[Federal Register Volume 60, Number 22 (Thursday, February 2, 1995)]
[Rules and Regulations]
[Pages 6616-6629]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-2114]




[[Page 6615]]

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Part V





Department of Transportation





_______________________________________________________________________



Federal Aviation Administration



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14 CFR Part 25 et al.



Improved Flammability Standards for Materials Used in the Interiors of 
Transport Category Airplane Cabins; Final Rule

  Federal Register / Vol. 60, No. 22 / Thursday, February 2, 1995 / 
Rules and Regulations  

[[Page 6616]]


DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 25, 121, and 135

[Docket No. 26192, Amendments Nos. 25-83, 121-247 and 135-55]
RIN 2120-AD28


Improved Flammability Standards for Materials Used in the 
Interiors of Transport Category Airplane Cabins

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: These amendments clarify standards adopted in 1986 concerning 
the flammability of components used in the cabins of certain transport 
category airplanes. This action is being taken to preclude costly, 
unintended changes to airplane interiors. The clarifications, which are 
applicable to air carriers, air taxi operators and commercial 
operators, as well as manufacturers of such airplanes, will result in 
more appropriate, consistent application of those standards.

EFFECTIVE DATE: March 6, 1995.

FOR FURTHER INFORMATION CONTACT: Gary L. Killion, Manager, Regulations 
Branch, ANM-114, Transport Airplane Directorate, Aircraft Certification 
Service, FAA, 1601 Lind Avenue Southwest, Renton, Washington 98055-
4056; telephone (206) 227-2114.

SUPPLEMENTARY INFORMATION: 

Background

    These amendments are based on Notice of Proposed Rulemaking (NPRM) 
90-12, that was published in the Federal Register on April 12, 1990 (55 
FR 13886).
    As discussed in the notice, Amendments 25-61 and 121-189 (51 FR 
26206, July 26, 1986) were adopted to upgrade the flammability 
standards for materials used in the interiors of transport category 
airplanes. The improved flammability standards were developed following 
a research and development program managed and conducted primarily at 
the FAA Technical Center in Atlantic City, New Jersey, to study 
aircraft fire characteristics and develop practical test methods. Among 
the tests conducted at the Technical Center were full-scale fire tests 
using the fuselage of a military C-133 configured to represent a wide-
body jet transport airplane. The test conditions simulated 
representative post-crash external fuel-fed fires. Numerous laboratory 
tests were also conducted to correlate possible material qualification 
test methods with the full-scale tests. As a result of those tests, the 
Ohio State University (OSU) radiant rate-of-heat-release apparatus was 
determined to be the most suitable for material qualification. These 
tests led to the adoption of Amendment 25-61.
    Amendment 25-61 established flammability standards for transport 
category airplanes with passenger seating capacities of 20 or more and 
specified the test method and apparatus to be used in showing 
compliance with those standards. It specified that interior ceiling and 
wall panels (other than lighting lenses), partitions, and the outer 
surfaces of galleys, large cabinets and stowage compartments (other 
than underseat stowage compartments and compartments for stowing small 
items such as magazines and maps) must meet the new standards. As 
outlined in the amendment, an average of three or more test specimens 
must not exceed 65 kilowatts per square meter peak heat release nor 65 
kilowatt minutes per square meter total heat release during the first 
two minutes of sample exposure time (65/65) when tested using the OSU 
test apparatus. These acceptance criteria were chosen in order to 
produce a significant retardation of the flashover event which controls 
occupant survivability, as experienced in the full-scale testing. 
(Burning cabin materials give off unburned gases that collect in the 
upper portions of the cabin. After a very short time, these unburned 
gases are heated to the point where they ignite and burn 
instantaneously. When this occurs, the temperature in the whole cabin 
becomes so hot that survival is impossible for anyone remaining in the 
cabin. This phenomenon, known as flashover, also makes further survival 
impossible by consuming the oxygen in the cabin.)
    Because Amendment 25-61 applies explicitly only to airplanes for 
which an application for type certificate is made after August 20, 
1986, Amendment 121-189 to Part 121 of the FAR was also adopted to 
require operators of certain other airplanes used in air carrier or 
commercial service to meet the new 65/65 standards. Those airplanes 
must meet the new standards if they were newly manufactured after 
August 19, 1990. Airplanes type certificated on or after January 1, 
1958, and manufactured prior to August 20, 1990, must also comply with 
the new standards upon the first substantially complete replacement of 
the specified cabin interior components on or after the latter date.
    Although Part 135 was not amended at that time, air taxi and 
commercial operators of large airplanes are required to comply as well 
because Sec. 135.169 incorporated the newly adopted provisions of Part 
121 by reference.
    At the time the amendments were adopted, the FAA understood that 
some persons were planning to install components which, even though 
they would meet the previously existing requirements of Part 25 for 
flammability, were more flammable than the components that were in 
general use at that time. In order to preclude a possible degradation 
in the flammability characteristics of the cabin interiors, Amendment 
121-189 also established interim standards of 100 kilowatts per square 
meter peak heat release and 100 kilowatt minutes per square meter total 
heat release (100/100). The interim standards are applicable to 
airplanes manufactured during the two-year period prior to August 20, 
1990; and, unless there is a substantially complete replacement of the 
specified cabin interior components after August 19, 1990, they will 
remain applicable to those airplanes as long as they are operated under 
the provisions of Part 121 or Part 135. (If there is a substantially 
complete replacement on or after August 19, 1990, the definitive 65/65 
standards would be applicable.) In addition, the interim standards are 
also applicable to airplanes in which there is a substantially complete 
replacement of the specified interior components during that two-year 
period.
    Prior to the adoption of Amendment 121-189, Sec. 121.312 required 
certain airplanes to meet earlier flammability standards upon the first 
substantially complete replacement of the cabin interior. (Note that 
this earlier rulemaking refers to a substantially complete replacement 
of all cabin interior components, while the later rulemaking refers to 
a substantially complete replacement of the specified interior 
components. Whether certain other interior components, e.g., seat 
cushions and flooring, are replaced is not relevant to whether there is 
a substantially complete replacement in the latter case. Also, the 
earlier rulemaking applies to all airplanes while the later rulemaking 
applies only to airplanes with 20 or more passengers.) This earlier 
requirement is partially superseded if there is a substantially 
complete replacement of the interior components specified in 
Sec. 25.853 (a-l) after August 19, 1988. It does, however, remain 
applicable insofar as interior components not specified in 
Sec. 25.853(a-l) are concerned. The earlier requirement also remains 
applicable to airplanes in which there has not been a substantially 
complete 

[[Page 6617]]
replacement of the cabin interior since August 19, 1988, and to 
airplanes with 19 or fewer passengers.
    The date of manufacture, as used in Sec. 121.312, is the date on 
which inspection records show that an airplane is in a condition for 
safe flight. This is not necessarily the date on which the airplane is 
in conformity to the approved type design, or the date on which a 
certificate of airworthiness is issued, since some items not relevant 
to safe flight, such as passenger seats, may not be installed at that 
time. It could be earlier, but would be no later than the date on which 
the first flight of the airplane occurs.
    For reasons discussed in the preamble to that amendment, Amendment 
25-66 was adopted (53 FR 37542, September 27, 1988) to make minor 
refinements in the test procedures and apparatus required to show 
compliance with the standards adopted by Amendment 25-61 and to add a 
requirement for smoke testing. Amendment 121-198, which was adopted at 
the same time, added a provision allowing deviations to be granted for 
certain components.
    In the preamble to Amendment 25-61, the FAA noted that the new heat 
release standards apply to all large-surface cabin interior components, 
such as sidewalls, ceilings, bins and partitions, and galley 
structures. It was also noted that the new standards do not apply to 
smaller items because their small masses would preclude significant 
contributions to the total heat release in the cabin area. The FAA has 
received a number of requests for clarification as to the maximum size 
a component may be without having to comply with the new heat release 
standards.
    The distinction between parts with large surface areas, which must 
meet the new standards, and those with smaller surface areas is very 
difficult because of the size of the cabin and other factors that may 
vary from one airplane to another. For example, a specific component 
might be insignificant when installed in a large wide-body airplane 
because it would make a minor contribution to the overall flammability 
of the area of the cabin in which it is installed. On the other hand, 
it might represent a major contribution when installed in a smaller 
transport category airplane. The proximity of the component to a 
potential source of fire, such as an exit or galley, is also a 
consideration. It is not possible to cite a specific size that will 
apply in all installations; however, as a general rule, components with 
exposed-surface areas of one square foot or less may be considered 
small enough that they do not have to meet the new standards. 
Components with exposed-surface areas greater than two square feet may 
be considered large enough that they do have to meet the new standards. 
Those with exposed-surface areas greater than one square foot, but less 
than two square feet, must be considered in conjunction with the areas 
of the cabin in which they are installed before a determination could 
be made.

