What happened
On an undetermined date between October 12, 2021, and January 18, 2022, a Reims Aviation F172P, registration HB-CHX, experienced an uncontrolled ground contact. The event involved significant vertical impact energy, though the crew did not report the incident to authorities or maintenance providers. Following a separate incident involving a carburetor fire on January 15, 2022, the aircraft was taken in for a scheduled 200-hour inspection. During this maintenance period, mechanics discovered extensive structural deformations that had previously gone unnoticed.
The investigation
The SUST investigation focused on the discovery of structural damage during maintenance. Prior to the window of the accident, the aircraft had undergone 100-hour and 50-hour inspections in late 2021, which showed no structural issues. On January 2, 2022, the aircraft suffered a nosewheel tire failure, which was repaired by January 3. However, during the January 18 maintenance session, investigators found that the fuselage, engine mount, and wing strut had been severely compromised. The investigation found no records of any reported hard landings or incidents in the ECCAIRS 2 database or with the operator, Motorfluggruppe Zürich, that would account for the damage.
Findings
- The aircraft sustained heavy structural damage, including deformations to the fuselage, cabin floor, engine mount, and right wing strut, as well as broken rivets.
- The extent of the damage is consistent with a hard landing, potentially caused by porpoising.
- The damage was not visible during standard pre-flight inspections because many affected areas were located beneath the fuselage or obscured by fairings and floor coverings.
- The crew failed to report the uncontrolled ground contact, which prevented maintenance personnel from performing a targeted inspection for structural integrity.
Safety action
- The failure to report the event endangered subsequent users of the aircraft by allowing it to remain in flight service with compromised structural components.