81-16-02 DOWTY ROTOL, LTD.: Amendment 39-4170. Applies to the 7 Dowty Rotol propeller types listed which have Mod. No. (c)VP2833 (Service Bulletin 61-838) or Mod. No. (c)VP2866 (Service Bulletin 61-889) incorporated, as installed on, but not limited to the airplane models shown, and pitch lock cylinders and lock support sleeves, P/N 601027277, held as spares.
(Note: This AD does not apply to propellers Serial No. DRG 67/78 and subsequent or any pitch lock assembly having a 3/4 inch white paint spot on the cylinder cover.)
Propeller Type
Installed Airplane Model
R184/4-30-4/50
Grumman G-159
R193/4-30-4/50 & 61
Fairchild F-27A, F, G, and J
Fokker F-27 Mks 200, 400, 500 & 600
Fairchild Hiller FH-227 Series
R257/4-30-4/60
Fairchild F-27M
Fairchild Hiller FH-227 B, C, D & E
R209/4-40-4.5/2
YS11 & 11A
R245/4-40-4.5/13
GD/Convair 240 with STC # SA1054WE installed
GD/Convair 340/440 with STC # SA1096WE installed
R259/4-40-4.5/17
GD/Convair 340/440 with STC #SA1096WE installed
R179/4-20-4/33
Viscount 810 Series
Compliance is required as indicated, unless already accomplished.
To prevent cracks in the propeller pitch lock cylinder, accomplish the following one-time only actions:
(a) Within the next 1,000 hours time in service after the effective date of this AD, or at the next propeller overhaul, whichever occurs first, inspect the propeller pitch lock cylinder for cracks in accordance with paragraph 2.A., "Accomplishment Instructions," of Dowty Rotol Service Bulletin 61-906, Revision 4, dated June 12, 1980 (hereinafter referred to as service bulletin), or an FAA-approved equivalent, and -
(1) If any cracks are found, before further flight, remove the pitch lock cylinder from service and replace it with a crack-free pitch lock cylinder of the same part number, which has been inspected and, if necessary, reworked and reprotected in accordance with paragraphs (b) and (c) of this AD.
(2) If no cracks are found, comply with paragraphs (b) and (c) of this AD before further flight.
(b) Inspect the chamfer around the snout adjacent to the radius at the base of the bore at the forward end of the pitch lock cylinder in accordance with paragraph 2.A.(5) of the service bulletin, or an FAA-approved equivalent, and -
(1) If the chamfer is found to be within the dimensions shown in Figure 2 of the service bulletin, or an FAA-approved equivalent, the pitch lock cylinder may be returned to service.
(2) If the chamfer is found to be outside the dimensions shown in Figure 2 of the service bulletin, or an FAA-approved equivalent, rework and reprotect it in accordance with paragraph 2.A.(5) of the service bulletin or an FAA-approved equivalent, before returning the pitch lock cylinder to service.
(c) Inspect the large internal chamfer at the rear end of the lock support sleeve, P/N 601027277, in accordance with Paragraph 2.A.(6) of the service bulletin, or an FAA-approved equivalent, and -
(1) If the dimensions are found to be within the dimensions shown in Figure 3 of the service bulletin, or an FAA-approved equivalent, the lock support sleeve may be returned to service.
(2) If the dimensions are found to be outside the dimensions shown in Figure 3 of the service bulletin, or an FAA-approved equivalent, rework and reprotect the lock support sleeve, P/N 601027277, in accordance with paragraph 2.A.(6) of the service bulletin, or an FAA- approved equivalent, before returning the lock support sleeve to service.
(d) Before releasing to service any pitch lock cylinders held as spares, irrespective of part number, inspect them and remove from spares or rework and reprotect, as required, in accordance with paragraphs (a) and (b) of this AD.
(e) Before releasing to service any support sleeves, P/N 601027277, held as spares, inspect them and remove from spares or rework and reprotect, as required, in accordance with paragraph (c) of this AD.
Upon request of an operator, the Chief, Engineering and Manufacturing Branch, AGL- 210, Federal Aviation Administration, Great Lakes Region, may adjust the compliance time specified in paragraph (a) of this AD provided such requests are made through an FAA maintenance inspector, and the request contains substantiating data to justify the request for that operator.
For purposes of this AD, an FAA-approved equivalent must be approved by the Chief, Engineering and Manufacturing Branch, AGL-210, Federal Aviation Administration, Great Lakes Region.
The manufacturer's specifications and procedures identified in this directive are incorporated herein and made part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by the directive who have not already received these documents from the manufacturer may obtain copies upon request to Dowty Rotol, Inc., Staverton West, Sulley Road, Box 5000, Sterling, VA 22170 or Dowty Rotol, Ltd., Cheltenham Road, Gloucester, England GL2 9QH. These documents may also be examined at the Great Lakes Regional Office, FAA, 2300 East Devon Avenue, Des Plaines, Illinois 60018.
This amendment becomes effective July 28, 1981.