March 4th 2010
The purpose of the Advisory is to inform Operators and Maintenance Personnel of a potential problem with the aft nose landing gear door (ANLGD).
Transport Canada Civil Aviation (TCCA) has become aware of problems with the ANLGD upper attachment hinge assemblies. In one instance, during flight operation on a CL-600-2C10 aircraft, the landing gear extension appeared to function normally, although unusual noises were heard from the nose landing gear area. The post landing inspection revealed damage to ANLGD and to the surrounding structure. In that case, evidence suggested that one of the self-locking nuts (Refer to figure 1, Item 110), which held the hinge pin (Item 95) in place, backed out enough to cause the hinge pin to disengage. This caused the door to bind, causing damage when the landing gear extended.
Bombardier Inc. has since revised the relevant Aircraft Maintenance Manuals (AMM) through temporary revisions recommending installation of a new nut (Item 110), each time the door is removed and reinstalled.
While conducting this investigation, Bombardier Inc. also became aware of excessive bearing (item 145 & 250) wear on the fleet and is currently investigating this issue.
In the interim, TCCA strongly recommends that Operators and Maintenance Personnel pay extra attention to the upper attachment hinge assemblies for security and any abnormalities whenever maintenance is carried out around the ANLGD area.
Any findings should be reported to Bombardier Customer Response Center. Please refer to Service Letter CRJ700/900-SL-32-040 dated 16 November 2009.
Defects, malfunctions and failures occurring on aeronautical products are to be reported to Transport Canada in accordance with the requirements of CAR 521, Service Difficulty Reporting.
For further information, contact a Transport Canada Centre, or Mr. Guy Richard, Continuing Airworthiness, Ottawa at 613-952-4357, facsimile 613-996-9178, or email firstname.lastname@example.org
For Director, National Aircraft Certification
ORIGINAL SIGNED BY
Philip Tang for
Chief, Continuing Airworthiness
IPC 32-22-05 Figure 1 CRJ 700