|Title:||Nosewheel failure on landing, Boeing 757-225, G-OOOV, 27 January|
|Micro summary:||Following landing, the right hand nosewheel of this Boeing 757-225 was found canted at an angle.|
|Event Time:||1997-01-27 at 0121 UTC|
|Publishing Agency:||Aircraft Accident Investigation Board (AAIB)|
|Publishing Country:||United Kingdom|
|Site of event:||Malaga|
|Departure:||Manchester International Airport, Manchester, England|
|Destination:||Malaga Airport, Malaga, Spain|
|Airplane Type(s):||Boeing 757-225|
|Type of flight:||Revenue|
|Executive Summary:||The aircraft was engaged on two sectors; Birmingham to Malaga and return. At the end of the first sector at 1655 hrs,after an uneventful landing at Malaga, the aircraft left the runway via the rapid exit taxiway. At a speed of about 20 kt a vibration was felt through the steering as the aircraft was turned left through approximately 120°, onto the parallel taxiway. The commander initially thought that the vibration was due to the taxiway surface, however, after 100 to 150 yards of straight taxying the vibration returned again in a more marked fashion. The aircraft was brought to a stop immediately and ATC and the airport emergency services were informed. Passengers were disembarked via steps and taken by bus from the taxiway. |
Upon inspection the right hand nosewheel was found canted over at an angle, the outer bearing having disintegrated.The operator's Duty Engineer, in Maintenance Control at Manchester,was informed at 1715 hrs and despatched an authorised certifying engineer (a Licenced Aircraft Engineer - referred to throughout this Bulletin as 'the LAE'), and a wheel change kit from Manchesterby diverting another Boeing 757, GOOOW bound for Tangier,to Malaga where it landed at 2115 hrs. The LAE visually examined the axle and found some axle damage that had been caused by the wheel bearing failure. He dressed out this damage, changed both nosewheels and OV took off from Malaga on its return flight toBirmingham. The nose gear axle failed inboard of the right hand outer bearing land (Figure 1) as the aircraft turned off the runway at Birmingham.
Subsequent metallurgical examination showed that the fracture of the axle was the result of the degradation of the axle material properties, due to penetration of liquid cadmium from the surface plating into the steel wall of the axle (cadmium embrittlement), while it was subjected to heating and tensile stresses during break up of the bearing at Malaga. Additionally, the axle had been further weakened by mechanical damage to a depth of 33% of the wall thickness, also caused during the break up of the bearing at Malaga.
Chapter 055117 of the Aircraft Maintenance Manual (AMM) called up an examination of the nose gear axle for overheating after a wheel bearing failure (Appendix 1) and required the use of a borescope to enable the internal bore of the axle to be examined for evidence of overheating of the cadmium plating.This check was not known to the Duty Engineer or to the LAE before OW departed for Tangier via Malaga, nor was it foundby the Duty Engineer during his subsequent document search. Consequently the examination was not carried out. The Duty Engineer continued to search for repair limits to the axle, but was unsuccessful (because no repairs were authorised).