89-11-03 BOEING: Amendment 39-6223. \n\tApplicability: Model 737-300 and -400 series airplanes, certificated in any category. \n\n\tCompliance: Required as indicated, unless previously accomplished. \n\n\tTo prevent the ingestion of "blue ice" into the engine and the potential loss of an engine, accomplish the following: \n\n\tA.\tWithin 200 hours time-in-service after the effective date of this AD: \n\n\t\t1.\tConduct a leak check of the forward lavatory service system, in accordance with Boeing Telex M-7272-89-2127 dated April 25, 1989, and repeat the check at intervals thereafter not to exceed 200 hours time-in-service; or \n\n\t\t2.\tDrain the forward lavatory system, lock the lavatory(s), and placard the lavatory(s) inoperative. \n\n\tB.\tLeaks discovered at any time must be repaired prior to further flight, or the forward lavatory system must be drained, and the lavatory(s) locked and placarded inoperative, prior to further flight. \n\n\tC.\tAn alternate means of compliance or adjustmentof 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 will either concur or comment and then send it to the Manager, Seattle Aircraft Certification Office. \n\n\tD.\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 inspections and/or modifications required by this AD. \n\n\tAll persons affected by this directive who have not already received the appropriate service information from the manufacturer may obtain copies upon request to Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington, 98124. This information may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or at the Seattle Aircraft Certification Office, FAA, Northwest Mountain Region, 9010 East Marginal Way South, Seattle, Washington. \n\n\tThis amendment (39-6223, AD 89-11-03) becomes effective on June 5, 1989.