78-17-05: Automatic Fuel Control Unit
FAA order 78-17-05 is an airworthiness directive in force since August 31, 1978. The FAA's subject line: Automatic Fuel Control Unit. It names the Pratt & Whitney Canada PT6T-3, Pratt & Whitney Canada PT6T-3 series, Pratt & Whitney Canada PT6T-6 engines: about 30 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
- Pratt & Whitney Canada Corp.; Pratt & Whitney Canada Corp.; Pratt & Whitney Canada Corp.; Pratt & Whitney Canada Corp.; Pratt & Whitney Canada Corp.; Pratt & Whitney Canada Corp.; Pratt & Whitney Canada Corp.; Pratt & Whitney Canada Corp.; Pratt & Whitney Canada Corp.; Pratt & Whitney Canada Corp.; Pratt & Whitney Canada Corp.
- Models
- PT6T-3, PT6T-3A, PT6T-6
- Engine series
- Pratt & Whitney Canada PT6T-3 8 aircraft
Pratt & Whitney Canada PT6T-3 series 17 aircraft
Pratt & Whitney Canada PT6T-6 5 aircraft
Dates and paperwork
- In force since
- August 31, 1978
- 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 (1,157 characters)
78-17-05 PRATT & WHITNEY AIRCRAFT OF CANADA, LIMITED: Amendment 39-3285. Applies to all Pratt & Whitney Aircraft of Canada, Limited PT6T-3 and PT6T-6 turboshaft engines with automatic fuel control with Aviation Electric Ltd. Parts List 2524381-5, 3244712-1 and -2, 3244717-1 through -5, 3244721-1 through -5, 3244735-1 through -7 and 3244737-1 through -7.
Compliance required within the next 50 hours in service, after the effective date of this AD, unless already accomplished.
To preclude rupture of the bypass valve diaphragm in the automatic fuel control unit, replace the part number 2526477 diaphragm with part number 323451 diaphragm in accordance with Paragraph 2, Accomplishment Instructions in Pratt & Whitney Aircraft of Canada, Limited, Alert Service Bulletin No. 5153, or approved equivalent parts and procedure.
Aircraft may be flown to a base for performance of maintenance required by this AD per FAR 21.197.
Any equivalent parts and procedure must be approvedby the Chief, Engineering and Manufacturing Branch, of the Eastern Region of the Federal Aviation Administration (FAA).
This amendment is effective August 31, 1978.
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 October 5, 2026. Connections as data: /graph/directive/78-17-05.json · aircraft systems.