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Two separate right main landing gear failures involving the same Gippsland Aeronautics GA8 Airvan during beach landings on Fraser Island, Queensland highlight the need to not only conduct required inspections in line with the manufacturer’s maintenance schedule, but that operators consider additional inspections when routinely operating aircraft in challenging conditions.
In both instances – a right main landing gear collapse on 24 August 2019 and a right main wheel and axle separation on 31 October 2019 – it is probable that the faults that led to the failures were detectable during recent maintenance activity on the aircraft, an ATSB investigation found. Neither incident resulted in injuries.
In the August 2019 incident the right main landing gear collapsed when a number of the eight mounting bolts securing the landing gear loosened and wound out, placing excessive loads on the remaining bolts causing them to eventually shear and the landing gear leg to collapse.
Although the unsecured bolts would have been apparent during one or more periodic inspections, the investigation found recent maintenance had not detected any problems.
The 31 October landing gear failure occurred when, during the landing roll, the right main wheel and axle separated from the landing gear at slow speed. The ATSB’s investigation noted that surface contamination and corrosion in the axle inspection area indicated that the required pre-inspection cleaning had not been conducted for an extended period, decreasing the likelihood of any visual identification of cracking.
An inspection 27 flight hours before the second occurrence did not detect fatigue cracking at the main landing gear axle attach sleeve that led to the axle failure.
Further, the required axle magnetic partial inspection was about 470 flight hours overdue at the time of the axle failure.
“The operator’s aircraft experienced increased loads on the landing gear in operating from beach landing areas on Fraser Island as frequently as 20–30 times a day,” ATSB Director Transport Safety Dr Mike Walker said.
“In this challenging salt-laden and humid environment, the ATSB concluded that the operator did not place appropriate emphasis on ensuring the continuing airworthiness of the landing gear of its GA8 Airvan aircraft fleet.”
Following the two incidents, the operator, Air Fraser Island, appointed a new head of aircraft airworthiness and maintenance control, employed a quality assurance officer to audit its maintenance system, and made changes to the personnel conducting maintenance on its aircraft.
“Operators routinely conducting operations to beach landing areas should ensure that they are conducting the required inspections in accordance with the manufacturer’s maintenance schedule and procedures as a minimum standard," Dr Walker said.
“They should also consider improved and additional inspections when frequently operating aircraft in challenging conditions.”
Read the report: Landing gear failures involving a GA8 Airvan, VH-BFS, Fraser Island, Queensland, 24 August 2019 and 31 October 2019