AD 63-13-05

63-13-05 VERTOL: Amdt 578 Part 507 Federal Register June 22, 1963. Applies to All Model 107-II Helicopters, Serial Numbers 2 and Up.

Compliance required as indicated.

As a result of fatigue cracks which have occurred in service on the aft rotor vertical drive shaft and a fatigue failure of the mixing gearbox collector gear during bench testing, accomplish the following:

(a) Replace before further flight, all forward rotor transmission shafts and carrier assemblies P/N's 107D1259-1, -3 or -5 and the aft rotor drive shafts extensions P/N's 107D3147-1 or -3 which have accumulated 150 or more hours' time in service as of the effective date of this AD. Thereafter, all shafts shall be retired from service prior to the accumulation of 150 hours' time in service, except that those modified by the manufacturer to the later designs may have the service life as designated for the particular design in paragraphs (c)(1) or (c)(2) as applicable. (These components are subunits ofthe P/N's 107D1210 and 107D3011 shaft assemblies respectively.)

(b) At not more than 150 hours total time in service or 8 hours of gearbox cumulative single engine time, whichever occurs first, retire from service collector gear P/N 107D2066-4 (shot peened). If replacement gear is same part number, same retirement time applies. If improved design gear P/N 107D2066-10 is installed, the above retirement time does not apply. If P/N 107D2066-10 gear is installed change mixing gearbox to P/N 107D2003-10. Recording of accumulated single engine time is to be continued.

(c) (1) Replace before further flight, all forward transmission rotor shaft and carrier assemblies P/N's 107D1259-6 and 107D1259-8 which have accumulated 2,500 or more hours' time in service as of the effective date of this AD. Thereafter, all such shafts are to be retired from service prior to the accumulation of 2,500 hours' time in service. (These components are subunits of planetary assemblies P/N's 107D1210-5 and -6 respectively.)

(2) Replace before further flight, all aft rotor drive shaft extensions P/N's 107D3147-4 and 107D3147-6 which have accumulated 1,500 hours' time in service as of the effective date of this AD. Thereafter all such shafts are to be retired from service prior to the accumulation of 1,500 hours' time in service. (These components are subunits of aft shaft assemblies P/N's 107D3011-4 and -5 respectively.)

NOTE: Although P/N's 107D1259-6, -8 and 107D3147-4, -6, were not covered by AD 62-17-07 as amended, they are FAA engineering approved shafts equivalent to 107D1259-1, -3, - 5 and 107D3147-1, -3 respectively and originally had the same service life limits as those shafts.

(Vertol Service Bulletins Nos. 107-3 (R-3) and 107-2 cover these subjects.)

This supersedes AD 62-17-07. This directive effective July 3, 1963.