Aviation safety investigations & reports

Landing gear failures involving a GA8 Airvan, VH-BFS, Fraser Island, Queensland, 24 August 2019 and 31 October 2019

Investigation number:
AO-2019-045
Status: Completed
Investigation completed
Phase: Final report: Dissemination Read more information on this investigation phase

Final

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Safety summary

What happened

In August and October 2019, a Gippsland Aeronautics GA8 Airvan (GA8) aircraft, registered VH‑BFS and operated by Air Fraser Island, sustained failures of the right main landing gear, with both occurrences occurring during landings on beach aeroplane landing areas (ALAs) on Fraser Island. Both landings were described as normal with no excessive loads.

On 24 August 2019, during the landing roll, and just prior to reaching taxi speed, the right main landing gear collapsed, resulting in minor damage to the aircraft as it came to a stop. There were no reported injuries to the pilot or passengers on board. On 31 October 2019, during the landing roll the right main wheel and axle separated from the landing gear at slow speed, resulting in minor damage. There were no reported injuries to the pilot (the only occupant).

What the ATSB found

The ATSB found it was probable that a number of the eight mounting bolts securing the right main landing gear had loosened and wound out, placing excessive loads on the remaining bolts. The remaining bolts eventually sheared, resulting in the gear leg collapsing during landing on 24 August 2019. Although the bolts not being securely fastened would have been apparent during one or more periodic inspections, recent maintenance had not detected any problems.

The ATSB found that because of low weld penetration from manufacture at the right main landing gear axle attach sleeve, it was likely that a fatigue crack formed and propagated undetected, eventually resulting in the axle failure on 31 October 2019. It was likely the axle cracks were present, and detectable visually, when last inspected 27 flight hours before the occurrence. In addition, the axle inspection area had surface contamination and corrosion that indicated the requirement for cleaning prior to inspection had not been conducted for an extended period, thereby decreasing the likelihood of identifying cracks by visual means. Furthermore, the requirement for a magnetic particle inspection of the axles had not been carried out, and was about 470 flight hours overdue at the time of the 31 October 2019 axle failure.

The operator’s aircraft experienced increased loads on the landing gear when routinely operating from beach ALAs up to 20–30 times daily, and they were subjected to a salt-laden and humid environment. With consideration of this context, the ATSB concluded that the operator did not place appropriate emphasis on ensuring the continuing airworthiness of the landing gear of its GA8 fleet.

What has been done as a result

Following the incidents, Air Fraser Island made changes to the control and conduct of maintenance on its aircraft. This included the appointment of a new head of aircraft airworthiness and maintenance control (HAAMC), the appointment of a quality assurance officer to audit the operator’s maintenance system, and changes to the personnel conducting maintenance.

Safety message

Operators routinely conducting operations to beach landing areas should consider the options available for improving the resilience of their landing gear. In particular, they should ensure that they are conducting the required inspections in accordance with the manufacturer’s maintenance schedule and procedures as a minimum standard. Improved and additional inspections should also be considered by operators when aircraft are frequently operated in challenging conditions.

Download Final report
[Download  PDF: 2.08MB]
 
 
 

The occurrences

Context

Safety analysis

Findings

Safety issues and actions

Sources and submissions

Safety Issue

Go to AO-2019-045-SI-01 -

Maintenance processes for landing gear

The operator did not place appropriate emphasis on ensuring the continuing airworthiness of the landing gear of its GA8 fleet, although being aware of:

  • the increased loads on the landing gear when routinely operating from beach landing areas up to 20–30 times daily, and being subjected to a salt-laden and humid environment
  • the axle failure of VH-BFS in 2009
  • the mandatory inspection requirements of service bulletin SB-GA8-2016-169.
Safety issue details
Issue number: AO-2019-045-SI-01
Status: Closed – Adequately addressed
General details
Date: 24 August 2019   Investigation status: Completed  
Time: 13:15 EST   Investigation level: Defined - click for an explanation of investigation levels  
Location   (show map): Fraser Island   Investigation phase: Final report: Dissemination  
State: Queensland   Occurrence type: Landing gear/indication  
Release date: 29 April 2021   Occurrence category: Serious Incident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Gippsland Aeronautics Pty Ltd  
Aircraft model GA-8  
Aircraft registration VH-BFS  
Serial number GA8-03-035  
Operator Air Fraser Island  
Type of operation Charter  
Sector Piston  
Damage to aircraft Minor  
Departure point Oaks, Queensland  
Destination Eurong, Queensland  
Last update 29 April 2021