Discussion

    Since the time Amendments 25-61 and 121-189 were adopted, the FAA 
became aware of four areas in which the wording of the new rules does 
not clearly reflect the intent of the agency as discussed in the 
preamble to those amendments. Because the new rules do not clearly 
reflect the intent in those areas and because the comments that were 
received may have been based on the intent, as expressed in the 
preambles, rather than the literal wording of the rules, the following 
clarifications were proposed in Notice 90-12.
    Cabin windows and clear vision panels in cabin partitions: The 
preamble to Amendments 25-61 and 121-189 states, ``The new flammability 
standards do not apply to transparent or translucent components such as 
lenses used in interior lights and illuminated signs, and window anti-
scratch panels, because of the lack of materials which will meet the 
flammability standards and still have the light transmissibility 
characteristics which are vital in emergency situations.'' Although not 
specifically mentioned in the earlier rulemaking, transparent panels 
are sometimes inserted in cabin partitions to enhance cabin safety. For 
example, they are sometimes used to provide seated flight attendants a 
clear, unobstructed view of the cabin or to provide passengers a view 
of an exit as an aid to an emergency evacuation. As in the case of 
lighting lenses and windows, the need for transparent partition panels 
that enhance cabin safety outweighs the increased safety provided by 
components that meet the new flammability standards considering the 
small area such transparencies would involve. In order to preclude 
confusion concerning the applicability of the standards to such 
transparent or translucent panels, Sec. 25.853(a-l) (1) and (2) were 
proposed to read, ``Interior ceiling and wall panels, other than 
lighting lenses and windows,'' and, ``Partitions, other than 
transparent panels needed to enhance cabin safety,'' respectively. The 
maximum size of a transparent panel would, of course, be limited to 
that which is actually needed to enhance cabin safety.
    It was noted that the FAA would consider further rulemaking to 
require those components to meet the new flammability standards should 
materials capable of meeting the new flammability standards and having 
the necessary light transmissibility characteristics for use as 
windows, etc., be developed later.
    Galleys: As currently worded, Sec. 25.853(a-1) states that the new 
flammability standards apply to the ``outer surfaces of galleys.'' This 
phrase was intended to make an exception for the interior surfaces of 
galley cabinets, etc., that would not be exposed to a cabin fire. It is 
ambiguous, however, because most galleys are not isolated from the main 
cabin by a door. While one might consider the surfaces of a galley 
working are to be ``inner surfaces,'' they are actually outer surfaces 
in most installations in the sense that they could be exposed to a 
cabin fire. In addition, the inner walls of the galley cart cavity or 
standard container cavity may also be exposed on some lightly loaded 
flights when there is not a full complement of carts or containers on 
board. In order to preclude any confusion in this regard, it was 
proposed that Sec. 25.853(a-1) would be amended to clarify that any 
galley surface exposed to the passenger cabin must meet the new 
standards.
    Isolated compartments: Unlike previously existing paragraphs (a) 
and (b) of Sec. 25.853, the new flammability standards of paragraph (a-
1) were intended to apply only to the passenger cabin and not to 
compartments that are isolated from the passenger cabin. Due, however, 
to the organization of Sec. 25.853(a-1), if taken literally, the new 
standards also pertain to each compartment occupied by crew (including 
one occupied only on a temporary basis) or passengers regardless of 
whether the particular compartment is isolated from the passenger 
cabin.
    Neither the research and development program nor the regulatory 
evaluations on which the new flammability standards were based 
considered that compartments isolated from the passenger cabin (or 
cabins in the case of airplanes with passenger cabins located on two 
different decks) would have to comply with the new standards. Unlike 
most galleys located in the main cabin, remote galleys and other 
compartments, such as lavatories, pilot compartments and crew rest or 
sleeping areas, are generally isolated from the passenger cabin by at 
least a door. In some instances, they are located on separate decks. 
They would, therefore, not be exposed to a cabin fire until well after 

[[Page 6618]]
flashover had occurred in the cabin and egress was no longer possible. 
Should an external fire enter the airplane at one of those 
compartments, the flammability of the materials used in them would not 
directly affect the cabin due to their isolation. As stated in the 
earlier rulemaking, the new standards address a post-crash, external 
fuel-fed fire situation. With the exception of the pilot compartment, 
it can be assumed that such compartments would not be occupied by 
passengers or crewmembers during a post-crash situation.
    Although the rulemaking was undertaken to address a post-crash 
scenario, there is also the question of whether or not requiring the 
lavatories to meet the new flammability standards would enhance safety 
significantly in the event a fire originated in a lavatory during 
flight. This question is particularly pertinent in light of the 
recently adopted ban on smoking on domestic airline flights. Although 
some persons might be more tempted to smoke illicitly in a lavatory 
during such flights, the lavatory smoke detector required by recently 
adopted Amendment 121-185 (50 FR 12726, March 29, 1985) serves as a 
deterrent and provides warning of illicit smoking to the crew. In 
addition, the new standards would not apply to many of the components 
in a lavatory due to their small size. The doors and most sidewalls 
have to meet the new standards regardless of whether the new standards 
are applicable to lavatories because their outer sides also form 
surfaces of the passenger cabin. Some portions of the lavatory are 
generally constructed of fireproof stainless steel due to functional 
considerations. Requiring the few remaining large components to meet 
the new standards would have very little impact on the overall 
flammability of the lavatory and would not significantly enhance safety 
in the event of an inflight fire.
    Pilot compartments are generally isolated from the passenger cabin 
by a bulkhead and door. Although they are obviously occupied full-time, 
requiring them to meet the new standards would not significantly 
enhance safety in the event of an inflight fire for essentially the 
same reasons. Pilot compartments are generally constructed of many 
small components which would not have to meet the new standards due to 
their small size. The bulkhead and entry door have to meet the new 
standards regardless of whether they are applicable to the pilot 
compartment because the aft sides of those components also form 
surfaces of the passenger cabin. As in the case of the lavatories, 
requiring the few remaining large components to meet the new standards 
would have very little impact on the overall flammability of the pilot 
compartment. Although there is no smoke detector required, a fire would 
be detected immediately by the flight crewmembers. In addition, at 
least one hand fire extinguisher must be conveniently located in the 
pilot compartment in accordance with Sec. 25.851.(a)(6).
    In view of these considerations, it was proposed that Sec. 25.853 
would be amended to clarify that compartments that are isolated from 
the cabin need not meet the standards. Sidewalls, doors etc., that 
separate such compartments from the passenger cabin would, of course, 
have to meet the new standards because their outer sides also form 
surfaces of the passenger cabin.
    Galley carts and other rotatable galley equipment: The earlier 
rulemaking contained the statement, ``Service items, such as pillows or 
blankets, magazines, food, and alcoholic beverages, are not part of the 
certification process and would not have to meet the new flammability 
standard.'' Galley carts are considered to be service items; however, 
unlike the items cited in the preamble statement, they are generally 
approved as part of the airplane type design. Although the new 
flammability standards do not apply expressly to galley carts, it was 
intended that they would apply implicitly to the extent that, when 
stowed, the galley carts form exterior surfaces of the galley. 
Typically, at least one end of each cart remains exposed and forms a 
galley surface while the cart is stowed. In addition to galley carts, 
these are galley standard containers used for various meal courses, 
beverages, plates, etc., that also form galley surfaces when stowed.
    Operators have pointed out that galley carts are removable items 
that are rotated from one airplane to another with each flight. In this 
regard, they note that their fleets will include older airplanes that 
are not required to meet the new standards, as well as new airplanes 
(or airplanes in which the interiors have been replaced) that will be 
required to meet the new standards. They further note that the carts 
are loaded before a flight by persons, usually independent caterers, 
who have no way of knowing whether or not the airplane that will be 
used on a particular flight is required to meet the new standards. 
Unless all existing noncomplying galley carts are replaced with galley 
carts that meet the new standards, there is no practical means to 
ensure that galley carts meeting the new standards will be loaded on 
the airplanes that are required to have them. It is estimated that 
there are now approximately 125,000 galley carts in use with the U.S. 
air carrier fleet. Typically, the cost per cart ranges from $800 to 
$3,500; and the service life is about eight to ten years. While it is 
feasible to replace the existing carts on an attrition basis, it would 
be impractical to produce enough galley carts meeting the new standards 
in time to meet the established deadlines. In addition, such immediate 
replacement would be very costly. The operators note that they would 
have commented accordingly had they not believed that, as service 
items, galley carts did not have to meet the new standards.
    The galley standard containers are also rotated from airplane to 
airplane; and they, too, are filled prior to the flight by persons who 
have no way of knowing whether the airplane that will be used on the 
flight is one required to meet the new standards. While the cost of 
each galley standard container would be less than that of a beverage 
cart, replacing the entire inventory of containers would be very 
costly.
    Although it was intended that the exposed surfaces of stowed galley 
carts and standard containers should meet the new standards, the FAA 
has concluded, upon further review, that it was not clearly stated that 
the galley carts and containers would be required to comply. The FAA 
does, however, consider that the exposed surfaces of stowed galley 
carts and standard containers must ultimately meet the new flammability 
standards. It was, therefore, proposed that Sec. 25.853(a-1) would be 
amended to specifically require the exposed surfaces of those 
components to meet the new standards.
    The FAA concurs that unless all carts and containers are replaced, 
it would be extremely difficult to ensure that galley carts and 
standard containers meeting the new standards are loaded on the 
airplanes that are required to meet them. Furthermore, the immediate 
replacement of all galley carts and standard containers would be 
logistically impossible and would present an unreasonable economic 
burden. If, on the other hand, galley carts and standard containers 
that meet the new standards are acquired at a rate commensurate with 
the rate at which new airplanes are acquired (and interiors of older 
airplanes are replaced), it can be assumed that the overall level of 
safety of the air carrier fleet will not be adversely affected by 
intermixing carts and containers complying with the new standards with 
those that do not. The small decrement of safety that would be suffered 
due to 

