COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Piper PA-25 (Pawnee) Series Aeroplanes
AD/PA-25/8 Improved Protection from Crash Fires 8/62
Applicability: Model PA-25.
Requirement: 1. To reduce the possibility of a crash fire occurring in the fuel tank bay, the following rework shall be performed:
2. Re-inforce the upper longerons in the fuel tank bay (Tubes No. 61001-23 and -78) by installing an external split tube welded sleeve of material to specification AMS 6360D (SA 4130) or approved equivalent. The sleeve shall extend from the forward weld cluster for a distance of 30 inches aft and shall be not less than 0.035 in. gauge thickness.
3. A transverse reinforcing member shall be installed across the forward face of the engine compartment firewall, between the two upper engine mount attach brackets. The reinforcement achieved shall be at least equivalent to that provided by a hat section stiffener of 16 gauge AN-A-13 or equivalent material to the following dimensions:
Attach Flanges - .75 inches. Side Walls - 1.125 inches. Crown - 2.875 inches.
4. The attachment fittings and lid fasteners of the battery but shall be reworked to realise the strength requirements of ANO 100.20, para. 7.3.
5. The electrical system shall be reworked to re-locate the engine starter switch or relay, on, or immediately adjacent to the battery box, in order that the live lead from the battery to the switch or relay is kept as short as possible. All live electrical wires in the fuel tank bay shall have sufficient slack to prevent them from breaking due to moderate structural distortion of the bay. All live electrical terminals in the fuel tank bay shall be fitted with suitable protective rubber caps.
6. All openings between the fuselage fuel tank bay and the hopper bay shall be sealed with plates of 2024ST material not less than 24 gauge or other material having at least equivalent fire resistant properties.
Compliance: Before 1 September 1971.