{"id":"F2006B09666","name":"AD/F100/9 - Forward Partial Pressure Bulkhead","slug":"ad-f100-9-forward-partial-pressure-bulkhead","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115796,"registerId":"commonwealth-F2006B09666-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F100/9 - Forward Partial Pressure Bulkhead","content":"OMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nFokker F100 (F28 Mk 100) Series Aeroplanes\n\nAD/F100/9 Forward Partial Pressure Bulkhead 4/99\n\nApplicability: F.28 Mk.0100 aircraft, serial numbers 11244 through 11286, 11289, 11291 through\n\n11293, 11295, 11297, 11300, 11303, 11306 and 11308.\n\nRequirement: Install new doubler assemblies at the avionics cooling outlet valve fitting on the LH forward partial pressure bulkhead, in accordance with Part 1 of the Accomplishment Instructions of Fokker Service Bulletin (SB) F100-53-052 dated 17 January 1992 and at the cargo bay outlet valve fitting on the RH forward partial pressure bulkhead, in accordance with Part 2 of the Accomplishment Instructions of Fokker SB F100-53- 052 Revision 1 dated 7 June 1993.\n\nNote: RLD BLA 92-029/2(A) refers.\n\nCompliance: Unless previously accomplished, before accumulating 15,000 flight cycles since new.\n\nThis Airworthiness Directive becomes effective on 22 April 1999.\n\nBackground: During fatigue tests on the F.28 Mk.0100, cracks were found in the area of the avionics cooling outlet valve fitting. This AD requires a modification to prevent cracks developing in service and to improve the fatigue life of the affected structure to above 45,000 flight cycles.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted airworthiness directive addressing a specific structural fatigue issue identified during testing. It has not expanded beyond its original purpose of mandating a specific repair/modification to prevent cracks in the forward pressure bulkhead of affected Fokker F100 aircraft."},"complexity_factors":["Single, specific technical requirement with clear reference to external manufacturer documentation (Fokker Service Bulletins)","Limited applicability — only 47 specific aircraft serial numbers affected","Straightforward compliance deadline (15,000 flight cycles or before)","No nested exceptions, conditional logic, or extensive defined terms","Self-contained — minimal cross-referencing to other legislation beyond standard Civil Aviation Regulations framework","Technical aviation terminology requires some domain knowledge but is standard for the industry"],"plain_english_summary":"This Airworthiness Directive mandates owners/operators of certain Fokker F100 serial-numbered aircraft to install reinforcement doubler plates at two forward pressure-bulkhead outlets (avionics cooling and cargo bay) before 15,000 flight cycles. It’s required because fatigue cracking was found around valve fittings; the modification prevents pressure-vessel failure and extends safe bulkhead life well beyond 45,000 cycles."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The instrument implements a specific, time-limited modification for listed aircraft to prevent cracking of forward partial-pressure bulkheads (Applicability, Requirement, Background). There is no text indicating an expansion, relaxation, or amendment of scope beyond the original directive: it remains limited to the specified serial numbers, fittings, and the SB-prescribed modification with a 15,000-flight-cycle compliance trigger (Requirement, Compliance)."},"complexity_factors":["Technical repair: structural doubler installation requires specialised maintenance skills and parts (Requirement).","Narrowly targeted: applies only to specific serial numbers listed (Applicability), which demands serial-number verification.","External dependence: work must follow a Fokker Service Bulletin (SB F100-53-052 and Revision 1), creating reliance on manufacturer's procedures (Requirement).","Compliance metric: deadline set by flight cycles (15,000 cycles) rather than calendar time, complicating tracking for operators (Compliance).","Safety-performance target specified: modification intended to increase fatigue life above 45,000 cycles (Background), creating a measurable post-modification expectation.","Regulatory enforcement: effective date and mandatory nature mean operators face regulatory consequences for non-compliance (effective date/Compliance).","Operational cost and downtime: installation likely requires aircraft out-of-service time and expense borne by operators."],"plain_english_summary":"This Airworthiness Directive orders operators of listed Fokker F100 (F.28 Mk.0100) aircraft to fit doubler assemblies at two forward partial-pressure bulkhead valve fittings, following the specified Fokker Service Bulletin. CASA set an effective date (22 April 1999) and requires compliance before the aircraft reach 15,000 flight cycles if not already done. The stated aim is to prevent cracks and raise the bulkhead fatigue life above 45,000 cycles; aircraft operators pay for and schedule the modification."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f100-9-forward-partial-pressure-bulkhead","history":"/api/acts/ad-f100-9-forward-partial-pressure-bulkhead/history","analysis":"/api/acts/ad-f100-9-forward-partial-pressure-bulkhead/analysis","conflicts":"/api/acts/ad-f100-9-forward-partial-pressure-bulkhead/conflicts","importantCases":"/api/acts/ad-f100-9-forward-partial-pressure-bulkhead/important-cases","documents":"/api/acts/ad-f100-9-forward-partial-pressure-bulkhead/documents"}}