(5) The required crew emergency exits are accessible under any cargo loading condition.
b. Guidance.
(1) Paragraphs (b), (c), and (e). When the liner requirements were transferred to § 25.855, in addition to being fire resistant, the liner also had to meet the flammability requirements of § 25.853(b). (Amendment 25-32)
(2) Paragraphs (a), (b), (c), and (e). Guidance material was developed to assure that approvals of cargo compartments would meet the intent of the rule and DOT/FAA Order 8110.27A, CAR 4b.383 and CFR 25.855 and 25.857, “Cargo Compartment Classification Requirements,” was written for that purpose in 1978. The order is pertinent to all certificated airplanes engaged in cargo operations and previous approvals not commensurate with the order will not be accepted as precedent. The following is based on the procedures from that order:
(Amendment 25-32)
(i) Class A. A compartment in which the presence of a fire would be easily discovered by a crewmember while at his station, all parts of which are easily accessible in flight. This is typically a small compartment used for crew luggage and located in the cockpit where a fire would be readily detected and extinguished by a crewmember. Due to the small size and location of the compartment, and the relatively brief time required to extinguish a fire, a liner is not needed to protect adjacent structure. (Amendment 25-32)
(ii) Class B. A compartment with sufficient access in flight to enable a crewmember to effectively reach any part of the compartment with the contents of a hand held fire extinguisher and that incorporates a separate, approved smoke or fire detection system to give warning at the pilot or flight engineer station. A Class B compartment is typically much larger than a Class A compartment and can be located in an area remote from the cockpit.
Because of the larger size of the compartment and the greater time interval likely to occur before a fire would be controlled, a liner meeting the flame penetration standards of § 25.855 and Appendix F of part 25 must be provided to protect adjacent structure. (Amendment 25-32)
(iii) Class C. As defined at the time of initial classification, any compartment that did not fall into either Class A or B was a Class C compartment. Class C compartments differ from Class B compartments primarily in that built-in extinguishment systems are provided for control of fires in lieu of crewmember accessibility. (Amendment 25-32)
(iv) Later, an additional class was established and defined as follows: (Amendment 25-32) (A) Class E. The main cargo compartment of an airplane used only for the carriage of cargo. A fire in a Class E compartment is controlled through crew action to shut off the ventilating air flow. The capability of the liner to resist flame penetration is especially important. (Amendment 25-32)
(v) Liner materials must currently meet the same flame penetration standards regardless of the class of compartment in which they are used. (Amendment 25-32)
(vi) No specific volume limits were established for the various classes of compartments although, as noted above, Class A compartments were envisioned as small, open compartments located in the cockpit area. (Amendment 25-32)
(vii) A nonaccessible compartment located below the main cabin could be either a Class C compartment for passenger airplanes or Class C, or E for all cargo airplanes. Cabin flooring utilized to protect adjacent structure from fire originating in a cargo or baggage compartment located above the floor should not also serve as the lining for a compartment located below the floor. (Amendment 25-32)
(3) Paragraphs (b)(3), (c)(1) and (e)(2). An acceptable detection time for smoke detectors is 5 minutes. Use the smoke quantity and location criteria of AC 25-9A, “Smoke Detection, Penetration, and Evacuation Tests, and Related Flight Manual Emergency Procedures,” dated 1/6/94, for showing that the smoke detection system detects a fire in satisfactory time. The time for fire detection systems was changed to one minute by Amendment 25-54 in § 25.858. (Amendment 25-0)
(4) Paragraphs (b), (c), and (e). Refer to AC 25-9A, “Smoke Detection, Penetration, and Evacuation Test, and Related Flight Manual Emergency Procedures,” dated 1/6/94.
(Amendment 25-0)
(5) Paragraphs (b), (c), and (e). The lining discussed in the Class B, C, and E, compartments refers to the sidewalls, ceilings and forward and aft panels of the compartments.
(Amendment 25-0) 675 - 730. [RESERVED]
587 SECTION 25.869 FIRE PROTECTION: SYSTEMS
731. Section 25.869 Did Not Exist Prior to Amendment 25-72.
732. AMENDMENT 25-72, Effective July 20, 1990.
a. Regulation.
[Fire protection: systems.] [(a) Electrical system components:
(1) Components of the electrical system must meet the applicable fire and smoke protection requirements of §§ 25.831(c) and 25.863.
(2) Electrical cables, terminals, and equipment in designated fire zones, that are used during emergency procedures, must be at least fire resistant.
(3) Main power cables (including generator cables) in the fuselage must be designed to allow a reasonable degree of deformation and stretching without failure and must be-
(i) Isolated from flammable fluid lines; or
(ii) Shrouded by means of electrically insulated, flexible conduit, or equivalent, which is in addition to the normal cable insulation.
(4) Insulation on electrical wire and electrical cable installed in any area of the fuselage must be self-extinguishing when tested in accordance with the applicable portions of Part I, Appendix F of this part.
