COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
De Havilland DHC-1 (Chipmunk) Series Aeroplanes
AD/DHC-1/37 Engine Start Isolation Switch 7/97
Applicability: All DHC-1 Chipmunk Aircraft fitted with Mod H85 or similar Electric Start installation.
Requirement: Unless previously incorporated, install an isolation switch in accordance with British Aerospace Aerostructures Ltd Technical News Sheet (TNS) CT (C1) No. 201 Issue 1, dated 1 March 1997.
Note: This TNS is classified Mandatory by UK CAA.
Compliance: Prior to 19 June 1998.
This Airworthiness Directive becomes effective on 19 June 1997.
Background: The manufacturer has determined that there is a possibility that a safety hazard could arise with ground power applied to the aeroplane. With the aeroplane electrically safe, an undetected fault in the starter switch, or inadvertent operation of the starter switch could render the engine start system live. The subsequent connection to ground power would cause an uncommanded rotation of the propeller and possibly endanger maintenance personnel.
Overview
The Civil Aviation Regulations 1998, introduced by the Australian Parliament, are a comprehensive set of regulations designed to ensure the safety and efficiency of civil aviation within Australia. Part 39 of these regulations pertains to the Civil Aviation Safety Authority (CASA) and includes Airworthiness Directives aimed at maintaining high safety standards in aircraft operations. The policy objective of these regulations is to ensure that all aircraft, including specific models such as the de Havilland DHC-1 (Chipmunk) series aeroplanes, meet stringent safety criteria to prevent hazards and ensure the safety of passengers and personnel. This particular legislative instrument, F2006B09018, addresses a specific safety concern with the engine start isolation switch in DHC-1 Chipmunk Aircraft fitted with Mod H85 or similar electric start installations. The directive mandates the installation of an isolation switch to prevent uncommanded propeller rotation when ground power is applied, thereby mitigating the risk of injury to maintenance personnel.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105, mandates the Civil Aviation Safety Authority’s Schedule of Airworthiness Directives, which applies to all De Havilland DHC-1 Chipmunk aircraft fitted with Mod H85 or similar electric start installations. This directive addresses the potential safety hazard associated with ground power applied to the aeroplane and requires the installation of an isolation switch in accordance with British Aerospace Aerostructures Ltd Technical News Sheet (TNS) CT (C1) No. 201 Issue 1, dated 1 March 1997. The directive is classified as mandatory by the UK Civil Aviation Authority and must be complied with prior to 19 June 1998. This Airworthiness Directive became effective on 19 June 1997, underscoring the importance of adhering to these safety requirements to prevent uncommanded propeller rotation and potential harm to maintenance personnel.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, address the safety requirements for aircraft through Airworthiness Directives. One such directive, AD/DHC-1/37, pertains to De Havilland DHC-1 (Chipmunk) Series Aeroplanes and mandates the installation of an engine start isolation switch. This requirement is outlined in section 7/97 and applies to all DHC-1 Chipmunk Aircraft equipped with Mod H85 or similar electric start installations (section 7/97). The directive necessitates the installation of an isolation switch according to the British Aerospace Aerostructures Ltd Technical News Sheet (TNS) CT (C1) No. 201 Issue 1, dated 1 March 1997 (section 7/97). This technical news sheet is classified as mandatory by the UK Civil Aviation Authority.
Compliance with AD/DHC-1/37 is mandatory for all applicable aircraft, with a compliance deadline set prior to 19 June 1998 (section 7/97). The Airworthiness Directive became effective on 19 June 1997, meaning that operators of DHC-1 Chipmunk Aircraft with the specified electric start installations must ensure the installation of the isolation switch by the compliance deadline. This requirement aims to mitigate the safety hazard identified by the manufacturer, where an undetected fault in the starter switch or inadvertent operation could result in the engine start system becoming live when connected to ground power. Such a scenario could lead to an uncommanded rotation of the propeller, potentially endangering maintenance personnel.
The Airworthiness Directive imposes specific obligations on aircraft operators, including the necessity to adhere to the technical specifications outlined in the British Aerospace Aerostructures Ltd TNS. Operators must ensure that the isolation switch is installed correctly and in compliance with the technical news sheet's instructions. This involves verifying the aircraft's configuration against the directive's applicability criteria and implementing the necessary modifications. The directive also necessitates that the installation be completed prior to the specified compliance date, underscoring the urgency and importance of timely action by aircraft operators.
Failure to comply with the requirements of AD/DHC-1/37 may result in significant legal consequences. While the specific penalties are not detailed in the text, non-compliance with airworthiness directives under the Civil Aviation Regulations 1998 can lead to enforcement actions by the Civil Aviation Safety Authority (CASA). These actions can include fines, penalties, and potential grounding of the aircraft. The severity of the consequences may depend on the nature and extent of the non-compliance, as well as any resulting safety risks. Ensuring adherence to the directive is therefore crucial for maintaining airworthiness and avoiding adverse regulatory outcomes.