| AD Number | 81-16-03 | Status | Active |
| Effective Date | July 28, 1981 | Issue Date | Not specified |
| Docket Number | Unknown | Amendment | 39-4171 |
| Product Type | ["Propeller"] | Product Subtype | Not specified |
| CFR Part | --- - Part 39 | CFR Section | N/A |
| Citation | This information is not available. | ||
| Manufacturer(s) | Dowty Propellers |
| Model(s) | (c) R175/4-30-4/ |
81-16-03 DOWTY ROTOL LTD.: Amendment 39-4171. Applies to Dowty Rotol propellers Type R175/4-30-4/13E with hub and driving assembly, P/Ns 601022104 or 601022420 which do not have Dowty Rotol Service Bulletin 61-604 (Mod. No. (c)VP2388) incorporated, as installed on, but not limited to Fairchild F-27, F-27B, and Fokker F-27 Mks 100, 300 and 700 airplanes.
Compliance is required as indicated, unless already accomplished
To prevent propeller failure due to cracking of the propeller hub, accomplish the following repetitive actions until modified in accordance with paragraph (d) below:
(a) Propeller hubs with less than 20,000 total hours time in service, inspect in accordance with paragraph (c) at next overhaul or prior to accumulating 22,000 total hours, whichever occurs first, and reinspect in accordance with paragraph (c) at each subsequent overhaul. If an operator finds a cracked hub in his fleet, the reinspection interval must not exceed 2,000 operating hours on allof his propellers that exceed 20,000 total hours.
(b) Propeller hubs with 20,000 or more total hours time in service, inspect as follows:
(1) Hubs with more than 1400 hours since last inspection or overhaul, inspect in accordance with paragraph (c) prior to accumulating 600 additional operating hours after the effective date of this AD and reinspect in accordance with paragraph (c) at each subsequent overhaul. If an operator finds a cracked hub in his fleet, the reinspection interval must not exceed 2,000 operating hours on all of his propellers that exceed 20,000 total hours.
(2) Hubs with less than 1400 hours since last inspection or overhaul, inspect in accordance with paragraph (c) prior to accumulating 2000 hours since last inspection or overhaul and reinspect at each subsequent overhaul. If an operator finds a cracked hub in his fleet, the reinspection interval must not exceed 2,000 operating hours on all of his propellers that exceed 20,000 total hours.
(c) Inspection Procedure:
(1) During overhaul or propeller disassembly, crack test the hub front wall to snout radius in accordance with Part 2A of Dowty Rotol Service Bulletin No. 61-909 dated September 19, 1978, as revised March 12, 1979, or FAA approved equivalent. If cracks are found, replace the cracked hub with a hub known to be free of cracks.
(2) For propellers between overhauls, remove, disassemble, inspect, reassemble and reinstall in accordance with Part 2B of Dowty Rotol Service Bulletin No. 61-909 dated September 19, 1978, as revised March 12, 1979, or FAA approved equivalent. If cracks are found during inspection, additional propeller disassembly is necessary to replace the cracked hub with a hub known to be free of cracks, and testing and rebalancing and resetting blade angles is necessary.
(d) Terminating Action:
The inspections required by this AD may be discontinued when propellers are modified by Dowty Rotol Service Bulletin 61-604 (Mod. No. (c)VP2388) dated July 1968 as revised by Revision 2 dated November 24, 1971, or FAA approved equivalent.
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 the 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, Sully 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 Region, FAA, 2300 East Devon Avenue Des Plaines, Illinois 60018.
This amendment becomes effective July 28, 1981.