During the recent 57-day long machinists’ strike, which has already led to a 10-week delay on deliveries of all Boeing aircraft, and pushed back the 787 programme into 2009, Boeing and Wichita, Kansas based Spirit AeroSystems discovered that nutplates from an unidentified supplier had not been given an anti-corrosion coating of cadmium.
Boeing claims the problem is not “a safety of flight issue”, but the non-conforming nutplates must be replaced to comply with certified corrosion protection requirements. Each Boeing 737 uses between 3,000 and 5,000 nutplates.
The replacement process is elaborate and involves inspection and nutplate replacement on aircraft and sub-assemblies throughout the production lines at Spirit and Boeing. Aircraft already delivered will require corrosion inspections at intervals until an opportunity for replacement occurs.
Boeing had officially notified the FAA of the nonconforming nutplates on Oct. 31, 2008.
Boeing has already acknowledged the issue “is delaying the ramp-up a little bit” on the 737, and has now acknowledged that the non-conforming ‘nutplate’ issue is also impacting the 747, 767 and 777 production lines, some of which incorporated faulty nutplates as far back as September 2007.
Boeing claims the number of affected nutplates on the 747 and 767 models is “in the hundreds”, while the 777 has around 1,500 to 2,500 affected non conforming parts.
Images courtesy Boeing