DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0161; Product Identifier 2017-NM-088-AD; Amendment
39-19450; AD 2018-20-16]

RIN 2120-AA64

Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: We are superseding Airworthiness Directive (AD) 2013-11-12,
which applied to certain Bombardier, Inc., Model BD-100-1A10 airplanes.
AD 2013-11-12 required inspecting for the correct serial number of a
certain hydraulic system accumulator, and replacing affected hydraulic
system accumulators with new or serviceable accumulators. This AD
expands the applicability and requires modifying or replacing certain
hydraulic brake system accumulators. This AD also requires revising the
maintenance or inspection program to add life limits for the
accumulators. This AD was prompted by a determination that certain
other hydraulic system accumulators must be modified or replaced and
life limits must be added. We are issuing this AD to address the unsafe
condition on these products.

DATES: This AD is effective November 23, 2018.

The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of November 23,
2018.

The Director of the Federal Register approved the incorporation by
reference of a certain other publication listed in this AD as of July
9, 2013 (78 FR 33206, June 4, 2013).

ADDRESSES: For service information identified in this final rule,
contact Bombardier, Inc., 400 Cote-Vertu Road West, Dorval,
Quebec H4S 1Y9, Canada; telephone 514-855-5000; fax 514-855-
7401; email thd.crj@aero.bombardier.com; internet http://www.
bombardier.com. You may view this referenced service information at
the FAA, Transport Standards 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 on the internet at http://www.
regulations.gov by searching for and locating Docket No. FAA-2018-0161.

Examining the AD Docket

You may examine the AD docket on the internet at http://www.regulations.
gov by searching for and locating Docket No. FAA-2018-
0161; 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 regulatory evaluation, any comments received, and
other information. The address for Docket Operations (phone: 800-647-
5527) 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.

FOR FURTHER INFORMATION CONTACT: Cesar Gomez, Aerospace Engineer,
Airframe and Mechanical Systems Section, FAA, New York ACO Branch, 1600
Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7318;
fax 516-794-5531.

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to supersede AD 2013-11-12, Amendment 39-17472 (78 FR 33206,
June 4, 2013) (``AD 2013-11-12''). AD 2013-11-12 applied to certain
Bombardier, Inc., Model BD-100-1A10 airplanes. The NPRM published in
the Federal Register on March 9, 2018 (83 FR 10415). The NPRM was
prompted by a determination that certain other hydraulic system
accumulators must be modified or replaced and life limits must be
added. The NPRM proposed to continue to require inspecting for the
correct serial number of a certain hydraulic system accumulator, and
replacing affected hydraulic system accumulators with new or
serviceable accumulators. The NPRM also proposed to expand the
applicability and require modifying or replacing certain hydraulic
brake system accumulators. The NPRM also proposed to require revising
the maintenance or inspection program to add life limits for the
accumulators. We are issuing this AD to prevent failure of a screw cap
or end cap and loss of the related hydraulic system, which could result
in damage to airplane structure and consequent reduced controllability
of the airplane.

Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued Canadian Airworthiness Directive CF-
2011-41R1, dated March 27, 2017 (referred to after this as the
Mandatory Continuing Airworthiness Information, or ``the MCAI''), to
correct an unsafe condition for certain Bombardier, Inc. Model BD-100-
1A10 airplanes. The MCAI states:

Seven cases of on-ground hydraulic accumulator screw cap/end cap
failure have been experienced on CL-600-2B19 aeroplanes, resulting
in loss of the associated hydraulic system and high-energy impact
damage to adjacent systems and structure. To date, the lowest number
of flight cycles accumulated at the time of failure has been 6991.

Although there have been no failures to date on any BD-100-1A10
aeroplanes, accumulators similar to those installed on the CL-600-
2B19 are installed on the BD-100-1A10. The affected part numbers (P/
Ns) of the accumulators installed on BD-100-1A10 are 900095-1

(Auxiliary Hydraulic System accumulator), 33-155500 (Inboard Brake
accumulator), and 33-147500 (Outboard Brake accumulator).

A detailed analysis of the calculated line of trajectory of a
failed screw cap/end cap for the accumulators has been conducted,
resulting in the identification of areas where systems and/or
structural components could potentially be damaged. Although all of
the failures on the CL-600-2B19 to date have occurred on the ground,
an in-flight failure affecting such components could potentially
have an adverse effect on the controllability of the aeroplane.

Revision 1 of this [Canadian] AD is issued to mandate the
[inspection and] replacement [of] Brake System Hydraulic
accumulators that are not identified by the letter ``E'' or ``NAE''
after the serial number on the identification plate. Revision 1 also
mandates the re-orientation of the brake accumulators P/N 33-147500
and P/N 33-155500 and the insertion of three discard tasks in the
Challenger 300 Time Limits/Maintenance Checks (TLMC) Manual.

You may examine the MCAI in the AD docket on the internet at http://
www.regulations.gov by searching for and locating Docket No. FAA-2018-0161.

