AD 70-16-01

70-16-01 WOODWARD: Amdt. 39-1054. Applies to Woodward Governor Company primary turbo propeller governors mounted on United Aircraft of Canada PT6A series engines installed in airplanes incorporating propeller reversing provisions and Woodward Governor Company overspeed turbo propeller governors mounted on United Aircraft of Canada PT6A series engines installed in airplanes having auto feathering provisions.

Compliance: Required within the next 50 hours' time in service after the effective date of this AD, unless previously accomplished.

To prevent uncontrolled feathering accomplish the following or an equivalent procedure approved by the Chief, Engineering & Manufacturing Branch, FAA, Central Region.

A) On primary propeller governors inspect for safety wire security the three coil retaining screws on the lock pitch solenoid valve, Woodward P/N 1310-506 or 1310-511.

B) On overspeed propeller governors inspect for safety wire security the three coil retaining screws on the autofeathering solenoid valve, Woodward P/N 1310-110 or 1310-115.

C) If screws inspected in accordance with Paragraphs A and B are not secured by safety wire, prior to return to service, replace said screws with socket head screws, Woodward P/N 1039-240, torque 18 to 22 lb. in., and secure by AMS 5685 0.024 to 0.026 in. dia. safety wire. Screws must be removed, replaced and torqued one at a time to avoid valve disassembly.

NOTE: It may be necessary to remove two solenoid valve base retaining screws, Woodward P/N 33048-201 to gain access to the coil retaining screws. Removal and replacement of these two screws should be accomplished in the manner prescribed for the coil retaining screws.

Woodward Service Bulletin 33532B, Supplement 1 and United Aircraft of Canada, Limited, Engine Service Bulletin No. 198 pertain to this subject.

The inspections and modifications prescribed in this AD may be accomplished by a certified mechanic with a powerplant rating.NOTE: Governors to which this AD applies are known to be installed on the following airplanes, but this listing is not necessarily all inclusive:

Primary propeller governors - Beech Models 65-90, 65-A90, 65-A90-1, 65-A90-2, 65-A90-3, B90, 99, 99A, 100; DeHavilland Models 1, 100, 200, 300; Helio Models HST-550, HST-550A; Swearingen Model SA26-5; Pilatus Model PC-6/B-H2, PC-6/B1-H2; McKinnon Models G21C, G21D, G21E, G21G; Grumman Model G21A (Serial Number B52 only); and Beech 18 series airplanes modified per STC SA 1016 WE.

Overspeed propeller governors - Beech Model 65-A90-1, 68-A90-2, 65-A90-3, B90, 99, 99A and 100 airplanes.

This amendment shall become effective August 4, 1970.