{"id":"F2009L02661","name":"AD/F100/91 Amdt 1 - Fuel System - Crossfeed Valve Actuator","slug":"ad-f100-91-amdt-1-fuel-system-crossfeed-valve-actuator","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":79713,"registerId":"commonwealth-F2009L02661-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/F100/91 Amdt 1 | Fuel System - Crossfeed Valve Actuator | 8/2009 |\n| ----------------- | -------------------------------------- | ------ |\n\n| Applicability: | Fokker Aircraft B.V. F28 Mark 0070 and Mark 0100 aircraft, all serial numbers, if an actuator Part Number (P/N) 9409122 or P/N 53-0013 is installed on one or both fuel crossfeed valves. |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. For aeroplanes in pre-SBF100-28-046 configuration - Accomplish either Requirement 1a or 1b below:a. Remove each fuel crossfeed valve actuator with P/N 9409122 from the aeroplane and replace it with a fuel crossfeed valve actuator P/N 53-0013 and accomplish the associated modifications in accordance with the Accomplishment Instructions of Fokker Services SBF100-28-046 dated27 March 2008.b. Remove each fuel crossfeed valve actuator with P/N 9409122 from the aeroplane and replace it with a fuel crossfeed valve actuator P/N 53-0027 and accomplish the associated modifications in accordance with Part 1A or 1B, as applicable, of the Accomplishment Instructions of Fokker Services SBF100-28-061 dated 20 April 2009.2. For aeroplanes in post-SBF100-28-046 configuration, which includes aeroplanes that have complied with Requirement 1a of this AD:Remove each fuel crossfeed valve actuator with P/N 53-0013 from the aeroplane and replace it with a fuel crossfeed valve actuator P/N 53-0027 in accordance with Part 2 of the Accomplishment Instructions of Fokker ServicesSBF100-28-061.3. Do not install a P/N 53-0013 fuel crossfeed valve actuator on any aeroplane.The use of later approved revisions of these documents is acceptable for compliance with the requirements of this AD.Note 1: After installation of P/N 53-0013 or P/N 53-0027 fuel crossfeed valve actuators on an aeroplane, the requirements of CASA AD/F100/84 no longer apply to the fuel crossfeed valve actuators installed on that aeroplane. |\n\n| | Note 2: EASA AD 2009-0116 dated 29 May 2009 refers. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | For Requirement 1 - Remains unchanged as detailed in the original issue of this AD as within 12 months from 28 August 2008 (The effective date of the original issue of this AD), unless previously accomplished.For Requirement 2 - Within the next 18 months after the effective date of this AD.For Requirement 3 - After 12 December 2010. |\n| | This Amendment becomes effective on 30 July 2009. |\n| Background: | Due to their position on the aeroplane, fuel crossfeed valve actuators P/N 9409122 are susceptible to freezing, which has an adverse effect on the operation of the valve. This condition, if not corrected, may generate fuel asymmetry alerts when a valve remains in the open position after being selected closed. It may also prevent the flight crew from correcting a fuel asymmetry when a valve remains in the closed position after being selected open. One event was reported where, due to such problems, the flight crew shut down an engine in-flight and diverted the aircraft.Aeroplanes with serial numbers 11244 through 11441 were delivered from the production line with actuators P/N 9401037 (“chimney type”) installed. However, on some aeroplanes, these actuators have subsequently been replaced in service with actuators P/N 9409122 (using mounting blocks P/N 7923505) on one or both fuel crossfeed valves. As a result, those aeroplanes are also affected by this unsafe condition.To address and correct this unsafe condition, EASA issued AD 2008-0126 that required the replacement of all P/N 9409122 fuel crossfeed valve actuators in accordance with Fokker Services SBF100-28-046 with new actuators developed by the manufacturer Eaton Aerospace, P/N 53-0013, which have improved reliability and are less susceptible to freezing.Following the introduction of actuator P/N 53-0013 in service, Eaton Aerospace reported manufacturing and design errors on actuators with P/N 53-0013. As a result of these errors, the top-cap of the actuator may become loose, possibly leading to actuator failure. Eaton Aerospace has eliminated these problems by introducing a new actuator P/N 53-0027 and Fokker Services have published SBF100-28-061 to introduce these improved actuators on aeroplanes.This AD also allows direct installation of P/N 53-0027 on aeroplanes that are still in pre-SBF100-28-046 configuration. |\n\n| | The original issue of this AD became effective on 28 August 2008. |\n| --- | ----------------------------------------------------------------- |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n16 June 