COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Eurocopter BK 117 Series Helicopters
AD/GBK 117/11
Amdt 1
Tension-Torsion Straps 11/99
Applicability: All Eurocopter MBB-BK 117 helicopters.
Requirement: Action in accordance with Eurocopter Alert Service Bulletin ASB-MBB-BK 117-10- 120 Revision 1, dated August 31 1999.
Note 1: The calendar time in service commences with date of issue of the initial certificate of airworthiness issued for the aircraft, or date of first installation for any replacement tension-torsion straps fitted, and is continuous from that date.
Note 2: LBA AD 1999-284/2 dated 1 September 1999 refers.
Compliance: At the times or number of flights stated in Eurocopter Alert Service Bulletin ASB- MBB-BK 117-10-120 Revision 1, dated 31 August 1999. For the purpose of section
1.D.3 a date of 18 August 1999 must be used as the reference date. Return to service of tension-torsion straps in accordance with section 1.D.4 applies only to parts which exceed 10 years calendar time in service on 18 August 1999.
This Amendment becomes effective on 4 November 1999.
Background: Failure of a tension-torsion strap installed in a US registered BK-117 helicopter caused a fatal crash of the aircraft. The actions of the Eurocopter Service Bulletin have been taken as a precautionary measure. The service limit placed on the tension- torsion strap is presently 10 years (since installation) or 25000 flights, whichever occurs first. Limited return to service of tension torsion straps following inspection is permitted for parts installed for less than 15 years, provided an inspection of the part is made.
Amendment 1 is issued in response to minor amendments of the Eurocopter Service Bulletin. As the amendments are for clarification, the initial compliance date is unchanged from the initial issue of this Directive.
The original issue of this Airworthiness Directive became effective on 18 August 1999.
Overview
The Civil Aviation Regulations 1998, enacted by the Australian Parliament, form a comprehensive framework for ensuring the safety and efficiency of civil aviation within Australia. Specifically, Part 39 of these regulations addresses the maintenance and safety of aircraft through the issuance of airworthiness directives. One such directive, AD/GBK 117/11, targets the safety of Eurocopter BK 117 Series Helicopters by addressing the potential failure of tension-torsion straps. This directive was introduced to mitigate the risk of catastrophic failure, as evidenced by a fatal crash of a US registered BK-117 helicopter attributed to the failure of such a strap. The policy objective behind this regulation is to enhance aviation safety by mandating timely inspections and replacements of critical components, thereby preventing similar incidents in the future.
The legislative instrument F2006B10258, which pertains to the Eurocopter BK 117 Series Helicopters, underscores the importance of adhering to manufacturer service bulletins and compliance timelines to ensure the continued airworthiness of these aircraft. The directive mandates specific actions as outlined in Eurocopter Alert Service Bulletin ASB-MBB-BK 117-10-120 Revision 1, dated August 31, 1999, and sets forth clear timelines and conditions for the inspection and replacement of tension-torsion straps. This regulatory measure aims to address the identified safety gap and prevent the recurrence of similar accidents by ensuring that operators follow stringent maintenance protocols.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105 Civil Aviation Safety Authority Schedule of Airworthiness Directives, applies to all Eurocopter MBB-BK 117 helicopters. The regulation mandates action in accordance with Eurocopter Alert Service Bulletin ASB-MBB-BK 117-10-120 Revision 1, dated August 31, 1999. Compliance with this directive requires adherence to the specified times or number of flights as outlined in the service bulletin. The calendar time in service for these helicopters starts from the date of the initial certificate of airworthiness or the date of first installation for any replacement tension-torsion straps. The directive is effective from 4 November 1999 and references LBA AD 1999-284/2 dated 1 September 1999. Notably, return to service of tension-torsion straps is conditional on parts not exceeding 10 years of calendar time in service as of 18 August 1999. This amendment is a precautionary measure following a fatal crash of a US-registered BK-117 helicopter due to a tension-torsion strap failure. The service limit for these straps is set at 10 years (since installation) or 25,000 flights, whichever comes first, with limited return to service permitted for parts installed for less than 15 years, subject to inspection.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, include a schedule of airworthiness directives that govern the maintenance and safety standards for various aircraft, including the Eurocopter BK 117 Series Helicopters. The key provision in the regulation is AD/GBK 117/11 Amendment 1, which mandates actions regarding the tension-torsion straps of these helicopters (section 11/99). This directive applies to all Eurocopter MBB-BK 117 helicopters and requires compliance with Eurocopter Alert Service Bulletin ASB-MBB-BK 117-10-120 Revision 1, dated 31 August 1999. The compliance requirements are set forth within this bulletin, which specifies the times or number of flights by which certain actions must be taken.
Operators of Eurocopter BK 117 Series Helicopters must adhere to the instructions provided in the Eurocopter Alert Service Bulletin ASB-MBB-BK 117-10-120 Revision 1. This includes performing necessary actions at specified intervals, such as after a certain number of flights or within a particular timeframe. The calendar time in service for these helicopters starts from the date of the initial certificate of airworthiness or the date of first installation for any replacement tension-torsion straps. The bulletin also clarifies that a reference date of 18 August 1999 must be used for specific compliance purposes. Furthermore, any tension-torsion straps that have exceeded 10 years of calendar time in service on 18 August 1999 must return to service in accordance with the detailed instructions in section 1.D.4 of the bulletin.
Failure to comply with the provisions outlined in the Eurocopter Alert Service Bulletin ASB-MBB-BK 117-10-120 Revision 1 can lead to serious safety issues and potential regulatory consequences. The directive was issued in response to a fatal crash involving a US-registered BK-117 helicopter, which was caused by the failure of a tension-torsion strap. Therefore, non-compliance with the airworthiness directive may result in significant risks to flight safety and could lead to enforcement actions by the Civil Aviation Safety Authority (CASA). While the specific penalties for non-compliance are not detailed in the text, they could potentially include fines, suspension of airworthiness certificates, or other regulatory sanctions under the Civil Aviation Act 1988 and associated regulations.