ATSB report highlights Saab 340 wheel cracking risk
By Andrew Curran.
The Australian Transport Safety Bureau (ATSB) has highlighted the risk of in-service wheel fractures on Saab 340 aircraft after a Link Airways Saab 340B experienced a fracture and separation incident involving the main landing gear wheel at Melbourne Airport in April.
The aircraft, VH-VEF (msn 340B-457), arrived in Melbourne Airport (MEL) on April 1, 2026, following a passenger flight from Orange (OAG). A routine post-flight inspection found that the left inboard main landing gear tyre had deflated, and a section of the inner wheel rim had fractured and separated while the aircraft was taxiing towards its parking bay.
The flight crew had not noticed anything abnormal during the landing or taxiing, and no other damage was sustained by the aircraft.
The ATSB’s final report, released on 14 October, found that the wheel fracture resulted from fatigue cracking in the bead seat area of the wheel. The fractured wheel and a second wheel on the same landing gear leg, which was found to have a crack in a similar location, were of a design previously identified as susceptible to cracking.
The report noted that the manufacturer had introduced a revised wheel design in December 1995 to reduce stress in the bead seat area. However, earlier wheel assemblies were permitted to remain in service provided operators maintained the prescribed inspection standards.
Runway inspection prompts diversion
After discovering the damage, a member of the flight crew contacted air traffic control to report that a section of the wheel rim might have been lost during landing.
Airside safety officers inspected the runway for foreign object debris, while another officer retraced the aircraft’s taxi route to its parking bay. During the search, another aircraft diverted from Melbourne after its crew deemed it unsafe to land.
However, the missing wheel section was swiftly located on the lead-in to Link Airways’ parking bay. The pilot matched the recovered piece to the fractured wheel and confirmed that it was the only missing section, allowing the runway inspection to be concluded.
Link Airways subsequently removed the other wheel on the same landing gear leg for a precautionary, non-destructive inspection. This identified a hairline crack in the inboard bead seat area.
The aircraft, manufactured in Sweden in 1998, had accumulated 143 landings on the affected wheels since they were fitted. Both wheels had been supplied in an overhauled condition and installed on the same landing gear leg at the same time.
Link Airways told the ATSB there had been no reports of a hard landing involving VH-VEF and no reports of potholes or damaged runways at airports visited since the wheels were installed.
Photo: Australia Pacific Airports (left), VSE Aviation (right) via ATSB.
Previous Saab 340 wheel fractures
The ATSB noted that the incident was the third main landing gear wheel fracture involving a Saab 340 that it had investigated. Similar occurrences were examined in 2009 and 2019, with fatigue cracking in the bead seat area also identified as the cause.
The wheel manufacturer issued a service bulletin in April 1994 introducing inspection techniques and intervals to detect cracking in the affected area. These included eddy-current inspections at each tyre change and during overhaul.
The ATSB’s review of maintenance records found that an MRO provider had inspected 676 wheel assemblies between April 2022 and April 2026. Of these, 26 assemblies, or approximately 4%, had inner subassembly serial numbers dating from October 1995 or earlier.
None of the 676 assemblies had been rejected because of cracking in the bead seat area. However, the ATSB’s search of the Civil Aviation Safety Authority’s defect reporting database identified 30 reports of Saab 340 main wheel cracks over the preceding 20 years. These included three in-service wheel fractures, as well as reports of cracked wheels.
The ATSB said it could not conclusively determine all the factors that contributed to the April 2026 fracture. It considered several possibilities, including a crack that had gone undetected during overhaul or an abnormal loading event affecting the landing gear.
While the existing inspection regime appeared generally adequate to identify cracks before they progressed to failure, the investigation concluded that the older wheel design remained susceptible to cracking.
Remaining affected wheels removed from service
Link Airways advised the ATSB that it had eight wheels of the susceptible original design remaining in service at the time of the occurrence. Although the wheels were permitted to remain in use under the existing maintenance requirements, the operator removed them from service to mitigate the ongoing safety risk.
The ATSB’s safety message emphasised that operators and maintainers rely on information from aircraft and component manufacturers to maintain safety and reliability. However, an inspection regime that reduces the risk associated with a known component weakness does not necessarily eliminate it.
The bureau said operators should independently assess whether any residual risk is tolerable and take further steps to reduce or eliminate it where practicable.
You can read the ATSB’s final report here.
Photo: Link Airways.
Contact the writer: andrew@aerosouthpacific.com