COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Bell Helicopter Textron 412 Series Helicopters
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 CAR 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.
AD/BELL 412/43 Tail Rotor Counterweight Bellcrank Retention Nut
Applicability: Model 412, 412EP, and 412CF helicopters. Requirement: 1. For Model 412 or 412EP helicopters:
9/2001
DM
- Remove the two existing retention nuts retaining the bellcranks, part number 212-011-705-001, and install retention nuts, part number MS14145L6 or MS17826-6, in accordance with paragraphs (1) through (5) of the Accomplishment Instructions in Bell Helicopter Textron Alert Service Bulletin (ASB) 412-00-102 Revision A, dated 13 September 2000. A used nut must not be installed.
b. Inspect the retention nuts and corrosion preventive compound (CPC) coating in accordance with paragraph (6) of the Accomplishment Instructions in ASB 412-00-102 Revision A. Reapply the CPC coating if deficiencies are found in the coverage and protection of the area. Replace any retention nut found with any corrosion, mechanical damage, a crack, or looseness, with a serviceable new retention nut before further flight.
2. For Model 412CF helicopters:
- Remove the two existing retention nuts retaining the bellcranks, part number 212-011-705-001, and install retention nuts, part number MS14145L6 or MS17826-6, in accordance with paragraphs (1) through (5) of the Accomplishment Instructions in ASB 412CF-00-10 Revision A, dated 13 September 2000. A used nut must not be installed.
b. Inspect the retention nuts and CPC coating in accordance with paragraph (6) of the Accomplishment Instructions in ASB 412CF-00-10 Revision A. Reapply the CPC coating if deficiencies are found in the coverage and protection of the area. Replace any retention nut found with any corrosion, mechanical damage, a crack, or looseness, with a serviceable new nut before further flight.
Note: FAA AD 2001-13-01 Amdt 39-12281 refers.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Compliance: 1.a. and 2.a: Within 100 hours time in service or 90 days after 1 August 2001, whichever occurs first, unless already accomplished.
1.b. and 2.b: At intervals not to exceed 100 hours time in service after accomplishing Requirement 1.a. or 2.a., as applicable.
This Airworthiness Directive becomes effective on 1 August 2001.
Background: The FAA received a report of an in-flight loss of a tail rotor counterweight bellcrank due to failure of the retention nut. Failure of the retention nut could result in the bellcrank migrating off the crosshead spindle, loss of tail rotor control, and subsequent loss of control of the helicopter.
David Alan Villiers
Delegate of the Civil Aviation Safety Authority 25 July 2001
The above AD is notified in the Commonwealth of Australia Gazette on 1 August 2001.
Overview
The Civil Aviation Regulations 1998 were enacted to regulate civil aviation and ensure the safety of aircraft operations in Australia. The specific legislative instrument, F2006B04677, is an Airworthiness Directive issued by the Civil Aviation Safety Authority (CASA) in 2001. This directive was introduced to address the unsafe condition identified in the Bell Helicopter Textron 412 Series helicopters, specifically concerning the tail rotor counterweight bellcrank retention nut. The directive aims to mitigate the risk of in-flight loss of the tail rotor counterweight bellcrank, which could lead to loss of tail rotor control and subsequent loss of control of the helicopter. The directive mandates the removal and replacement of the existing retention nuts with new ones, and includes inspection and maintenance requirements to ensure ongoing airworthiness.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105 Civil Aviation Safety Authority Schedule of Airworthiness Directives, mandates actions to address safety concerns regarding the tail rotor counterweight bellcrank retention nut on Bell Helicopter Textron 412 Series Helicopters. This Airworthiness Directive applies to Model 412, 412EP, and 412CF helicopters. The directive requires the removal and replacement of the existing retention nuts with specified new ones, following detailed instructions provided in the relevant service bulletins. Additionally, it mandates periodic inspections and maintenance of the retention nuts and their corrosion preventive compound coating to ensure continued airworthiness. The AD is effective as of 1 August 2001 and requires compliance within specific timeframes following the directive's issuance. This regulation ensures that the specified helicopters meet stringent safety standards, mitigating risks associated with the failure of the tail rotor counterweight bellcrank retention nut, which could lead to loss of control of the aircraft.
Key Provisions
The Airworthiness Directive (AD) outlined in the Civil Aviation Regulations 1998 pertains specifically to Bell Helicopter Textron 412 Series Helicopters, namely Models 412, 412EP, and 412CF. The directive mandates certain actions to be taken to rectify an identified unsafe condition concerning the tail rotor counterweight bellcrank retention nuts. The directive, as per section (a) of the applicability, applies to the aforementioned helicopter models. Under section (b), the requirement involves the removal and replacement of the existing retention nuts, which must be done in accordance with the instructions provided in the respective service bulletins (ASB 412-00-102 Revision A for Models 412 and 412EP, and ASB 412CF-00-10 Revision A for Model 412CF). The replacement nuts must be of specified part numbers (MS14145L6 or MS17826-6) and should not be reused. Additionally, the directive requires the inspection of these nuts and their corrosion preventive compound (CPC) coating, with any deficiencies in coating coverage or signs of corrosion, mechanical damage, cracks, or looseness necessitating corrective action, including reapplication of CPC coating or replacement of the nuts.
The AD imposes several obligations on the parties governed by it. These include the timely removal and replacement of the specified retention nuts within a defined timeframe, specifically within 100 hours of service or 90 days after 1 August 2001, whichever comes first. Furthermore, the directive mandates regular inspections of the retention nuts and CPC coating at intervals not exceeding 100 hours of service following the initial action. Compliance with these requirements is critical to maintaining the airworthiness of the affected helicopters, ensuring that they meet the safety standards set by the Civil Aviation Safety Authority (CASA).
Failure to comply with the AD may result in serious consequences, as it directly addresses a safety-critical issue that could lead to loss of tail rotor control and subsequent loss of control of the helicopter. The AD does not explicitly state penalties, but non-compliance could lead to enforcement actions under the Civil Aviation Act 1988 and associated regulations. Such actions could include fines, the grounding of non-compliant aircraft, or other measures deemed necessary by CASA to ensure compliance and maintain aviation safety standards.