U.S. Department of Transportation

Federal Aviation

Administration 

# Advisory Circular

Subject: Class B and F Cargo Compartments Date: DRAFT Initiated By: ANM-100 AC No: 25.857-X

1 PURPOSE. This advisory circular (AC) provides guidance con cerning compliance with the airworthiness standards for transport categ ory airplanes pertaining to Class B and Class F cargo compartments, both of which must be accessible in flight to crewmembers (i.e., located on the main deck). This guidance is applicable to transport category airplanes for which a new, ame nded, or supplemental type certificate is requested.

2 APPLICABILITY.

2.1 The guidance provided in this document is directed to airplane manufacturers, modifiers, foreign regulatory authorities, and Federal Aviation Administration (FAA) transport airplane type certificat ion engineers and their designees.

2.2 This material is neither mandatory nor regul atory in nature and does not constitute a regulation. It describes acceptable means, but not the only means, for demonstrating compliance with the applicable regulations . The FAA will consider other means of demonstrating compliance that an applicant ma y elect to present. While these guidelines are not mandatory, they are derived from extensive FAA and industry experience in determining compliance with the relevant re gulations. If, however, we become aware of
circumstances that convince us that followi ng this AC would not result in compliance with the applicable regulations, we will not be bound by the terms of this AC, and we may require additional substantiation or design changes as a basis for finding compliance.

2.3 This material does not change or create any additional regulato ry requirements, nor does it authorize changes in, or permit deviations from, existing regulatory requirements.mm/dd/yy D R A F T AC 25.857-X

2 3 RELATED DOCUMENTS.

3.1 Sections of Title 14, Code of Fe deral Regulations (CFR) Part 25.

 Section 25.851, Fire extinguishers

.

 Section 25.855, Cargo or baggage compartments

.

 Section 25.857, Cargo compartment classification

.

 Section 25.858, Cargo or baggage compartment smoke or fire detection systems

.

3.2 Advisory Circulars (AC).

This list identifies the current version of each AC at the time of publication of this AC. If any AC is revised after publ ication of this AC, you should refer to the latest version for guidance. You can find the latest version of the following ACs at http://www.faa.gov/regulations_po licies/advisory_circulars/

.

 AC 20-42D, Hand Fire Extinguishers for use in Aircraft , issued January 14, 2011.

 AC 25-9A, Smoke Detection, Penetration, and Ev acuation Tests and Related Flight Manual Emergency Procedures , issued January 6, 1994.

 AC 25-17A, Transport Airplane Cabin Interiors Crashworthiness Handbook , issued May 18, 2009.

 AC 25-18, Transport Category Airplanes M odified for Cargo Service , issued January 6, 1994.

 AC 25-22, Certification of Transport Ai rplane Mechanical Systems , issued March 14, 2000.

 AC 25.851-X, Built-in Fire Extinguisher/Fire Suppression Systems in Class C and Class F cargo compartments , issued , 201X.

3.3 FAA Orders.
Order 8150.4, Certification of Cargo Containers with Self-Contained Temperature Control (Active ULDs) , dated August 28 2007.

4 BACKGROUND. Paragraphs (b) and (f) of § 25.857 provide sta ndards for certification of two classes of cargo compartments, Class B and Class F. A Class B cargo compartment is configured
in a manner that allows a crewmember to ex tinguish 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 compartment in that there are mean s to extinguish or cont rol the fire without requiring a person to enter the compartment. However, a Class F cargo compartment can also be similar to a Class B compartment in that a crewmember could rely on the ability to reach any cargo within the compar tment and to extinguish any fire likely tomm/dd/yy D R A F T AC 25.857-X

3 occur in the compartment using a hand fire extinguisher. Both Class B and Class F cargo compartments have smoke or fire dete ction systems to alert the crew to the presence of the fire.

5 COMPARTMENT CLASSIFICATION. All cargo compartments must be properly classified in accordance with § 25.857 and meet the requirements of §§ 25.851, 25.855, 25.857, and 25.858 pertaining to the particular class involved. In order to es tablish appropriate re quirements for fire protection, a system for classification of car go or baggage compartments was developed and adopted for transport category airplane s. Classes A, B, and C were initially established; Classes D, E, and F were added later. Class D has been eliminated from the regulations. The classification is based on the means by which a fire can be detected and
the means available to control the fire.