[[Page 6619]]
the use of noncomplying carts and containers in an airplane that must 
meet the new standards would be compensated by an increment of safety 
enjoyed due to the use of complying carts and containers in another 
airplane that is not required to meet them. It was, therefore, proposed 
that Sec. 121.312 would be amended to allow such intermixing of galley 
carts and standard containers, provided that all carts and containers 
manufactured after a specified date meet the new standards.
    Other changes: Certain minor refinements in the test apparatus and 
procedures were identified; and it was proposed that Appendix F of Part 
25, including the associated figures, would be revised accordingly. The 
proposed refinements would not preclude the use of materials previously 
found to be acceptable under the new standards; nor enable the use of 
materials previously found unacceptable; however, they would improve 
the repeatability of test results from one test run to another and from 
one laboratory to another. Other minor nonsubstantive editing changes 
would be made for consistency in style. Nonsubstantive editing changes 
would also be made to Sec. 25.853 for clarity.
    It was also proposed that the organization and language of 
Sec. 121.312(a) would be revised for clarity.
    As noted above, Part 135 was not amended at the time the new 
standards were adopted; however, they are equally applicable to Part 
135 operators because Sec. 135.169(a) incorporates the provisions of 
Sec. 121.312 by cross reference. Since that time, it has come to the 
attention of the FAA that the practice of incorporating certain 
provisions of Part 121 in Part 135 by cross reference may cause 
confusion. In order to preclude any confusion in this regard, it was 
proposed that Part 135 would be amended to include the new standards 
explicitly rather than by reference. Because Part 135 operators are 
already required to meet these standards due to the incorporation by 
cross reference, this change would not place any additional burden on 
any person.
    The reference to ``November 26, 1987'' in Sec. 121.312(b) is no 
longer relevant because that date has already passed. It would, 
therefore, be removed for simplification. The redundant reference to 
Appendix F of Part 25 would also be removed from Sec. 121.312(b) for 
simplification and consistency with the editorial style used in 
Sec. 121.312(a). (Appendix F, Part II, is incorporated by cross 
reference in Sec. 25.853(c); and Appendix F, Part IV, is incorporated 
by cross reference in Sec. 25.853(a-1).)
    Since the time Notice 90-12 was issued, Amendment 25-72 was adopted 
(55 FR 29756, July 20, 1990). Although no substantive changes to 
Sec. 25.853 were adopted, the requirements of that section were 
rearranged considerably for clarity, and the test acceptance criteria 
formerly contained in that section were transferred to Part I of 
Appendix F. It is, therefore, necessary to make a number of 
nonsubstantive conforming changes for consistency with Sec. 25.853 in 
its present format.
    Among the changes made to Sec. 25.853 as a result of the adoption 
of Amendment 25-72 was the transfer of the seat cushion flammability 
standards from former Sec. 25.853(c) to new Sec. 25.853(b). It has been 
brought to the attention of the FAA that this change is causing 
considerable confusion.
    Seats are frequently transferred from one airplane to another; 
therefore, as a practical matter, they must be marked to show that 
their cushions comply with the flammability standards. With the change 
in section number, the previous markings indicating compliance with 
Sec. 25.853(c) are no longer accurate. In order to eliminate further 
confusion in that regard, Sec. 25.853(b) has been marked ``Reserved,'' 
and the seat cushion flammability standards have been transferred back 
to Sec. 25.853(c).
    For convenience, the proposed changes to Sec. 25.853 are discussed 
below both in terms of their identity in Notice 90-12 and as rearranged 
for conformity with the changes resulting from the adoption of 
Amendment 25-72.

Discussion of Comments

    Seven commenters responded to the request for comments contained in 
Notice 90-12. These included manufacturers, a foreign airworthiness 
authority, and organizations representing manufacturers, airlines, and 
airline employees.
    One commenter notes that the restructuring and numbering of 
Sec. 25.853 may have inadvertently excluded such items as lighting 
lenses, windows, transparent panels needed to enhance cabin safety, 
etc., from compliance with any of the flammability standards of 
Sec. 25.853. The FAA concurs that the wording proposed in Notice 90-12 
could have led to an incorrect interpretation of that nature. Section 
25.853 is, therefore, changed by transferring the statement ``Except as 
provided * * *'' to Sec. 25.853(d), which would have been 
Sec. 25.853(a-1) as proposed in Notice 90-12.
    One commenter opposes the proposal to clarify that compartments 
isolated from the cabin are not required to meet the heat release 
standards of Sec. 25.853(a-l). The commenter states that all 
compartment components should be of the same standard and that meeting 
the same standard would ensure that the net amount of material 
contributing to fire development and propagation is at the absolute 
minimum. In that regard, the commenter cites the accident involving a 
McDonnell Douglas DC-9 operated by Air Canada on June 2, 1983, at the 
Greater Cincinnati Airport, Covington, Kentucky. The commenter notes 
that, while the origin of the fire that destroyed the airplane could 
not be identified, the lavatory compartment's interior material was the 
primary source of fuel and that the fire burned undetected for almost 
15 minutes before the smoke was first noticed. The commenter asserts 
that requiring the compartment to meet the same low heat release 
standards as the main cabin would significantly reduce the amount of 
fuel available for such a fire.
    Contrary to the commenter's assertion, requiring all lavatory 
components to meet the new standards for heat release would not 
significantly reduce the amount of fuel available for a fire 
originating in the lavatory. As noted above under Background, the heat 
release standards do not apply to small surface-area components. As 
further noted above under Discussion, many of the components in the 
lavatory are small enough that they would not have to meet the new 
standards in any event. The doors and most sidewalls have to meet the 
new standards regardless of whether the new standards are applicable to 
lavatories because their outer sides also form surfaces of the 
passenger cabin. Some portions of the lavatory are generally 
constructed of stainless steel due to functional considerations. 
Stainless steel is, of course, fireproof. Requiring the few remaining 
large components to meet the new standards would have very little 
impact on the overall flammability of the lavatory and would not 
significantly enhance safety in the event of an inflight fire.
    In the accident cited by the commenter, smoke was discovered coming 
from the left-hand lavatory in the aft cabin while the airplane was 
enroute from Dallas, Texas to Montreal, Quebec. An emergency landing 
was not made until 17 minutes later. By that time, the fire and smoke 
had grown in intensity to the point that only half of the 46 occupants 
were able to escape. As noted in their official accident report, NTSB/
AAR-86/02, the National Transportation Safety Board determined that the 
probable causes of the accident were a fire of unknown origin, an 
underestimate of the fire severity, and 

