Airworthiness Directive · Amendment 39-14385 · Boeing Vertol Model 107-II Helicopters
Boeing Vertol Model 107-II Helicopters
Model 107-II helicopters, all serial numbers, with a quill shaft, part number (P/N) 107D2067, all dash numbers, and a spiral bevel pinion gear (pinion gear), P/N 107D2215, installed, certificated in any category.
This amendment adopts a new airworthiness directive (AD) for Boeing Vertol (Boeing) Model 107-II helicopters. This action requires a visual and magnetic particle inspection of the quill shaft. This amendment is prompted by the discovery of cracks in a quill shaft during a routine inspection. The actions specified in this AD are intended to detect a fatigue crack in a quill shaft and prevent separation of the quill shaft between the aft transmission and the mix box assembly, loss of rotor synchronization, and subsequent loss of control of the helicopter.
To detect a fatigue crack in a quill shaft to prevent separation of the quill shaft between the aft transmission and the mix box assembly, loss of rotor synchronization, and subsequent loss of control of the helicopter, accomplish the following:
(a) For a helicopter with a pinion gear installed with the following hours time-in-service (TIS):
| Pinion gear hours TIS | Compliance time |
|---|---|
| 700 or more hours TIS | Within 50 hours TIS, unless accomplished within the previous 350 hours TIS. |
| Less than 700 hours TIS | On or before reaching 750 hours TIS. |
(1) Remove the aft transmission assembly, separate the mix box assembly from the aft transmission, and remove the quill shaft from the pinion gear assembly;
(2) Visually inspect the external spline of the quill shaft for a chipped or cracked tooth around the pinhole; and
(3) Magnetic particle inspect the quill shaft for a crack.
(b) Before further flight, replace any quill shaft that has a crack or a chipped or cracked tooth with an airworthy quill shaft.
Note 1: Boeing Service Bulletin No. 107-63-1005, Revision 1, dated April 27, 2005, pertains to the subject of this AD.
Note 2: Replacement quill shafts manufactured by Kawasaki Heavy Industries (KHI) for use on their Model KV107-II helicopters must be approved by the geographic Aircraft Certification Office (ACO) on a case-by-case basis for installation on a Boeing Model 107-II helicopter.
(c) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Manager, New York ACO, Engine and Propeller Directorate, FAA, for information about previously approved alternative methods of compliance.
