Ryanair is introducing ultrasonic inspection of its aircraft wheel hubs following two separate incidents.

In the first, in March 2022, a Boeing 737-800 was taxiing to its gate at Manchester airport, UK, when the left main gear failed due to fatigue cracking in the wheel hub, the UK’s Air Accident Investigation Bureau has reported. 

CCTV images showed the gear on fire as the 2010-vintage aircraft turned off the apron – the result of leaking hydraulic fluid combusting in the heat generated by the misaligned wheel. 

Subsequently a similar incident occurred in Spain, which that country’s accident investigation office is investigating. 

After the Manchester incident – in which no-one was injured – the wheel and brake manufacturer identified that the inboard wheel hub had fractured radially in four locations due to corrosion, and said it would amend the component maintenance manual to introduce an optional ultrasonic inspection of the inner wheel half hub lead-in chamfers.

This inspection assesses the condition of the internal bore of the wheel hub to identify the presence of cracks originating at the lead in chamfer of the bearing bore.

While wheel hubs are usually alloy-based, ultrasonic inspections are commonly used with composite components, such as on the wing where the transition from transportable to portable ultrasonic phased array inspection devices has improved productivity and increased demand for the solution.