AD 88-07-08

88-07-08 GENERAL ELECTRIC: Amendment 39-5869. Applies to General Electric (GE) CT7-5A, -5A1, and -5A2 turbopropeller engines as installed in Saab-Fairchild SF340A aircraft.

Compliance is required as indicated, unless already accomplished.

To prevent power turbine (PT) overspeed resulting in an uncontained failure or adverse aircraft yaw due to reaction of the fuel control to an erroneous PT speed signal during ground operation with the bottoming governor (BG) enabled, accomplish the following no later than May 16, 1988:

(a) Remove propeller overspeed governor (OSG), Dowty Rotol (DR) Part Number (P/N) 661001001, and replace with OSG, DR P/N 661001002, in accordance with procedures contained in DR Service Bulletin (SB) SF340-61-11, dated October 8, 1986.

(b) Install cable, GE P/N 6068T47P01, between the propeller OSG and the hydromechanical unit in accordance with GE CT7 Turboprop SB 74-09, dated October 10, 1986.

(c) Install engine BG deactivation switches,Mod Kit Saab SF340-76-018-01, in the power lever quadrant in accordance with procedures contained in Saab SB SF340-76-018, dated October 24, 1986.

(d) Upon accomplishment of paragraphs (a) through (c) above:

(1) Remove from the SF340A Aircraft Flight Manual (AFM) the BG disabling procedures required by AD 86-10-51, paragraphs (a)(1) and (a)2.

(2) Discontinue operating in accordance with the procedures listed in AD 86-10-51, paragraph (b).

NOTE: Subsequent to compliance with this AD, aircraft operation shall be conducted in accordance with the latest AFM revision.

(e) Aircraft may be ferried in accordance with the provisions of Federal Aviation Regulations (FAR) 21.197 and 21.199 to a base where the AD can be accomplished.

(f) Upon request, an equivalent means of compliance with the requirements of this AD may be approved by the Manager, Engine Certification Office, Aircraft Certification Division, Federal Aviation Administration, New England Region, 12New England Executive Park, Burlington, Massachusetts 01803.

(g) Upon submission of substantiating data by an owner or operator through an FAA maintenance inspector, the Manager, Engine Certification Office, New England Region, may adjust the compliance time specified in this AD.

Dowty Rotol SB SF340-61-11, dated October 8, 1986; General Electric CT7 Turboprop SB 74-09, dated October 10, 1986; and Saab SB SF340-76-018, dated October 24, 1986, identified and described in this document are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552 (a)(1). All persons affected by this directive who have not already received these documents from the manufacturer, may obtain copies upon request to Dowty Rotol Limited, Cheltenham Road East, Gloucester, England GL2 9QH; General Electric Company, 1000 Western Avenue, Lynn, Massachusetts 01910; and Saab-Scania AB, S-581 88, Linkoping, Sweden.

This document may also be examined at the Office of the Regional Counsel, Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803, Rules Docket Number 86-ANE-21, Room 311, between the hours of 8:00 a.m. and 4:30 p.m., Monday through Friday, except federal holidays.

This amendment supersedes Amendment 39-5473 (51 FR 44439; December 9, 1986), AD 86-10-51.

This amendment becomes effective on May 9, 1988.