Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
2023-06
April 04, 2023
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) advises the
owners and operators of transport category airplanes of the potential
for an uncontrolled fire to occur based on the amount, type, and
placement of flammable cargo in the cargo compartment. Multiple
accidents have occurred over the last few decades demonstrating an
elevated risk when carrying certain quantities of hazardous materials,
such as flammable aerosols, gases, solids and explosives, and lithium
batteries. Lithium batteries can act as both an ignition source and
contribute significantly to a fire once ignited. Aircraft operators
must comply with the Hazardous Materials Regulations (HMR) under title
49 of the Code of Federal Regulations (49 CFR) parts 171 through 180,
when transporting hazardous materials by aircraft. However, these
regulations do not address the aircraft-level risk posed by an
aggregate shipment of these items. Therefore, in the absence of other
controls, certain cargo shipments can exceed the capabilities of design
features of aircraft fire protection systems required by 14 CFR
sections 25.851, 25.853, and 25.855 through 25.858.
At this time, the airworthiness concern is not an unsafe condition that
would warrant airworthiness directive (AD) action under 14 CFR part 39.
Background
The FAA is issuing this SAIB in response to National Transportation
Safety Board (NTSB) safety recommendations (SRs) and feedback from
industry stakeholders. Three catastrophic in-flight cargo fires aboard
transport category cargo airplanes prompted NTSB SRs A-12-068 through
A-12-0701.
These SRs are intended to:
- Improve early detection of fires originating within cargo containers and palletized cargo;
- Improve the fire resistance of cargo containers and covers by developing materials standards; and,
- Require active fire suppression systems in all cargo compartments, containers, or both.
The FAA agrees with the enhanced safety goals of these SRs and has
multi-year research programs in place to support the development of
minimum performance standards in these key areas. As relevant research
is completed, the FAA publishes the research reports at
https://www.fire.tc.faa.gov. In addition, the FAA presents the status
and results of the research at regular public meetings; the
registration link for these meetings is provided on the same website as
the research reports.
Airframe manufacturers have also recognized a potential incompatibility
with cargo compartment fire protection systems and the type of cargo
being carried. For more information, Boeing operators may reference
Boeing Multi Operator Message MOM-MOM-15-0469-01B, dated July 17, 2015;
and Airbus operators may reference Airbus In-Service Information
00.00.00182, dated July 24, 2015.
The FAA expects operators to understand the capabilities and
limitations of aircraft cargo compartments and to consider this
information when deciding what to load in those compartments.
Recommendations
The FAA continues to collaborate with industry, consensus standards
organizations such as SAE International, safety forums, the
International Civil Aviation Organization (ICAO)2, and other
regulatory authorities on best practices, technical solutions at the
container- and aircraft-levels, and packaging standards that support
the safe carriage of goods. In the interim, the FAA recommends that all
aircraft owners and operators who carry cargo:
1. Retain or include Class C cargo compartments on all-cargo aircraft.
Class C compartments are required to have a built-in fire extinguishing
or suppression system controllable from the cockpit, according to 14
CFR 25.857. Class E compartments are not required to have this built-in
system. Class E compartments have a means to shut off ventilating
airflow to reduce the oxygen content in the compartment. These
procedures can take minutes to accomplish, during which time the fire
may grow. Coupled with de-pressurization procedures, Class E cargo
compartments do afford a certain ability to control and suppress fires.
However, Class C cargo compartments provide increased protection
against re-ignition during descent and may contribute to reducing fire
temperatures by limiting the involvement of materials. Reference FAA
Report DOT/FAA/TC-17/39, "Cargo Fire Suppression by Depressurization."3
2. Follow the guidance in FAA Advisory Circular (AC) 120-121, "Safety
Risk Management (SRM) Involving Items in Aircraft Cargo Compartments,"4
for performing a risk assessment specific to cargo. This assessment
should consider the hazards posed by typical cargo shipments, in
particular, those that contain lithium battery shipments, batteries
shipped in or with equipment, and powered devices integrated into
palletized cargo or passenger baggage. The operator should analyze key
parameters such as the volume of the items listed above, the likelihood
the items exist in undeclared shipments, the spacing between the items,
and the safest locations to place the cargo on the aircraft. In
addition, existing design mitigations such as fire containment covers
(FCCs), fire resistant containers (FRCs), and other industry
innovations at the container- or packaging-level may provide additional
protection in the event of a fire. The AC discusses additional risk
mitigations such as third-party validation of declared lithium battery
shipments, which is an evaluation process on supply chain entities who
offer cargo.
