AIRWORTHINESS DIRECTIVE
For 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.
Kawasaki BK 117 Series Helicopters
AD/JBK 117/22 Airwork Hoist Modification 11/2004
TX
Applicability: BK-117 helicopters with fitted with Airwork (NZ) Ltd hoist modification ARD/721, ARD/741, ARD/752, ARD/977, ARD/999.STC or STC.AW.0003.
Requirement: 1. Inspect the CABLE CUT switch guard in accordance with Airwork (NZ) Ltd Service Bulletin (SB) SB.AW.0001 Issue 1 dated 19 August 2004 to determine the part number (P/N) of the switch guard.
2. If, as a result of the Requirement 1 inspection, the P/N of the switch guard is not MS25224-1, -2 or -3, replace the switch guard in accordance with SB.AW.0001 Issue 1.
3. Replace the two position switch with a momentary action switch P/N MS24523- 26 or MS24524-26, as applicable, and if not already installed, fit switch guard P/N MS25224-3 in accordance with SB.AW.0001 Issue 1.
Note 1: Only switch guard P/N MS25224-3 is acceptable with the new momentary contact switch (P/N MS25224-1, -2 or -3 are acceptable prior to replacement of the switch).
Note 2: CAA(NZ) AD DCA/BK117/14 refers.
Compliance: For Requirement 1 - Before the next hoist operation after the effective date of this Directive.
For Requirement 2 - Before further operation of the hoist after the Requirement 1 inspection.
For Requirement 3 - Within 100 hours time in service after the effective date of this Directive.
This Airworthiness Directive becomes effective on 1 September 2004.
Kawasaki BK 117 Series Helicopters
AD/JBK 117/22 (continued)
Background: The Civil Aviation Authority of New Zealand has advised that an uncommanded activation of the pyrotechnic cable cutter has occurred on a helicopter fitted with Airwork hoist Modification ARD/741. Investigation of the incident identified two contributing factors.
The cable cut switch had developed a fault allowing the switch toggle to rest in the neutral position. The switch is a two position switch and when serviceable is spring loaded to either CLOSED or OPEN positions. Additionally, the cable cut switch guard was an incorrect part number. In combination, the unserviceable switch and the incorrect switch guard allowed the allowed the cable cut circuit to be activated when the guard was closed.
This Directive initially requires the correct switch guard to be installed, followed by a terminating action, which replaces the switch.
James Coyne
Delegate of the Civil Aviation Safety Authority 31 August 2004
The above AD is notified in the Commonwealth of Australia Gazette on 1 September 2004.
Overview
The Airworthiness Directive issued under the Civil Aviation Act 1988, was enacted to address safety concerns identified with the Kawasaki BK 117 Series Helicopters, specifically those fitted with the Airwork hoist modification. This legislation, issued by the Civil Aviation Safety Authority (CASA) in 2004, was introduced to ensure the airworthiness of these helicopters by rectifying an unsafe condition that could potentially lead to uncommanded activation of the pyrotechnic cable cutter. The policy objective of this directive was to mandate specific actions to correct the identified issue, thereby maintaining the safety standards required by the Civil Aviation Safety Regulations 1998. The directive required the replacement of the cable cut switch guard and the switch itself to prevent the risk of accidental activation, ensuring that the helicopters remain compliant with airworthiness standards.
Scope and Application
The Airworthiness Directive AD/JBK 117/22 applies specifically to Kawasaki BK 117 Series Helicopters that are fitted with Airwork (NZ) Ltd hoist modifications ARD/721, ARD/741, ARD/752, ARD/977, and ARD/999, or STC or STC.AW.0003. This legislative instrument is issued under the Civil Aviation Safety Authority (CASA) and aims to address an unsafe condition related to the cable cut switch and its guard. The directive requires inspections and modifications to be carried out by operators or maintenance personnel to ensure the helicopters meet the specified airworthiness standards. The directive mandates that these actions must be completed within specified timeframes following the effective date of the directive, which is 1 September 2004. Failure to comply with this directive could result in the aircraft being considered unairworthy. This AD extends across the Commonwealth of Australia and is applicable to all relevant helicopters operating within its jurisdiction.
Key Provisions
This Airworthiness Directive (AD), issued by the Civil Aviation Safety Authority (CASA) delegate, applies to BK-117 helicopters that have been modified with an Airwork hoist (section 1). The AD mandates specific actions to address an unsafe condition identified with the cable cut switch and its guard on these helicopters (section 2). These actions must be carried out under the circumstances outlined and in accordance with the instructions given in the requirement section of the AD. Compliance with these requirements must be achieved within specified timeframes as detailed in the compliance section (section 3).
The AD imposes several obligations on the holders of the airworthiness certificates for the affected helicopters. Firstly, they must inspect the cable cut switch guard to determine its part number, in accordance with the instructions provided in the Airwork (NZ) Ltd Service Bulletin SB.AW.0001 Issue 1 dated 19 August 2004 (section 2.1). If the part number of the switch guard is not MS25224-1, -2, or -3, it must be replaced (section 2.2). Additionally, the two-position switch must be replaced with a momentary action switch, and a switch guard P/N MS25224-3 must be fitted if not already installed (section 2.3). These actions must be completed before certain events, such as the next hoist operation or within 100 hours of time in service after the effective date of the AD (section 3).
Failure to comply with the requirements of this AD may result in the aircraft being deemed unairworthy, which could lead to severe operational and legal repercussions. Although the AD does not explicitly state penalties for non-compliance, it is clear that failure to adhere to the specified requirements can result in serious safety risks. The consequences of not following this AD could include grounding of the affected helicopters, potential accidents, and enforcement actions by CASA, which may include fines or other legal penalties under the Civil Aviation Act 1988 and related regulations. The seriousness of the safety issue highlighted by this AD underscores the importance of strict compliance to ensure the continued airworthiness of the affected helicopters.