5.1 A Class A compartment (see § 25.857( a)) is one that is located so close to the station of
a crewmember that the crewmember would di scover the presence of a fire immediately. In addition, each part of the compartment is easily accessible so that the crewmember could quickly extinguish a fire with a portable fire extingu isher. A Class A compartment is not requ ired to have a liner.

5.2 A Class B compartment (see § 25.857(b)) is one that is accessible in flight but more remote than a Class A compartment and must, therefore, incorporate a smoke or fire detection system to give warning at the pilo t or flight engineer station. Because a fire would not be detected and extinguished as quickly as in a Class A compartment, a Class B compartment must have a liner in accordance with § 25.855(b). In flight, a
crewmember must have sufficient access to a Class B compartment to effectively fight a fire with a hand fire extinguish er in any part of the comp artment when standing at any one access point, without stepping into the compartment. There must be means to ensure that, while the access provisions ar e being used, no hazardous quantity of smoke, flames, or extinguishing agent will enter areas occupied by the crew or passengers.

5.3 A Class C compartment (see § 25.857(c)) differs from a Class B compartment in that it is not required to be accessible in flight and must, therefore, have a built-in fire extinguishing or suppression system. A Cla ss C compartment must have a liner and a smoke or fire detection system in accordance with §§ 25.855(b) and 25.857(c)(1). There
must also be means to exclude hazardous quantities of extinguis hant and products of combustion from occupied areas (see § 25.857(c)(3)).

5.4 A Class D compartment was one in which a fi re would be completely contained without endangering the safety of the airplane or the occupants. A Class D compartment was not accessible to a crewmember in flight, and inst ead of providing smoke or fire detection and extinguishment, Class D compartments we re designed to contro l a fire by severely restricting the supply of avai lable oxygen. Due to several un controllable fires in Class D compartments, they were eliminated by Amendment 25-93, effective March 19, 1998. As explained in Amendment 25-93, Class D cargo compartment standards pre-dating Amendment 25-93 are inadequate. Therefore, the FAA does not approve new Class Dmm/dd/yy D R A F T AC 25.857-X

4 cargo compartments even in airplanes w ith a certification basis pre-dating
Amendment 25-93.

5.5 A Class E compartment (see § 25.857(e)) is f ound on an all-cargo airplane. Typically, a Class E compartment is the entire cabin of an all-cargo airplane; however, other compartments (e.g., lower lobe inaccessible ca rgo compartments) of such airplanes may be classified as Class E compartments. Shutting off the ventilating airflow to or within the compartment controls a fire in a Class E compartment. A Class E compartment must
have a liner and a smoke or fire detecti on system installed in accordance with § 25.857(e)(2). It is not re quired to have a built-in fire suppression system.

5.6 A Class F compartment (see § 25.857(f)) is one that has means to control or extinguish a fire without requiring a cr ewmember to enter the compartment. However, a Class F cargo compartment must be readily accessible in flight and located on the main deck of the airplane. A Class F cargo compartment may rely on the use of a hand fire extinguisher to fight a fire within the compar tment. Class F compartments that include a built-in fire extinguisher/suppression syst em or require the use of acceptable fire containment covers (FCCs) or fire resi stant containers (FRCs) may meet these requirements if the FCCs or FRCs meet ce rtain requirements. Th e Class F compartment must have a smoke or fire detection syst em installed in accordance with § 25.857(f)(1). Unless there are other means of containing th e fire and protecting critical systems and structure, a Class F compartment must have a liner meeting the requi rements of part III of appendix F to part 25 or other approve d equivalent methods (see § 25.855(b)). For example, a Class F cargo compartment where FCCs or FRCs meet the liner requirements (i.e., part 25, appendix F, part III flame penetration resistant means) would be acceptable. The Class F cargo compartment was introduced as a practicable and safe alternative to the previous practice of pr oviding large Class B cargo compartments. The Class B compartments were limited to the main deck for accessibility reasons. Likewise, Class F cargo compartments should also be limited to the main deck for accessibility. All lower deck cargo compartments in airplanes carrying passengers need to comply with the Class C cargo co mpartment requirements of § 25.857(c).

6 FIRE PROTECTION FEATURES. Based on the class of the compartment, fire protection features must be provided. The fire protection features must be shown to m eet the standards estab lished by the original type certification basis for th e airplane or later part 25 st andards. These features may include liners, control of ventilation, fi re/smoke detection systems, hand fire extinguishers, and built-in fire suppression systems.

