{"id":"F2009L01500","name":"AD/F100/85 Amdt 1 - Flight Controls - Elevator Booster Control Unit","slug":"ad-f100-85-amdt-1-flight-controls-elevator-booster-control-unit","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":78110,"registerId":"commonwealth-F2009L01500-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Fokker F100 (F28 Mk 100) Series Aeroplan","sectionType":"division","heading":"Fokker F100 (F28 Mk 100) Series Aeroplanes","content":"### Fokker F100 (F28 Mk 100) Series Aeroplanes\n\n| AD/F100/85 Amdt 1 | Flight Controls - Elevator Booster Control Unit | 5/2009 |\n| ----------------- | ----------------------------------------------- | ------ |\n\n| Applicability: | F28 Mark 0070 and Mark 0100 aircraft, all serial numbers. |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. For aircraft equipped with Elevator Booster Control Unit (BCU) part number (P/N) 23400-3B or P/N 23400-7:Perform a one-time inspection of the Elevator BCU as defined in Part 1 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-27-088 dated4 June 2007.2. For aircraft equipped with BCU P/N 23400-3 or P/N 23400-5:Perform a one-time inspection of the Elevator BCU as defined in Part 1 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-27-088.3. Replace the Elevator BCU with a P/N 23400-3B or P/N 23400-7 unit that has been modified in accordance with Goodrich CSB 23400-27-27.4. Replace all remaining unmodified Elevator BCU P/N 23400-3B and P/N 23400-7 with units modified in accordance with Goodrich CSB 23400-27-27 and Part 2 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-27-088.5. Replace all remaining unmodified Elevator BCU P/N 23400-3 and P/N 23400-5 with, respectively, P/N 23400-3B and P/N 23400-7 units modified in accordance with Goodrich CSB 23400-27-27 and Part 2 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-27-088.6. Do not install a spare Goodrich P/N 23400-3B or P/N 23400-7 Elevator BCU on any aircraft, unless it has been modified in accordance with Goodrich CSB 23400-27-27.7. Do not install Goodrich P/N 23400-3 or P/N 23400-5 Elevator BCU on any aircraft.The use of later approved revisions of these documents is acceptable for compliance with the requirements of this AD. |\n\n| | Note: EASA AD 2009-0032 dated 17 February 2009 refers. This AD supersedes EASA AD 2007-0228. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Compliance: | For Requirement 1 - Remains unchanged as detailed in the original issue of this AD as prior to 25 October 2008.For Requirement 2 - Within 12 months from the effective date of this AD.For Requirement 3 - Depending on the result of the inspection conducted in Requirement 1 or 2 of this AD, as applicable, within the time interval as indicated in Table 2 on page 8 of the referenced Fokker SB.For Requirement 4 - Within 5 years after the 25 October 2007.For Requirement 5 - Within 5 years after the effective date of this AD.For Requirement 6 - From 29 August 2012.For Requirement 7 - From 3 March 2014. |\n| | This Amendment becomes effective on 7 May 2009. |\n| Background: | Excessive wear and tear of the backlash remover mechanism has been found several times. The wear and tear may result in a (partly) blocked operation of the elevator system in the normal (hydraulic) mode. Together with the manufacturer of this equipment (Goodrich) it has been decided to modify the Elevator Booster Control Unit in accordance with Goodrich Component Service Bulletin (CSB) 23400-27-27. In order to detect and correct an excessively worn backlash remover mechanism, this AD required a one-time inspection and eventual replacement of the affected Elevator Booster Control Units.Amendment 1 includes inspections for addition BCUs and eventual replacement of all affected units.The original issue of this AD became effective on 25 October 2007. |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n26 March 2009","sortOrder":0},{"sectionNumber":"AD/F100/85 Amdt 1","sectionType":"part","heading":"AD/F100/85 Amdt 1","content":"## AD/F100/85 Amdt 1","sortOrder":1},{"sectionNumber":"Flight Controls - Elevator Booster Contr","sectionType":"part","heading":"Flight Controls - Elevator Booster Control Unit","content":"## Flight Controls - Elevator Booster Control Unit","sortOrder":2},{"sectionNumber":"5/2009","sectionType":"part","heading":"5/2009","content":"## 5/2009","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"Amendment 1 expanded the original AD’s scope by adding inspections for additional BCU part numbers and by specifying further replacement and installation‑prohibition requirements with new compliance dates. The amendment therefore broadened the set of affected units and imposed staged deadlines for inspection, modification and prohibition of unmodified spares (see Requirement 1–7 and Background)."