[[Page 6620]]
misleading fire progress information provided to the captain. 
Considering the few lavatory components that would be affected and the 
time that the fire had been burning prior to the emergency landing, it 
is unlikely that the outcome of the accident would have been more 
favorable if the lavatory of that airplane had met the new heat release 
standards.
    Subsequent to the accident, the FAA adopted Amendments 25-58 and 
121-183 (49 FR 43182, October 26, 1984), and 25-59 and 121-184 (49 FR 
43188, October 26, 1984), that require, respectively, low-level 
lighting to enable occupants to locate emergency exits in smoke-filled 
cabins and new flammability standards for seat cushions. Unlike the 
heat release standards of Amendment 25-61, the new flammability 
standards for seat cushions are designed to slow the progression of a 
fire through the cabin. The standards of Amendment 25-61 are, on the 
other hand, designed to reduce the overall release of heat into the 
cabin during a post-crash fire situation and provide more time for 
egress before flashover makes further escape impossible. Amendment 121-
185 (50 FR 12726, March 29, 1985) was also adopted to require each 
lavatory to be equipped with a smoke detection system, or equivalent, 
and a fire extinguisher that discharges automatically upon the 
occurrence of a fire in the trash receptacle. In addition, the 
amendment requires the passenger cabins of certain airplanes to be 
equipped with additional hand fire extinguishers, some of which must 
contain the improved agent Halon 1211.
    The commenter also notes that all compartments with essential 
systems adjacent to their surfaces should be required to meet the heat 
release standards of Sec. 25.853(a-1) in order to protect the essential 
conductors of those systems from the high heat releases of burning 
interior materials.
    The commenter appears to be confusing the standards for heat 
release with other standards for flame resistance. As noted above, the 
heat release standards are designed to reduce the overall release of 
heat into an area and thereby delay the time until flashover occurs. It 
is assumed, on the other hand, that the insulation of electrical wiring 
and cables could be enveloped by flame. They must, therefore, be tested 
by actual application of flame to the insulation surface.
    The same commenter recommends that, if an isolated compartment does 
not have to meet the heat release standards, the doors separating the 
compartment from the main cabin should be able to contain the heat and 
smoke in the isolated compartment for at least five minutes. (Such 
doors would be `fire-resistant' as defined in Part 1 of the FAR.)
    The commenter's recommendation is apparently based on the 
assumption that there will be an uncontrollable fire originating from 
an isolated compartment. In view of the fire protection measures that 
have been adopted for lavatories since the above noted accident, there 
is no evident need for fire-resistant lavatory doors. Furthermore, 
service history does not support a need for such doors to other 
isolated compartments. The exception proposed as Sec. 25.853(a-2) is, 
therefore, adopted as Sec. 25.853(e).
    One commenter recommends that Sec. 25.853(a-1)(1) be amended to 
read, ``other than lighting lenses, illuminated signs and windows,'' 
since illuminated signs are discussed in the preamble to Notice 90-12 
as examples of excluded items. While it is true that the illuminated 
portions of passenger information signs are not required to meet the 
heat release standards of that section, it is not necessary to refer to 
them specifically in Sec. 25.853(a-1)(1) because they are ``lighting 
lenses.'' Proposed Sec. 25.853(a-1)(1) is adopted as Sec. 25.853(d)(1).
    The same commenter and one other recommend that Sec. 25.853(a-2) be 
clarified by adding ``lavatories'' to the list of compartments whose 
interiors are excluded. Unlike the illuminated signs discussed above, 
it may not be as clear that lavatories are considered isolated 
compartments and, as such, are already excluded. Proposed 
Sec. 25.853(a-2) is, therefore, changed to read, ``* * * such as pilot 
compartments, galleys, lavatories, crew rest quarters, cabinets and 
stowage compartments, * * *,'' and adopted as Sec. 25.853(e).
    One commenter suggests that Sec. 25.853(a-2) should stipulate ``20 
or more passengers.'' Since the only purpose of this paragraph, adopted 
as paragraph (e), is to make an exception to paragraph (a-1), adopted 
as paragraph (d), which is already so limited, there is no need to 
repeat this limitation of applicability.
    Because the flammability standards of Sec. 25.853(d), formerly 
Sec. 25.853(a-1), are applicable only to airplanes with 20 or more 
passengers, some persons have mistakenly assumed that the seat cushion 
standards of Sec. 25.853(c) are also applicable only to airplanes with 
20 or more passengers. To preclude any confusion in this regard, the 
phrase, ``regardless of the passenger capacity of the airplane,'' has 
been added to Sec. 25.853 (a) and (c).
    Another commenter suggests that Part IV of Appendix F should be 
amended to permit the use of the optional 14-hole upper pilot burner 
that has been found satisfactory. Actually, the use of this optional 
burner has already been accepted by the FAA under the equivalent safety 
provisions of Sec. 21.21(b)(1). The FAA notes that test data obtained 
during testing with the three-hole burner are sometimes invalidated 
because the pilot burner would not remain lighted for the entire 5-
minute duration of the test. With the optional 14-hole burner, there is 
a greater probability of reigniting any flamelets that might extinguish 
during a test. Because the 14-hole burner may be preferable in some 
instances, Part IV is amended to describe the optional use of that 
burner, as suggested by the commenter. Testing with this optional 
burner is already permitted under the equivalent safety provisions of 
Sec. 21.21(b)(1); therefore, this is a minor nonsubstantive change that 
places no additional burden on any person.
    Paragraph (b)(8) states that the pilot burners must remain lighted 
for the entire duration of the test. In regard to the difficulties 
experienced in keeping the three-hole upper pilot burner lighted for 
the entire duration of the test, the FAA proposed to add the statement, 
``Intermittent pilot flame extinguishment for more than 3 seconds would 
invalidate the test results.'' The same commenter notes that further 
clarification is required. According to the commenter, it is normal for 
some of the upper pilot-burner flamelets to be extinguished for periods 
that can exceed three seconds when samples containing flame retardants 
are tested. The commenter notes that the results of such tests have 
been considered acceptable provided some of the flamelets have remained 
lighted.
    The FAA concurs that it is not necessary for each flamelet of the 
three-hole upper pilot burner to remain lighted for the entire 5-minute 
duration of the test; however, test results may be invalidated if two 
flamelets are unlighted for more than 3 seconds. In order to preclude, 
such intermittent flamelet extinguishment, the FAA has permitted 
applicants to install an igniter. Intermittent flame extinguishment has 
not posed a problem with the optional 14-hole upper pilot burner since 
it was developed to preclude flame extinguishment. Paragraph (b)(8) is, 
therefore, changed to read, ``Since intermittent pilot flame 
extinguishment for more than 3 seconds would invalidate the test 
results, a spark igniter may be installed to ensure that the burners 
remain lighted.'' Paragraph 

[[Page 6621]]
(e)(8), which is considered a more appropriate location than paragraph 
(b)(8), is amended to clarify the requirements for burners and 
flamelets to remain lighted.
    Part IV, paragraph (e)(3) states that the proper air flow may be 
set and monitored by either an orifice meter or a rotometer. Because of 
difficulties experienced in setting and monitoring the air flow with a 
rotometer, the FAA proposed in Notice 90-12 to amend that paragraph to 
refer only to an orifice meter. The same commenter cited the successful 
use of a rotometer by the National Research Council of Canada and 
recommended that the reference to a rotormeter be retained in that 
paragraph. While the use of a rotometer may be successful in some 
instances, the FAA does not have sufficient information at this time to 
conclude that a rotometer is acceptable on a general basis. It is, 
therefore, not considered appropriate to specifically cite the 
rotormeter in that paragraph as an acceptable alternative means of 
setting and monitoring air flow. The FAA does recognize, however, that 
rotometers, or any other devices for that matter, may be improved to 
the point that their use is acceptable. In that event, those devices 
could be used under the equivalent safety provisions of 
Sec. 21.21(b)(1).
    The same commenter notes that the area of .02323 m2 specified 
in the heat release equation of paragraph (f)(2) is based on a test 
specimen size of 6 x 6 inches. Since the actual size of the sample is 
150 x 150 mm, the commenter believes that an area factor of .0225 
m2 should actually be used in the heat release equation.
    Although the commenter is technically correct, the definitive 65/65 
and the interim 100/100 standards were established based on the use of 
a factor of .02323 m2. Furthermore all testing completed to date 
has been based on the use of the .02323 factor. Changing the factor to 
.0225 at this late date would mean that the 65/65 and 100/100 standards 
would have to be changed to 67/67 and 103/103, respectively, in order 
to preclude a degradation of the components approved for use in 
airplane cabins. This would no doubt cause considerable confusion, 
particularly when test results obtained with the .0225 factor are 
compared with earlier test results obtained with the original .02323 
factor.
    The same commenter notes that considerable confusion is created by 
the fact that dimensions of the the test apparatus are specified in 
U.S. units in some instances and in metric units in others. The FAA 
concurs. For clarity, part IV is revised to show dimensions in both 
U.S. units and their metric equivalents. Other minor, nonsubstantive 
changes are also made to Part IV for clarity.
    Section 121.312(a) incorporates the heat release standards of 
Sec. 25.853(a-1) by cross reference. Since the latter section applies 
only to airplanes with passenger capacities of 20 or more, 
Sec. 121.312(a) requires compliance with these heat release standards 
only for airplanes with passenger capacities of 20 or more. As one 
commenter notes, Sec. 121.312(a) can be misinterpreted to require 
compliance for all transport category airplanes regardless of their 
passenger capacity. In order to preclude possible confusion in this 
regard, both Sec. 121.312(a) and newly adopted Sec. 135.170(b)(1) state 
specifically that compliance is required only for airplanes with 
passenger capacities of 20 or more.
    Another commenter notes that Sec. 121.312(a) (1) through (6) and 
the corresponding Sec. 135.170(b)(1) (i) through (vi) are complex and 
difficult to understand. The FAA acknowledges that these sections are 
very complex. This is due primarily to the fact that there are 
differing requirements dependent on such factors as when the airplane 
was type certificated, when it was manufactured, when there was a 
substantially complete replacement of the cabin interior components, 
etc. There is even a distinction between complete replacement of all 
cabin interior components in one case and just those components 
identified in Sec. 25.853(a-1) in another. The only way in which the 
provisions of these sections could be significantly simplified would be 
to require compliance for all airplanes at one time. While that would 
simplify the regulatory language considerably, it would impose costly 
additional burdens on some operators with no commensurate improvement 
in safety. Nevertheless, minor nonsubstantive changes have been made 
wherever possible to clarify these requirements.
    Proposed Sec. 121.312(a)(8) states, in part, that ``* * * galley 
carts and galley standard containers that do not meet the heat release 
rate testing requirements * * * may be used * * * provided the galley 
carts or standard containers were manufactured prior to August 20, 
1990.'' One commenter believes that this section should refer to galley 
carts and standard containers manufactured prior to a date two years 
after the effective date of this amendment.
    The FAA concurs that it is inappropriate to specify a date earlier 
than the date on which this final rule becomes effective. The FAA does 
not, however, agree that an additional two-year compliance time is 
necessary. The amendment does not require galley carts and standard 
containers manufactured after the specified date to comply. Instead, it 
relieves operators of the burden of ensuring that only complying galley 
carts and standard containers are loaded on airplanes that are required 
to meet the new flammability standards provided the galley carts and 
standard containers are manufactured prior to that date. Section 
121.312(a)(8) and the corresponding Sec. 135.170(b)(viii) are, 
therefore, changed to read, ``* * * provided the galley carts or 
standard containers were manufactured prior to March 6, 1995.
    One commenter believes that there should be a specific definition 
of what constitutes ``substantially complete replacement'' as stated in 
Sec. 121.312. The commenter expresses concern that the definition 
should allow for the individual replacement of cabin interior 
components without the mandatory replacement of all components at the 
same time.
    ``Complete replacement,'' as used in Sec. 121.312 and newly adopted 
Sec. 135.170(b), means that all of the affected components in the cabin 
are replaced. (As noted above under Background, whether the other 
components that are not affected, e.g. seat cushions and flooring, are 
replaced is not relevant.) The qualifying word ``substantially'' was 
added simply to prevent operators from avoiding compliance by not 
replacing a minor, inconsequential cabin component and claiming that 
there had not been a ``complete replacement.'' Section 212.312 does, 
therefore, permit individual replacement of cabin interior components 
without the mandatory replacement of all components at the same time. 
This, of course, assumes that the cabin components did not already have 
to meet the heat release standards because of the date of manufacture 
of the airplane or because they had been completely replaced 
previously. It should also be noted that removing components for 
refinishing and reinstalling them in the same airplane is considered 
``refurbishment,'' not ``replacement.''
    Proposed Sec. 135.170(b) states, ``No person may operate a large 
airplane unless * * *'' Several commenters note that Part 23 commuter 
category airplanes are ``large airplanes,'' as defined by Part 1 of the 
FAR, and, as such, would be required to meet the new flammability 
standards contained in that section. Another commenter has a similar 
concern that proposed 

