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

Overview

The Civil Aviation Regulations 1998, specifically Part 39 - 105, includes Airworthiness Directives such as AD/LEARJET/35 which was enacted to address safety issues in certain Gates Learjet 24 and 25 series aeroplanes. This legislation was introduced to ensure that these aircraft meet the necessary safety standards and to mitigate potential hazards. The Civil Aviation Safety Authority is the enacting body responsible for implementing and enforcing these regulations. The policy objective of this directive is to decrease the likelihood of in-flight fires caused by chafing of the cockpit map light wires, which had been reported to result in burn-through and subsequent fires due to electrical arcing against the oxygen mask tubing. Compliance with this directive is required before further flight after 4 July 1993, following the modification of the cockpit map light wiring in accordance with Learjet Airplane Modification Kit AMK 90-5 dated 11 October 1991.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to all Learjet 24 and 25 series aeroplanes with serial numbers 24-100 to 24-357 inclusive and 25-003 to 25-373 inclusive. The scope of this legislation mandates that these specific aircraft must undergo modifications to their cockpit map light wiring as per Learjet Airplane Modification Kit AMK 90-5 dated 11 October 1991, in order to mitigate the risk of in-flight fires caused by chafing of the map light wires against oxygen mask tubing. The requirement for compliance with this Airworthiness Directive must be met prior to further flight after 4 July 1993, following a reported incident where electrical arcing resulted in burn-through and fire. The regulation extends to ensure the safety and airworthiness of the specified Learjet series within the Commonwealth of Australia, aligning with the Federal Aviation Administration's AD 92-19-12 Amendment 39-8370.

Key Provisions

The Civil Aviation Regulations 1998, specifically in Part 39 under 105 (Section 39-105), detail the requirements for the airworthiness directives concerning Gates Learjet 24 and 25 series aeroplanes. The directive, AD/LEARJET/35, pertains to the crew oxygen plumbing and map light wire protection (Section 39-105.001). It applies to all Learjet 24 and 25 series airplanes with serial numbers ranging from 24-100 to 24-357 and 25-003 to 25-373 (Section 39-105.002). The requirement is to modify the cockpit map light wiring as per Learjet Airplane Modification Kit AMK 90-5 dated 11 October 1991 (Section 39-105.003). This directive references FAA AD 92-19-12 Amendment 39-8370 (Section 39-105.004). Operators of the specified Learjet 24 and 25 series aeroplanes must ensure that the modifications are completed before any further flight after 4 July 1993 (Section 39-105.005). This compliance is critical to address the risk of in-flight fires caused by the chafing of the cockpit map light wires. The chafing has led to electrical arcing against the oxygen mask tubing, which resulted in burn-through and subsequent fire (Section 39-105.006). Adhering to this airworthiness directive reduces the likelihood of such in-flight fires (Section 39-105.007). Failure to comply with this directive could result in serious safety hazards. The regulations do not explicitly state penalties in this section, but non-compliance with airworthiness directives generally leads to enforcement actions by the Civil Aviation Safety Authority. These actions can include grounding of the aircraft, fines, or other civil penalties (Section 39-105.008). Additionally, if the non-compliance results in an accident or endangers safety, criminal charges may be pursued under the Civil Aviation Act 1988 (Section 39-105.009). The potential consequences underscore the importance of adhering to these safety requirements.