89-07-13 BOEING: Amendment 39-6165. \n\tApplicability: Model 737 series airplanes, certificated in any category. \n\n\tCompliance: Required within the next 18 months after the effective date of this AD, unless previously accomplished. \n\n\tTo prevent smoke in the cockpit and partial loss of electrical power caused by the failures of the Generator Control Unit (GCU) filter modules, accomplish the following: \n\n\tA.\tReplace or modify the GCU filter modules, in Westinghouse GCU P/N 915F212- 5 and GCU P/N 948F458-1, in accordance with Westinghouse Service Bulletin 87-101, dated March 1987, or Westinghouse Service Bulletin 87-102, dated August 1987. \n\n\tB.\tAn alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region. \n\n\tNOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who mayadd any comments and then send it to the Manager, Seattle Aircraft Certification Office. \n\n\tC.\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of the modification by this AD. \n\n\tAll persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Westinghouse, Electrical Systems Division, P.O. Box 989, Lima, Ohio 45802. These documents may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Seattle Aircraft Certification Office, FAA, 9010 East Marginal Way South, Seattle, Washington. \n\n\tThis amendment (39-6165, 89-07-13) becomes effective on April 28, 1989.