[[Page 6622]]
Sec. 135.170(b) would appear to add substantial requirements for 
airplanes type certificated under the provisions of Part 23 and Special 
Federal Aviation Regulations (SFAR) No. 41.
    Although commuter category airplanes may be large enough to be 
``large airplanes'' as defined by Part 1, they are not permitted to 
carry more than 19 passengers. Since the flammability standards of 
Sec. 135.170(b) apply only to airplanes with more than 19 passengers, 
commuter category airplanes would not be required to comply even though 
they may be ``large airplanes.'' SFAR No. 41 provides that, contrary 
provisions of Part 1 notwithstanding, airplanes certificated under the 
provisions of that SFAR are considered to be ``small airplanes'' in 
regard to compliance with Part 135. Furthermore they, like commuter 
category airplanes, are not permitted to carry more than 19 passengers.
    Since neither commuter category airplanes nor those type 
certificated under the provisions of SFAR No. 41 are permitted to carry 
more than 19 passengers, there is no need to amend Sec. 135.170(b) of 
specifically exclude those airplanes. Specifically stating in 
Secs. 121.312(a) and 135.170(b)(1) that only airplanes with 20 or more 
passengers seats are required to comply, as discussed above, will 
preclude confusion in this regard.
    One commenter reiterates a belief that the seat cushion 
flammability standards of Sec. 25.853(c) are an unnecessary burden for 
operators of small transport category airplanes with passenger seating 
capacities of fewer than 19 passengers. The commenter is referring in 
this regard to the provisions of Sec. 121.312 which were previously 
incorporated by cross reference in Sec. 135.169 and now are stated 
explicitly as new Sec. 135.170(b)(2). Section 121.312(b) and the new 
Sec. 135.170(b)(2), in turn specify that the operator must have seat 
cushions that meet the flammability standards of Sec. 25.853(c). That 
issue has already been addressed by FAA in earlier rulemaking and is 
not related, in any substantive manner, to the present rulemaking.
    Another commenter notes an inadvertent error in proposed 
Sec. 135.169(a) in that it would incorporate Sec. 121.311 by cross 
reference. The intent was to move the no longer needed reference to 
Sec. 121.312, not to replace it with Sec. 121.311. Section 135.169(a) 
is corrected accordingly.

Regulatory Evaluation

Regulatory Evaluation

    Exeuctive Order 12291, dated February 17, 1981, directs Federal 
agencies to promulgate new regulations or modify existing regulations 
only if potential benefits to society for each regulatory change 
outweigh potential costs. This section summarizes the full regulatory 
evaluation prepared by the FAA that provides more detailed estimates of 
the economic consequences of this regulatory action.
    The evaluations prepared for Amendments 25-61 and 121-189, and 
Amendments 25-66 and 121-198 remain unchanged by this rule with respect 
to costs and benefits, regulatory flexibility determinations, and trade 
impact assessment.
    None of the amendments in this rule will generate significant costs 
or benefits. In part, the rule clarifies the original intent of the 
earlier amendments. The changes to the test apparatus and procedures 
for determining heat release rate are minor refinements that will 
result only in negligible costs and benefits. The amendment to Part 135 
is a nonsubstantive change that incorporates existing requirements 
explicitly rather than by cross reference. The remaining changes are 
editorial or conforming in nature.

Regulatory Flexibility Determination

    The Regulatory Flexibility Act of 1989 (RFA) was enacted by 
Congress to ensure that small entities are not unnecessarily or 
disproportionately burdened by Government regulations. The RFA requires 
a Regulatory Flexibility Analysis if a rule has a significant economic 
impact, either detrimental or beneficial, on a substantial number of 
small entities. FAA Order 2100.14A, Regulatory Flexibility Criteria and 
Guidance, established threshold cost values and small entity size 
standards for complying with RFA review requirements in FAA rulemaking 
actions. The FAA has determined that this rule will not have a 
significant economic impact on a substantial number of small entities.
International Trade Impact Analysis

    This rule will not have an adverse impact either on the trade 
opportunities of U.S. operators or manufacturers of transport category 
airplanes doing business abroad, or on foreign operators or aircraft 
manufacturers doing business in the United States.

Federalism Implications

    The regulations adopted herein will not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule will not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    Conclusion: Because the regulations adopted herein are expected to 
result only in negligible costs, the FAA has determined that this final 
rule is not major as defined in Executive Order 12291. Because this is 
an issue that has not prompted a great deal of public concern, this 
final rule is not considered to be significant as defined in Department 
of Transportation Regulatory Policies and Procedures (44 FR 11034, 
February 26, 1979). In addition, since there are no small entities 
affected by this rulemaking, it is certified, under the criteria of the 
Regulatory Flexibility Act, that this final rule, at promulgation, will 
not have a significant economic impact, positive or negative, on a 
substantial number of small entities. The regulatory evaluation 
prepared for Amendments 25-66 and 121-198 remains applicable and has 
been placed on the docket. A copy of this evaluation may be obtained by 
contacting the person identified under the caption FOR FURTHER 
INFORMATION CONTACT.

List of Subjects

14 CFR Part 25

    Aircraft, Air transportation, Aviation safety, Safety.

14 CFR Part 121

    Air carriers, Aircraft, Airplanes, Air transportation, Aviation 
safety, Common carriers, Flammable materials, Safety, Transportation.

14 CFR Part 135

    Air carriers, Aircraft, Airplanes, Air transportation, Aviation 
safety, Cargo, Hazardous materials, Mail, Safety, Transportation.

Adption of the Amendment

    Accordingly, 14 CFR Parts 25, 121 and 135 of the Federal Aviation 
Regulations (FAR) are amended as follows:

PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES

    1. The authority citation for Part 25 is revised to read as 
follows:

    Authority: 49 U.S.C. 106(g), 1344, 1354(a), 1355, 1421, 1423, 
1424, 1425, 1428, 1429, 1430.

    2. By revising Sec. 25.853 to read as follows:

[[Page 6623]]



Sec. 25.853  Compartment interiors.

