{"id":"F2006B05576","name":"AD/PA-25/4 - Front Spar Attachment Fittings - Modification","slug":"ad-pa-25-4-front-spar-attachment-fittings-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46592,"registerId":"commonwealth-F2006B05576-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-25/4 - Front Spar Attachment Fittings - Modification","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nPiper PA-25 (Pawnee) Series Aeroplanes\n\nAD/PA-25/4 Front Spar Attachment Fittings \\- Modification 9/61\n\nApplicability: Model PA-25 and variants of that model with S/Nos. 25-1 to 25-619, 25-622, 25-623, 26-625, 25-626.\n\nRequirement: 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.\n\n2. 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\n\n0.439 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:-\n\n    (a) Ream the oversize holes to a diameter of 0.5637 inches.\n\n    (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.\n\n    (c) Coat the bushes with zinc chromate primer and press while wet into the reamed holes in the lugs of the fuselage brackets.\n\n    (d) Line ream the bushes to an internal diameter of 0.437 to 0.439 inches.\n\nNote: 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.\n\nCompliance: Before 1 September 1971.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":2125},"content_quality":"ok","complexity_score":5,"scope_assessment":{"changed":false,"description":"This airworthiness directive maintains its original narrow scope addressing a specific structural defect in specific Piper aircraft models. It has not expanded beyond its initial purpose of mandating front spar fitting modifications."},"complexity_factors":["Technical aerospace engineering terminology (spar fittings, AN bolts, line reaming)","Precise dimensional tolerances specified to three decimal places (0.437-0.439 inches)","Multi-step remedial manufacturing process with material specifications (SAE 4130 steel)","Conditional logic requiring measurement-based alternative compliance paths","Specific serial number applicability ranges with gaps (25-619 then 25-622)"],"plain_english_summary":"This mandatory safety order requires owners of specific Piper PA-25 Pawnee aircraft (serials 25-1 through 25-619, plus 25-622, 25-623, 25-625, 25-626) to strengthen the wing-to-fuselage attachments to prevent wing separation. It mandates installing steel front spar fittings (60113-00/60113-01), close-tolerance AN177-21A bolts, and verifying fuselage wing-bracket hole diameter (0.437–0.439 in).\n\nIf holes exceed 0.439 in, owners must repair by installing steel bushings via the prescribed reaming/sleeving process. Aircraft already fitted with Commonwealth steel fittings need only the bolts and hole checks. Original compliance date: 1 Sept 1971."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-25-4-front-spar-attachment-fittings-modification","history":"/api/acts/ad-pa-25-4-front-spar-attachment-fittings-modification/history","analysis":"/api/acts/ad-pa-25-4-front-spar-attachment-fittings-modification/analysis","conflicts":"/api/acts/ad-pa-25-4-front-spar-attachment-fittings-modification/conflicts","importantCases":"/api/acts/ad-pa-25-4-front-spar-attachment-fittings-modification/important-cases","documents":"/api/acts/ad-pa-25-4-front-spar-attachment-fittings-modification/documents"}}