{"id":"F2009L03833","name":"AD/GBK 117/6 Amdt 6 - Main Rotor Blade","slug":"ad-gbk-117-6-amdt-6-main-rotor-blade","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":81070,"registerId":"commonwealth-F2009L03833-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Eurocopter BK 117 Series Helicopters","sectionType":"division","heading":"Eurocopter BK 117 Series Helicopters","content":"### Eurocopter BK 117 Series Helicopters\n\n| AD/GBK 117/6 Amdt 6 | Main Rotor Blade | 12/2009 |\n| ------------------- | ---------------- | ------- |\n\n| Applicability: | Models MBB-BK117A-1, A-3, A-4, B-1, B-2, and C-1, all serial numbers, if equipped with MR Blades as identified by Part Number (P/N) in Eurocopter Deutschland GmbH Alert Service Bulletin (ASB) ASB-MBB-BK117-10-108 Revision 4 or later revision. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement: | 1. Inspect the affected MR blades in accordance with the instructions contained in Eurocopter Deutschland GmbH Alert Service Bulletin (ASB)ASB-MBB-BK117-10-108 Revision 4 or later revision.Inspections and corrective actions accomplished prior to the effective date of this AD, in accordance with ECD ASB-MBB-BK117-10-108 at original issue or Revision 1 or Revision 2 or Revision 3, are acceptable to comply with the initial requirements of paragraph (1) of this AD. After the effective date of this AD, repetitive inspections and corrective actions must be accomplished in accordance with ECD ASB-MBB-BK117-10-108 at Revision 4.During any inspection required by this AD, if damage is detected that is outside the allowable limits as specified in Eurocopter Deutschland GmbH Alert Service Bulletin (ASB) ASB-MBB-BK117-10-108 Revision 4 or later revision, before further flight replace each affected blade with a serviceable blade.Replacement of MR blades does not constitute terminating action for the repetitive inspection requirements of this AD, except when all MR blades installed on a helicopter are MR blades that have a P/N not listed in ECDASB-MBB-BK117-10-108. In that case, this AD no longer applies to that helicopter.Note: EASA AD 2009-0199, dated 08 September 2009 refers. |\n| Compliance: | 1. a. For MR Blades with less than 1800 FH time since new:Within 300 FH after the effective date of this AD but not later than upon the accumulation of 1800 FH of the MR blade, whichever occurs first. Inspect thereafter at intervals not to exceed 300 FH. |\n\n| | b. For MR Blades with more than 1800 FH time since new:Within 300 FH after the effective date of this AD, or within 300 FH since the last required inspection. Inspect thereafter at intervals not to exceed 300 FH. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | This Amendment becomes effective on 19 November 2009. |\n| Background: | In response to recent incidents, the manufacturer recommends an immediate inspection for bulging on the upper and lower surfaces of the main rotor blades in the area of the outboard lead balance weight.Amendment 1 included all main rotor blades.Amendment 2 reflected the changed issue date of the LBA AD, no further work was required.Amendment 3 was issued in response to a revision of the related LBA AD. The amendment corrected applicability and specified the requirements of the latest LBA AD.Amendment 4 was issued to exclude certain Main Rotor Blade part numbers from inspection in accordance with this Airworthiness Directive. There was no change to the requirements or compliance.Amendment 5 was issued to advise that blades are now available that do not have lead balance weights and that fitment of these blades is terminating action for the requirements of this Airworthiness Directive. The inspection requirements for those blades that have balance weights were retained.This Amendment extends the repetitive inspection interval from 50 to 300 Flight Hours and depending on inspection findings requires replacement of MR blades. Additionally the prohibition of reinstallation of MR blades with lead balance weights (having a P/N not listed in ECD ASB-MBB-BK117-10-108) has been deleted. |\n\n![](image.001.png) \nDavid Villiers \nDelegate of the Civil Aviation Safety Authority\n\n28 September 2009","sortOrder":0},{"sectionNumber":"AD/GBK 117/6 Amdt 6","sectionType":"part","heading":"AD/GBK 117/6 Amdt 6","content":"## AD/GBK 117/6 Amdt 6","sortOrder":1},{"sectionNumber":"Main Rotor Blade","sectionType":"part","heading":"Main Rotor Blade","content":"## Main Rotor Blade","sortOrder":2},{"sectionNumber":"12/2009","sectionType":"part","heading":"12/2009","content":"## 12/2009","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"Compared with earlier versions, this amendment changes scope by extending the repetitive inspection interval from 50 to 300 flight hours, excluding certain MR blade part numbers from inspection, recognising blades without lead balance weights as terminating action for the AD, and deleting the earlier prohibition on reinstallation of MR blades with lead balance weights for certain P/Ns. See Background and Requirement."