(b) Each vacuum air system line and fitting on the discharge side of the pump that might contain flammable vapors or fluids must meet the requirements of § 25.1183 if the line or fitting is in a designated fire zone. Other vacuum air system components in designated fire zones must be at least fire resistant.
(c) Oxygen equipment and lines must-
(1) Not be located in any designated fire zone,
(2) Be protected from heat that may be generated in, or escape from, any designated fire zone, and
(3) Be installed so that escaping oxygen cannot cause ignition of grease, fluid, or vapor accumulations that are present in normal operation or as a result of failure or malfunction of any system.]
b. Guidance.
(1) Paragraph (a)(4). Wiring qualified to military specifications, which require flammability testing equivalent to that specified by the certification basis, do not have to be retested with an FAA representative. Refer to AC 25-10, “Guidance for Installation of Miscellaneous, Nonrequired Electrical Equipment,” dated 3/6/87. (Amendment 25-32)
(2) Paragraph (c). Oxygen distribution systems are considered as part of the interior and should meet the applicable standards of § 25.853. (Amendment 25-0) 733-750. [RESERVED]
589 SECTION 25.1307 MISCELLANEOUS
751. REGULATION IN EFFECT AT ADOPTION OF PART 25.
a. Regulation.
The following is required miscellaneous equipment:
(a) An approved seat for each occupant.
(b) An approved safety belt for each occupant.
(c) An adequate source of electrical energy.
(d) Electrical protective devices.
(e) A two way radio communication system.
(f) A radio navigation system.
(g) A windshield wiper, or equivalent, for each pilot station.
(h) An ignition switch for each engine meeting the requirements of § 25.1145(b).
(i) An approved portable fire extinguisher.
b. Guidance. There is no guidance relating to crashworthiness for this regulation.
752. AMENDMENT 25-23, Effective May 8, 1970.
a. Regulation.
[The following is required miscellaneous equipment:
(a) A seat and safety belt, for each occupant.
(b) Two or more independent sources of electrical energy.
(c) Electrical protective devices, as prescribed in this part.
(d) Two systems for two-way radio communications, with controls for each accessible from each pilot station, designed and installed so that failure of one system will not preclude operation of the other system. The use of a common antenna system is acceptable if adequate reliability is shown.
(e) Two systems for radio navigation, with controls for each accessible from each pilot station, designed and installed so that failure of one system will not preclude operation of the other system. The use of a common antenna system is acceptable if adequate reliability is shown.
(f) A windshield wiper, or equivalent, for each pilot station.
(g) An ignition switch, for each engine.
(h) Portable fire extinguishers as prescribed in § 25.853(e) and (f).]
b. Guidance.
(l) While equipment listed in § 25.1307 may be referred to in other sections of part 25, the listing of such equipment in § 25.1307 is necessary since it is only there that the equipment is required. The other sections generally treat the equipment from the standpoint of performance, reliability and installation. (Amendment 25-23)
(2) Regarding duplication of communication and navigation radio equipment, although under parts 91 and 121, there are situations in which an airplane can be operated without two communication and navigation systems, there are always operations in which a transport category airplane would be involved which do require dual systems. Therefore, it is considered necessary to make this a design requirement for all future transport category airplanes.
(Amendment 25-23)
(3) In order to make it clear that some interconnection or component sharing is permissible if system reliability is not impaired, the regulation now requires that there be two systems for two way radio communication designed and installed so that failure of one system will not preclude operation of the other system. (Amendment 25-23)
753. AMENDMENT 25-46, Effective December 1, 1978.
a. Regulation.
The following is required miscellaneous equipment:
[(a) A seat for each occupant.]
(b) Two or more independent sources of electrical energy.
(c) Electrical protective devices, as prescribed in this part.
(d) Two systems for two-way radio communications, with controls for each accessible from each pilot station, designed and installed so that failure of one system
591 will not preclude operation of the other system. The use of a common antenna system is acceptable if adequate reliability is shown.
(e) Two systems for radio navigation, with controls for each accessible from each pilot station, designed and installed so that failure of one system will not preclude operation of the other system. The use of a common antenna system is acceptable if adequate reliability is shown.
(f) A windshield wiper, or equivalent, for each pilot station.
(g) An ignition switch, for each engine.
(h) Portable fire extinguishers as prescribed in § 25.853(e) and (f).
b. Guidance.
(l) While equipment listed in § 25.1307 may be referred to in other sections of part 25, the listing of such equipment in § 25.1307 is necessary since it is only there that the equipment is required. The other sections generally treat the equipment from the standpoint of performance, reliability and installation. (Amendment 25-23)
(2) Regarding duplication of communication and navigation radio equipment, although under parts 91 and 121, there are situations in which an airplane can be operated without two communication and navigation systems, there are always operations in which a transport category airplane would be involved which do require dual systems. Therefore, it is considered necessary to make this a design requirement for all future transport category airplanes.