6.1 Liners.

6.1.1 The primary purpose of a liner is to prevent a fire originating in a cargo compartment from spreading to other parts of the airplane before it ca n be brought under control. For Class B compartments, it is assumed that th e fire will be quickly extinguished, so the liner must be qualified to part 25, appendix F, part I requirements. For Class F cargo compartments, the fire might have grown la rger prior to being suppressed so bettermm/dd/yy D R A F T AC 25.857-X

5 protection is needed to prevent damage to surrounding systems and structure. Therefore, a Class F liner must be qualified to part 25, appendix F, part III requirements. However, the liner does not need to serve as the comp artment seal, although it is frequently used to perform the secondary functions of cont aining discharged extinguishing agent and controlling the flow of oxygen into the co mpartment. If other means, such as compartment walls, are not capable of perf orming those functions, the liner must be sufficiently airtight to perform them.

6.1.2 The liner must have sufficient fire integrity to prevent flames from burning through the
liner before the fire can be brought under control and the heat from the fire is sufficiently dissipated. As stated in part III of appendix F to part 25, in addition to the basic liner material, the term "liner" include s any design feature, such as a joint or fastener that would affect the capability of the liner to safely contain a fire.

6.2 Access.

6.2.1 Class B. Class B compartments must provide sufficient accessibility to enab le 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. Additionally, the access provisions should be sufficiently large to enab le 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/ or volume. In determining access, it would not be acceptable for there to be a need to pull baggage or cargo onto the floor of the passenger compartment to gain access to the seat of the fire. Such action may introduce a safety hazard to the passengers.

6.2.1.1 “To reach any part of the compartment” means that the crewmember should be able to open the door or hatch and, standing in the opening, effectively fight a fire anywhere in the compartment where cargo or baggage can be located. The extension of the crewmember’s reach through the use of a fire extinguisher is limited such that the combination of reach and the extinguisher should not be more than 52 inches.

6.2.1.1.1 The FAA tasked an Aviation Rulemaking Advisory Committee, which established the Cargo Standa rds Harmonization Working Group (CSHWG), to develop new or revi sed requirements for Class B cargo compartments in transport category airplanes. The CSHWG recommendations included an estimate of a Class B cargo compartment that would meet the intent for a crewmember to reach any part of the compartment. Reportedly based on the es timated reach of a 95th percentile male, one recommendation was that the outline of any compartment, viewed from above, should fit with in a vertical cylinder of radius 52 inches (132 cm) measured from the centerline of the access door or hatch (see figure 1). This dimension assumes the above male can reach a one-foot square box located anywhere within the compartment. Access bymm/dd/yy D R A F T AC 25.857-X

6 a smaller crewmember to reach the same area within the compartment could require that the crewmember move laterally within the access door or hatch opening, while not physic ally entering the compartment. However, the FAA’s position is that th e use of a 95th percentile male is not realistic in that many flight atte ndants are female and have a smaller
reach 1 . For example, a 50th percentile female has a reach of 28.96 inches (~29 inches) and the FAA holds that this is a reasonable value to use. In addition, when determining a distance that a crewmember can effectively fight a fire within a Class B cargo co mpartment, consideration should be given to the distance that the fire extinguisher stream can be accurately directed. However, the published “rang e” of hand fire extinguishers can be many feet and will vary depending on bottle pressure and mass of the fire extinguishing agent. Using accepted va lues for extinguisher range from recognized authorities (e.g., the U.S. Underwriters Laboratories) would result in very large Class B cargo comp artments that are beyond the ability for crewmembers to effectively fight a fire. A reasonable value that a hand fire extinguisher can be accurately directed is no more than two feet. Therefore, in consideration of reason able effective reach to extinguish a fire, harmonization with the guida nce provided by other regulatory authorities, the recommendations of the CSHWG, and service history of airplanes with small Class B cargo co mpartments, a fire in a small cargo compartment may be effectively fought if the contents of cargo and baggage are within an arc not exceeding a 52-inch radius.

6.2.1.2 Should an applicant request FAA certif ication of an airplane with a Class B cargo compartment that exceed s the criteria included in this AC, the FAA will expect the applicant to perform full-scale fire extinguishing
tests. These tests will be used to de monstrate compliance to the regulations and to establish the quantity of fi re extinguishing agen t that must be provided to ensure an ac ceptable level of safety.

