{"id":"F2008L03422","name":"AD/B727/100 Amdt 4 - Elevator Rear Spar","slug":"ad-b727-100-amdt-4-elevator-rear-spar","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":120450,"registerId":"commonwealth-F2008L03422-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 727 Series Aeroplanes","sectionType":"division","heading":"Boeing 727 Series Aeroplanes","content":"### Boeing 727 Series Aeroplanes\n\n| AD/B727/100 Amdt 4 | Elevator Rear Spar | 11/2008 DM |\n| ------------------ | ------------------ | ---------- |\n\n| Applicability: | Boeing model 727 series aircraft, line numbers 1 through 1832.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the technical requirements of FAA AD 2008-17-14 Amdt 39-15652.Note: Boeing Service Bulletin 727-55-0089Revision 1, or later FAA approved revision, refers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n| Compliance:    | As specified in the requirement document.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |\n|                | This Amendment becomes effective on 2 October 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n| Background:    | Several cases of fatigue cracking were reported. The cracking was believed to be initiated by interference between the spar flange bend radii and the sharp edges on the shear plates mounted between the spar and the elevator tab hinges.Amendment 1 introduced SB 727-55-0087, which similarly covers the early design elevator rear spar as a result of recent Australian and overseas reports of cracking.Amendment 2 clarified the compliance for operators of certain aircraft.Amendment 3 was issued in response to a new FAA AD which adds new inspections to detect cracks and loose brackets of the elevator rear spar and a new terminating modification for the inspections. Reports were received of cracking in the spar radii at the tab hinge location of the elevator rear spar. |\n\n|     | Amendment 4 is issued due to change the requirement document from FAA AD96-06-05 to FAA AD 2008-17-14. This directive reduces the repetitive intervals of the inspections, mandates the previously optional terminating action for the repetitive inspections and no longer allows stop-drilling. The FAA received further reports of cracks, elongated fastener holes, and loose fittings of the elevator rear spar. This directive is issued to prevent cracking of the elevator rear spar at the tab hinge locations, which could cause excessive freeplay of the elevator control tab and possible tab flutter, and consequent loss of control. |\n| --- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n2 September 2008","sortOrder":0},{"sectionNumber":"AD/B727/100 Amdt 4","sectionType":"part","heading":"AD/B727/100 Amdt 4","content":"## AD/B727/100 Amdt 4","sortOrder":1},{"sectionNumber":"Elevator Rear Spar","sectionType":"part","heading":"Elevator Rear Spar","content":"## Elevator Rear Spar","sortOrder":2},{"sectionNumber":"11/2008 DM","sectionType":"part","heading":"11/2008 DM","content":"## 11/2008 DM","sortOrder":3}],"analysis":{"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 original directive (implied by Amendment 1) addressed fatigue cracking with basic inspections. Over four amendments, the scope has progressively tightened: Amendment 1 expanded coverage to early design variants; Amendment 3 added new inspections and terminating modifications; Amendment 4 (this version) significantly strengthens requirements by mandating previously optional permanent repairs, banning temporary stop-drilling repairs, and shortening inspection intervals. The directive has evolved from a monitoring requirement to an active risk mitigation mandate."},"complexity_factors":["Short, single-purpose document (1 page)","Only 1 defined term implicitly used ('line numbers' — aircraft production serial numbers)","Minimal conditional logic — applies to all listed aircraft uniformly","Heavy reliance on external documents (FAA AD 2008-17-14 and Boeing Service Bulletin) for actual technical requirements — the directive itself is essentially a pointer","No nested exceptions or complex compliance calculations within the text itself","Clear, tabular format with standard aviation regulatory structure"],"plain_english_summary":"This airworthiness directive requires mandatory inspection and repair of the Boeing 727 elevator rear spar after fatigue cracks were found worldwide. It affects essentially all 727s (line numbers 1–1832) because unchecked cracking can cause elevator freeplay, flutter, and potential loss of control.\n\nThe rule shortens inspection intervals, forbids stop‑drilling, and requires a permanent terminating modification using Boeing Service Bulletin guidance; Amendment 4 tightens requirements based on new damage reports."},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"Amendment 4 replaces the prior FAA AD reference (FAA AD96-06-05) with FAA AD 2008-17-14 and imposes substantive changes: it shortens repetitive inspection intervals, mandates a previously optional terminating modification for the repetitive inspections, and removes stop-drilling as an allowable action. These changes expand the compliance burden and alter acceptable corrective techniques (Background; Requirement)."},"complexity_factors":["Cross-reference to FAA AD 2008-17-14 and Boeing Service Bulletin 727-55-0089 (Requirement; Applicability) — requires operators to follow external technical documents.","Technical subject matter: fatigue cracking at spar flange bend radii, shear plates and tab hinge locations — needs specialised inspection and repair skills (Background).","Change in mandated actions versus prior amendments: reduced repetitive inspection intervals, mandatory terminating modification, prohibition of stop-drilling (Background) — alters maintenance programmes.","Wide applicability: affects all Boeing 727 line numbers 1–1832 (Applicability) — many operators and airframes potentially impacted.","Operational timing and enforcement: compliance deadlines and effective date are set by CASA via the AD (Compliance; effective date 2 October 2008).","Document revision control: reference to 'Revision 1, or later FAA approved revision' of the service bulletin introduces dependence on future FAA-approved revisions (Requirement).","History of iterative amendments and prior ADs (Amendments 1–3 referenced) increasing interpretive complexity for operators tracking applicable terminating actions and inspection histories (Background)."],"plain_english_summary":"This amendment requires operators of Boeing 727 series aircraft (line numbers 1–1832) to follow FAA AD 2008-17-14 and the Boeing service bulletin for inspections and corrective work on the elevator rear spar (Applicability; Requirement). It shortens inspection intervals, makes a previously optional terminating modification mandatory, and removes stop‑drilling as an option. Operators fund and carry out inspections and repairs; CASA enforces compliance and sets the required timing (Background; Compliance)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-100-amdt-4-elevator-rear-spar","history":"/api/acts/ad-b727-100-amdt-4-elevator-rear-spar/history","analysis":"/api/acts/ad-b727-100-amdt-4-elevator-rear-spar/analysis","conflicts":"/api/acts/ad-b727-100-amdt-4-elevator-rear-spar/conflicts","importantCases":"/api/acts/ad-b727-100-amdt-4-elevator-rear-spar/important-cases","documents":"/api/acts/ad-b727-100-amdt-4-elevator-rear-spar/documents"}}