59-02-01 CONVAIR: Applies to All 240 and 340 Aircraft, Serial Numbers 2 Through 188.
Compliance required not later than December 31, 1960.
Inflight fire experience with the Convair 240 engine nacelle has shown the zone three wheel well area vulnerable to the entrance of fire originating in the forward fire zones. While various improvements have been incorporated to contain fires in the forward zones by AD 56-20- 04, further improvements are necessary to either prevent the entry of fire into the zone three wheel well area or to supplement the requirements of AD 56-04-02 to cover remaining flammable fluid system lines, fittings and components in zone three.
To accomplish the above, modifications must be made to the airplane in accordance with either Parts I or II of this airworthiness directive:
Part I. Fireproof skin must be installed on the entire circumference of each nacelle from the firewall aft to Station 135 and on the forward portion of the wheel well doors aft to Station 150. Attachment of the skin to the structure must be made with fireproof fasteners.
(Convair Service Bulletins 240-466 and 340-170 cover acceptable methods of accomplishing the above.)
Part II.
(1) Replace all existing nonfireproof flammable fluid system lines and fittings in each zone three wheel well area with similar lines and fittings constructed of fireproof material or otherwise qualified as fireproof. This extends to the following:
a. The aircraft hydraulic system supply lines and fittings to the engine driven pump.
b. The engine driven pump supply, return and control lines and fittings of those aircraft equipped with an integral oil supply for the cabin supercharger hydraulic system.
c. The hydraulic supply lines and fittings from the reservoir to the shutoff valve of those aircraft equipped with a separate tank supply for the cabin supercharger compressor.
(2) Provide additional fire protection to those components of flammable fluid systems in each zone three wheel well area as specified below:
a. Shroud the fuel system firewall shutoff valve, the fuel strainer and boost pump body with fireproof material. As an alternate, shroud the fuel tank valve and motor with fireproof material, install fire-resistant electrical cable for this component in the wheel well area and revise the emergency procedures on page 42.0.1 of the FAA approved 240 Airplane Flight Manual to require fuel and cross-feed selector valves in the "off" position prior to release of extinguisher agent. Electrical cable complying with Military Specification MIL-C-25038 and appearing on Military Qualified Products List QPL-25038 meets fire-resistant requirements for this application.
b. Shroud the firewall shutoff valves for the engine, cabin supercharger and hydraulic oil systems with fireproof materials.
c. As an alternate to the fireproof shrouding required by items (2) a. and b., the components specified above maybe qualified as fireproof by test, in which case test proposals shall be submitted to the FAA Regional Office in Los Angeles for approval. In general, this test must subject the component to an enveloping fire of 2000 degrees F. under simulated operating pressure and vibratory conditions of the installation. Shutoff valves must remain operable for a 5-minute period and continue to withstand fire without leakage for an additional 10 minutes. Other components must withstand fire under similar environmental conditions for 15 minutes without leakage.