79-23-05 BEECH: Amendment 39-3611. Applies to Model 77 (S/N's WA-1 through WA-39, WA-41, WA-42 and WA-44 through WA-46) airplanes certificated in all categories.
COMPLIANCE: Required as indicated unless already accomplished.
To assure structural integrity of the attachment of the left and right wing to the fuselage carry-thru structure, accomplish the following:
A) Prior to the next flight, in accordance with instructions in (1) Beech Mailgram sent to owners on October 3, 1979 or (2) Beechcraft Service Instructions No. 1088 (whichever is available):
1. Remove the four NAS1112-11 or -15 wing main spar to fuselage carry- thru structure attachment bolts and visually inspect (1) the threads on the bolts and (2) the threads in the Part Number 108-120010-5 internal nut plate for each bolt, for stripped threads or other damage.
2. Replace any damaged NAS1112-11 or -15 bolts or any Part Number 108-120010-5 internal nut plates with new components.
NOTE: Ifnew NAS1112 bolts are obtained locally, the heads must have a .093 to .103 inch diameter hole drilled in them to accommodate MS20995-NC32 safety wire. Locate the hole in the bolt head at approximately the same location as the safety wire hole in the bolt removed.
3. Modify, apply zinc chromate primer to, and install the correct number of AN960-1216 washers under the NAS1112-11 or -15 bolts.
NOTE: The Beech Part Number 108-120013-1 radius washer must be installed between the AN960-1216 washers and the main spar tube on each of the four NAS1112-11 or - 15 bolts. The total shank length of a NAS1112-11 bolt is 1.26 inches and for the NAS1112-15 1.51 inches.
B) Aircraft may be flown in accordance with Federal Aviation Regulation 21.197 to a location where this AD can be accomplished provided that inspection of each of the four NAS1112-11 or -15 wing main spar to fuselage carry-thru attachment bolts shows that all four bolts are (1) in place, (2) safety wired in place and(3) secure when an attempt is made to turn or pull the bolts by hand. This inspection must be accomplished by an FAA certificated aircraft mechanic or persons authorized under Federal Aviation Regulations 43.3.
C) Any equivalent method of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region.
This amendment becomes effective on November 19, 1979, to all persons except those to whom it has already been made effective by an airmail letter from the FAA dated October 5, 1979.