75-16-13 MITSUBISHI HEAVY INDUSTRIES, LIMITED: Amendment 39-2286. Applies to Mitsubishi MU-2B-20/-25 (serial numbers 201 through 311 except 285, 291, 301, 305, and 309), and MU-2B-30/-35 (serial numbers 541 through 650 except 559, 612, 632, 645, and 648) airplanes certificated in all categories.
Compliance is required within the next 100 hours time in service after the effective date of this AD, unless already accomplished.
To prevent fatigue failure of the wing flap main actuator jack screw, accomplish the following:
(a) Irrespective of the airplane total hours time in service, inspect the left and right wing flap main actuator jack screws for cracks, replace the jack screws that are found cracked, and realign all the main actuator gear box housing units in accordance with the instructions contained in Mitsubishi MU-2 Service Bulletin No. 167 as revised January 9, 1975 (hereinafter MU-2 Service Bulletin 167), or an equivalent approved by the Chief, Engineering and Manufacturing District Office, FAA, Pacific-Asia Region.
(b) During the realignment process, ensure there is a nominal clearance of 2.0 mm (.080 inch), and under no circumstances less than 0.5 mm (.020 inch), between the main actuator gear box housings and wing rear spar.
(c) For airplanes equipped with a rubber bearing pad between a main actuator gear box housing and the wing rear spar, accomplish the modification of the main gear box and removal of the rubber pad, as described in paragraph 3.l(7) or paragraph 3.2 1(b) of MU-2 Service Bulletin 167, as applicable, prior to realignment of the main gear box housings.
NOTE: MU-2 Service Bulletin 167, paragraphs 4 and 5, and the appropriate Mitsubishi MU-2 Maintenance Manuals contain information on adjustment and operational check of the flap system.
This amendment becomes effective August 5, 1975.