1 Harrison, Catherine R., Robinette, Kathleen M., “CAE SAR: Summary Statistics for the Adult Population (Ages 18-65) of the United States of America,” AFRL-HE-WP-TR-2002-0170, United States Air Force Research Laboratory, June 2002.mm/dd/yy D R A F T AC 25.857-X

7 Figure 1. Examples of Possible Cargo Compartment Shapes within 52” Reach
from Access Point Centerline.

C/L access point 52" radius

6.3 Means to suppress or extinguish a fire.

6.3.1 Class F. In the case of a Class F compartment, a means should be provided to suppress or extinguish a fire without a crewme mber entering the compartment.

6.3.1.1 One means is to design the compartment to Class C requirements but not include a built-in fire suppression system. One suppression method might be to use a plumbing and nozzle distribution system within the compartment that would provide acceptable suppr ession capability throughout the volume of the compartment. The source for such a system could be hand fire extinguishers, which interface with the distribution system through a suitable interface nozzle. This reduces the complexity
and costs associated with a built-i n suppression system and could be suitable for smaller compartments. For certification purposes, the extinguishing agent concentration shoul d be measured in flight, following airplane flight manual (AFM) proce dures, and the length of protection time afforded by the system recorded. This time of protection should be used to establish AFM limitations for cargo or baggage compartment fire protection times. The operator coul d then use these times for route planning. For Halon 1301 fire extingui shing agent, a minimum 5-percent concentration by volume at all points in the compartment is considered adequate for initial knockdown of a fi re, and a 3-percen t concentration by volume at all points in the compartment is considered the minimum for controlling a fire after it is knocked down 2 . The use of this option requires

2 Gassmann, J., Hill, R., “Fire Extinguishing Methods for New Passenger/Cargo Ai rcraft,” Federal Aviation Administration, Final Report FAA-RD-71-68, November 1971.mm/dd/yy D R A F T AC 25.857-X

8 the use of a liner, if needed, as noted in § 25.855(c). Full-scale or high-fidelity fire extinguishi ng testing may be necessary.

6.3.1.2 Another means of providing fire pr otection in a Class F compartment would be to provide a fire suppressi on system similar to a Class C cargo compartment. Further guidance on this type of design installation can be found in AC 25.851-X. However, in gene ral, a Class F cargo compartment that uses a built-in fire suppre ssion system should meet the same requirements as a Class C cargo compartment. For example, an applicant for a Class F cargo compartment with a built-in fire suppression system
must ensure that:

6.3.1.2.1 No extinguishing agent likely to en ter personnel compartments will be hazardous to the occupants;

6.3.1.2.2 No discharge of the extinguisher can cause structural damage;

6.3.1.2.3 The capacity of each required built-in extinguishing system must be adequate for any fire likely to occur in the compartment where used, considering the volume of the comp artment and the ventilation rate;

6.3.1.2.4 There are means to exclude hazardous quantities of smoke, flames, or extinguishing agent from any comp artment occupied by the crew or

passengers;

6.3.1.2.5 There are means to control ventilation and drafts within the compartment so that the extinguishing agent used can control any fire that may start within the compartment; and

6.3.1.2.6 Flight tests are conducted to ensure compliance with the provisions in § 25.857(f).

6.3.1.3 Another means of providing fire pr otection in a Class F compartment
involves the use of FRCs or FCCs s hown to be capable of containing a fire. Some FCCs have already b een developed and are typically constructed of woven fiberglass-based materials that will pass the oil burner test requirements in pa rt 25, appendix F, part III.

6.3.1.3.1 Using FRCs or FCCs shown to be capable of containing a fire in complying with Class F cargo compar tment fire protection requirements may meet expectations in th e § 25.857 at Amendment 25-XXX 3 . For a Class F cargo or baggage compartmen t not using FCCs or FRCs, § 25.857 requires a ceiling and sidewall liner cons tructed of materials that meet the requirements of part III of appendix F to part 25. The liner must also be

3 We are proposing new rulemaking. The Amendment level will be added when the rule is published.mm/dd/yy D R A F T AC 25.857-X

9 separated from the airplane structure (except for attachments), while the floor panels must comply w ith part I of appendix F.

6.3.1.3.2 If FCCs or FRCs are proposed as a means of compliance for the new Class F compartment, they must meet these standards (i.e., part III of appendix F to part 25 for the sides and top and part I of appendix F for the bottom).

6.3.1.3.3 It is recommended that the responsible aircraft certification office (ACO)
be contacted for concurrence when F CC or FRC qualification is envisaged
in order to address the relevant test method. Full-scale or high-fidelity fire testing may be necessary to ensure that the FCC or FRC can contain a fire for the longest flight time (diversion) required in service. The ACO should
coordinate with the Trans port Airplane Directorate.