    For each compartment occupied by the crew or passengers, the 
following apply:
    (a) Materials (including finishes or decorative surfaces applied to 
the materials) must meet the applicable test criteria prescribed in 
Part I of Appendix F of this Part, or other approved equivalent 
methods, regardless of the passenger capacity of the airplane.
    (b) [Reserved]
    (c) In addition to meeting the requirements of paragraph (a) of 
this section, seat cushions, except those on flight crewmember seats, 
must meet the test requirements of part II of Appendix F of this Part, 
or other equivalent methods, regardless of the passenger capacity of 
the airplane.
    (d) Except as provided in paragraph (e) of this section, the 
following interior components of airplanes with passenger capacities of 
20 or more must also meet the test requirements of parts IV and V of 
Appendix F of this Part, or other approved equivalent method, in 
addition to the flammability requirements prescribed in paragraph (a) 
of this section:
    (1) Interior ceiling and wall panels, other than lighting lenses 
and windows;
    (2) Partitions, other than transparent panels needed to enhance 
cabin safety;
    (3) Galley structure, including exposed surfaces of stowed carts 
and standard containers and the cavity walls that are exposed when a 
full complement of such carts or containers is not carried; and
    (4) Large cabinets and cabin stowage compartments, other than 
underseat stowage compartments for stowing small items such as 
magazines and maps.
    (e) The interiors of compartments, such as pilot compartments, 
galleys, lavatories, crew rest quarters, cabinets and stowage 
compartments, need not meet the standards of paragraph (d) of this 
section, provided the interiors of such compartments are isolated from 
the main passenger cabin by doors or equivalent means that would 
normally be closed during an emergency landing condition.
    (f) Smoking is not to be allowed in lavatories. If smoking is to be 
allowed in any other compartment occupied by the crew or passengers, an 
adequate number of self-contained, removable ashtrays must be provided 
for all seated occupants.
    (g) Regardless of whether smoking is allowed in any other part of 
the airplane, lavatories must have self-contained, removable ashtrays 
located conspicuously on or near the entry side of each lavatory door, 
except that one ashtray may serve more than one lavatory door if the 
ashtray can be seen readily from the cabin side of each lavatory 
served.
    (h) Each receptacle used for the disposal of flammable waste 
material must be fully enclosed, constructed of at least fire resistant 
materials, and must contain fires likely to occur in it under normal 
use. The capability of the receptacle to contain those fires under all 
probable conditions of wear, misalignment, and ventilation expected in 
service must be demonstrated by test.
    3. By amending part IV of Appendix F to Part 25 by revising 
paragraphs (a), (b)(1) through (6), (b)(8), (c)(1), (d) heading and 
(d)(1), (d)(3), (e)(1) through (5), (e)(8), (f)(2), and by adding 
paragraph (c)(3); transferring Figures 1 through 5 at the end of 
Appendix F to the end of part IV of Appendix F and adding a heading 
preceding the figures, and by removing Figure 1 of part IV and adding 
Figures 1A and 1B in its place to read as follows:

Appendix F to Part 25

* * * * *
    Part IV--Test Method to Determine the Heat Release Rate from Cabin 
Materials Exposed to Radiant Heat.
    (a) Summary of Method. Three or more specimens representing the 
completed aircraft component are tested. Each test specimen is injected 
into an environmental chamber through which a constant flow of air 
passes. The specimen's exposure is determined by a radiant heat source 
adjusted to produce, on the specimen, the desired total heat flux of 
3.5 W/cm2. The specimen is tested with the exposed surface 
vertical. Combustion is initiated by piloted ignition. The combustion 
products leaving the chamber are monitored in order to calculate the 
release rate of heat.
    (b) * * *
    (1) This apparatus is shown in Figures 1A and 1B of this part IV. 
All exterior surfaces of the apparatus, except the holding chamber, 
must be insulated with 1 inch (25 mm) thick, low density, high 
temperature, fiberglass board insulation. A gasketed door, through 
which the sample injection rod slides, must be used to form an airtight 
closure on the specimen hold chamber.
    (2) Thermopile. The temperature difference between the air entering 
the environmental chamber and that leaving must be monitored by a 
thermopile having five hot, and five cold, 24-guage Chromel-Alumel 
junctions. The hot junctions must be spaced across the top of the 
exhaust stack, .38 inches (10 mm) below the top of the chimney. The 
thermocouples must have a .050  .010 inch (1.3  
.3mm) diameter, ball-type, welded tip. One thermocouple must be located 
in the geometric center, with the other four located 1.18 inch (30 mm) 
from the center along the diagonal toward each of the corners (Figure 5 
of this part IV). The cold junctions must be located in the pan below 
the lower air distribution plate (see paragraph (b)(4) of this part 
IV). Thermopile hot junctions must be cleared of soot deposits as 
needed to maintain the calibrated sensitivity.
    (3) Radiation Source. A radiant heat source incorporating four Type 
LL silicon carbide elements, 20 inches (508 mm) long by .63 inch (16 
mm) O.D., must be used, as shown in Figures 2A and 2B of this part IV. 
The heat source must have a nominal resistance of 1.4 ohms and be 
capable of generating a flux up to 100 kW/m\2\. The silicone carbide 
elements must be mounted in the stainless steel panel box by inserting 
them through .63 inch (16 mm) holes in .03 inch (1 mm) thick ceramic 
fiber or calcium-silicate millboard. Locations of the holes in the pads 
and stainless steel cover plates are shown in Figure 2B of this part 
IV. The truncated diamond-shaped mask of .042.002 inch 
(1.07.05mm) stainless steel must be added to provide 
uniform heat flux density over the area occupied by the vertical 
sample.
    (4) Air Distribution System. The air entering the environmental 
chamber must be distributed by a .25 inch (6.3 mm) thick aluminum plate 
having eight No. 4 drill-holes, located 2 inches (51 mm) from sides on 
4 inch (102 mm) centers, mounted at the base of the environmental 
chamber. A second plate of 18 guage stainless steel having 120, evenly 
spaced, No. 28 drill holes must be mounted 6 inches (152 mm) above the 
aluminum plate. A well-regulated air supply is required. The air-supply 
manifold at the base of the pyramidal section must have 48, evenly 
spaced, No. 26 drill holes located .38 inch (10 mm) from the inner edge 
of the manifold, resulting in an airflow split of approximately three 
to one within the apparatus.
    (5) Exhaust Stack. An exhaust stack, 5.25 x 2.75 inches (133 x 70 
mm) in cross section, and 10 inches (254 mm) long, fabricated from 28 
guage stainless steel must be mounted on the outlet of the pyramidal 
section. A. 1.0 x 3.0 inch (25 x 76 mm) baffle plate of 
0.18.002 inch (.50.05 mm) stainless steel must 
be centered inside the stack, perpendicular to the air flow, 3 inches 
(76 mm) above the base of the stack.
    (6) Specimen Holders. (i) The specimen must be tested in a vertical 


