SAIB NE-03-28 —

1 SPECIAL AIRWORTHINESS INFORMATION BULLETIN Aircraft Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration No. NE-03-28 March 10, 2003 We post SAIBs on the internet at www.airweb.faa.gov This is information only. Recommendations are not mandatory. Introduction The Special Airworthiness Information Bulletin (SAIB) advises you, owners and operators of Bombardier CL 600 Challenger CL-600-1A11 (CL-600), CL-600-2A12 (CL-601), CL-600-2B16 (CL-601-3A) & (CL-601-3R)& (CL-604) as well as the RJ 100 (CL 600-2B19) series aircraft that Transport Canada (TC) has recently received a Service Difficulty Report regarding a bearing failure in the Aileron Quadrant/Feel Unit, P/N 600-91178-7, on a CL 600 2A12 (601) Challenger aircraft. TC has released Service Difficulty Alert No. AL-2003-01 dated January 9, 2003, to perform an operational check on the aileron system.

Background Maintenance personnel performed a 600-hour inspection and after completing operational tests on the aileron system, they exercised the ailerons bleeding off the hydraulic system pressure. When the pressure was released, they heard a loud bang while moving the controls. While troubleshooting and moving the aileron controls again, they heard the bang again. They determined the source of the noise was the wheel well quadrant. The removed and disassembled the quadrant. They found quadrant bearing, P/N MS 27646-39 (Item 59, figure 1 of this SAIB, Re: IPC 27-12-00, Page 3 Figure 1(D)) was dry of grease and the balls had worn a deep groove into the inner race. It is important to note that the operator did not experience any symptoms that would have lead to the discovery of this degradation prior to its failure; example: stiff or ratcheting control wheel. This quadrant has a common part number throughout the Challenger and Regional Jet 100 fleet. Recommendations The FAA strongly recommends that you carry out an operational check on the aileron system similar to the scenario above to ensure the presence of sufficient lubrication in the subject bearing. If left undetected, aileron control operation could be compromised. You should report any defects or further occurrences to the New York Aircraft Certification Office (NYACO).

2 Figure 1 For Transport Canada Alert Information, Contact TCCA, Steve Dudka, Continuing Airworthiness, Ottawa, phone: (613) 952-4361; fax: (613) 996-9178; email: [email protected] For Further Information Contact Dan Parrillo, Aerospace Engineer, FAA NYACO, ANE-172, 10 Fifth Street, Valley Stream, NY 11581-1200; phone: (516) 256-7505; fax: (516) 568-2716; email: [email protected]