88-19-04 BOEING: Amendment 39-6007. Applies to Model 737 series airplanes, which have been approved for operation above 35,000 feet, certificated in any category. \n\n\tCompliance required within the next 15 months after the effective date of this AD, unless previously accomplished. \n\n\tTo prevent fuselage pressures in excess of design limits due to freezing of cabin pressure safety relief valves if pressurization malfunctions occur, accomplish the following: \n\n\tA.\tReplace the cabin pressure safety relief valves (2) in accordance with Boeing Service Bulletin 737-21-1096, dated December 10, 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 Transport Airplane Office, FAA, Northwest Mountain Region. \n\n\tNOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who may add any comments and then send it to the Manager,Seattle Transport Airplane 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 rework required 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 Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. These documents may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Seattle Transport Airplane Office, 9010 East Marginal Way South, Seattle, Washington. \n\n\tThis amendment, 39-6007, becomes effective October 3, 1988.