AD 74-11-06

74-11-06 AIRESEARCH MANUFACTURING COMPANY of ARIZONA: Amendment 39-1853 as amended by Amendment 39-1962. Applies to AiResearch Model TFE731-2-1C and -2-2B engines installed in, but not limited to, AMD-BA Falcon 10 and Lear-Gates Learjet model 35/36 aircraft, certificated in all categories.

Compliance required after the effective date of this AD, as amended, as indicated, unless previously accomplished.

To prevent improper operation of the engine fuel control computer due to voltage transients in the electrical system, accomplish the following:

(A) Before further engine operation, modify the fuel control computer, P/N 949572-5, in accordance with AiResearch Service Bulletin TFE731-76-3002, dated April 25, 1974, or later FAA-approved revisions; or

(B) Replace the fuel control computer P/N 949572-5, with a fuel control computer P/N 949572-8.

Note: 1. With regard to the AMD-BA Falcon 10 aircraft, modified per (A) or (B) above, the Secretariat General A L' Aviation Civile (SGAC), in agreement with AiResearch, has advised that no airplane flight manual modification is required. Immediate implementation by operators of the procedures set forth in AiResearch operating information letter, OI731-2, dated April 20, 1974, is urgently recommended by the Federal Aviation Administration.

2. With regard to the Lear-Gates Model 35/36, modified per (A) or (B) above, the FAA- approved AFM provides appropriate operation instructions.

(C) This is interim AD action. Further modifications are under development by the manufacturer.

(D) Aircraft may be flown to a base for performance of maintenance required by this AD per FAR's 21.197 and 21.199."

Amendment 39-1853 became effective May 28, 1974, for all persons except those to whom it was made effective immediately by telegram dated May 3, 1974.

This amendment 39-1962 becomes effective September 23, 1974.