1AD/PA-25/4 - Front Spar Attachment Fittings - Modification

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Piper PA-25 (Pawnee) Series Aeroplanes

AD/PA-25/4 Front Spar Attachment Fittings - Modification 9/61

Applicability: Model PA-25 and variants of that model with S/Nos. 25-1 to 25-619, 25-622, 25-623, 26-625, 25-626.

Requirement: 1. Install steel front spar fittings, P/N 60113-00 and 60113-01, and close tolerance AN177-21A spar hinge bolts in accordance with Piper SB No. 206.

2. Check that the diameter of the holes in the fuselage wing attachment brackets, P/N 61005-00 and 61006-00 is within the tolerance of 0.437 inches minimum and

0.439 inches maximum. If the diameter of the holes in the fuselage wing attachment brackets is greater than 0.439 inches the brackets shall be restored to within tolerances by the following method or by an approved alternative method:-

(a) Ream the oversize holes to a diameter of 0.5637 inches.

(b) Make up bushes of SAE 4130 steel to the following dimensions: Outside Diameter \- 0.5640 to 0.5645 inches. Inside Diameter \- 0.420 to 0.425 inches. Width - 0.157 inches.

(c) Coat the bushes with zinc chromate primer and press while wet into the reamed holes in the lugs of the fuselage brackets.

(d) Line ream the bushes to an internal diameter of 0.437 to 0.439 inches.

Note: Aeroplanes having steel spar fittings manufactured by the Commonwealth Aircraft Corporation are regarded as meeting the intent of this requirement provided they are fitted with close tolerance AN177-21A bolts and conform to the dimensional tolerances specified above.

Compliance: Before 1 September 1971.