},"complexity_factors":["Technical specificity of components and allowable replacements — multiple Goodrich BCU part numbers listed and distinct upgrade paths (Requirement 1–5).","Multiple, staggered compliance deadlines with different effective dates for different actions (Compliance).","Dependency on external manufacturer documents (Goodrich CSB 23400‑27‑27 and Fokker SB SBF100‑27‑088) and allowance for later approved revisions (Requirement: use of later approved revisions).","Installation prohibitions that commence on set future dates for specific P/Ns (Requirement 6–7).","Applicability to all serial numbers of listed Marks, creating a fleet‑wide compliance obligation (Applicability).","Safety rationale tied to a specific failure mode (excessive wear of the backlash remover) requiring inspections and potential replacement (Background).","Cross‑reference and supersession of earlier EASA ADs, creating regulatory linkage and traceability requirements (Note/Background)."],"plain_english_summary":"This airworthiness directive requires operators of Fokker F100 (F28 Mk 100) aeroplanes to carry out one‑time inspections of specified Goodrich Elevator Booster Control Units (BCUs) and to modify or replace affected units per Goodrich CSB 23400‑27‑27 and Fokker Service Bulletin SBF100‑27‑088. It imposes staged compliance deadlines and forbids fitting unmodified spare BCUs. The measure addresses repeated excessive wear of the backlash remover that can (partly) block elevator movement; operators bear the inspection and modification costs and must meet CASA’s deadlines."},"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":4,"scope_assessment":{"changed":true,"description":"The original 2007 AD only required inspection and replacement of specific worn units. Amendment 1 significantly expanded the scope: it added inspections for additional BCU part numbers (23400-3 and 23400-5), mandated eventual replacement of ALL affected units (not just worn ones), and introduced installation prohibitions that would phase out unmodified and older units entirely by 2014. This transformed from a 'inspect and fix if broken' approach to a 'inspect everything and replace everything over time' mandate."},"complexity_factors":["Multiple part numbers (P/N 23400-3, 23400-5, 23400-3B, 23400-7) with different requirements for each","Seven distinct requirements with different compliance dates ranging from 2008 to 2014","Cross-references to external technical documents (Fokker Service Bulletin SBF100-27-088 and Goodrich CSB 23400-27-27) that are not reproduced in the AD itself","Conditional logic: Requirement 3 timing depends on inspection results from Requirements 1 or 2","Nested effective dates: Amendment 1 effective 7 May 2009, but compliance dates reference original AD effective date (25 October 2007) and various future dates","Reference to EASA (European) AD 2009-0032 for context"],"plain_english_summary":"This AD mandates inspections and phased replacement of worn elevator booster control units on Fokker F100s after excessive wear was found. It bans installation of certain older part numbers and requires mod‑upgraded units per Goodrich instructions.\n\nBy removing vulnerable units on a staged timetable, the directive prevents possible elevator jam or loss of pitch control."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f100-85-amdt-1-flight-controls-elevator-booster-control-unit","history":"/api/acts/ad-f100-85-amdt-1-flight-controls-elevator-booster-control-unit/history","analysis":"/api/acts/ad-f100-85-amdt-1-flight-controls-elevator-booster-control-unit/analysis","conflicts":"/api/acts/ad-f100-85-amdt-1-flight-controls-elevator-booster-control-unit/conflicts","importantCases":"/api/acts/ad-f100-85-amdt-1-flight-controls-elevator-booster-control-unit/important-cases","documents":"/api/acts/ad-f100-85-amdt-1-flight-controls-elevator-booster-control-unit/documents"}}