2009","sortOrder":0},{"sectionNumber":"AD/F100/91 Amdt 1","sectionType":"part","heading":"AD/F100/91 Amdt 1","content":"## AD/F100/91 Amdt 1","sortOrder":1},{"sectionNumber":"Fuel System - Crossfeed Valve Actuator","sectionType":"part","heading":"Fuel System - Crossfeed Valve Actuator","content":"## Fuel System - Crossfeed Valve Actuator","sortOrder":2},{"sectionNumber":"8/2009","sectionType":"part","heading":"8/2009","content":"## 8/2009","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"This amendment modifies the original AD by introducing P/N 53-0027 as the preferred compliant actuator, allowing its direct installation on pre‑SBF100-28-046 aeroplanes, and requiring replacement of earlier P/N 53-0013 units with P/N 53-0027. It also imposes a prohibition on installing P/N 53-0013 going forward and sets new staged compliance deadlines, thereby expanding and clarifying the remedial pathway from the original directive."},"complexity_factors":["Applicability depends on aircraft model, serial numbers, and the specific actuator part installed (conditional applicability)","Alternative compliance paths (replace 9409122 with 53-0013 or directly with 53-0027) and a subsequent mandatory replacement of 53-0013 with 53-0027","Multiple external technical references required for compliance (Fokker Services SBF100-28-046 and SBF100-28-061 and EASA AD reference)","Staggered compliance deadlines for different requirements and an effective amendment date","An explicit prohibition on future installation of a specific part number (53-0013) creating a post‑installation compliance state","Interaction with prior AD (CASA AD/F100/84) whereby compliance with new parts removes earlier obligations for those actuators"],"plain_english_summary":"This airworthiness directive forces operators of Fokker F100 (F28 Mk 0070/0100) aeroplanes fitted with fuel crossfeed valve actuators P/N 9409122 or P/N 53-0013 to replace those actuators with an improved P/N 53-0027 (or, as a transitional option, P/N 53-0013 followed by P/N 53-0027). It also prohibits future installation of P/N 53-0013. The change is intended to prevent actuator freezing or failure that can cause fuel asymmetry alerts or loss of crew control. Operators must perform part replacements and associated modifications per the Fokker Service Bulletins within specified deadlines, bearing the cost and scheduling burden."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":true,"description":"The original AD (August 2008) was narrowly scoped to address freezing issues with P/N 9409122 actuators. This Amendment 1 (July 2009) significantly expanded scope when the replacement part (P/N 53-0013) itself was found defective. The directive now covers a two-stage replacement cascade: first the original freezing problem, then the defective replacement. It also introduces a prohibition on installing the intermediate part, effectively managing a fleet-wide transition through three part generations rather than the original two."},"complexity_factors":["Multiple part numbers (P/N 9409122, 53-0013, 53-0027) with different compliance paths depending on aircraft configuration history","Conditional logic based on whether aircraft is in 'pre-SBF100-28-046' or 'post-SBF100-28-046' configuration (referencing manufacturer service bulletins)","Three distinct compliance deadlines with different trigger dates (12 months from Aug 2008, 18 months from July 2009, fixed date of 12 Dec 2010)","Cross-reference to superseded CASA AD/F100/84 and EASA AD 2009-0116","Nested requirements: Requirement 1 has sub-options 1a and 1b; Requirement 2 applies only to aircraft that complied with 1a","Technical aviation terminology requiring knowledge of aircraft fuel systems and manufacturer service bulletin numbering conventions"],"plain_english_summary":"This AD mandates replacement of faulty fuel crossfeed valve actuators on Fokker F100 (F28 Mark 0070/0100) aircraft because the original part could freeze and the interim replacement had manufacturing defects that risk complete failure. Affected operators must install the improved actuator (P/N 53‑0027) within the prescribed compliance windows, and the defective interim part (P/N 53‑0013) is prohibited from installation after 12 December 2010. This prevents fuel imbalances and in‑flight engine shutdowns."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-f100-91-amdt-1-fuel-system-crossfeed-valve-actuator","history":"/api/acts/ad-f100-91-amdt-1-fuel-system-crossfeed-valve-actuator/history","analysis":"/api/acts/ad-f100-91-amdt-1-fuel-system-crossfeed-valve-actuator/analysis","conflicts":"/api/acts/ad-f100-91-amdt-1-fuel-system-crossfeed-valve-actuator/conflicts","importantCases":"/api/acts/ad-f100-91-amdt-1-fuel-system-crossfeed-valve-actuator/important-cases","documents":"/api/acts/ad-f100-91-amdt-1-fuel-system-crossfeed-valve-actuator/documents"}}