The Ryanair plane that caught fire at Manchester Airport was the subject of a “serious incident,” according to the Air Accident Investigation Branch (AAIB).
The crew was given permission to taxi to Terminal 3 of the airport after landing on the runway. Once on the taxiway, they discovered that a “higher-than-usual” thrust was needed to maintain normal taxi speed.
The crew assumed that a flat tire was to blame, so they carried on as usual with no issues maintaining their straightness despite the additional thrust.
The AAIB report states that as the aircraft approached the stand, the crew received radio calls for the fire department to respond to a plane with “brakes on fire.”
The crew decided on performing an emergency evacuation after putting out the fire on the left main landing gear wheels.
The AAIB assessment said that the left main gear’s outboard wheel collapsed due to a fatigue crack in the wheel hub while the aircraft was taxiing to the gate after landing.
The wheel breakdown led to a hydraulic leak from the brake piston, and the heat produced by the out-of-balance wheel caused the hydraulic fluid to catch fire and start a fire.
The report also stated that the “left main wheel inner hub had shattered” and that the wheel’s subsequent misalignment “damaged the brake piston, producing a hydraulic fluid leak.”
It came to the conclusion that “the misaligned wheel’s heat generated was sufficient to ignite the hydraulic fluid.”
After the incident, the manufacturer of the wheels developed an ultrasonic inspection method to examine the internal bore of the wheel hub and find any cracks. The checks have now been implemented by Ryanair for its Boeing 737-8AS fleet.
A Ryanair spokesperson said: “Ryanair fully participated in this AAIB investigation and we welcome the report in which there are no safety recommendations for Ryanair.”