{"id":"F2006B09914","name":"AD/F50/83 - Grimes Aerospace Passenger Service Units","slug":"ad-f50-83-grimes-aerospace-passenger-service-units","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55118,"registerId":"commonwealth-F2006B09914-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nFokker F50 (F27 Mk 50) Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/F50/83 Grimes Aerospace Passenger Ser","sectionType":"part","heading":"AD/F50/83 Grimes Aerospace Passenger Service Units 6/2003","content":"# AD/F50/83 Grimes Aerospace Passenger Service Units 6/2003\n\nApplicability: Model F.27 Mk.050 and F.27 Mk.0502 aeroplanes, all serial numbers (S/N), with Grimes Aerospace Passenger Service Unit (PSU) Part Number (P/N) 10-1178-XX (XX may be any number) installed.\n\nRequirement: 1. Unless previously modified in accordance with either Grimes Aerospace Company Service Bulletin (SB) 10-1178-33-0140 dated 15 October 1993 or Revision 1 dated 25 March 1996, modify the Grimes Aerospace PSUs P/N 10- 1178-XX (XX may be any number) in accordance with SB 10-1178-33-0040 Revis ion 1.\n\n2. Apply sealant to the aft air-conditioning duct ends in accordance with the Accomplishment Instructions of Fokker Services SB F50-25-055 dated 17 March 2003.\n\nNote 1: Aeroplane S/N 20306, 20307, 20309, 20310 and 20312 had the air- conditioning duct sealant modification incorporated before delivery.\n\nNote 2: CAA(NL) BLA 2003-035 (A) refers.\n\nCompliance: For Requirements 1 and 2 \\- Within three years after the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 12 June 2003.\n\nBackground: Over the years Fokker 50 operators have reported incidents of smoke in the aft passenger compartment during flight, apparently due to overheating of a PSU. Investigation has shown the overheating to occur due to water leakage onto the PSU electrical connector.\n\nTo address this problem, Fokker Aircraft issued a SB which recommended a one-time inspection of the PSU panels and, if leakage was detected, the cleaning of the connector and modification of the PSU panel. As the smoke problems appeared to be minor and were not considered hazardous at the time, the inspection and modification were not made mandatory. As a result, only few operators accomplished the inspection/modification on affected PSU panels.","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The AD converts earlier manufacturer recommendations and a non-mandatory one-time inspection into mandatory corrective actions for all applicable aircraft with Grimes PSU P/N 10-1178-XX. It therefore broadens enforceability (making previously optional work compulsory) while exempting specific serial numbers already modified."},"complexity_factors":["Narrow, well-defined applicability (specific aircraft models and PSU part number) reduces legal complexity.","Technical work relies on multiple external service bulletins (Grimes SB 10-1178-33-0040 Rev 1 and Fokker SB F50-25-055), requiring shop-level procedures and parts knowledge.","Two distinct mandated actions (PSU modification and duct sealant) increase coordination and maintenance planning.","Compliance deadline (three years) creates scheduling and potential operational downtime for operators.","Notes referencing specific serial numbers already modified introduce record-checking and administrative steps.","Legal basis is straightforward (CASR 1998 subreg 39.1(1)), limiting discretionary interpretation."],"plain_english_summary":"This Airworthiness Directive requires operators of Fokker F.27 Mk.050 and Mk.0502 aeroplanes with Grimes Aerospace Passenger Service Units (PSU) P/N 10-1178-XX to modify those PSUs per Grimes SB 10-1178-33-0040 Revision 1 and to apply sealant to the aft air‑conditioning duct ends per Fokker Services SB F50-25-055. Compliance is required within three years of the AD's effective date.\n\nCASA issued the AD after reports of in‑flight smoke caused by PSU overheating from water ingress onto PSU electrical connectors; the AD makes previously non‑mandatory inspections/modifications mandatory."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope. It addresses a specific unsafe condition (water leakage onto PSU electrical connectors) in specific aircraft models. The background explains the evolution from optional manufacturer recommendation to mandatory directive, but this represents standard regulatory escalation rather than scope creep."},"complexity_factors":["Single-issue directive with only two technical requirements","Minimal cross-referencing (only to specific Service Bulletins by number and date)","Clear applicability section limited to specific aircraft models and part numbers","Straightforward compliance deadline (3 years from effective date)","Two explanatory notes but no nested exceptions or conditional logic","No defined terms section — relies on standard aviation terminology"],"plain_english_summary":"This CASA safety order mandates owners/operators of Fokker F.27 Mk.050 and Mk.0502 aircraft fitted with Grimes passenger service units (P/N beginning 10‑1178) to modify overhead passenger service units and seal rear cabin air‑conditioning ducts to eliminate a water‑ingress fire risk. The previously optional manufacturer fixes are required within three years of 12 June 2003 to prevent overheating, smoke, and potential in‑flight fires."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-83-grimes-aerospace-passenger-service-units","history":"/api/acts/ad-f50-83-grimes-aerospace-passenger-service-units/history","analysis":"/api/acts/ad-f50-83-grimes-aerospace-passenger-service-units/analysis","conflicts":"/api/acts/ad-f50-83-grimes-aerospace-passenger-service-units/conflicts","importantCases":"/api/acts/ad-f50-83-grimes-aerospace-passenger-service-units/important-cases","documents":"/api/acts/ad-f50-83-grimes-aerospace-passenger-service-units/documents"}}