to the accident. The investigation established that the aircraft was operating without a Certificate of Airworthiness, although it held a valid Special Flight Authorization (AEV).
Investigators found that the operator, Mercaer Aviação Agrícola Ltda., failed to report the accident to the regional investigation office (SERIPA V) promptly, only doing so after repeated requests. Furthermore, the aircraft was removed from the site without authorization from the investigation authority, which prevented investigators from establishing a definitive dynamic of the accident due to the loss of evidence.
Technical analysis of bolts provided by the operator showed fractures caused by overload, including bending and tension failures. However, it could not be confirmed if these specific bolts belonged to PR-NAS. The investigation also noted that maintenance records for the landing gear components, such as bolts, blades, and shims, were non-existent or incomplete, and the aircraft's logbooks contained numerous unauthenticated erasures and discrepancies.
Findings
- The primary cause of the landing gear failure was identified as overload on the components.
- There was a lack of control and maintenance tracking for critical landing gear components, including bolts, blades, and shims.
- Maintenance records for the airframe, engine, and propeller were inaccurate, incomplete, and lacked proper authorization signatures.
- The operator's safety management oversight was insufficient, as the Safety Manager demonstrated a lack of effective control over aircraft maintenance and operations.
- The failure to preserve the accident site and the aircraft hindered the ability to reconstruct the exact sequence of events.