[[Page 6624]]
orientation. The specimen holder (Figure 3 of this part IV) must 
incorporate a frame that touches the specimen (which is wrapped with 
aluminum foil as required by paragraph (d)(3) of this Part) along only 
the .25 inch (6 mm) perimeter. A ``V'' shaped spring is used to hold 
the assembly together. A detachable .50 x .50 x 5.91 inch 
(12 x 12 x 150 mm) drip pan and two .020 inch (.5 mm) stainless steel 
wires (as shown in Figure 3 of this part IV) must be used for testing 
materials prone to melting and dripping. The positioning of the spring 
and frame may be changed to accommodate different specimen thicknesses 
by inserting the retaining rod in different holes on the specimen 
holder.
    (ii) Since the radiation shield described in ASTM E-906 is not 
used, a guide pin must be added to the injection mechanism. This fits 
into a slotted metal plate on the injection mechanism outside of the 
holding chamber. It can be used to provide accurate positioning of the 
specimen face after injection. The front surface of the specimen must 
be 3.9 inches (100 mm) from the closed radiation doors after injection.
    (iii) The specimen holder clips onto the mounted bracket (Figure 3 
of this part IV). The mounting bracket must be attached to the 
injection rod by three screws that pass through a wide-area washer 
welded onto a \1/2\-inch (13 mm) nut. The end of the injection rod must 
be threaded to screw into the nut, and a .020 inch (5.1 mm) thick wide 
area washer must be held between two \1/2\-inch (13 mm) nuts that are 
adjusted to tightly cover the hole in the radiation doors through which 
the injection rod or calibration calorimeter pass.
    (7) * * *
    (8) Pilot-Flame Positions. Pilot ignition of the specimen must be 
accomplished by simultaneously exposing the specimen to a lower pilot 
burner and an upper pilot burner, as described in paragraph (b)(8)(i) 
and (b)(8)(ii) or (b)(8)(iii) of this part IV, respectively. Since 
intermittent pilot flame extinguishment for more than 3 seconds would 
invalidate the test results, a spark ignitor may be installed to ensure 
that the lower pilot burner remains lighted.
    (i) Lower Pilot Burner. The pilot-flame tubing must be .25 inch 
(6.3 mm) O.D., .03 inch (0.8mm) wall, stainless steel tubing. A mixture 
of 120 cm3/min. of methane and 850 cm3/min. of air must be 
fed to the lower pilot flame burner. The normal position of the end of 
the pilot burner tubing is .40 inch (10 mm) from and perpendicular to 
the exposed vertical surface of the specimen. The centerline at the 
outlet of the burner tubing must intersect the vertical centerline of 
the sample at a point .20 inch (5 mm) above the lower exposed edge of 
the specimen.
    (ii) Standard Three-Hole Upper Burner. The pilot burner must be a 
straight length of .25 inch (6.3 mm) O.D., .03 inch (0.8 mm) wall, 
stainless steel tubing that is 14 inches (360 mm) long. One end of the 
tubing must be closed, and three No. 40 drill holes must be drilled 
into the tubing, 2.38 inch (60 mm) apart, for gas ports, all radiating 
in the same direction. The first hole must be .19 inch (5 mm) from the 
closed end of the tubing. The tube must be positioned .75 inch (19 mm) 
above and .75 inch (19 mm) behind the exposed upper edge of the 
specimen. The middle hole must be in the vertical plane perpendicular 
to the exposed surface of the specimen which passes through its 
vertical centerline and must be pointed toward the radiation source. 
The gas supplied to the burner must be methane and must be adjusted to 
produce flame lengths of 1 inch (25 mm).
    (iii) Optional Fourteen-Hole Upper Pilot Burner. This burner may be 
used in lieu of the standard three-hole burner described in paragraph 
(b)(8)(ii) of this part IV. The pilot burner must be a straight length 
of .25 inch (6.3 mm) O.D., .03 inch (0.8 mm) wall, stainless steel 
tubing that is 15.75 inches (400 mm) long. One end of the tubing must 
be closed, and 14 No. 59 drill holes must be drilled into the tubing, 
.50 inch (13 mm) apart, for gas ports, all radiating in the same 
direction. The first hole must be .50 inch (13 mm) from the closed end 
of the tubing. The tube must be positioned above the specimen holder so 
that the holes are placed above the specimen as shown in Figure 1B of 
this part IV. The fuel supplied to the burner must be methane mixed 
with air in a ratio of approximately 50/50 by volume. The total gas 
flow must be adjusted to produce flame lengths of 1 inch (25 mm). When 
the gas/air ratio and the flow rate are properly adjusted, 
approximately .25 inch (6 mm) of the flame length appears yellow in 
color.
    (c) * * * (1) Heat Release Rate. A calibration burner, as shown in 
Figure 4, must be placed over the end of the lower pilot flame tubing 
using a gas tight connection. The flow of gas to the pilot flame must 
be at least 99 percent methane and must be accurately metered. Prior to 
usage, the wet test meter must be properly leveled and filled with 
distilled water to the tip of the internal pointer while no gas is 
flowing. Ambient temperature and pressure of the water are based on the 
internal wet test meter temperature. A baseline flow rate of 
approximately 1 liter/min. must be set and increased to higher preset 
flows of 4, 6, 8, 6 and 4 liters/min. Immediately prior to recording 
methane flow rates, a flow rate of 8 liters/min. must be used for 2 
minutes to precondition the chamber. This is not recorded as part of 
calibration. The rate must be determined by using a stopwatch to time a 
complete revolution of the wet test meter for both the baseline and 
higher flow, with the flow returned to baseline before changing to the 
next higher flow. The thermopile baseline voltage must be measured. The 
gas flow to the burner must be increased to the higher preset flow and 
allowed to burn for 2.0 minutes, and the thermopile voltage must be 
measured. The sequence must be repeated until all five values have been 
determined. The average of the five values must be used as the 
calibration factor. The procedure must be repeated if the percent 
relative standard deviation is greater than 5 percent. Calculations are 
shown in paragraph (f) of this part IV.
    (2) * * *
    (3) As noted in paragraph (b)(2) of this part IV, thermopile hot 
junctions must be cleared of soot deposits as needed to maintain the 
calibrated sensitivity.
    (d) Preparation of Test Specimens. (1) The test specimens must be 
representative of the aircraft component in regard to materials and 
construction methods. The standard size for the test specimens is 5.91 
 .03  x  5.91  .03 inches (149  1 
x  149  1 mm). The thickness of the specimen must be the 
same as that of the aircraft component it represents up to a maximum 
thickness of 1.75 inches (45 mm). Test specimens representing thicker 
components must be 1.75 inches (45 mm).
    (2) * * *
    (3) Mounting. Each test specimen must be wrapped tightly on all 
sides of the specimen, except for the one surface that is exposed with 
a single layer of .001 inch (.025 mm) aluminum foil.
    (e) Procedure. (1) The power supply to the radiant panel must be 
set to produce a radiant flux of 3.5  .05 W/cm2, as 
measured at the point the center of the specimen surface will occupy 
when positioned for the test. The radiant flux must be measured after 
the air flow through the equipment is adjusted to the desired rate.
    (2) After the pilot flames are lighted, their position must be 
checked as described in paragraph (b)(8) of this part IV.
    (3) Air flow through the apparatus must be controlled by a circular 
plate orifice located in a 1.5 inch (38.1 mm) I.D. pipe with two 
pressure measuring 

[[Page 6625]]
points, located 1.5 inches (38 mm) upstream and .75 inches (19 mm) 
downstream of the orifice plate. The pipe must be connected to a 
manometer set at a pressure differential of 7.87 inches (200 mm) of Hg. 
(See Figure 1B of this part IV.) The total air flow to the equipment is 
approximately .04 m3/seconds. The stop on the vertical specimen 
holder rod must be adjusted so that the exposed surface of the specimen 
is positioned 3.9 inches (100 mm) from the entrance when injected into 
the environmental chamber.
    (4) The specimen must be placed in the hold chamber with the 
radiation doors closed. The airtight outer door must be secured, and 
the recording devices must be started. The specimen must be retained in 
the hold chamber for 60 seconds, plus or minus 10 seconds, before 
injection. The thermopile ``zero'' value must be determined during the 
last 20 seconds of the hold period. The sample must not be injected 
before completion of the ``Zero'' value determination.
    (5) When the specimen is to be injected, the radiation doors must 
be opened. After the specimen is injected into the environmental 
chamber, the radiation doors must be closed behind the specimen.
    (6) * * *
    (7) * * *
    (8) The test duration is five minutes. The lower pilot burner and 
the upper pilot burner must remain lighted for the entire duration of 
the test, except that there may be intermittent flame extinguishment 
for periods that do not exceed 3 seconds. Furthermore, if the optional 
three-hole upper burner is used, at least two flamelets must remain 
lighted for the entire duration of the test, except that there may be 
intermittent flame extinguishment of all three flamelets for periods 
that do not exceed 3 seconds.
    (9) * * *
    (f) * * *
    (2) Heat release rates may be calculated from the reading of the 
thermopile output voltage at any instant of time as:
[GRAPHIC][TIFF OMITTED]TR02FE95.006

HRR=heat release rate (kw/m\2\)
Vb=baseline voltage (mv)
Vm=measured thermopile voltage (mv)
Kh=calibration factor (kw/mv)
* * * * *
Figures to Part IV of Appendix F
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[[Page 6626]]
[GRAPHIC][TIFF OMITTED]TR02FE95.004



[[Page 6627]]
[GRAPHIC][TIFF OMITTED]TR02FE95.005


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[[Page 6628]]

* * * * *

PART 121--CERTIFICATION AND OPERATIONS: DOMESTIC, FLAG, AND 
SUPPLEMENTAL AIR CARRIERS AND COMMERCIAL OPERATORS OF LARGE 
AIRCRAFT

    4. The authority citation for Part 121 continues to read as 
follows:

    Authority: 49 U.S.C. 1354(a), 1355, 1356, 1357, 1401, 1421-1430, 
1472, 1485, and 1502; 49 U.S.C. 106(g); 49 CFR 1.47(a).

    5. By amending Sec. 121.312 by revising paragraphs (a)(1) through 
(a)(6), adding a new paragraph (a)(8), and revising paragraph (b) to 
read as follows:


Sec. 121.312  Materials for compartment interiors.

