AD/LEARJET 35/34 Amdt 1 - Auxiliary Cabin Heater Wiring

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of the Commonwealth of Australia, was introduced to address safety issues in the aviation industry by setting standards and regulations for aircraft and operations. One of the key legislative instruments under this regulation is the Civil Aviation Safety Authority Schedule of Airworthiness Directives, which mandates specific safety measures to be undertaken by operators of certain aircraft models to ensure continued airworthiness and passenger safety. AD/LEARJET 35/34 Amendment 1 is a specific directive aimed at addressing a safety concern identified in Gates Learjet 35 and 36 series aeroplanes, particularly focusing on the auxiliary cabin heater wiring. This directive was issued to mitigate the risk of fire hazards caused by inadequate current carrying capacity in certain wire segments, and it became effective on 21 May 1998. The policy objective behind this amendment is to enhance the safety of air travel by ensuring that the wiring in specified aircraft models meets the necessary standards to prevent overheating and associated fire risks.

Scope and Application

The Civil Aviation Regulations 1998, as amended, applies to all civil aviation activities and aircraft within Australia's jurisdiction, ensuring compliance with international safety standards. Specifically, the AD/LEARJET 35/34 Amendment 1 pertains to Gates Learjet 35 and 36 Series aeroplanes, more precisely model 35A aeroplanes with serial numbers ranging from 35-647 to 35-670 inclusive. This directive mandates the replacement of two segments of 16 American Wire Gauge (AWG) wire with 8 AWG wire at connector P190, in accordance with Learjet Service Bulletin SB 35-21-24 Revision 1 dated 13 August 1996. The directive was issued to address an identified fire hazard due to the inadequate current carrying capacity of the original wiring, and it must be completed by 31 August 1998. This amendment became effective on 21 May 1998, with compliance required irrespective of whether the replacement follows the procedures specified in the original service bulletin or an equivalent method using identical or equivalent equipment. The directive references FAA AD 98-06-28 Amendment 39-10406 and was prompted by a correction from the Federal Aviation Administration regarding the socket contact in the original service bulletin.

Key Provisions

The Civil Aviation Regulations 1998, specifically under Part 39 - 105, address the safety requirements for Gates Learjet 35 and 36 series aeroplanes. Section AD/LEARJET 35/34 Amendment 1 pertains to the auxiliary cabin heater wiring of Model 35A aeroplanes with serial numbers 35-647 through 35-670 inclusive. The directive mandates the replacement of two segments of 16 American Wire Gauge (AWG) wire with 8 AWG wire at connector P190, following the procedures outlined in Learjet Service Bulletin SB 35-21-24 Revision 1 dated 13 August 1996. This requirement ensures the adequacy of the wire size for the circuit, mitigating the risk of overheating and fire hazards. The obligations imposed on the parties governed by this Act are clear and specific. Operators and owners of the affected Model 35A aeroplanes must ensure that the mandated wire replacement is carried out in compliance with the procedures specified in the Learjet Service Bulletin. Additionally, the use of equipment identical or equivalent to that specified in the bulletin's Revision 1 is accepted as a method of compliance. This ensures that the modifications are performed correctly and safely, adhering to the standards set forth by the Federal Aviation Administration (FAA). Failure to comply with the airworthiness directive can result in significant consequences. The directive specifies that compliance must be achieved prior to 31 August 1998. Non-compliance could potentially lead to safety issues, as the original 16 AWG wire segments are deemed insufficient for the circuit's needs, posing a fire hazard. Furthermore, the directive became effective on 21 May 1998, and any aeroplanes failing to meet the compliance deadline could face penalties or other regulatory actions. The directive references FAA AD 98-06-28 Amendment 39-10406, indicating that the issue is of international concern and the directive is issued following FAA advice. The background information provided elucidates the rationale behind the airworthiness directive. The insufficiency of the 16 AWG wire segments in the auxiliary cabin heater circuit can lead to overheating and subsequent fire hazards. The directive aims to rectify this by requiring the replacement of the wire segments with 8 AWG wire, ensuring that the circuit can safely handle the necessary current. Additionally, the amendment addresses an issue identified in the original service bulletin, where the socket contact supplied in the kit was an incorrect part number for use in connector P190. This correction is essential for the safe and effective implementation of the wiring modification.