49-25-01 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 and 61.30 and Amendment 42-8.
To be accomplished not later than the dates specified in the above amendments, as revised by Special Civil Air Regulation No. 329, and any subsequent regulations affecting these compliance dates.
When engaged in passenger-carrying operations, all applicable cargo-compartment fire- prevention measures including those concerning controls, wiring, lines, equipment, tie-down and lining materials, etc., must be complied with unless these cargo compartment(s) are not utilized and are placarded accordingly.
(Note: This Airworthiness Directive pertains only to the baggage and cargo-compartment fire-protection aspects of the above Regulation Amendments. Airworthiness Directives 49-19-1 and 49-18-1 have been issued covering fire protection for the powerplant installation and for the cabin-heater installation, respectively.)
(1) Lower Forward Cargo Compartment. When access provisions suitable for ready entrance by a crew member are available for use, the lower forward cargo compartment can be classified in the "B" category and as such must meet the requirements of CAR 4b. (It is recommended that a mask suitable for protecting a crew member from the effects of both smoke and fire-extinguishing agents be provided, since entry into the compartment will be a necessary part of any fire-fighting procedure.)
(Note: That portion of 4b requiring cargo-compartment fire-detection means need not presently be complied with.)
(2) Lower Rear Cargo Compartment. This compartment must be considered a "C" category compartment unless provisions suitable for ready entrance by a crew member are provided. As a "C" category compartment, compliance with CAR 4b must be shown. If the compartment is modified to provide suitable access, compliancewith the requirements of CAR 4b for a "B" category compartment must be demonstrated.
(Note: That portion of 4b requiring cargo-compartment fire-detection means need not presently be complied with.)
(3) It must be demonstrated that hazardous quantities of smoke or extinguishing agent cannot enter crew or passenger compartments as a result of a cargo-compartment fire. If the cargo compartment is determined to be in the "B" category, utilizing portable fire extinguishers, it is not necessary to test for excessive extinguishing agent concentrations. "C" category compartments protected by build-in, remotely operated fire extinguishing systems will necessitate tests to determine that hazardous quantities of the agent cannot enter crew or passenger-occupied areas. Crew and passenger compartment smoke evacuation procedures must be established.
Tests to determine smoke evacuation procedures, and, where necessary, to determine fire-extinguishing-agent concentrations in crew or passenger compartments, should simulate fire conditions as nearly as possible in flight. Where it can be established that the airplane is identical or sufficiently similar to others on which tests have been conducted, it will not be necessary to repeat these tests.
(Note: Carbon-dioxide concentrations in excess of 3 percent by volume in crew compartment are considered hazardous.)
(4) The provisions of Safety Regulation Release No. 259, "Compliance of Equipment and Materials Used in Air-Carrier Aircraft with Fire-Prevention Requirements," must be considered in demonstrating compliance with this directive.
(5) Airplane Flight Manual. Appropriate changes to the Airplane Flight Manual shall be prepared to cover the emergency procedures associated with cargo- and baggage-compartment fire control.