AD 75-21-03

75-21-03 SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE (formerly Sud Aviation). Amendment 39-2381. Applies to Alouette III Model SE.3160, SA.316B, SA.316C, and SA.319B helicopters incorporating tail boom P/N 3160S.23.11.000.9 to 3160S.23.11.000.13, inclusive, certificated in all categories.

Compliance is required as indicated, unless already accomplished in accordance with Alouette Service Bulletin No. 53.31.

To prevent failure of the tail boom, accomplish the following:

(a) Within the next 10 hours' time in service after the effective date of this AD, and thereafter at intervals not to exceed 50 hours' time in service since the last check, until reinforced in accordance with paragraph (d) of this AD, check the upper section of the tailboom at Frame 8 for loose rivets.

(b) If more than one rivet is found loose, comply with paragraph (d) of this AD before further flight, except that the helicopter may be flown in accordance with FAR Sections 21.197 and 21.199 to abase where the work can be performed.

(c) If no more than one rivet is found loose, within the next 400 hours' time in service after the effective date of this AD, comply with paragraph (d) of this AD.

(d) Where required by paragraph (b) or (c) of this AD, reinforce the tail boom attachment at Frame 8 in accordance with subparagraph 1C of Alouette Service Bulletin No. 53.31, as revised April 29, 1974, or equivalent approved by the Chief, Aircraft Certification Staff, FAA, Europe, Africa, and Middle East Region, c/o American Embassy, A.P.O. New York, N.Y. 09667.

The checks required by paragraph (a) of this AD may be performed by the pilot.

This amendment becomes effective October 20, 1975.