AD 86-11-05 SUPERSEDED

86-11-05 GARRETT TURBINE ENGINE COMPANY (formerly the AiResearch Manufacturing Company of Arizona): Amendment 39-5325. Applies to all Model TFE731-2, -3, and -3R turbofan engines installed in aircraft certified in all categories equipped with fan rotor discs, part number 3073436-1, -2, -3, and -4 and 3072162-1, -2, -3, and -4.

Compliance is required as indicated unless already accomplished.

To prevent failure of the fan rotor disc due to fatigue cracking, accomplish the following:

(a) For fan rotor discs with 4000 or less operating cycles on the effective date of this AD, remove fan rotor disc from service before reaching 4100 total operating cycles.

(b) For fan rotor discs with more than 4000 but with 6000 or less operating cycles on the effective date of this AD, remove fan rotor disc from service within the next 100 operating cycles or prior to reaching 6005 total operating cycles whichever occurs first.

(c) For fan rotor discs with more than 6000 but with 8000 or less operating cycles on the effective date of this AD, remove fan rotor disc from service within the next 5 operating cycles or prior to reaching 8001 total operating cycles whichever occurs first.

(d) For fan rotor discs with more than 8000 operating cycles on the effective date of this AD, remove fan rotor disc from service prior to further flight.

NOTES: (1) An operating cycle is considered as any engine operating sequence involving an engine start, at least one acceleration to 80 percent or more low pressure rotor speed, and an engine shutdown. An alternate method of determining cycles is to consider each airplane landing as one cycle. Fan rotor discs which have had their cyclic lives calculated by any other method are to have their cyclic lives recalculated using one of the two methods specified above.

(2) It has come to the attention of the FAA that some life limit log cards in the engine log book were incorrectly filled out in that the "dash number" of the disc part numbers (i.e., -1/-2/-3/-4) may have been left off. This should be corrected when the disc is next available to read the entire part number. All fan rotor discs are -1, -2, -3, or -4, and are affected by this AD. Fan rotor discs may be returned to GTEC for evaluation. Shipping information is contained in Garrett Alert Service Bulletin No. TFE731-A72-3328 Revision 2 dated April 4, 1986.

Aircraft may be ferried in accordance with the provisions of FAR 21.197 and 21.199 to a base where the AD can be accomplished.

Upon request, an equivalent means of compliance with the requirements of this AD may be approved by the Manager, Western Aircraft Certification Office, P.O. Box 92007, Worldway Postal Center, Los Angeles, California 90009.

Upon submission of substantiating data by an owner or operator through an FAA maintenance inspector, the Manager, Western Aircraft Certification Office, P.O. Box 92007, Worldway Postal Center, Los Angeles, California 90009-2007 may adjust the compliance time specified in this AD.

This amendment supersedes priority letter AD 86-04-02 issued February 14, 1986.

There are two effective dates for this superseding AD.

For those operators who received priority letter AD 86-04-02, the effective date of this AD is the date of the priority letter AD (issued February 14, 1986).

The effective date of this AD is June 16, 1986, for operators with fan rotor disc part number 3073436-4 or 3072162-4 installed and for operators who did not receive the priority letter AD.