{"id":"F2010L03228","name":"AD/JBK 117/36 - Pressure Altitude Limitation and Max N1 Check","slug":"ad-jbk-117-36-pressure-altitude-limitation-and-max-n1-check","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":85438,"registerId":"commonwealth-F2010L03228-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Kawasaki BK 117 Series Helicopters","sectionType":"division","heading":"Kawasaki BK 117 Series Helicopters","content":"### Kawasaki BK 117 Series Helicopters\n\n| AD/JBK 117/36 | Pressure Altitude Limitationand Max N1 Check | 25/2010 |\n| ------------- | -------------------------------------------- | ------- |\n\n| Applicability: | Kawasaki BK117C-1 and C-2 helicopters.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Fuel Control Units which have not been Modified in accordance with Turboméca Service Bulletin No.292 73 0358 (TU358) must not be installed in any helicopter.Note: JCAB AD TCD-7000-1-2008 refers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |\n| Compliance:    | After the effective date of this Directive.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n|                | This Airworthiness Directive becomes effective on 24 December 2010.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| Background:    | During supplementary testing the “MAX N1 CHECK” at maximum certification altitude, a few helicopters could not reach the specified N1 power threshold value. The cause was identified as an engine acceleration limitation due to a delivered fuel flow lower than the engine fuel flow demand to achieve the OEI rating at high altitude. The fuel flow is limited by the FCU acceleration law in those cases. This limitation could potentially occur at altitudes exceeding 10,000 feet, depending on the engine and FCU characteristics.Turboméca has now developed a modification (TU358) that will, when accomplished on both engines installed on the helicopter, cancel the required checks and allow the removal of the placard and flight manual changes. |\n\n![](image.001.png)\n\nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n9 December 2010","sortOrder":0},{"sectionNumber":"AD/JBK 117/36","sectionType":"part","heading":"AD/JBK 117/36","content":"## AD/JBK 117/36","sortOrder":1},{"sectionNumber":"Pressure Altitude Limitationand Max N1 C","sectionType":"part","heading":"Pressure Altitude Limitationand Max N1 Check","content":"## Pressure Altitude Limitation  \nand Max N1 Check","sortOrder":2},{"sectionNumber":"25/2010","sectionType":"part","heading":"25/2010","content":"## 25/2010","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific technical deficiency in fuel control units for a specific helicopter model. The scope has not expanded beyond the original safety issue identified."},"complexity_factors":["Single, clear prohibition with straightforward applicability","Only one defined technical reference (Turboméca Service Bulletin TU358)","No nested exceptions or conditional logic — simple binary compliance (modified vs unmodified FCU)","Short document with minimal cross-referencing (only references Japanese JCAB AD for background context)","Single compliance date with no phased implementation"],"plain_english_summary":"Owners and operators of Kawasaki BK117C-1/C-2 helicopters and their maintenance organisations must not install Fuel Control Units (FCUs) that lack Turboméca’s TU358 modification. CASA issued this mandatory ban effective 24 December 2010.\n\nThe change fixes inadequate fuel delivery that caused failures to meet required OEI power at altitudes above 10,000 ft, restoring required emergency power performance and removing related checks once both engines are modified."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive restricts installation of unmodified FCUs and prescribes a specific modification path (TU358) to remove the restriction. It does not broaden applicability beyond the stated Kawasaki BK117C‑1/C‑2 fleet or add obligations outside the FCU modification/installation and associated placard/flight‑manual treatment."},"complexity_factors":["Narrow applicability: only Kawasaki BK117C‑1 and C‑2 helicopters (Applicability).","Single technical remedy required: Turboméca Service Bulletin TU358 (Requirement / Background).","Modification must be accomplished on both engines to remove restrictions (Background / Requirement).","Immediate compliance timing: effective date 24 December 2010 (Compliance).","Operational consequence: placard and flight‑manual changes tied to modification status (Background).","Safety performance tied to pressure altitude (above ~10,000 ft) and FCU fuel‑flow law (Background).","Regulatory reliance on an OEM service bulletin to resolve the issue; enforcement via installation prohibition (Requirement).","Compliance cost borne by operators (modification of both engines) and operators’ operational choice between restrictions or modification (implicit in Requirement/Background)."],"plain_english_summary":"This Airworthiness Directive forbids fitting Kawasaki BK117C‑1 and C‑2 helicopters with Fuel Control Units (FCUs) unless they are modified per Turboméca Service Bulletin TU358, effective 24 December 2010. It responds to tests showing some helicopters cannot reach the required MAX N1 at high pressure altitudes (around 10,000 ft+) because the FCU limits fuel flow. Operators must either keep the altitude/power limitation or pay to have both engines modified to remove placard and flight‑manual restrictions."},"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-jbk-117-36-pressure-altitude-limitation-and-max-n1-check","history":"/api/acts/ad-jbk-117-36-pressure-altitude-limitation-and-max-n1-check/history","analysis":"/api/acts/ad-jbk-117-36-pressure-altitude-limitation-and-max-n1-check/analysis","conflicts":"/api/acts/ad-jbk-117-36-pressure-altitude-limitation-and-max-n1-check/conflicts","importantCases":"/api/acts/ad-jbk-117-36-pressure-altitude-limitation-and-max-n1-check/important-cases","documents":"/api/acts/ad-jbk-117-36-pressure-altitude-limitation-and-max-n1-check/documents"}}