},"complexity_factors":["Applicability tied to specific BK117 models and MR blade part numbers listed in the Eurocopter ASB (Applicability).","Requirement cross‑references an external document and its later revisions (Eurocopter ASB‑MBB‑BK117‑10‑108 Rev 4 or later) (Requirement).","Different initial compliance timing based on blade time‑since‑new thresholds (<1800 FH vs >1800 FH) (Compliance).","Repetitive inspection interval set at 300 flight hours, replacing a prior 50 FH interval — affects inspection scheduling and operational planning (Background/Requirement).","Immediate replacement before further flight if damage exceeds ASB allowable limits — creates operational downtime and parts needs (Requirement).","Replacement generally does not terminate repetitive inspections unless all installed blades are P/Ns not listed in the ASB — conditional terminating action complicates compliance tracking (Requirement).","Acceptance of prior inspections done under earlier ASB revisions for initial compliance requires document history tracking (Requirement).","Amendment history and interaction with EASA/LBA ADs increase interpretive complexity for applicability and compliance (Background)."],"plain_english_summary":"This Airworthiness Directive requires operators of MBB‑BK117 series helicopters fitted with specified main rotor (MR) blades to perform initial and recurring inspections per Eurocopter ASB‑MBB‑BK117‑10‑108 (Rev 4 or later), replace blades that exceed the ASB's damage limits, and inspect at intervals not to exceed 300 flight hours. Compliance requires operators to conduct inspections at specified intervals, replace non‑compliant blades, and maintain inspection records in accordance with the service bulletin. Operators bear the cost of inspections and blade replacement."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":true,"description":"Originally intended as an immediate safety response to blade bulging incidents requiring frequent 50-hour inspections, the legislation has evolved through six amendments to become a more nuanced maintenance program. Amendment 6 significantly relaxes the inspection burden (300 vs 50 hours), introduces blade replacement options, and recognises terminating actions through design changes. The scope has shifted from emergency containment to long-term fleet management."},"complexity_factors":["Multiple amendment history referenced (Amendments 1-6) requiring context tracking","Conditional compliance deadlines based on blade flight hours (two distinct thresholds: <1800 FH vs >1800 FH)","Cross-reference to external manufacturer document (Eurocopter ASB-MBB-BK117-10-108 Revision 4) for actual inspection procedures","Nested exception logic: replacement doesn't terminate requirements UNLESS all blades are non-listed P/Ns","Grandfathering clause allowing prior inspections under earlier ASB revisions to count","Reference to parallel European regulation (EASA AD 2009-0199)"],"plain_english_summary":"This AD requires owners and operators of certain Eurocopter BK 117 helicopters to perform repetitive inspections of main rotor blades for bulging around lead balance weights, and to replace any blade that exceeds damage limits. It extends the inspection interval from 50 to 300 flight hours and notes that fitting new blades without lead weights removes the inspection requirement. It responds to recent incidents and affects operators, maintenance organizations, and pilots."},"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-gbk-117-6-amdt-6-main-rotor-blade","history":"/api/acts/ad-gbk-117-6-amdt-6-main-rotor-blade/history","analysis":"/api/acts/ad-gbk-117-6-amdt-6-main-rotor-blade/analysis","conflicts":"/api/acts/ad-gbk-117-6-amdt-6-main-rotor-blade/conflicts","importantCases":"/api/acts/ad-gbk-117-6-amdt-6-main-rotor-blade/important-cases","documents":"/api/acts/ad-gbk-117-6-amdt-6-main-rotor-blade/documents"}}