3. Consider the cargo safety information provided by the FAA at the
following websites: https://www.faa.gov/aircraft/safety/cargosafety and
https://www.fire.tc.faa.gov/cargosafety. Operators should consider this
information when implementing and maintaining their SRM process as it
pertains to the transport of cargo.
4. Use FRCs as a risk mitigation. The FAA has adopted SAE Standard
AS8992, "Fire Resistant Container Design, Performance, and Testing
Requirements,"5 into FAA Technical Standard Order (TSO) TSO-C90e, "Unit Load Devices (ULDs)."6
While the standard provides testing requirements that involve a Class A
challenge fire composed of shredded paper, FAA testing has shown that
these containers are also able to suppress certain fire loads
comprising small amounts of lithium batteries. See the FAA Fire Safety
website provided above for research results involving additional
challenge fires. When using standard ULDs or FRCs to ship hazardous
materials, the risk assessment should contain a detailed analysis of
this operational scenario, backed with test data to support this type
of operation.
5. Use FCCs as a risk mitigation. The FAA has adopted SAE Standard
AS6453, "Fire Containment Cover - Design, Performance, and Testing
Requirements,"7 into FAA TSO-C203, "Fire Containment Covers."8
Similar to the case with FRCs, the standard provides testing
requirements that involve a Class A challenge fire composed of shredded
paper, FAA testing has shown that these covers are also able to
suppress certain fire loads comprising small amounts of lithium
batteries. See the FAA Fire Safety website provided above for research
results involving additional challenge fires. When using FCCs, or
standard pallets without an FCC, to ship hazardous materials, the risk
assessment should contain a detailed analysis of this operational
scenario, backed with test data to support this type of operation.
6. Participate in industry forums to develop standards or to stay
apprised of the development stages of future cargo fire safety risk
controls. The FAA collaborates with:
a. SAE AGE-2 Air Cargo Committee and additional industry and standards
organizations to develop testing requirements for a next generation of
passive fire resistant containers and fire containment covers, in
addition to active fire suppression technologies for palletized cargo.
b. SAE G-27 Lithium Battery Packaging Performance Committee to improve battery packaging standards.
Visit SAE International at https://www.sae.org to engage with these committees.
7. Consider the cargo safety enhancements recommended by the Commercial
Aviation Safety Team (CAST) at https://www.cast-safety.org/.
For Further Information Contact
Jamie Lessard, Aerospace Engineer, Policy and Standards Division, 800
Independence Avenue SW, Washington, DC 20591; e-mail:
Jamie.Lessard@faa.gov.
For Related Service Information Contact
Boeing Commercial Airplanes, Attention: Contractual & Data Services
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA
90740-5600; telephone 562-797-1717; website myboeingfleet.com.
1 Available on the internet at http://www.ntsb.gov/safety/safety-recs/recletters/A-12-068-070.pdf
2 For related information, refer to ICAO Document 10102,
"Guidance for Safe Operations Involving Aeroplane Cargo Compartments,"
at
https://store.icao.int/en/guidance-for-safe-operations-involving-aeroplane-cargo-compartments-doc-10102
3 Available on the internet at https://www.fire.tc.faa.gov/pdf/TC-17-39.pdf
4 Available on the internet at https://drs.faa.gov/browse/excelExternalWindow/8F1348EDECDF85DB86258761000ADD54.0001
5 Available on the internet at https://www.sae.org/standards/content/as8992/
6 Available on the internet at https://drs.faa.gov/browse/excelExternalWindow/0787200B17B61FDA86258711005CCFE3.0001
7 Available on the internet at https://www.sae.org/standards/content/as6453/
8 Available on the internet at https://drs.faa.gov/browse/excelExternalWindow/40602449E2C3AF8086257D09004EB95A.0001