AD 82-25-10

82-25-10 AVCO LYCOMING: Amendment 39-4511. Applies to Avco Lycoming ALF502L, L-2, R-3, and R-4 Turbofan Engines.

Compliance is required as indicated unless already accomplished.

To prevent engine power loss, uncontained engine failure, and in-flight engine shutdown, caused by separation of first stage compressor stator vane airfoils and/or separation of fourth stage turbine blade airfoils, one of which was not contained, accomplish the following:

(a) Prior to December 16, 1982, and thereafter at intervals not to exceed 50 operating cycles since the last inspection, perform boroscope inspections of first stator vane segments in accordance with Avco Lycoming Service Bulletin ALF502-72-0012, Revision 2, dated June 17, 1982, until paragraph (b) is accomplished.

(b) Prior to July 1, 1983, replace first stage compressor stator vane assembly with the improved first stage compressor stator vane assembly in accordance with Avco Lycoming Service Bulletin ALF502-72-0025,Revision 1, dated June 17, 1982.

(c) Prior to December 16, 1982, conduct eddy current inspections of fourth stage turbine blades in accordance with Avco Lycoming Service Bulletin ALF502-72-0027 dated May 26, 1982.

(d) Prior to July 1, 1983, replace fourth stage turbine nozzle with the improved fourth stage turbine nozzle in accordance with Avco Lycoming Service Bulletin ALF502-72-0021, dated April 16, 1982.

(e) Later FAA approved revisions of the service bulletins, referred to in this AD, and/or equivalent means approved by the Manager, Engine Certification Branch, FAA, New England Region, may be used in lieu of the above listed service bulletins.

(f) Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Manager, Engine Certification Branch, FAA, New England Region, may adjust the compliance date specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiatingdata to justify the increase for that operator.

This amendment becomes effective December 16, 1982.