    (a) * * *
    (1) Except as provided in paragraph (a)(6) of this section, each 
airplane with a passenger capacity of 20 or more and manufactured after 
August 19, 1988, but prior to August 20, 1990, must comply with the 
heat release rate testing provisions of Sec. 25.853(d) in effect March 
6, 1995 (formerly Sec. 25.853(a-1) in effect on August 20, 1986), 
except that the total heat release over the first 2 minutes of sample 
exposure must not exceed 100 kilowatt minutes per square meter and the 
peak heat release rate must not exceed 100 kilowatts per square meter.
    (2) Each airplane with a passenger capacity of 20 or more and 
manufactured after August 19, 1990, must comply with the heat release 
rate and smoke testing provisions of Sec. 25.853(d) in effect March 6, 
1995 (formerly Sec. 25.853(a-1) in effect on September 26, 1988).
    (3) Except as provided in paragraph (a)(5) or (a)(6) of this 
section, each airplane for which the application for type certificate 
was filed prior to May 1, 1972, must comply with the provisions of 
Sec. 25.853 in effect on April 30, 1972, regardless of the passenger 
capacity if there is a substantially complete replacement of the cabin 
interior after April 30, 1972.
    (4) Except as provided in paragraph (a)(5) or (a)(6) of this 
section, each airplane for which the application for type certificate 
was filed after May 1, 1972, must comply with the material requirements 
under which the airplane was type certificated regardless of the 
passenger capacity if there is a substantially complete replacement of 
the cabin interior after that date.
    (5) Except as provided in paragraph (a)(6) of this section, each 
airplane that was type certificated after January 1, 1958, and has a 
passenger capacity of 20 or more, must comply with the heat release 
rate testing provisions of Sec. 25.853(d) in effect March 6, 1995 
(formerly Sec. 25.853(a-1) in effect on August 20, 1986), if there is 
substantially complete replacement of the cabin interior components 
identified in Sec. 25.853(d) on or after that date, except that the 
total heat release over the first 2 minutes of sample exposure shall 
not exceed 100 killowatt-minutes per square meter and the peak heat 
release rate shall not exceed 100 kilowatts per square meter.
    (6) Each airplane that was type certificated after January 1, 1958, 
and has a passenger capacity of 20 or more, must comply with the heat 
release rate and smoke testing provisions of Sec. 25.853(d) in effect 
March 6, 1995 (formerly Sec. 25.853(a-1) in effect on September 26, 
1988), if there is a substantially complete replacement of the cabin 
interior components identified in Sec. 25.853(d) on or after August 20, 
1990.
* * * * *
    (8) Contrary provisions of this section notwithstanding, galley 
carts and galley standard containers that do not meet the flammability 
and smoke emission requirements of Sec. 25.853(d) in effect March 6, 
1995 (formerly Sec. 25.853(a-1)) may be used in airplanes that must 
meet the requirements of paragraph (a-1), (a)(2), (a)(5) or (a)(6) of 
this section, provided the galley carts or standard containers were 
manufactured prior to March 6, 1995.
    (b) For airplanes type certificated after January 1, 1958, seat 
cushions, except those on flight crewmember seats, in any compartment 
occupied by crew or passengers must comply with the requirements 
pertaining to fire protection of seat cushions in Sec. 25.853(c) 
effective on November 26, 1984.

PART 135--AIR TAXI OPERATORS AND COMMERCIAL OPERATORS

    6. The authority citation for Part 135 continues to read as 
follows:

    Authority: 49 U.S.C. 1354(a), 1355(a), 1421-1431, and 1502; 49 
U.S.C. 106(g); 49 CFR 1.47(a).

    7. By amending Sec. 135.169 by revising paragraph (a) to read as 
follows:


Sec. 135.169  Additional airworthiness requirements.

    (a) Except for commuter category airplanes, no person may operate a 
large airplane unless it meets the additional airworthiness 
requirements of Secs. 121.213 through 121.283 and 121.307 of this 
chapter.
* * * * *
    8. By revising Sec. 135.170 to read as follows:


Sec. 135.170  Materials for compartment interiors.

    (a) No person may operate an airplane that conforms to an amended 
or supplemental type certificate issued in accordance with SFAR No. 41 
for a maximum certificated takeoff weight in excess of 12,500 pounds 
unless within one year after issuance of the initial airworthiness 
certificate under that SFAR, the airplane meets the compartment 
interior requirements set forth in Sec. 25.853(a) in effect March 6, 
1995 (formerly Sec. 25.853 (a), (b), (b-1), (b-2), and (b-3) of this 
chapter in effect on September 26, 1978).
    (b) No person may operate a large airplane unless it meets the 
following additional airworthiness requirements:
    (1) Except for those materials covered by paragraph (b)(2) of this 
section, all materials in each compartment used by the crewmembers or 
passengers must meet the requirements of Sec. 25.853 of this chapter in 
effect as follows or later amendment thereto:
    (i) Except as provided in paragraph (b)(1)(iv) of this section, 
each airplane with a passenger capacity of 20 or more and manufactured 
after August 19, 1988, but prior to August 20, 1990, must comply with 
the heat release rate testing provisions of Sec. 25.853(d) in effect 
March 6, 1995 (formerly Sec. 25.853(a-1) in effect on August 20, 1986), 
except that the total heat release over the first 2 minutes of sample 
exposure rate must not exceed 100 kilowatt minutes per square meter and 
the peak heat release rate must not exceed 100 kilowatts per square 
meter.
    (ii) Each airplane with a passenger capacity of 20 or more and 
manufactured after August 19, 1990, must comply with the heat release 
rate and smoke testing provisions of Sec. 25.853(d) in effect March 6, 
1995 (formerly Sec. 25.83(a-1) in effect on September 26, 1988).
    (iii) Except as provided in paragraph (b)(1) (v) or (vi) of this 
section, each airplane for which the application for type certificate 
was filed prior to May 1, 1972, must comply with the provisions of 
Sec. 25.853 in effect on April 30, 1972, regardless of the passenger 
capacity, if there is a substantially complete replacement of the cabin 
interior after April 30, 1972.
    (iv) Except as provided in paragraph (b)(1) (v) or (vi) of this 
section, each airplane for which the application for type certificate 
was filed after May 1, 1972, must comply with the material requirements 
under which the airplane was type certificated regardless of the 
passenger capacity if there is a substantially complete replacement of 
the cabin interior after that date.

[[Page 6629]]

    (v) Except as provided in paragraph (b)(1)(vi) of this section, 
each airplane that was type certificated after January 1, 1958, must 
comply with the heat release testing provisions of Sec. 25.853(d) in 
effect March 6, 1995 (formerly Sec. 25.853(a-1) in effect on August 20, 
1986), if there is a substantially complete replacement of the cabin 
interior components identified in that paragraph on or after that date, 
except that the total heat release over the first 2 minutes of sample 
exposure shall not exceed 100 kilowatt-minutes per square meter and the 
peak heat release rate shall not exceed 100 kilowatts per square meter.
    (vi) Each airplane that was type certificated after January 1, 
1958, must comply with the heat release rate and smoke testing 
provisions of Sec. 25.853(d) in effect March 6, 1995 (formerly 
Sec. 25.853(a-1) in effect on August 20, 1986), if there is a 
substantially complete replacement of the cabin interior components 
identified in that paragraph after August 19, 1990.
    (vii) Contrary provisions of this section notwithstanding, the 
Manager of the Transport Airplane Directorate, Aircraft Certification 
Service, Federal Aviation Administration, may authorize deviation from 
the requirements of paragraph (b)(1)(i), (b)(1)(ii), (b)(1)(v), or 
(b)(1)(vi) of this section for specific components of the cabin 
interior that do not meet applicable flammability and smoke emission 
requirements, if the determination is made that special circumstances 
exist that make compliance impractical. Such grants of deviation will 
be limited to those airplanes manufactured within 1 year after the 
applicable date specified in this section and those airplanes in which 
the interior is replaced within 1 year of that date. A request for such 
grant of deviation must include a thorough and accurate analysis of 
each component subject to Sec. 25.853(d) in effect March 6, 1995 
(formerly Sec. 25.853(a-1) in effect on August 20, 1986), the steps 
being taken to achieve compliance, and for the few components for which 
timely compliance will not be achieved, credible reasons for such 
noncompliance.
    (viii) Contrary provisions of this section notwithstanding, galley 
carts and standard galley containers that do not meet the flammability 
and smoke emission requirements of Sec. 25.853(d) in effect March 6, 
1995 (formerly Sec. 25.853(a-1) in effect on August 20, 1986), may be 
used in airplanes that must meet the requirements of paragraph 
(b)(1)(i), (b)(1)(ii), (b)(1)(iv) or (b)(1)(vi) of this section 
provided the galley carts or standard containers were manufactured 
prior to March 6, 1995.
    (2) For airplanes type certificated after January 1, 1958, seat 
cushions, except those on flight crewmember seats, in any compartment 
occupied by crew or passengers must comply with the requirements 
pertaining to fire protection of seat cushions in Sec. 25.853(c) 
effective November 26, 1984.
    Issued in Washington, D.C., on January 24, 1995.
David R. Hinson,
Administrator.
[FR Doc. 95-2114 Filed 2-1-95; 8:45 am]
BILLING CODE 4910-13-M