COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Piper PA-23 (Apache and Aztec) Series Aeroplanes
AD/PA-23/56 Fire-Proofing Turbo-Charger Oil Tanks in Engine Compartment
4/73
Applicability: All models equipped with turbochargers having separate oil tanks installed in the engine compartment forward of the firewall.
Requirement: 1. Inspect all aircraft fitted with turbochargers for the installation of a separate turbocharger oil supply tank. (This tank is not installed on aircraft where the turbocharger oil system is supplied from the engine sump).
2. If this tank is of aluminium alloy construction or other non- fireproof material, replace the tank and fittings with a fire proof equivalent or render the tank fireproof in accordance with an approved scheme, or remove the tank from the engine compartment and re-install behind the firewall in accordance with an approved scheme. The cut-outs in the firewall for the drain plug and oil level sight tube must also be sealed and rendered fire proof.
3. Inspect all line assemblies carrying flammable fluids in the engine compartment to ensure they are fire resistant to the extent of being capable of withstanding exposure to flame at a temperature of 1093º + 28ºC for five minutes without failure. Free hose and clamp assemblies shall not be used in such lines. This requirement need not apply to breather, vent or drain lines, the failure of which will not result in or add to a fire hazard. ANO Section 101.22 para. 6.25 also refers.
Note: Flexible hose assemblies approved as “fire resistant” by the British CAA or complying with the requirements of FAA Technical Standard Order C53A of Type C or D hoses are acceptable. Rigid lines and fittings composed of steel or copper base alloy are also acceptable.
Compliance: At next major inspection after 30 April 1973 or before 30 June 1974 whichever occurs first.