{"id":"F2006B09619","name":"AD/F100/19 Amdt 1 - Horizontal Stabiliser Structure","slug":"ad-f100-19-amdt-1-horizontal-stabiliser-structure","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54382,"registerId":"commonwealth-F2006B09619-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F100/19 Amdt 1 - Horizontal Stabiliser Structure","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)  \nFokker F100 (F28 Mk 100) Series Aeroplanes\n\nAD/F100/19\n\nAmdt 1\n\n  \nHorizontal Stabiliser Structure 6/99\n\nApplicability: All F.28 Mk.0100 specified in Fokker Service Bulletin (SB) F100-55-021 Revision 2, except those aircraft which have already fully complied with Fokker SB F100-55-021 Revision 1.\n\nRequirement: 1. Unless modified per requirement 2a before 1000 flight cycles since new, inspect the horizontal stabiliser main hinge fitting Hi-lok bolt holes in accordance with Part 5 of the Accomplishment Instructions of Fokker SB F100-55-021 Revision 2.\n\n    2. Modify the horizontal stabiliser main hinge fittings and replace or modify, as applicable, the connecting angles at Rib 215 in accordance with either:\n\n    Part 3 or Part 4 of the accomplishment instructions of Fokker SB F100-55-021 Revision 2, for aircraft with less than 1000 flight cycles since new at time of modification, or;\n\n    b. Part 6 or Part 7 of the accomplishment instructions of Fokker SB F100-55-021 Revision 2, for aircraft with 1000 flight cycles, or more, since new, or;\n\n    c. Instructions issued by Fokker Aircraft Services for inspection, modification or repair where cracks indications during requirement 1 inspection are beyond the limits listed in Fokker SB F100-55-021 Revision 2.\n\n    3. Modify Rib 215 of the horizontal stabilizer either;\n\n    In accordance with Part 8 of the accomplishment instructions of Fokker SB F100-55-021 Revision 2, or;\n\n    b. Instructions issued by Fokker Aircraft Services for inspection, modification or repair where cracks indications during requirement 1 inspection are beyond the limits listed in Fokker SB F100-55-021 Revision 2.\n\nNote: RLD BLA 93-137/2(A) refers.\n\nCompliance: 1. Inspect before accumulating 15,000 flight cycles since new or before 17 August 1999, whichever occurs later.\n\n    2. Unless already accomplished, before further flight following the inspection in accordance with Requirement 1.\n\n    3. Before further flight following the inspection in accordance with Requirement 1 or in conjunction with requirement 2 compliance.\n\nThis Amendment becomes effective on 17 June 1999.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nBackground: During fatigue tests on the F.28 Mk.0100 for the stabilisers, cracks were found in the flanges of the LH and RH main hinge fittings. If not corrected, these cracks may lead to a deteriorated fatigue life of the horizontal stabiliser main hinge fitting structure. This AD requires an inspection and modification to detect cracks at an early stage and to improve fatigue life.\n\nAmendment 1 is issued to update the service bulletin reference, as experience has resulted in revisions to the Accomplishment Instructions. Aircraft that have been modified in accordance with previous revision do not require further work.\n\nThe initial issue of this Airworthiness Directive became effective on 22 April 1999.","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"},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"Amendment 1 updates the service bulletin reference to Fokker SB F100‑55‑021 Revision 2 and incorporates revised Accomplishment Instructions developed from operational experience. It clarifies that aircraft already modified to Revision 1 need no further work. The amendment does not broaden the types of aircraft affected but revises the technical instructions operators must follow."},"complexity_factors":["Conditional compliance pathways based on flight cycles since new (<1000 vs ≥1000) determining which SB Parts apply (Requirement 2a/2b).","Multiple referenced Parts of Fokker SB F100‑55‑021 Revision 2 (Parts 3–8 and Part 5 inspection) and allowance for alternate Fokker instructions when crack indications exceed bulletin limits (Requirements 1–3).","Strict timing: initial inspection required before 15,000 flight cycles or before 17 August 1999, whichever is later (Compliance 1), plus 'before further flight' mandates after inspection (Compliance 2–3).","Applicability limited to aircraft listed in the SB except those already fully compliant with Revision 1, requiring accurate aircraft-level tracking (Applicability).","Technical inspection and structural modification work (Hi‑lok bolt hole crack detection, hinge fitting and Rib 215 modifications) requiring specialised maintenance capability (Requirement 1–3; Background).","Enforcement and operational impact: CASA sets the directive and enforces 'no further flight' until compliance, creating immediate scheduling and operational constraints (Compliance).","Dependence on manufacturer documentation and judgement: Fokker‑issued instructions may be required where crack indications are beyond SB limits, adding operator reliance on manufacturer guidance (Requirements 2c and 3b)."],"plain_english_summary":"Requires Fokker F100 (F28 Mk.0100) operators to inspect the horizontal stabiliser main hinge Hi‑lok bolt holes and, where specified, modify hinge fittings and Rib 215 in line with Fokker Service Bulletin F100‑55‑021 Revision 2. The rule ties deadlines to flight‑cycle counts and a calendar date, allows Fokker‑issued repair instructions if crack limits are exceeded, and prevents further flight until required work is done. Operators and maintenance organisations pay and schedule the work; CASA enforces compliance."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This amendment remains tightly scoped to its original purpose: addressing fatigue cracks in Fokker F100 horizontal stabiliser hinge fittings. Amendment 1 simply updates the referenced technical instructions to a newer revision of the manufacturer's service bulletin — it does not expand the aircraft types affected, add new structural areas, or introduce additional safety issues beyond the original fatigue crack concern."},"complexity_factors":["Multiple conditional pathways based on aircraft flight cycles (less than 1,000 vs 1,000 or more)","Cross-references to external technical documents (Fokker Service Bulletin F100-55-021 Revision 2) without reproducing their content","Nested alternative compliance methods (Parts 3, 4, 6, 7, or 8 of accomplishment instructions, plus custom Fokker Aircraft Services instructions for out-of-limit cracks)","Three separate compliance deadlines with interdependencies (inspection deadline vs before-further-flight requirements)","Applicability exception for aircraft already complying with Revision 1 of the service bulletin","Technical aviation terminology requiring domain knowledge (flight cycles, Hi-lok bolts, Rib 215, hinge fittings)"],"plain_english_summary":"This Airworthiness Directive orders owners/operators of Fokker F100 aircraft to inspect and modify the horizontal stabiliser after fatigue testing found cracking around critical bolt holes. It affects all F100s covered by the manufacturer’s service bulletin (except those already modified under the earlier revision) and requires timely inspection and repair before further flight to restore structural integrity. The amendment updates the directive to the newer service bulletin revision, avoiding duplicate work for aircraft already corrected."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f100-19-amdt-1-horizontal-stabiliser-structure","history":"/api/acts/ad-f100-19-amdt-1-horizontal-stabiliser-structure/history","analysis":"/api/acts/ad-f100-19-amdt-1-horizontal-stabiliser-structure/analysis","conflicts":"/api/acts/ad-f100-19-amdt-1-horizontal-stabiliser-structure/conflicts","importantCases":"/api/acts/ad-f100-19-amdt-1-horizontal-stabiliser-structure/important-cases","documents":"/api/acts/ad-f100-19-amdt-1-horizontal-stabiliser-structure/documents"}}