DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2022-1154; Project Identifier MCAI-2022-00550-T;
Amendment 39-22250; AD 2022-24-10]
Airworthiness Directives; MHI RJ Aviation ULC (Type Certificate
Previously Held by Bombardier, Inc.) Airplanes
AGENCY: Federal Aviation Administration (FAA), Department of
ACTION: Final rule.
SUMMARY: The FAA is adopting a new airworthiness directive (AD)
MHI RJ Aviation ULC Model CL-600-2C10 (Regional Jet Series 700, 701 &
702) airplanes, Model CL-600-2C11 (Regional Jet Series 550) airplanes,
Model CL-600-2D15 (Regional Jet Series 705) airplanes, Model CL-600-
2D24 (Regional Jet Series 900) airplanes, and Model CL-600-2E25
(Regional Jet Series 1000) airplanes. This AD was prompted by a report
that the pressure switch gauge assembly for the cargo bay fire
extinguisher container has the potential to display an incorrect
pressure under certain environmental conditions. This AD requires
replacing affected high rate of discharge (HRD) and low rate of
discharge (LRD) pressure switch gauge assemblies for the cargo bay fire
extinguisher container. The FAA is issuing this AD to address the
unsafe condition on these products.
DATES: This AD is effective January 18, 2023.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of January 18,
AD Docket: You may examine the AD docket at regulations.gov under
Docket No. FAA-2022-1154; or in person at Docket Operations between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD
docket contains this final rule, the mandatory continuing airworthiness
information (MCAI), any comments received, and other information. The
address for Docket Operations is U.S. Department of Transportation,
Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200
New Jersey Avenue SE, Washington, DC 20590.
Material Incorporated by Reference:
For service information identified in this final rule,
contact MHI RJ Aviation Group, Customer Response Center, 3655 Ave. des
Grandes-Tourelles, Suite 110, Boisbriand, Quebec J7H 0E2 Canada;
North America toll-free telephone 833-990-7272 or direct-dial telephone
450-990-7272; fax 514-855-8501; email email@example.com; website
You may view this service information at the FAA,
Airworthiness Products Section, Operational Safety Branch, 2200 South
216th St., Des Moines, WA. For information on the availability of this
material at the FAA, call 206-231-3195. It is also available at
regulations.gov under Docket No. FAA-2022-1154.
FOR FURTHER INFORMATION CONTACT: Gabriel Kim, Aerospace Engineer,
Mechanical Systems and Administrative Services Section, FAA, New York
ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
telephone 516-228-7300; email firstname.lastname@example.org.
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to all MHI RJ Aviation ULC
Model CL-600-2C10 (Regional Jet Series 700, 701 & 702) airplanes, Model
CL-600-2C11 (Regional Jet Series 550) airplanes, Model CL-600-2D15
(Regional Jet Series 705) airplanes, Model CL-600-2D24 (Regional Jet
Series 900) airplanes, and Model CL-600-2E25 (Regional Jet Series 1000)
airplanes. The NPRM published in the Federal Register on September 12,
2022 (87 FR 55735). The NPRM was prompted by AD CF-2022-20, dated April
19, 2022, issued by Transport Canada, which is the aviation authority
for Canada (referred to after this as the MCAI). The MCAI states that
the pressure switch gauge assembly for the cargo bay fire extinguisher
container has the potential to display an incorrect pressure under
certain environmental conditions. The supplier attributed the root
cause of the container pressure display error to the use of a room
temperature vulcanizing (RTV) silicone. Both the HRD and LRD cargo bay
fire extinguisher containers are affected. The airplane is intended to
be operated at temperatures as low as -53.8°C (-65°F).
However, testing has shown that at temperatures below-49.4°C (-57°
F), the RTV silicone goes through a glass transition that causes
locking of the discharge indication microswitch in a closed state
(showing normal pressure) on 50 percent of the assemblies tested. After
returning to above -35.0°C (-31.5°F) for more than 6 minutes,
the pressure switch gauge assembly returns to normal operation. If the
flightcrew does not receive an indication of low pressure and there is
a fire in the cargo bay, reduced fire extinguisher container capacity
below the level required to appropriately suppress a cargo fire could
lead to an uncontrollable fire and loss of the airplane.
In the NPRM, the FAA proposed to require replacing affected HRD and
LRD pressure switch gauge assemblies for the cargo bay fire
You may examine the MCAI in the AD docket at regulations.gov under
Docket No. FAA-2022-1154.
Discussion of Final Airworthiness Directive
The FAA received comments from Air Line Pilots Association,
International, who supported the NPRM without change.
This product has been approved by the aviation authority of another
country and is approved for operation in the United States. Pursuant to
the FAA's bilateral agreement with this State of Design Authority, it
has notified the FAA of the unsafe condition described in the MCAI
referenced above. The FAA reviewed the relevant data, considered the
comments received, and determined that air safety requires adopting
this AD as proposed. Accordingly, the FAA is issuing this AD to address
the unsafe condition on this product. Except for
minor editorial changes, this AD is adopted as proposed in the NPRM.
None of the changes will increase the economic burden on any operator.
Related Service Information Under 1 CFR Part 51
MHI RJ Aviation ULC has issued Service Bulletin 670BA-26-013, dated
October 8, 2021. This service information describes procedures for
replacing the HRD and LRD pressure switch gauge assemblies for cargo
bay fire extinguisher containers part numbers (P/N) 473919-1, P/N
473920-1, and P/N 474901-1, manufactured prior to March 2020 as
indicated on the identification plate. This service information is
reasonably available because the interested parties have access to it
through their normal course of business or by the means identified in
Costs of Compliance
The FAA estimates that this AD affects 564 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:
Estimated Costs for Required Actions
|4 work-hours x $85 per hour =
The FAA has included all known costs
in its cost estimate.
According to the manufacturer, however, some or all of the costs of
this AD may be covered under warranty, thereby reducing the cost impact
on affected operators.
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. Subtitle VII: Aviation Programs,
describes in more detail the scope of the Agency's authority.
The FAA is issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701: General requirements.
Under that section, Congress charges the FAA with promoting safe flight
of civil aircraft in air commerce by prescribing regulations for
practices, methods, and procedures the Administrator finds necessary
for safety in air commerce. This regulation is within the scope of that
authority because it addresses an unsafe condition that is likely to
exist or develop on products identified in this rulemaking action.
This AD will not have federalism implications under Executive Order
13132. This AD will not have a substantial direct effect 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.
For the reasons discussed above, I certify that this AD:
(1) Is not a ``significant regulatory action'' under Executive
(2) Will not affect intrastate aviation in Alaska, and
(3) Will not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. The FAA amends Sec. 39.13 by adding the following new airworthiness