AD 75-22-21

75-22-21 SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE: (S.N.I.A.S., formerly SUD AVIATION). Amendment 39-2393. Applies to Model SA316B Alouette III helicopters, certificated in all categories, incorporating main rotor transmission gearbox (MGB), Serial Number 9,999 or lower, P/N 3160S.62.00.000.10 through .12 incorporating Modification AM1212, or P/N 3160S.62.00.000.13 or .14.

Compliance is required as indicated, unless already accomplished.

To prevent possible failure of the main gearbox, accomplish the following:

(a) Within the next 10 hours' time in service after the effective date of this AD, install a temporary operating limitations placard on the instrument panel in full view of the pilot reading as follows: "Operate in accordance with the limitations specified in the Alouette III SE.3160 Helicopter Flight Manual. Limitations or performance specified in Appendix 2 of that manual are not applicable to this helicopter."

(b) Within the next 450 hours' time inservice after the effective date of this AD, replace the MGB with a serviceable MGB having a part number specified in Subparagraph 1C of Alouette Service Bulletin No. 01.34 dated June 24, 1974, or an FAA-approved equivalent.

(c) After complying with paragraph (b) of this AD, the placard required by paragraph (a) may be removed.

This amendment becomes effective October 30, 1975.