{"id":"F2006B02658","name":"AD/B727/136 Amdt 2 - MLG Door Actuator Rib Fitting and Attach Bolts","slug":"ad-b727-136-amdt-2-mlg-door-actuator-rib-fitting-and-attach-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41974,"registerId":"commonwealth-F2006B02658-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/136 Amdt 2 - MLG Door Actuator Rib Fitting and Attach Bolts","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)  \nBoeing 727 Series Aeroplanes\n\nAD/B727/136\n\nAmdt 2\n\n  \n\nMLG Door Actuator Rib Fitting and Attach Bolts\n\n  \n6/97\n\nApplicability: Model 727 series aircraft.\n\nRequirement: Action in accordance with the technical requirements of FAA AD 97-02-09 Amdt 39-9894.\n\nNote: Boeing Service Bulletins 727-32-0364, 727-32-0383 Revision 1, and 727-32A0399 refer.\n\nCompliance: As specified in the Requirement Document with a revised effective date of 22 May 1997; until replacement of the aluminium actuator rib fittings with new steel actuator rib fittings in accordance with Part III of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-32A0399.\n\nThis Airworthiness Directive becomes effective on 22 May 1997.\n\nBackground: The FAA received reports of loose main landing gear actuator attach fitting bolts that allowed movement of the fitting, which jammed the gear door and prevented full extension of one main gear; resulting in a landing with that gear partially extended.\n\nAmendment 1 responded to an FAA AD which reassessed the corrective actions that were in place.\n\nAmendment 2 is issued in response to a new FAA AD which supersedes two existing AD’s, and requires inspections to detect cracking in an expanded area of the actuator rib fitting, and various follow-on actions. A report was received of a fractured rib fitting that had been reworked in accordance with one of the existing ADs.\n\nAmendment 1 of this Airworthiness Directive became effective on 1 April 1993.\n\nThe original issue of this Airworthiness Directive became effective on 12 December 1991.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Yes. Amendment 2 broadened the AD’s technical scope compared with the original: it supersedes earlier ADs and requires inspections for cracking over an expanded area of the actuator rib fitting and additional follow-on actions, and it mandates replacement of aluminium actuator rib fittings with steel ones as the terminating action (Background; Compliance)."},"complexity_factors":["Cross-reference to an external FAA AD (FAA AD 97-02-09) — requires reading and following another instrument (Requirement).","Multiple referenced Boeing service bulletins (727-32-0364, 727-32-0383 Rev 1, 727-32A0399) that provide technical detail — coordination of documents increases compliance steps (Note).","Amendment history (original AD, Amendment 1, Amendment 2) and supersession of prior ADs — tracking effective dates and which actions remain mandatory (Background; Compliance).","Expanded inspection area and unspecified “various follow-on actions” — creates judgment calls for operators and maintenance providers about scope and extent of corrective work (Background).","Interim compliance phrasing (actions required until aluminium fittings are replaced with steel ones) — imposes staged obligations and transitional compliance monitoring (Compliance)."],"plain_english_summary":"This Airworthiness Directive requires operators of Boeing 727 aircraft to follow FAA AD 97-02-09: inspect the main landing gear (MLG) door actuator rib fitting for cracking (expanded inspection area), take specified follow-on actions, and ultimately replace aluminium actuator rib fittings with new steel fittings until that replacement is done (Requirement; Compliance). Operators pay for inspections, repairs and replacements; the Civil Aviation Safety Authority enforces compliance for Model 727s (Applicability; Background)."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"The directive has expanded beyond its original scope. The original 1991 issue addressed loose bolts and fitting movement. Amendment 1 (1993) reassessed corrective actions. Amendment 2 (1997) significantly broadened the scope to include: (1) detection of cracking in an 'expanded area' of the actuator rib fitting, (2) new inspection requirements, and (3) mandatory replacement of aluminium fittings with steel ones. This represents a shift from addressing a specific mechanical looseness problem to a comprehensive structural integrity and material upgrade program."},"complexity_factors":["Short, single-purpose directive (approximately 250 words)","Only 1 defined applicability term ('Model 727 series aircraft')","Heavy reliance on external documents — the actual technical requirements are contained in FAA AD 97-02-09 and multiple Boeing Service Bulletins, not in the text itself","Simple conditional structure: one compliance pathway with a single endpoint (replacement of aluminium with steel fittings)","Clear amendment history explaining evolution of the safety requirement","No nested exceptions or complex cross-referencing within the directive itself"],"plain_english_summary":"This CASA Airworthiness Directive requires Australian operators of Boeing 727s to inspect and, where needed, replace the main landing gear door actuator rib fittings and attachment bolts to prevent jams that can stop the MLG from fully extending. It implements FAA AD 97‑02‑09 and Boeing Alert SB 727‑32A0399 (aluminium fittings replaced with steel), and has been amended twice as new failure modes emerged."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-136-amdt-2-mlg-door-actuator-rib-fitting-and-attach-bolts","history":"/api/acts/ad-b727-136-amdt-2-mlg-door-actuator-rib-fitting-and-attach-bolts/history","analysis":"/api/acts/ad-b727-136-amdt-2-mlg-door-actuator-rib-fitting-and-attach-bolts/analysis","conflicts":"/api/acts/ad-b727-136-amdt-2-mlg-door-actuator-rib-fitting-and-attach-bolts/conflicts","importantCases":"/api/acts/ad-b727-136-amdt-2-mlg-door-actuator-rib-fitting-and-attach-bolts/important-cases","documents":"/api/acts/ad-b727-136-amdt-2-mlg-door-actuator-rib-fitting-and-attach-bolts/documents"}}