AD 61-03-01

61-03-01 BELL: Amdt. 249 Part 507 Federal Register February 7, 1961. Applies to All Model 47J-2 Helicopters Except Those Equipped With Lycoming VO-540-B1B3 Engines (Third Order Torsional Dampers).

Compliance required as indicated.

To preclude failures of the pinion gear on the inboard end of the P/N 47-620-539-1 cooling fan drive assembly which are associated with a poor tooth mesh condition, the following inspections and corrective action must be accomplished no later than the next 10 hours of flight time after the effective date of this directive, and by the completion of the 25 hour, 50 hour, 100 hour, and 300 hour flight time periods subsequent to the accomplishment of the initial inspection. Inspections accomplished in accordance with Bell Mandatory Service Bulletin 130SB prior to the effective date of this directive need not be repeated and only those remaining inspections necessary to complete the series are required.

(a) Remove cooling fan drive assembly, P/N 47-620-539-1, from transmission in accordance with instructions contained in Bell Model 47J-2 Maintenance and Overhaul Instructions, and inspect driven side of pinion gear teeth (P/N 47-620-530-1).

(b) Replace gear if conditions defined by Figure 2 of Bell Service Bulletin 130SB are found.

(c) If replacement of the pinion gear is required, further disassembly as necessary and inspection of the cooling fan driving gear (P/N 47-620-207-1) must be conducted. If conditions defined by Figure 4 of Bell Service Bulletin 130SB are found, this gear must also be replaced.

(d) If replacement of either gear is required, back lash and gear pattern must be established in accordance with instructions contained in Maintenance and Overhaul Instructions.

(e) Reassemble cooling fan drive assembly in accordance with Maintenance and Overhaul Instructions except that nut, P/N 47-620-565-1 shall be torqued to 960 inch-pounds and fan pulley bolt AN 6H5A shall be torqued to 300 inch-pounds.

(f) If either or both gears are replaced, perform the above inspections at 10, 25, 50, 100 and 300 hours of flight time following gear replacement. This procedure must be reconducted until a satisfactory wear pattern on the pinion gear and drive gear is maintained through 300 hours of flight time, after which inspections in accordance with this directive may be discontinued.

(Bell Mandatory Service Bulletin 130SB covers this same subject.)

This directive effective February 22, 1961.

Revised May 13, 1961.

Revised November 5, 1966.