What happened
On April 30, 2016, an Air Vallée Fokker F27 MK50, registration SE-LEZ, was operating a flight from Rimini to Catania Fontanarossa Airport with 18 passengers and 3 crew members. During the final approach to runway 08, the crew noticed an amber indication for the nose landing gear, signaling it was not properly extended.
Following standard procedures, the crew performed a low approach to allow the tower to visually confirm the gear status. Although the nose gear bay doors were open, the tower confirmed the gear remained unextended. The crew attempted several recovery maneuvers, including the "alternate down" procedure and a leveled 2G turn, but the nose gear failed to lock down. The aircraft eventually landed on its main gear only, causing the nose of the fuselage to scrape along the runway until the aircraft came to a stop. All occupants evacuated the aircraft without injury.
The investigation
The ANSV investigation focused on the maintenance performed on the nose landing gear (NLG) the day before the accident. Investigators found that the maintenance was carried to be performed by a team where only one of the three technicians had prior experience with the specific task of replacing internal shock absorber seals.
Technical examinations revealed several critical errors during the servicing of the NLG. The investigation established that the shock absorber had been overextended, creating an interference between the tires and the gear bay structure that physically prevented the gear from extending. The investigators also found that the maintenance team used improvised, locally manufactured tools because the required specialized tools were unavailable at the facility. Furthermore, the engineering department had opted not to require independent double-checks for these specific tasks, and the maintenance procedures were being used in low-quality black-and-white prints, which obscured important warnings.
Findings
- The primary cause of the incident was the failure of the nose gear to extend due to the overextension of the shock absorber.
- The overextension was caused by the improper installation of internal components during seal replacement.
- Maintenance personnel lacked sufficient experience for the specific tasks being performed.
- There was significant operational pressure on the maintenance staff to return the aircraft to service quickly.
- The maintenance process lacked essential independent inspections or double-checks.
- The use of improvised tools instead of manufacturer-specified special tools contributed to the error.
- Inconsistencies in the Aircraft Maintenance Manual (AMM) regarding alignment instructions were noted, though the manufacturer has since updated these procedures.