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Transport Airplanes

Transport Airplanes. Part 25 Amdt 25-142 Revised Class B and New Class F Cargo Compartments. Stephen Happenny ANM-112 Mechanical Systems. Revised Class B and New Class F Cargo Compartments. South African Airways Flight 295, Boeing 747-244B Combi, Serial Number 22171

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Transport Airplanes

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  1. Transport Airplanes Part 25 Amdt 25-142 Revised Class B and New Class F Cargo Compartments Stephen Happenny ANM-112 Mechanical Systems

  2. Revised Class B and New Class F Cargo Compartments • South African Airways Flight 295, Boeing 747-244B Combi, Serial Number 22171 • Location: Mauritius, Indian Ocean • Date: November 28, 1987 South African Airways Flight 295 crashed into the Indian Ocean en route from Taipai's Chiang Kai Shek Airport to Mauritius's Plaisance Airport as the result of an uncontrolled fire in the airplane's main deck cargo compartment. The airplane, a 747-200, was configured as a "combi," on which the main deck of the airplane is divided into two large sections, a passenger compartment and a cargo compartment.

  3. Revised Class B and New Class F Cargo Compartments …. the Class B cargo compartment was too large and the emergency diversion distances were too large for manual firefighting to be effective as the primary means to control a cargo fire.

  4. Revised Class B and New Class F Cargo Compartments 2. Amend § 25.851 by revising paragraphs (a)(3) and (b)(2) to read as follows: § 25.851 Fire extinguishers. (a) * * * (3) At least one readily accessible hand fire extinguisher must be available for use in each Class A or Class B cargo or baggage compartment and in each Class E or Class F cargo or baggage compartment that is accessible to crewmembers in flight. (b) * * * (2) The capacity of each required built-in fire extinguishing system must be adequate for any fire likely to occur in the compartment where used, considering the volume of the compartment and the ventilation rate. The capacity of each system is adequate if there is sufficient quantity of agent to extinguish the fire or suppress the fire anywhere baggage or cargo is placed within the cargo compartment for the duration required to land and evacuate the airplane.

  5. Revised Class B and New Class F Cargo Compartments 3. Amend § 25.855 by revising paragraphs (b), (c), and (h)(3) to read as follows: § 25.855 Cargo or baggage compartments. (b) Each of the following cargo or baggage compartments, as defined in § 25.857, must have a liner that is separate from, but may be attached to, the airplane structure: (1) Any Class B through Class E cargo or baggage compartment, and (2) Any Class F cargo or baggage compartment, unless other means of containing a fire and protecting critical systems and structure are provided. (c) Ceiling and sidewall liner panels of Class C cargo or baggage compartments, and ceiling and sidewall liner panels in Class F cargo or baggage compartments, if installed to meet the requirements of paragraph (b)(2) of this section, must meet the test requirements of part III of appendix F of this part or other approved equivalent methods. (h) * * * (3) The dissipation of the extinguishing agent in all Class C compartments and, if applicable, in any Class F compartments.

  6. Revised Class B and New Class F Cargo Compartments 4. Amend § 25.857 by revising paragraph (b)(1) and adding a new paragraph (f) to read as follows: § 25.857 Cargo compartment classification. (b) * * * • There is sufficient access in flight to enable a crewmember, standing at any one access point and without stepping into the compartment, to extinguish a fire occurring in any part of the compartment using a hand fire extinguisher; * * * (f) Class F. A Class F cargo or baggage compartment must be located on the main deck and is one in which— (1) There is a separate approved smoke detector or fire detector system to give warning at the pilot or flight engineer station; (2) There are means to extinguish or control a fire without requiring a crewmember to enter the compartment; and (3) There are means to exclude hazardous quantities of smoke, flames, or extinguishing agent from any compartment occupied by the crew or passengers.

  7. Revised Class B Cargo Compartment Compliance of Class B Cargo Compartments requires: (1) There is sufficient access in flight to enable a crewmember, standing at any one access point and without stepping into the compartment, to extinguish a fire occurring in any part of the compartment using a hand fire extinguisher;

  8. New Class F Cargo Compartment Class F Cargo Compartments require: (1) A means to detect smoke or fire to give warning at the pilot or flight engineer station; (2) A means to extinguish or control a fire without requiring a crewmember to enter the compartment; (3) A means to exclude hazardous quantities of smoke, flames, or extinguishing agent from any compartment occupied by the crew or passengers. However, how these requirements are met are up to the airplane manufacturer. The next slide has some examples but is not all inclusive.

  9. New Class F Cargo Compartments

  10. AC 25.851-1 and AC 25.857-1 Advisory Circular (AC) 25.851 Built-in Fire Extinguishing/Suppression Systems in Class C and Class F Cargo Compartments • Provides guidance concerning compliance with the airworthiness standards for transport category airplanes pertaining to Class C and Class F cargo compartments that incorporate built-in fire extinguishing/suppression systems. Advisory Circular (AC) 25.857 Class B and F Cargo Compartments • Provides guidance concerning compliance with the airworthiness standards for transport category airplanes pertaining to Class B and Class F cargo compartments.

