{"id":"F2006B02665","name":"AD/B727/142 Amdt 1 - Wing Slat Track Roller Bearing Bolts","slug":"ad-b727-142-amdt-1-wing-slat-track-roller-bearing-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41981,"registerId":"commonwealth-F2006B02665-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/142 Amdt 1 - Wing Slat Track Roller Bearing 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/B727/142\n\nAmdt 1\n\n  \nWing Slat Track Roller Bearing Bolts 2/95\n\nApplicability: All model B727 aircraft, except those which have had all slat track roller bolts and positional plates modified in accordance with Boeing Service Bulletin 727-57-0172 Revision 3, Paragraph III, Part II Modification.\n\nRequirement: 1. Inspect slat track roller bearing bolts for cracking and, if cracks are found, the rollers for condition, in accordance with Boeing Service Bulletin 727-57-0172 Revision 3, Paragraph III Accomplishment Instructions, Part I Inspection.\n\n2. Inspect and measure the gap between the slat track roller bearing bolts and the positional plates in accordance with Boeing Service Bulletin 727-57-0172 Revision 3, Paragraph III Accomplishment Instructions, Part III Positional Plate Inspection. Replace deficient positional plates in accordance with Boeing Service Bulletin 727-57-0172 Revision 3, Paragraph III, Part II Modification.\n\nNote: FAA AD 94-04-03 Amendment 39-8821 refers.\n\nCompliance: 1. Inspect in accordance with Requirement 1 within 2500 flights from 2 February 1995, unless previously accomplished in accordance with the original issue of this AD.\n\nRepeat the inspections at intervals not to exceed 5000 flights.\n\n2. Inspect in accordance with Requirement 2 before the accumulation of 5000 flights since modification in accordance with the original issue of this AD, or within 2500 flights after 2 February 1995, whichever is the later.\n\nBackground: 22 broken slat track roller bearing bolts have been reported, one of which resulted in an aircraft landing with a jammed and partially detached slat. Positional plates installed in accordance with the original issue of this AD may not provide the required locking of the bearing bolts.","sortOrder":0}],"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":"This is Amendment 1 to an existing Airworthiness Directive. The original AD (referenced as 'the original issue') required modifications that proved insufficient — the replacement positional plates didn't reliably lock the bolts. This amendment expands the scope by adding new mandatory inspections (Requirement 2) and tightening compliance timeframes, effectively acknowledging the original fix was inadequate and requiring additional layers of safety verification."},"complexity_factors":["Single technical subject matter (aviation hardware) but requires cross-referencing to external Boeing Service Bulletin 727-57-0172 Revision 3 for actual procedures","Multiple conditional compliance deadlines ('whichever is the later', 'unless previously accomplished')","Exemption clause based on prior modification status","Nested requirements: Requirement 2 references Part III for inspection but Part II for replacement","Relies on understanding of aviation maintenance terminology (slat tracks, roller bearings, positional plates) without glossary"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspections of wing slat track roller bearing bolts on Australian Boeing 727s (except aircraft already modified per Boeing SB 727‑57‑0172 Rev 3). It requires visual crack checks and measurement of bolt-to-positional‑plate gaps, with replacement of damaged bolts, rollers or deficient plates.\n\nThe amendment tightens and shortens inspection intervals after worldwide reports of 22 broken bolts and a slat‑jam/partial detachment, addressing failures of the earlier fix."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"This amendment extends the original directive's focus by adding a specific inspection/measurement of the gap between slat track roller bearing bolts and positional plates and by requiring replacement of deficient positional plates (see 'Requirement 2' and the Background noting original plates 'may not provide the required locking'). It also sets or clarifies compliance windows (2500/5000 flights) tied to prior modifications, thereby broadening enforcement beyond the original issue."},"complexity_factors":["References an external manufacturer document (Boeing Service Bulletin 727-57-0172 Rev 3) for detailed methods and parts, creating dependency on non-statutory material.","Different requirements and timeframes: immediate inspection window (2500 flights), repeating interval (5000 flights), and a separate timing rule tied to prior modifications.","Applicability carve-out for aircraft already modified per a specific paragraph of the service bulletin.","Requires technical inspections for cracking and precision measurement of gaps, implicating skilled labour and judgment.","Possible parts replacement (positional plates) if measurements fail, creating procurement and aircraft-downtime burdens.","Safety-critical context (reported broken bolts and one in-flight slat problem) increases operational urgency and compliance scrutiny."],"plain_english_summary":"This Airworthiness Directive requires operators of Boeing 727s (unless already modified per Boeing Service Bulletin 727-57-0172 Rev 3 Part II) to inspect slat track roller bearing bolts for cracking, measure the gap between bolts and positional plates, and replace deficient plates per the Boeing service instructions. The Civil Aviation Safety Authority sets the inspection deadlines and repeating intervals; operators pay for inspections, measurements and any replacements, and must schedule aircraft downtime to comply."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-142-amdt-1-wing-slat-track-roller-bearing-bolts","history":"/api/acts/ad-b727-142-amdt-1-wing-slat-track-roller-bearing-bolts/history","analysis":"/api/acts/ad-b727-142-amdt-1-wing-slat-track-roller-bearing-bolts/analysis","conflicts":"/api/acts/ad-b727-142-amdt-1-wing-slat-track-roller-bearing-bolts/conflicts","importantCases":"/api/acts/ad-b727-142-amdt-1-wing-slat-track-roller-bearing-bolts/important-cases","documents":"/api/acts/ad-b727-142-amdt-1-wing-slat-track-roller-bearing-bolts/documents"}}