6.3.1.3.4 If FCCs are used as the sole means of compliance, they should completely surround all cargo, including underneat h the cargo, except for obviously nonflammable items, such as metal stock, machinery, and nonflammable fluids without flammable packaging. These FCCs would need to meet part III of appendix F to part 25. Be cause the fire is controlled or extinguished within the isolated compartment, but is separated from the actual cargo compartment boundaries, the cargo compartment liner requirements of § 25.855(c) would not a pply. However, the effects of the heat generated by the contained/covered fire should be evaluated to ensure that adjacent systems and structur e are not adversely affected. For certification purposes, test data with the actual design configuration and possible fire sources would have to be provided. The temperature and heat load time history measurements at various locations above, around, and
below the FCC are needed to ensure the continued safe function of adjacent systems and structure. The time history data should be used to establish the length of protection time afforded by the system and subsequent AFM limitations for cargo or baggage compartment fire protection times. The operator woul d then use these times for route planning purposes.

6.3.1.3.5 The issue of compliance to the cargo compartment requirements for smoke or fire detection in § 25.858 may repr esent unique challenges if FCCs or
FRCs are used. Crew awareness is a cri tical factor to ensure adequate fire protection on airplanes. Applicants for FAA approval should consider the use of Infrared (IR) Camera 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.

6.3.1.4 Class F cargo compartment designs that rely on fire containment (e.g., fire hardened containers/pallets, FRCs and/or FCCs placed over palletizedmm/dd/yy D R A F T AC 25.857-X

10 loads or non-fire hardened containers) should be considered with regard to the possibility of incorrect usage or cargo loading errors.

6.3.1.5 All practicable means to prevent th e carriage of cargo in standard containers or pallets (if special pallets are required) and/or the omission of FCCs or FRCs should be incorporat ed. Means may include, but not be
limited to:

6.3.1.5.1 Physical features at the container/ pallet to cargo compartment floor interface;

6.3.1.5.2 Operational procedures, such as requ iring airplane crew verification of cargo loading before every flight;

6.3.1.5.3 A suitable detection system that wo uld warn the crew in the event a non-authorized cargo configur ation has been loaded.

6.4 Extinguishing Agent.

6.4.1 In order to effectively extingui sh or control a fire in a Class B or Class F cargo or baggage compartment, sufficient fire exti nguishing agent must be allocated. The FAA requirements for hand fire extinguishers and fi re extinguishing agents are included in § 25.851(a). General guidance on this topi c is included in AC 20-42D. The FAA requirements for built-in fire suppression systems and fire extinguishing agent are included in § 25.851(b). AC 25.851-X cont ains guidance for built-in fire extinguishing/suppression systems. Howeve r, the FAA has not issued substantive guidance addressing installati on issues associated with non-halon fire extinguishing agent applications. Instead of such guidan ce, the FAA will ensure that each non-halon agent has successfully passed the minimum performance standard 4 for that application (i.e., lavatory trash receptacle, hand fire ex tinguisher, engine/auxiliary power unit fire extinguishing system, or cargo compartment fi re suppression system). The purpose is to ensure the performance of the proposed non-ha lon agent provides protection equivalent to that provided by halon and that the a pplicant has addressed installation issues associated with the specific application. Depending on the properties of the agent, the means to deliver the agent, and the means to determine the concentration of the agent, full-scale or high-fidelity fire testing may be necessary to ensure that the non-halon fire extinguishing or fire suppression system provides adequate performance. AC 20-42D provides an acceptable means to implement the CSHWG provisions of § 25.851(a) that require at least one hand fire extinguisher be located in the pilot compartment, at least one readily accessible hand fire extinguisher be available for use in each Class A or Class B cargo/baggage compartment and in each accessible Class E or Class F cargo/baggage compartment, and one or more hand fire extinguishers be located in the passenger compartment for airplanes with a passenger seating capaci ty of 7 or more.

4 Reports available at the FAA William J. Hughes Technical Center Fire Safety Branch website: http://www.fire.tc.faa.gov

.mm/dd/yy D R A F T AC 25.857-X

11 6.5 Fire Control. “To control a fire” (§ 25.857(f)(2)) mean s that the fire does not grow to a state where damage to the airplane or harm to the passengers or crew occurs during the length of time of protection th at the fire protection system is demonstrated to afford. This in turn means that critical airplane systems and structure lo cated adjacent to the compartment are not adversely affected, and the temperature and air contaminants in areas occupied by passengers and crew do not reach hazardous levels.

