AD 69-18-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Rolls-Royce Corporation | 250-C10 (T63-A-5) | ALLISON Models 250-C10 and 250-C18 Series Engines |
| engine | Rolls-Royce Corporation | 250-C10B (T63-A-5A) | ALLISON Models 250-C10 and 250-C18 Series Engines |
| engine | Rolls-Royce Corporation | 250-C10D (T63-A-700) | ALLISON Models 250-C10 and 250-C18 Series Engines |
| engine | Rolls-Royce Corporation | 250-C18 | ALLISON Models 250-C10 and 250-C18 Series Engines |
| engine | Rolls-Royce Corporation | 250-C18A | ALLISON Models 250-C10 and 250-C18 Series Engines |
| engine | Rolls-Royce Corporation | 250-C18B | ALLISON Models 250-C10 and 250-C18 Series Engines |
| engine | Rolls-Royce Corporation | 250-C18C | ALLISON Models 250-C10 and 250-C18 Series Engines |
Unsafe Condition
Excessive wear of the internal splines on the P/N 6840847 helical power train drive gear.
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Required Actions
Inspect the internal spline using Allison P/N EX 83339 plug gage. Replace the gear with a new or serviceable part if the gage enters the spline. Modify the engine per Allison CEB-61 to eliminate future inspections.
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Compliance Time
Within the next 50 hours' time in service after the effective date, for engines with 750+ hours since new/overhaul, or at or before 800 hours' time in service for those with less than 750 hours at effective date.
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Affected Aircraft
Rolls-Royce Corporation Models 250-C10 (T63-A-5, T63-A-5A, T63-A-700) and 250-C18 (C18, C18A, C18B, C18C) series engines.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Internal Splines
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_69-18-02.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 69-18-02 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: ALLISON Models 250-C10 and 250-C18 Series Engines Subject: Internal Splines Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 09/03/1969 Make: Rolls-Royce Corporation Model: 250-C10 (T63-A-5) | 250-C10B (T63-A-5A) | 250-C10D (T63-A-700) | 250-C18 | 250-C18A | 250-C18B | 250-C18C Product Type: Engine Product Subtype: Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 69-18-02 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-831 AD NUMBER: 69-18-02 SUBJECT HEADING: ALLISON Models 250-C10 and 250-C18 Series Engines ACTION: SUMMARY: DATES: Effective September 3, 1969. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 69-18-02 ALLISON: Amdt. 39-831. Applies to Models 250-C10 and 250-C18 Series Engines. Compliance: Unless already accomplished, within the next 50 hours' time in service after the effective date of this AD, on all engines having 750 or more hours' time in service since new or last overhaul, or at or before 800 hours' time in service on engines that have less than 750 hours' time in service since new or last overhaul at the effective date of this AD, accomplish the following: To detect excessive wear of the internal splines: A) Inspect the internal spline on the P/N 6840847 helical power train drive gear using an Allison P/N EX 83339 plug gage. If this gage enters the spline, replace the gear with a new or serviceable part prior to returning the engine to service. Allison Commercial Service Letter No. 250 CSL-35, dated August 15, 1969, pertains to this inspection. B) When the engine is modified in accordance with Allison Commercial Engine Bulletin No. 250 CEB- 61, dated July 25, 1969, the inspections required by Paragraph A of this AD will no longer be required. Gear boxes having Serial Numbers ending in the suffix "B" incorporate Commercial Engine Bulletin No. 250 CEB-61. This amendment becomes effective September 3, 1969. FOOTER:
Document Text
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AD Final Rules - DRS_69-18-02.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 69-18-02 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: ALLISON Models 250-C10 and 250-C18 Series Engines Subject: Internal Splines Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 09/03/1969 Make: Rolls-Royce Corporation Model: 250-C10 (T63-A-5) | 250-C10B (T63-A-5A) | 250-C10D (T63-A-700) | 250-C18 | 250-C18A | 250-C18B | 250-C18C 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: 69-18-02 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-831 AD NUMBER: 69-18-02 SUBJECT HEADING: ALLISON Models 250-C10 and 250-C18 Series Engines ACTION: SUMMARY: DATES: Effective September 3, 1969. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 69-18-02 ALLISON: Amdt. 39-831. Applies to Models 250-C10 and 250-C18 Series Engines. Compliance: Unless already accomplished, within the next 50 hours' time in service after the effective date of this AD, on all engines having 750 or more hours' time in service since new or last overhaul, or at or before 800 hours' time in service on engines that have less than 750 hours' time in service since new or last overhaul at the effective date of this AD, accomplish the following: To detect excessive wear of the internal splines: A) Inspect the internal spline on the P/N 6840847 helical power train drive gear using an Allison P/N EX 83339 plug gage. If this gage enters the spline, replace the gear with a new or serviceable part prior to returning the engine to service. Allison Commercial Service Letter No. 250 CSL-35, dated August 15, 1969, pertains to this inspection. B) When the engine is modified in accordance with Allison Commercial Engine Bulletin No. 250 CEB- 61, dated July 25, 1969, the inspections required by Paragraph A of this AD will no longer be required. Gear boxes having Serial Numbers ending in the suffix "B" incorporate Commercial Engine Bulletin No. 250 CEB-61. This amendment becomes effective September 3, 1969. FOOTER:
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Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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