Comments

We gave the public the opportunity to participate in developing
this final rule. The following presents the comment received on the
NPRM and the FAA's response.

Request To Add Maintenance Manual

NetJets Aviation stated that paragraph (n) of the proposed AD,
which requires revising the maintenance or inspection program to
incorporate certain life limit tasks, does not reference the Bombardier
Challenger 350 Time Limits/Maintenance Check (TLMC) Manual. NetJets
Aviation noted that only the Bombardier Challenger 300 TLMC Manual is
referenced.

We infer that the commenter is asking that the Bombardier
Challenger 350 TLMC Manual be added as another source of service
information for accomplishing the actions required by paragraph (n) of
this AD. We agree with the commenter's request and have changed
paragraph (n) accordingly. Although the tasks identified in the
Bombardier Challenger 300 TLMC Manual also apply to Bombardier
Challenger 350 airplanes, we have included the Bombardier Challenger
350 TLMC in this AD for clarity.

Conclusion

We reviewed the relevant data, considered the comment received, and
determined that air safety and the public interest require adopting
this final rule with the change described previously and minor
editorial changes. We have determined that these minor changes:

Are consistent with the intent that was proposed in the
NPRM for addressing the unsafe condition; and

Do not add any additional burden upon the public than was
already proposed in the NPRM.

We also determined that this change will not increase the economic
burden on any operator or increase the scope of this final rule.

Related Service Information Under 1 CFR Part 51

Bombardier has issued the following service information:

Service Bulletin 100-32-20, Revision 02, dated April 14,
2015, which describes procedures for modifying (e.g., re-orienting) the
installation of the hydraulic brake accumulators.

Service Bulletin 100-32-21, dated May 24, 2012, which
describes procedures for replacing the hydraulic brake system
accumulators.

Task 29-21-13-101 Discard the Auxiliary Hydraulic System
Accumulator, Part No. 900095-1, of Section 5-10-11 of Part 2,
``Airworthiness Limitations,'' of Bombardier Challenger 300 BD-100 Time
Limits/Maintenance Checks Manual, Revision 17, dated December 15, 2016;
and Bombardier Challenger 350, BD-100 Time Limits/Maintenance Checks
Manual, Revision 9, dated December 18, 2017, which describes procedures
for removal and installation of the hydraulic brake system
accumulators. These tasks are distinct since they apply to different
airplane models.

Task 32-43-37-101 Discard the Brake Accumulator, Part No.
33-147500, of Section 5-10-11 of Part 2, ``Airworthiness Limitations,''
of Bombardier Challenger 300 BD-100 Time Limits/Maintenance Checks
Manual, Revision 17, dated December 15, 2016; and Bombardier Challenger
350, BD-100 Time Limits/Maintenance Checks Manual, Revision 9, dated
December 18, 2017, which describes procedures for removal and
installation of the brake accumulators. These tasks are distinct since
they apply to different airplane models.

Task 32-44-05-101 Discard the Emergency/Parking Brake

Accumulator, Part No. 33-155500, of Section 5-10-11 of Part 2,
``Airworthiness Limitations,'' of Bombardier Challenger 300 BD-100 Time
Limits/Maintenance Checks Manual, Revision 17, dated December 15, 2016;
and Bombardier Challenger 350, BD-100 Time Limits/Maintenance Checks
Manual, Revision 9, dated December 18, 2017, which describes procedures
for removal and installation of the emergency parking brake
accumulators. These tasks are distinct since they apply to different
airplane models.

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 the ADDRESSES section.

Costs of Compliance

We estimate that this AD affects 187 airplanes of U.S. registry.

We estimate the following costs to comply with this AD:

Estimated Costs

We have determined that revising the maintenance or inspection
program takes an average of 90 work-hours per operator, although we
recognize that this number may vary from operator to operator. In the
past, we have estimated that this action takes 1 work-hour per
airplane. Since operators incorporate maintenance or inspection program
changes for their affected fleet(s), we have determined that a per-
operator estimate is more accurate than a per-airplane estimate.

Therefore, we estimate the total cost per operator to be $7,650 (90
work-hours x $85 per work-hour).

We estimate the following costs to do any necessary replacements
that will be required based on the results of the inspection. We have
no way of determining the number of aircraft that might need these
replacements.

On-Condition Costs

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.

We are 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 is issued in accordance with authority delegated by the
Executive Director, Aircraft Certification Service, as authorized by
FAA Order 8000.51C. In accordance with that order, issuance of ADs is
normally a function of the Compliance and Airworthiness Division, but
during this transition period, the Executive Director has delegated the
authority to issue ADs applicable to transport category airplanes to
the Director of the System Oversight Division.

Regulatory Findings

We determined that 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 Order
12866;

2. Is not a ``significant rule'' under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979);

3. Will not affect intrastate aviation in Alaska; and

4. 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
reference, Safety.

Adoption of the Amendment

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 removing Airworthiness Directive (AD)
2013-11-12, Amendment 39-17472 (78 FR 33206, June 4, 2013), and adding
the following new AD: