AD 80-21-10 ACTIVE

80-21-10 BEECH: Amendment 39-3967. Applies to Model 77 (serial numbers WA-1 through WA-156, WA-158 through WA-161, WA-163 through WA-171, WA-173, WA-174, WA-177 and WA-178) airplanes certificated in all categories.

COMPLIANCE: Required as indicated unless already accomplished.

To ensure the structural integrity of the engine mount attachment to the airplane, accomplish the following:

A) Prior to further flight, accomplish the following:

1. Remove the engine cowling, support the tail of the airplane, and hoist the engine as required to remove weight from the engine mount attachment.

2. Remove and visually inspect for thread damage the four bolts and nuts attaching the engine mount to the firewall. Retain washers and nut retaining clips for reuse. The nut is held in place by a spring clip which may be removed with a magnet or wire hook.

NOTE: Remove and inspect the engine mount attachment bolts and nuts one at a time.

3. Align the holes in the engine mount, firewall and fuselage frame. Ream the attachment holes in the firewall and fuselage frame to .375/.379 inch diameter.

NOTE: A strap may be used between the engine mount tubes to pull the engine mount holes into alignment. If necessary to facilitate reaming of the firewall and attach fitting holes, support the engine and remove the remaining three bolts.

4. Replace damaged bolts and nuts with a new part of a P/N shown by Table I. Any thread damage on either a bolt or nut requires replacement of both the bolt and nut.

Table I

Bolt
Nut
130909B71
2452-064 (use existing
or
or
AN6-21A/M/(magnaflux inspected)
LH8065-064 (use existing retainer)

or

NAS577-6A (use NAS578-6 retainer)

5. Ensure the bolts, washers, nuts and holes are clean and free of grease and oil. Align parts, install bolts, washers and nuts, and torque to 325 +0 -20 inch-pounds. Do not use a power wrench to install the bolts.

6. Remove the engine hoist and tail support and reinstall the engine cowling.

B) Within five days report damaged bolts or other defects found as a result of any inspection required herein to the FAA via an M or D Report (FAA Form 8330-2) or a letter to the Chief, Aircraft Certification Program, Federal Aviation Administration, Room 238, Terminal Building 2299, Mid-Continent Airport, Wichita, Kansas 67209. Describe the defect found, location of bolt on firewall, total time-in-service on the airplane or part at time of discovery, and the aircraft serial number. (Reporting approved by the Office of Management and Budget under OMB No. 04-R0174.)

C) Any equivalent means of compliance with this AD must be approved by the Chief, Aircraft Certification Program, Federal Aviation Administration, Room 238, Terminal Building 2299, Mid-Continent Airport, Wichita, Kansas 67209, telephone (316) 942-4285.

Beechcraft Service Instructions No. 1153 and Beech Mailgram Number 80-452-940 pertain to the subject matter of this AD.

This amendment becomes effective on November 13, 1980, to all persons except those to whom it has already been made effective by an airmail letter from the FAA dated October 10, 1980, and is identified as AD 80-21-10.