AD 69-21-03

69-21-03 ALLISON GAS TURBINE DIVISION Amendment 39-862. Applies to Models 501-D13 and 501-D22 Series Engines.

Compliance: Required as indicated.

To insure adequate life limit margin for Allison P/Ns 6738651, 6788581, 6789681, 6805651, 6805701, 6844081, and 6829661 first stage compressor wheels with balance weight pin holes in the front lip of the outer rim, accomplish the following:

(A) Wheels which have 16,000 cycles or less on September 30, 1969, shall be removed from service prior to reaching 19,000 cycles or, unless already accomplished, must be inspected in accordance with Allison Commercial Service Letter CSL-120 Supplement dated October 2, 1969, or Allison Commercial Service Letter 501-D22 CSL-1001 Supplement dated October 2, 1969, or any other method approved by the Chief, Engineering and Manufacturing Branch, Central Region.

(B) Wheels which exceeded 16,000 cycles on September 30, 1969, must be removed from service in accordance with Inspection/Removal Chart contained on page 3 of Allison Commercial Service Letter CSL-120 Supplement dated October 2, 1969, or contained on page 3 of Allison Commercial Service Letter 501-D22 CSL- 1001 Supplement dated October 2, 1969, unless inspected in accordance with said Allison Commercial Letters.

(C) No first stage compressor wheels shall remain in service beyond 25,100 cycles.

(D) For the purposes of this airworthiness directive, a cycle is defined as one takeoff.

This amendment becomes effective October 21, 1969.