AD 81-07-09

81-07-09 DOWTY ROTOL: Amendment 39-4076. Applies to Dowty Rotol (c)R.289/3-110- F/1 and (c)R.289/3-110-F/11 propellers installed on the WSK-Pezetel Model PZL-3S engine used on Gulfstream American (formerly Grumman) Model G-164A, B, C airplanes modified by STC SA2731SW, and Ayres (formerly Rockwell) Model S2R-R3S, and Model S2R airplanes modified by STC SA3897WE.

Compliance is required as indicated unless previously accomplished. To preclude the possibility of blade tip failures, accomplish the following:

Within the next 50 hours time in service after the effective date of this AD or by April 30, 1981, whichever occurs first, perform the following:

(a) Reindex propeller shaft to engine crankshaft in accordance with Dowty Rotol Service Bulletin No. 61-941 dated February 5, 1981, and PZL-Rzeszow Service Instruction No. 28/PZL-3S/81 dated January 30, 1981, or FAA approved equivalent.

(b) After reindexing propeller shaft to engine crankshaft, replace all blades P/N660705335 that have been operated prior to reindexing in accordance with paragraph (a) above with new blades P/N 660705335 per Dowty Rotol Service Bulletin No. 61-941 dated February 5, 1981, or FAA approved equivalent.

(c) Establish a 600-hour safe life limit on all new blades P/N 660705335 installed per paragraph (b) above.

(d) Upon request of an operator, the Chief, Engineering and Manufacturing Branch, AGL-210, Federal Aviation Administration, Great Lakes Region, may adjust the compliance time specified in this AD provided such requests are made through an FAA Maintenance Inspector and the request contains substantiating data to justify the request for that operator.

(e) For purposes of this AD, an equivalent must be approved by the Chief, Engineering and Manufacturing and Manufacturing Branch, AGL-210, Federal Aviation Administration, Great Lakes Region.

This amendment becomes effective April 2, 1981.