- Models
- Double Row Cyclone 956C18CA1, Double Row Cyclone 975C18CB1, Double Row Turbo Cyclone 972TC18DA1 (R-3350-34, -91), Double Row Turbo Cyclone 972TC18DA2, Double Row Turbo Cyclone 972TC18DA3, Double Row Turbo Cyclone 972TC18DA4 and 7 more
- Product
- Engine
Unofficial copy of the text in the FAA’s Dynamic Regulatory System. The FAA’s own copy is the authoritative one. DRS record last changed May 30, 2024.
Copies of the files this page was built from, with their SHA-256. Retrieved October 18, 2026.
| File | Size | SHA-256 | Original |
|---|---|---|---|
| FAA DRS HTML | 20 KB | 4f382016…298b7c1 | FAA DRS (API key needed) |
On this page
The airworthiness directive
57-06-04 WRIGHT: Applies to All Aircraft Incorporating C18CA, C18CB, TC18DA, and TC18EA Series Engines.
Compliance required as indicated.
Results of recent investigations indicate that the engine front section bearing durability can be improved by accomplishing the following:
1. At next engine overhaul the engine front section must be assembled with the propeller shaft thrust bearing (ball bearing) behind the radial bearing (roller bearing) as viewed from the propeller end of the engine.
(Wright Aeronautical Division Service Bulletins Nos. C18C-252, TC18D-255, and TC-18E-66 cover this same subject.)
Propellers must be balanced in accordance with instructions contained in applicable propeller manufacturer's recommendations.
2. Engines overhauled after April 15, 1957, must incorporate engine propeller shaft thrust bearings (ball bearings) and radial bearings (roller bearings) that have been inspected for proper internal bearing clearances in accordance with instructions issued by the Wright Aeronautical Division in their Service Letter dated March 22, 1957.
Affected TCDS · 3
The type certificate data sheets for the models this AD names, matched by model and maker.