| AD Number | 49-18-01 | Status | Active |
| Effective Date | Not specified | Issue Date | Not specified |
| Docket Number | Unknown | Amendment | N/A |
| Product Type | ["Aircraft"] | Product Subtype | ["Large Airplane"] |
| CFR Part | --- - Part 39 | CFR Section | N/A |
| Citation | This information is not available. | ||
| Manufacturer(s) | Airlift International, Inc. Curtiss-Wright Corporation Flying Tiger Line, Inc. L. B. Smith Aircraft Corporation Skyways International Trading and Transport Co. Tempo Design Corporation |
| Model(s) | C-46A C-46D C-46F C-46R C-46E C-46A C-46D C-46E C-46F C-46A C-46D C-46F C-46F C-46/CW20-T Super C-46/CW20-T |
49-18-01 CURTISS-WRIGHT Applies to all Models of C-46 Series airplanes used in passenger operation under provisions of Part 41, 42, or 61 of the Civil Air Regulations as specified in Sections 41.20 (f), 61.30 and Amendment 42-8.
To be accomplished not later than the dates specified in above amendments as revised by Special Civil Air Regulation No. 329 and any subsequent regulations affecting these compliance dates.
(This AD pertains only to combustion heater fire protection aspects of the above Regulation Amendments. Separate AD's will be issued covering fire protection for the powerplant installation and for the baggage and cargo compartments of the airplane).
(1) Each heater exhaust pipe shall be completely enclosed with well-ventilated, fireproof shrouds.
(2) Each heater combustion chamber shall be drained to the exterior of the airplane. All such drain lines shall be of fireproof construction and contain no traps in the normal flight or ground attitudes.(3) The heater fuel components presently mounted on top of each heater shall be located in fuel and fume proof enclosures, ventilated and drained to the exterior of the airplane.
(4) The thermal overheat switches for each heater shall be rigged to shut off the fuel supply and ignition circuits of the heaters when overheating occurs. These switches must also be arranged so as to prevent their automatically recycling to "ON" once overheating has occurred. The present overheat switches are not intended to be used as cycling switches. In cycling to produce the required heat is necessary, it must be accomplished at a lower temperature by an additional cycling switch controlling a cycling solenoid.
(5) A manual fuel shutoff valve shall be provided. (USAF Technical Order 01- 25LA-211 describes such an installation.)
(6) Adequate fire extinguisher and fire detector installations shall be provided for each heater. The fire detector installation shall contain at least one detector centrally located over the heaters in the heater area and one detector in the ventilating air duct of each heater just aft of the combustion chamber. The fire extinguisher system should provide at least 1 pound of carbon dioxide for each heater directed into the inlet side of the ventilating air stream. Instructions for operating this carbon dioxide system should also require that the ventilating air duct valve be closed when carbon dioxide is injected to the heater. With the arrangement as described, no flight tests of carbon dioxide contamination of the pilots compartment or cabin area need be conducted. As outlined in the Airworthiness Directive concerning fire protection for the baggage and cargo compartments, however, flight tests to establish smoke evacuation procedures for the cargo compartments when these compartments are carrying cargo, will need to be accomplished. The results of these tests will determine the procedure to be followed to rid the airplane of noxious gases.
(7) Revision pages for the Airplane Flight Manual must be prepared to cover emergency fire procedures as well as smoke and other noxious gas elimination procedures.