AD 91-02-10

91-02-10 CFM INTERNATIONAL: Amendment 39-6839. Docket No. 89-ANE-39. Applicability: CFM International (CFMI) CFM56-3, -3B, -3C series turbofan engines, installed on, but not limited to, Boeing 737-300, 737-400 and 737-500 aircraft. Compliance: Required as indicated, unless previously accomplished. To prevent engine power loss or flameout while operating in heavy precipitation, accomplish the following: (a) Install fan splitter fairing, fan stage 1 vane assembly, and new centering shroud, in accordance with the Accomplishment Instructions contained in CFMI CFM 56-3, -3B, -3C series Service Bulletin (SB) 72-450, Revision 1, dated May 30, 1989, within 30 days after the effective date of this AD. (b) Install the 12 door variable bypass valve (VBV) configuration in accordance with the Accomplishment Instructions contained in CFMI CFM 56-3, -3B, -3C series SB 72-462, Revision 1, dated May 30, 1989, within 30 days after the effective date of this AD. (c) Aircraft may beferried in accordance with the provisions of FAR 21.197 and 21.199 to a base where the AD can be accomplished. (d) Upon submission of substantiating data by an owner or operator through an FAA Airworthiness Inspector, an alternate method of compliance with the requirements of this AD or adjustments to the compliance times specified in this AD may be approved by the Manager, Engine Certification Office, Engine and Propeller Directorate, Aircraft Certification Service, FAA, 12 New England Executive Park, Burlington, Massachusetts 01803. The installation procedures shall be done in accordance with the following CFM International documents:

Document Page Number Revision Date CFMI CFM 56-3, 1-4, 6-26 Revision 1 5/30/89 -3B, -3C 5 Original 4/17/89 SB 72-450

CFMI CFM 56-3, 1-27, 29-33 Revision 1 5/30/89 -3B, -3C 28 Original 4/10/89 SB 72-462

This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to CFM International, Technical Publications Department, 1 Neumann Way, Cincinnati, Ohio 45215. These documents may be examined at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Room 311, Burlington, Massachusetts 01803, or at the Office of the Federal Register, 1100 L Street, NW, Room 8301, Washington, DC 20591. This amendment (39-6839, AD 91-02-10) is effective on February 11, 1991.