# AD 68-05-03: Reverse Mode

- Type: Airworthiness directive
- Status: Current
- Products: Pratt & Whitney Canada PT6A-20 and PT6A-6B
- Effective: February 28, 1968
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- Amendment: 39-558
- Registered aircraft: 2,456 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/25586BE7D949C7888625682C00557161.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/68-05-03

## The airworthiness directive

68-05-03 UNITED AIRCRAFT of CANADA, LIMITED: Amdt. 39-558. Applies to Models PT6A-6B and PT6A-20 Turboprop Engines. Compliance, unless already accomplished, with (a) required prior to further flight and with (b) or (c) and where applicable (d) within the next 25 hours' time in service after the effective date of this AD. To preclude either failure of the propeller to reverse or immediate reversing upon selection of reverse mode, the selection of propeller reversing is prohibited until the following inspections or replacements have been accomplished. (a) Install a placard in the cockpit in full view of the pilot that reads: "Do not Use Propeller Reverse". (b) X-ray teleflex reversing control cable terminals P/N's 3010175 and 30101495 to determine that a minimum of 0.08-inch wall thickness exists between cable counterbore and shoulder of threaded yoke arm spindle undercut. Reject terminals with thickness below 0.08 inch. (c) If X-ray is unavailable, disassemble the terminals and physically inspect in accordance with the instructions in United Aircraft of Canada, Ltd., Special Inspection No. 68-1 or an equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region. (d) Replace terminals found below minimums with the same part number known to have sufficient wall thickness. (Spare terminals with walls verified to be in excess of 0.08-inch thick are identified with the letters DH within a circle marked on the hex of the coupling.) (The information in this AD is similar to that contained in Canadian Department of Transport AD No. DF-PT-68-2 issued telegraphically on February 6, 1968.) This amendment becomes effective February 28, 1968.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS E4EA](https://openairdocs.org/tcds/E4EA): Pratt & Whitney Canada Corp.; names 2 of 54 models: PT6A-6B, PT6A-20

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 2,456 (0 by airframe model, 2,456 by engine model)
- Makers: Beech 548, Cessna 449, Air Tractor 398, Raytheon 280, Piper 229, Pilatus 158, Socata 110, Dehavilland 61, Ayres 46, Piaggio 23

Models with the most aircraft:

- [Pratt & Whitney PT6A series](https://openairdocs.org/engine/pratt-whitney-pt6a-series): 2,217 aircraft (engine model)
- [Pratt & Whitney Canada PT6A-6 series](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-6-series): 170 aircraft (engine model)
- [Pratt & Whitney PT6 series](https://openairdocs.org/engine/pratt-whitney-pt6-series): 43 aircraft (engine model)
- [Pratt & Whitney Canada PT6A-20](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-20): 21 aircraft (engine model)
- [Pratt & Whitney Canada PT6 series](https://openairdocs.org/engine/pratt-whitney-canada-pt6-series): 3 aircraft (engine model)
- [U/A Canada PT6A-20](https://openairdocs.org/engine/u-a-canada-pt6a-20): 2 aircraft (engine model)

All 7 models: https://openairdocs.org/ad/68-05-03/models.md
Every aircraft: https://openairdocs.org/ad/68-05-03/aircraft.md

Its text cites no advisory circulars or STCs.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.