  11. AC 25.851-1 Advisory Circular (AC) 25.851 provides guidance concerning compliance pertaining to Class C and Class F cargo compartments that incorporate built-in fire extinguishing/suppression systems. • The applicant must demonstrate that the cargo fire extinguishing system provides adequate concentration levels of extinguishing agent to combat a fire anywhere baggage and cargo is placed within the cargo compartment for the time duration required to land and evacuate the airplane. Flight testing and analysis are used for compliance. • Compliance with § 25.851(b) requires the use of point-concentration data from each sensor and that the sensors closest to the cargo compartment ceiling be at least at the highest level that cargo and baggage can be loaded as specified by the manufacturer and certified by the FAA.

  12. AC 25.851-1 • Certification flight tests are required for demonstrating compliance for built-in systems for the duration of the intended diversion profile. If the built-in fire suppression system includes a metering system, then the metering system’s acceptability may be demonstrated through a limited flight test, in which a portion of the system is actually tested, and the full capability of the system is demonstrated via analysis. • The cargo compartment should be empty for the above tests. Analysis should be used to ensure compliance with different cargo load factors.

  13. AC 25.851-1 Evaluation of Alternative Gaseous Extinguishing/Suppression Systems and Alternate Agents • If the proposed design will use a halon replacement agent in the fire extinguishing / suppression system, then compliance would include: • Successfully demonstrates that the agent meets the minimum performance standards (MPS) for cargo compartments. • Successfully addresses installation issues (effects of altitude, temperature, humidity, vibration, material compatibility, etc.) which are dependent upon the properties of the halon replacement agent. • Completion of the testing according to the MPS does not mean that an agent is approved for use on an airplane. Additional testing, including full scale fire extinguishing testing within an actual cargo compartment or high-fidelity model simulator, may be necessary. • An applicant proposing to use a halon replacement fire extinguishing agent should contact the FAA as soon as possible to enable the FAA to consider their design, determine what testing is required, and to propose any additional testing and analysis to ensure the applicant’s design is acceptable.

  14. AC 25.851-1 AIRPLANE MANUAL CONSIDERATIONS. • To ensure fire extinguishing/suppression system effectiveness and continued safe flight and landing, the applicable airplane manuals should contain appropriate directives, • Any procedures related to fighting a cargo compartment fire should be clearly defined in the AFM. • AFMs should contain instructions on maximum diversion times and to land at the nearest suitable airport following detection of a cargo fire. • Cargo loading restrictions (certified type of loading according to compartment, limits for loading heights and width, etc.) should be clearly described in the weight and balance manual or any other appropriate airplane manual. • Placards and markings indicating the maximum loading height for the approved configuration should be installed in the cargo compartments and described in the airplane’s weight and balance manual. • All necessary information may be introduced in crew operating manuals or part of dedicated instructions for cargo loading personnel.

  15. AC 25.857-1 Advisory Circular (AC) 25.857-1 provides guidance concerning compliance with the airworthiness standards for transport category airplanes pertaining to Class B and Class F cargo compartments. • A Class B cargo compartment is configured in a manner that allows a crewmember to extinguish any fire likely to occur in the compartment using a hand fire extinguisher. While the person combating the fire must have access to the compartment, it must not be necessary for that person to physically enter the compartment to extinguish the fire. • A Class F cargo compartment is similar to a Class C (as defined in § 25.857(c)) compartment in that there are means to extinguish or suppress the fire without requiring a person to enter the compartment. However, compliance for Class F provides greater flexibility to the airplane manufacturer on the method of compliance.

  16. AC 25.857-1 • Class B compartments must provide sufficient accessibility to enable a crewmember to reach any part of the compartment by hand or with the contents of a hand fire extinguisher without physically entering the compartment. This requirement, by its nature, tends to limit the size and shape of the compartment. • Access provisions should be sufficiently large to enable the crewmember to determine visually that a fire has been extinguished. • Access is also a function of how the compartment is configured rather than just dimension and volume. In determining access, the FAA would not accept a design that requires a crewmember to pull baggage or cargo onto the floor of the passenger compartment to gain access to the source of the fire, because that action may introduce a safety hazard. • 52 inches is based upon an effective reach of a 50% female of ~ 28 inches and the average range of a typical small hand fire extinguisher of ~ 24 inches.

  17. AC 25.857-1 • The means of providing fire protection in a Class F compartment will have a significant impact on its design. For example, • If a design uses FCCs or FRCs for fire protection, compliance with the smoke or fire detection requirements in § 25.858 may present unique challenges. Crew awareness is a critical factor to ensure adequate fire protection on airplanes. Applicants for FAA approval should consider the use of infrared (IR) cameras or other means to ensure adequate detection of a fire within the cargo compartment where FCCs and FRCs are used. Full-scale or high-fidelity fire testing may be necessary to ensure that the smoke or fire detection system can provide adequate detection. • The means of providing fire protection in a Class F compartment may also have a significant impact on the operation. Traditional Class C cargo compartments offer great flexibility in accepting last minute cargo via the use of a bulk cargo zone where cargo nets provide the retention of mass. Fire detection and fire suppression systems installed in the airplane provide adequate safety. However, the use of FCCs may require additional time to arrange cargo and ensure that the containment cover and the cargo net and pallet are properly secured.

  18. Thank You Questions?

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