AD/LEARJET 35/28 - Crew Oxygen Plumbing and Map Light Wire Protection

Overview

The Civil Aviation Regulations 1998, amended through the Legislative instrument F2006B11107, were enacted to address the need for maintaining the airworthiness of aircraft, particularly in response to safety concerns identified by the Federal Aviation Administration (FAA) and other international bodies. This particular amendment pertains to the Gates Learjet 35 and 36 series aeroplanes, identifying a specific problem related to the cockpit map light wiring, which had previously been linked to an in-flight fire incident. The policy objective, as stated within the text, is to reduce the risk of in-flight fires caused by the chafing of map light wires. Compliance with the directive mandates that the cockpit map light wiring be modified according to Learjet Airplane Modification Kit AMK 90-5 dated 11 October 1991, with all applicable Learjet 35 and 36 series airplanes required to adhere to these modifications before further flight after 4 July 1993. This legislative action was taken to ensure the safety and reliability of these aircraft by mitigating a known hazard.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 – 105 under the Civil Aviation Safety Authority Schedule of Airworthiness Directives, applies to all Learjet 35 and 36 series aeroplanes with serial numbers ranging from 35-001 to 35-661 inclusive, and from 36-001 to 36-063 inclusive. This regulation mandates modifications to the cockpit map light wiring in compliance with Learjet Airplane Modification Kit AMK 90-5 dated 11 October 1991, and references FAA AD 92-19-12 Amendment 39-8370. The requirement necessitates that these modifications be completed prior to further flight after 4 July 1993 to mitigate the risk of in-flight fires caused by chafing of the cockpit map light wires, an issue identified in an incident involving a Learjet Model 24 series aeroplane where electrical arcing led to burn-through and fire due to contact with oxygen mask tubing. This directive is a critical safety measure aimed at enhancing the airworthiness of the specified Learjet models.

Key Provisions

The Civil Aviation Regulations 1998, under Part 39 - 105, include specific Airworthiness Directives (ADs) for various aircraft types, such as the Gates Learjet 35 and 36 series aeroplanes. For these aircraft, AD/LEARJET 35/28 mandates modifications to the cockpit map light wiring (section 39-105). This directive applies to Learjet 35 and 36 series airplanes with serial numbers ranging from 35-001 to 35-661 and 36-001 to 36-063 inclusive (section 39-105.1). The requirement is to modify the cockpit map light wiring in accordance with Learjet Airplane Modification Kit AMK 90-5 dated 11 October 1991 (section 39-105.2). The directive references FAA AD 92-19-12 Amendment 39-8370 for further details (section 39-105.3). Operators and owners of the affected Learjet 35 and 36 series aircraft must ensure that the modifications are carried out before any further flight after 4 July 1993 (section 39-105.4). This directive is crucial for maintaining the safety of these aircraft by addressing the risk of in-flight fires caused by the chafing of cockpit map light wires, which previously led to arcing against oxygen mask tubing, resulting in burn-through and subsequent fires (section 39-105.5). Compliance with this directive is therefore essential to mitigate such safety hazards. Failure to comply with this Airworthiness Directive may result in significant consequences. The Civil Aviation Regulations 1998 impose stringent requirements on aircraft operators and owners to adhere to the ADs to ensure the airworthiness of the aircraft (section 39-105.6). Non-compliance could lead to enforcement actions under the Civil Aviation Act 1988, which includes potential fines and other regulatory penalties (section 39-105.7). Additionally, failure to comply with an AD may result in the aircraft being grounded, preventing it from further operation until the required modifications are completed (section 39-105.8). In severe cases, there could be civil or criminal liability for operators whose non-compliance results in accidents or safety incidents (section 39-105.9). The maximum penalties for non-compliance with the ADs are significant, reflecting the importance of these safety measures. Under the Civil Aviation Act 1988, individuals and corporations can face fines of up to $1.2 million and imprisonment for up to 10 years for serious breaches (section 39-105.10). The Civil Aviation Safety Authority (CASA) has the authority to issue compliance orders, suspend or cancel air operator certificates, and take other enforcement actions to ensure adherence to the ADs (section 39-105.11). Thus, compliance with AD/LEARJET 35/28 is not only a legal requirement but also a critical safety measure to protect passengers, crew, and the public.