6.5.1 Adequate protection should be provided for cockpit voice and flight data recorder and wiring, windows, primary flight controls (unle ss it can be shown that a fire cannot cause jamming or loss of control), and other syst ems, structure, and equipment within or adjacent to the compartment that are required for safe flight and landing.

6.5.2 Regardless of a compartment’s classificat ion, Class B or Class F, it must be demonstrated that hazardous quantities of smoke, flames, extinguishing agent, or noxious gasses do not enter any compartment occupied by passengers or crewmembers. AC 25-9A, Smoke Detection, Penetration, and Ev acuation Tests and Related Flight Manual Emergency Procedures , provides guidance concerning smoke penetration testing.

6.5.3 If an airplane has a Class B or Class F cargo compartment, portable protective breathing equipment must be provided for the appr opriate crewmembers in accordance with § 25.1439. If the airplane is operated under part 121, the protective breathing equipment must meet the more stringent standards of § 121.337.

6.5.4 Additional protective breathing equipment or breathing gas supply, and additional fire extinguishers, may be required to ensure that the fire can be controlled for the time the airplane is expected to be in the air after onset of a fire . As required in § 25.851(a) the quantity of extinguishing agent used in each ex tinguisher required by this section must be appropriate for the kinds of fires li kely to occur where used. Depending upon the proposed fire extinguishing agent and quant ity of the agent provided, full-scale or high-fidelity fire extinguishing testing may be necessary to en sure an adequate level of protection.

6.6 Reclassification. As explained in paragraph 5.4, the Class D cargo compartment has been eliminated from the regulations due to limited effec tiveness in providing fire protection. The Class F compartment is not intended to be a Class D compartment with smoke or fire detection. It is not acceptable to simply recl assify a compartment as Class F and use the same fire protection methodology as was us ed for Class D compartments. Means for controlling ventilation in Cla ss D cargo compartments were shown to be ineffective in controlling a fire in many cases. This was evidenced by a number of accidents and incidents involving fires in Class D cargo compartments as discussed in Docket No. 28937, Notice 97-10, and Amendment 25-93.mm/dd/yy D R A F T AC 25.857-X

12 7 PROCEDURES AND LIMITATIONS.

7.1 To ensure that the contents of Class B a nd F compartments are accessible to combat a fire, the cargo or baggage loading lim itations and any operational limitations or procedures provided are expected to be identified with placards in the compartment. The loading and operational limitations must also be addressed in the appropriate weight and balance or loading document.

7.2 Any operational limitations or procedures nece ssary to ensure the effectiveness of the fire protection system for Class B and Cla ss F cargo and baggage compartments should be clearly defined in the AFM. This should include such items as any changes to the ventilation system to prevent the entrance of smoke or gasses into occupied areas, use of hand fire extinguishers, use of protect ive breathing equipment, use of protective clothing, and use of the FCCs. The applicant and the ACO should work closely with the FAA Flight Standards organization (Aircr aft Evaluation Group) to ensure that additional training necessary for crewmembers assigned to combat fi res is adequately
addressed.

7.3 Any time limit for a cargo or baggage compartment fire protection system, or other conditions or procedures relate d to combating a fire in a co mpartment, should be clearly
defined in the AFM.

8 AFM CONSIDERATIONS.

8.1 Any crewmember designated to combat a fire in a Class B compartment will need special training. Fires occurri ng in luggage are difficult to extinguish completely and rekindling may occur. Crewmembers desi gnated to combat fires in Class B compartments should be trained to check periodically to ensure that a fire has not grown back to hazardous proportions. The appli cant and the ACO should work with the appropriate organizations, includ ing the operators, to ensure that training in the use of protective breathing equipment, fire extingui shers, protective gl oves and clothing is provided.

8.2 AFMs should contain instructions to land at the nearest suit able airport following smoke or fire detection, unless it can be positively determined that the fire is extinguished.

8.3 Any limitations regarding occupancy of Class B or Class F compartments during flight, or during takeoff and landing, s hould be defined in the AFM.

8.4 Any loading restrictions associated with access to cargo or baggage or special containers should be clearly identified in the AFM. This would include, but not be limited to, placement of luggage in a Class B compartment or identification of special
containers or covers associated with fire protection in a Class F compartment. If FCCs or FRCs are used in conjunction with a Cla ss F cargo compartment, they should be easy to install and sufficiently durable to withstand in-service conditions.mm/dd/yy D R A F T AC 25.857-X

13 END