(Amendment 25-23)
(3) In order to make it clear that some interconnection or component sharing is permissible if system reliability is not impaired, the regulation now requires that there be two systems for two way radio communication designed and installed so that failure of one system will not preclude operation of the other system. (Amendment 25-23)
754. AMENDMENT 25-54, Effective October 14, 1980.
a. Regulation.
The following is required miscellaneous equipment:
(a) A seat for each occupant.
(b) Two or more independent sources of electrical energy.
(c) Electrical protective devices, as prescribed in this Part.
(d) Two systems for two-way radio communications, with controls for each accessible from each pilot station, designed and installed so that failure of one system will not preclude operation of the other system. The use of a common antenna system is acceptable if adequate reliability is shown.
(e) Two systems for radio navigation, with controls for each accessible from each pilot station, designed and installed so that failure of one system will not preclude operation of the other system. The use of a common antenna system is acceptable if adequate reliability is shown.
(f) A windshield wiper, or equivalent, for each pilot station.
(g) An ignition switch, for each engine.
[(h) Portable fire extinguishers as prescribed in § 25.851(a)(5) and (a)( 6).]
b. Guidance.
(l) While equipment listed in § 25.1307 may be referred to in other sections of part 25, the listing of such equipment in § 25.1307 is necessary since it is only there that the equipment is required. The other sections generally treat the equipment from the standpoint of performance, reliability and installation. (Amendment 25-23)
(2) Regarding duplication of communication and navigation radio equipment, although under parts 91 and 121, there are situations in which an airplane can be operated without two communication and navigation systems, there are always operations in which a transport category airplane would be involved which do require dual systems. Therefore, it is considered necessary to make this a design requirement for all future transport category airplanes.
(Amendment 25-23)
(3) In order to make it clear that some interconnection or component sharing is permissible if system reliability is not impaired, the regulation now requires that there be two systems for two way radio communication designed and installed so that failure of one system will not preclude operation of the other system. (Amendment 25-23)
755. AMENDMENT 25-72, Effective August 20, 1990.
a. Regulation.
The following is required miscellaneous equipment:
[(a) [Reserved.]]
(b) Two or more independent sources of electrical energy.
(c) Electrical protective devices, as prescribed in this part.
(d) Two systems for two-way radio communications, with controls for each accessible from each pilot station, designed and installed so that failure of one system will not preclude operation of the other system. The use of a common antenna system is acceptable if adequate reliability is shown.
(e) Two systems for radio navigation, with controls for each accessible from each pilot station, designed and installed so that failure of one system will not preclude operation of the other system. The use of a common antenna system is acceptable if adequate reliability is shown.
b. Guidance.
(l) While equipment listed in § 25.1307 may be referred to in other sections of part 25, the listing of such equipment in § 25.1307 is necessary since it is only there that the equipment is required. The other sections generally treat the equipment from the standpoint of performance, reliability and installation. (Amendment 25-23)
(2) Regarding duplication of communication and navigation radio equipment, although under parts 91 and 121, there are situations in which an airplane can be operated without two communication and navigation systems, there are always operations in which a transport category airplane would be involved which do require dual systems. Therefore, it is considered necessary to make this a design requirement for all future transport category airplanes.
(Amendment 25-23)
(3) In order to make it clear that some interconnection or component sharing is permissible if system reliability is not impaired, the regulation now requires that there be two systems for two way radio communication designed and installed so that failure of one system will not preclude operation of the other system. (Amendment 25-23) 756-780. [RESERVED]
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595 SECTION 25.1359 ELECTRICAL SYSTEM FIRE AND SMOKE PROTECTION
781. Section 25.1359(d) Did Not Exist Prior to Amendment 25-32.
[NOTE: Sections 25.1359(a),(b), and (c) are not considered to be germane to this AC]
782. AMENDMENT 25-32, Effective May 1, 1972.
a. Regulation.
(d) Insulation on electrical wire and electrical cable installed in any area of the fuselage must be self-extinguishing when tested at an angle of 60 degrees, in accordance with the applicable portions of Appendix F of this part, or other approved equivalent methods. The average burn length may not exceed 3-inches and the average flame time after removal of the flame source may not exceed 30 seconds. Drippings from the test specimen may not continue to flame for more than an average of 3 seconds after falling.
b. Guidance. Paragraph (d). Wiring qualified to military specifications, which require flammability testing equivalent to that specified by the certification basis, do not have to be retested with an FAA representative. Refer to AC 25-10, “Guidance for Installation of Miscellaneous, Nonrequired Electrical Equipment,” dated 3/6/87. (Amendment 25-32)
783. AMENDMENT 25-72, Effective August 20, 1990.
Section 25.1359(d) was relocated to Section 25.869(a)(4) at Amendment 25-72.
784 - 800. [RESERVED]