Overview

The Civil Aviation Safety Authority (CASA) has issued Airworthiness Directive (AD) AD/AIRCON/9 Amdt 7 under the Civil Aviation Regulations 1988 (CAR 1988). This AD was enacted to address safety concerns related to combustion type cabin heaters in aircraft, aiming to ensure they operate safely and effectively to prevent potential hazards such as carbon monoxide contamination in the cabin. This legislative instrument focuses on the inspection, functional testing, overhaul, and disabling of these heaters to mitigate risks associated with their operation. The AD specifies requirements for regular inspections and tests to maintain the airworthiness of the cabin heaters, ensuring they meet safety standards and do not pose a risk to passengers and crew.

Scope and Application

The Airworthiness Directive AD/AIRCON/9 Amdt 7 pertains to all combustion type cabin heaters used in aircraft, excluding those for which AD/AIRCON/12 applies. Issued by the Civil Aviation Safety Authority (CASA) delegate, this directive mandates specific actions to be taken to ensure the safe operation of these cabin heaters. The actions include thorough inspections of the combustion heater installation and associated components, checking for exhaust contamination and corrosion, cleaning the heater fuel filter, and ensuring the heater drain lines are free from obstructions. Furthermore, it requires a functional test measuring carbon monoxide levels in the cabin air, with a stipulation that levels must not exceed 1 part per 20,000 parts of air. If the heater fails this test, it must be disabled or repaired. The directive also outlines procedures for overhauling the heater and associated components, as well as disabling the heater if necessary, including capping the fuel supply line and ensuring the cabin heater system is disabled while maintaining other aircraft systems' functionality. This directive applies nationally across the Commonwealth of Australia and is effective from 3 October 2002. Compliance with these requirements is contingent upon the heater's operational hours or calendar time in service, whichever comes first, and must adhere to the manufacturer's recommendations or specified intervals if such recommendations are unavailable.

Key Provisions

The Airworthiness Directive (AD) AD/AIRCON/9 Amdt 7, issued by the Civil Aviation Safety Authority (CASA) delegate, applies to all combustion type cabin heaters except those covered by AD/AIRCON/12. The directive sets forth specific actions that must be taken to ensure the safety of these heaters. Firstly, it mandates an inspection of the heater installation, including airframe mounted components, to check for general condition and security (section 1(a)). The hot air outlet ducting adjacent to the heater must be inspected for exhaust contamination and corrosion (section 1(b)). The heater fuel filter should be cleaned, and the heater fuel system must be checked for loose connections and leaks using system pressure (section 1(c)). Additionally, heater drain lines must be inspected for obstructions (section 1(d)), and spark plugs and contact breaker points must be inspected and adjusted where necessary (section 1(e)). The AD also requires a functional test during which the carbon monoxide (CO) level in the heated air entering the cabin must be measured to ensure it is less than 1 part per 20,000 parts of air (section 2). If the heater fails this test, it must be either disabled or repaired/replaced. Furthermore, the AD mandates that the heater be overhauled in accordance with the manufacturer’s recommendations, or at intervals not exceeding 500 heater hours or 8 years, whichever occurs first, if such recommendations are unavailable (section 3). The AD also includes specific instructions for disabling the heater, which must be done in accordance with Minimum Equipment List (MEL) requirements or CAR (1988) 37 (section 4). This includes capping the fuel supply line, disconnecting electrical power, and ensuring that no other aircraft systems are affected. Compliance with this directive is required within 100 heater hours or 12 calendar months after the effective date of the AD, whichever occurs first, and then at intervals not exceeding 100 heater hours or 24 months thereafter (section 1). For the functional test, compliance must be achieved within the same timeframes (section 2). For overhaul, compliance must be according to the manufacturer’s recommendations or, in the absence of such, at intervals not exceeding 500 heater hours or 8 years (section 3). The directive also specifies that disabling the heater must occur if it fails the functional test (section 4). Failure to comply with the AD may result in civil or criminal penalties under the Civil Aviation Act 1988, including fines and imprisonment. Specifically, under section 20 of the Act, a person who contravenes an AD can be fined up to $12,600 for an individual and $63,000 for a body corporate, and may also face imprisonment for up to two years. These penalties underscore the seriousness with which the AD must be taken to ensure the safety of aircraft and their occupants.