69-18-02: Internal Splines
FAA order 69-18-02 is an airworthiness directive in force since September 3, 1969. The FAA's subject line: Internal Splines. It names the Rolls-Royce 250-C18, Rolls-Royce 250-C47 series engines: about 17 aircraft on the U.S. register today across them, though an order usually covers particular versions or serial numbers rather than every one. System: engine.
What it applies to as the FAA lists it
- Kind of product
- Engine
- Makes
- Rolls-Royce Corporation
- Models
- 250-C10 (T63-A-5), 250-C10B (T63-A-5A), 250-C10D (T63-A-700), 250-C18, 250-C18A, 250-C18B, 250-C18C
- Engine series
- Rolls-Royce 250-C18 1 aircraft
Rolls-Royce 250-C47 series 16 aircraft
Dates and paperwork
- In force since
- September 3, 1969
- Docket
- Unknown
- Status
- Current
- The FAA's document
- Read the order on the FAA's site
The order itself the regulatory text, as published
Show the full text (1,261 characters)
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.
Source: FAA Dynamic Regulatory System, airworthiness directives. The FAA's document is the authority; the register counts are this site's, from the FAA register of November 3, 2026. Connections as data: /graph/directive/69-18-02.json · aircraft systems.