AD 83-08-04 R3 ACTIVE

83-08-04 R3 SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE (SNIAS): Amendment 39-4712, as revised by letter issued September 23, 1983. Applies to Societe Nationale Industrielle Aerospatiale Model AS355 series helicopters certificated in all categories, equipped with epicyclic planet pinion cages, P/N's 350A32-3147-20 and 350A32-1081-20 or -21 installed.

Compliance is required as indicated (unless already accomplished).

To prevent loss of drive to the main rotor, accomplish the following:

(a) Within 10 hours time in service after the effective date of this AD, remove from service all helicopter transmission epicyclic planet pinion cages, P/N 350A32-3147-20, having 150 hours or m;ore total time in service and replace with a serviceable part.

(b) For epicyclic planet pinion cages, P/N 350A32-3147-20, with less than 150 hours time in service, replace with a serviceable part prior to accumulation of 160 hours total time in service.

(c) Within 10 hours time in service after receipt of this letter, remove from service all helicopter transmission epicyclic planet pinion cages, P/N 350A32-1081-20 or -21, having 350 hours or more total time in service and replace with a serviceable part.

(d) For epicyclic planet pinion cages, P/N 350A32-1081-20 or -21, with less than 350 hours time in service, replace with a serviceable part prior to accumulation of 360 hours total time in service.

Equivalent means of compliance must be approved by the Manager, Aircraft Certification Staff, FAA, Europe, Africa, and Middle East Office, c/o American Embassy, Brussels, Beligum.

Amendment 39-4712 became effective September 6, 1983, to all persons except those persons to whom it was made immediately effective by priority letter AD 83-08-04, issued April 21, 1983, revised July 21, 1983, which contained this amendment.

This airworthiness directive becomes effective upon receipt.