AD 57-06-04
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Cyclone 956C18CA1 | WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines |
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Cyclone 975C18CB1 | WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines |
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Turbo Cyclone 972TC18DA1 (R-3350-34, -91) | WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines |
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Turbo Cyclone 972TC18DA2 | WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines |
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Turbo Cyclone 972TC18DA3 | WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines |
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Turbo Cyclone 972TC18DA4 | WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines |
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Turbo Cyclone 981TC18EA1 | WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines |
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Turbo Cyclone 988TC18EA1 | WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines |
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Turbo Cyclone 988TC18EA2 | WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines |
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Turbo Cyclone 988TC18EA3 | WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines |
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Turbo Cyclone 988TC18EA4 | WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines |
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Turbo Cyclone 988TC18EA5 | WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines |
| engine | Curtiss-Wright/Marquette, Inc. | Double Row Turbo Cyclone 988TC18EA6 | WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines |
Unsafe Condition
The engine front section bearing durability may be insufficient due to improper assembly of the propeller shaft thrust bearing (ball bearing) and radial bearing (roller bearing).
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Required Actions
At next engine overhaul, assemble the engine front section with the propeller shaft thrust bearing (ball bearing) behind the radial bearing (roller bearing) as viewed from the propeller end. Inspect propeller shaft thrust and radial bearings for proper internal clearances if overhauled after April 15, 1957, per Wright Aeronautical Division Service Letter dated March 22, 1957. Balance propellers according to propeller manufacturer's recommendations.
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Compliance Time
Compliance required as indicated.
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Affected Aircraft
Curtiss-Wright/Marquette, Inc. models Double Row Cyclone 956C18CA1, Double Row Cyclone 975C18CB1, Double Row Turbo Cyclone 972TC18DA1, and TC18EA series engines.
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Federal Register Abstract
Engine Front Section
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_57-06-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 57-06-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines Subject: Engine Front Section Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Curtiss-Wright/Marquette, Inc. Model: Double Row Cyclone 956C18CA1 | Double Row Cyclone 975C18CB1 | Double Row Turbo Cyclone 972TC18DA1 (R...Show more Product Type: Engine Product Subtype: Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 57-06-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 57-06-04 SUBJECT HEADING: WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 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. FOOTER:
Document Text
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AD Final Rules - DRS_57-06-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 57-06-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines Subject: Engine Front Section Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Curtiss-Wright/Marquette, Inc. Model: Double Row Cyclone 956C18CA1 | Double Row Cyclone 975C18CB1 | Double Row Turbo Cyclone 972TC18DA1 (R...Show more Product Type: Engine Product Subtype: Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 57-06-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 57-06-04 SUBJECT HEADING: WRIGHT Models C18CA, C18CB, TC18DA, and TC18EA Series Engines ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 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. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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