AD 73-12-03 R1

73-12-03 R1 ROLLS ROYCE LTD: Amendment 39-1652 as amended by Amendment 39-4277. Applies to Rolls-Royce DART engine models 542-10, 542-10J, and 542-10K which do not have Rolls-Royce, Ltd., Modification No. 1681 and Modification No. 1768 incorporated, as installed on, but not limited to, NAMC YS-11 airplanes.

Compliance is required as indicated.

To detect engine mounting foot cracks, and engine mounting foot stud fractures, looseness, and loose nuts, accomplish the following:

(a) Within the next 400 hours time in service after the effective date of this AD, or within 400 hours time in service since the last inspection, whichever occurs sooner, and thereafter at intervals not to exceed 400 hours time in service since the last inspection, inspect engine top mounting feet which do not incorporate Modification 1681 and side mounting feet which do not incorporate Modification 1768 for cracks and the mounting feet studs for fracture, looseness, and loose nuts, in accordancewith Rolls-Royce Service Bulletin Da72-384, Revision 2, dated September 1979.

(b) If any engine mounting feet are found cracked or any engine mounting feet studs are found to have loose nuts, or to be loose or fractured during an inspection required by paragraph (a), before further flight, repair in accordance with Rolls Royce Service Bulletin Da72-384 Revision 2, dated September 1979 or an FAA- approved equivalent.

NOTE: Rolls-Royce DART Service Bulletins Da72-411 and Da72-444 concern Modification No. 1681 and Modification No. 1768, respectively.

Amendment 39-1652 became effective July 1, 1973.

This amendment 39-4277 becomes effective December 10, 1981.