As part of a recent accident investigation (RJ100 NLG failure on landing, February 13, 2009), the examination of a fractured NLG main fitting showed that Messier-Dowty SB.146-32-150 had not been accomplished, although the records indicated that it had been BAE Systems has determined that more NLG units could be similarly affected. These NLG units have been overhauled at Messier Services in Sterling, Virginia, in the United States. This condition, if not corrected, could result in NLG failure.
To address this situation, EASA issued Emergency AD 2009-0043-E to require repetitive NDT inspections of each affected NLG unit and, if cracks are found, replacement with a serviceable unit, in accordance with the instructions of BAE Systems (Operations) Limited Alert Inspection Service Bulletin ISB.A32-180 and Messier-Dowty (M-D) SB 146-32-149. Subsequently, investigation and analysis by M-D has identified the need for
a reduction of the inspection threshold and the repetitive inspection interval for the affected NLG units and has replaced M-D SB 146-32-149 with M-D SB 146-32-174. Consequently, BAE Systems SB 32-158 has been withdrawn and superseded by BAE Systems Alert ISB.A32-180 Revision 1. (EASA)