DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0775; Product Identifier 2017-NM-048-AD; Amendment
39-19272; AD 2018-09-15]
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) 2016-25-18,
which applied to certain Bombardier, Inc., Model BD-700-1A10 and BD-
700-1A11 airplanes. AD 2016-25-18 required an inspection for
discrepancies of the attachment points of the links between the engine
rear mount assemblies, and corrective actions if necessary. This AD
requires an inspection of certain attachment points, corrective action
if necessary, and replacement of certain bolts and nuts in the engine
rear mount assemblies. This AD also adds airplanes to the
applicability. This AD was prompted by the determination that
replacement of certain nuts and bolts in the engine rear mount
assemblies is necessary. We are issuing this AD to address the unsafe
condition on these products.

DATES: This AD is effective June 15, 2018.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of June 15,
2018.
The Director of the Federal Register approved the incorporation by
reference of certain other publications listed in this AD as of January
3, 2017 (81 FR 90961, December 16, 2016).

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 Street, 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-2017-
0775.

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-2017-
0775; or in person at the Docket Management Facility between 9 a.m. and
5 p.m., Monday through Friday, except Federal holidays. The AD docket
contains this AD, the regulatory evaluation, any comments received, and
other information. The address for the Docket Office (telephone: 800-
647-5527) is Docket Management Facility, 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: Aziz Ahmed, Aerospace Engineer,
Airframe and Mechanical Systems Section, FAA, New York ACO Branch, 1600
Stewart Avenue, Suite 410, Westbury, NY 11590; telephone: 516-228-7329;
fax: 516-794-5531.

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to supersede AD 2016-25-18, Amendment 39-18744 (81 FR 90961,
December 16, 2016) (``AD 2016-25-18''). AD 2016-25-18 applied to
certain Bombardier, Inc., Model BD-700-1A10 and BD-700-1A11 airplanes.
The NPRM published in the Federal Register on August 15, 2017 (82 FR
38626). The NPRM was prompted by the determination that replacement of
certain nuts and bolts in the engine rear mount assemblies is
necessary. The NPRM proposed to continue to require an inspection for
discrepancies of the attachment points of the links between the engine
rear mount assemblies, and corrective actions if necessary. The NPRM
also proposed to require an inspection of certain attachment points,
corrective action if necessary, and replacement of certain bolts and
nuts in the engine rear mount assemblies. The NPRM also proposed to add
airplanes to the applicability. We are issuing this AD to detect and
correct broken engine attachment hardware, which could result in
separation of an engine from the airplane.
Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued Canadian AD CF-2016-23R1, dated
February 20, 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-700-1A10 and BD-700-
1A11 airplanes. The MCAI states:

Bombardier reported that during maintenance of a BD-700
aeroplane, the engine mount pin, part number (P/N) BRR15838, was
found backed out of the rear mount link. The retaining bolt, P/N
AS54020, which passes through the engine mount pin was also found
fractured at the groove which holds the locking spring. An
investigation revealed the most probable root cause of failure to be
a single axial tension static overload, with no evidence of fatigue
contributing to the failure.
The above condition if not detected, may result in the loss of
engine attachment to the airframe.
As an interim corrective action, Bombardier issued Service
Bulletins (SBs) 700-71-002, 700-71-6002, 700-71-5002, and 700-1A11-
71-002 to inspect the attachment points of the links between the
engine rear mount assemblies, and install replacement hardware if
required.
The original version of this [Canadian] AD was issued to mandate
incorporation of the above Bombardier SBs to inspect and maintain
integrity of the affected engine rear mount assembly.
Revision 1 of this [Canadian] AD is issued to mandate
incorporation of the Bombardier SBs 700-71-003, 700-71-6003, 700-71-
5003, and 700-1A11-71-003 to replace the existing bolts and self-
locking nuts with new bolts and nuts, as a final corrective action.

The MCAI also adds airplanes having serial numbers 9764, 9766, and
9771 through 9785 inclusive to the applicability. Those airplanes are
also affected by the identified unsafe condition. 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-2017-0775.

Comments

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

Requests To Provide Credit for Actions Previously Accomplished

NetJets Aviation requested that we provide credit for accomplishing
the actions specified in paragraphs (j) and (k) of the proposed AD
prior to the effective date of this AD. Bombardier requested that we
provide credit for accomplishing the actions specified in paragraphs
(k) and (l) of the proposed AD prior to the effective date of this AD.
We acknowledge the commenters' requests and agree to clarify.
Paragraph (f) of this AD states to accomplish the required actions
within the compliance times specified, ``unless already done.''
Therefore, if operators have accomplished the actions required for
compliance with this AD before the effective date of this AD, no
further action is necessary. We have not revised this AD in this
regard.

Conclusion

We reviewed the available data, including the comments received,
and determined that air safety and the public interest require adopting
this AD as proposed except for minor editorial changes. We have
determined that these minor changes:
Are consistent with the intent that was proposed in the
NPRM for correcting the unsafe condition; and
Do not add any additional burden upon the public than was
already proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

Bombardier, Inc. has issued the following service information. This
service information describes procedures for an inspection for
discrepancies of the attachment points of the links between the engine
rear mount assemblies and corrective actions. These documents are
distinct since they apply to different airplane models and serial
numbers.
Bombardier Service Bulletin 700-1A11-71-002, Revision 01,
dated June 30, 2016.
Bombardier Service Bulletin 700-71-002, Revision 01, dated
June 30, 2016.
Bombardier Service Bulletin 700-71-5002, Revision 01,
dated June 30, 2016.
Bombardier Service Bulletin 700-71-6002, Revision 01,
dated June 30, 2016.
Bombardier, Inc. has also issued the following service information.
This service information describes procedures for nut and bolt
replacements. These documents are distinct since they apply to
different airplane models and serial numbers.
Bombardier Service Bulletin 700-1A11-71-003, dated
December 5, 2016.
Bombardier Service Bulletin 700-71-003, dated December 5,
2016.
Bombardier Service Bulletin 700-71-5003, dated December 5,
2016.
Bombardier Service Bulletin 700-71-6003, dated December 5,
2016.
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 97 airplanes of U.S. registry.
The actions required by AD 2016-25-18, and retained in this AD take
about 1 work-hour per product, at an average labor rate of $85 per
work-hour. Based on these figures, the estimated cost of the actions
that are required by AD 2016-25-18 is $85 per product.
The retained on-condition costs in this AD take about 2 work-hours
per product, at an average labor rate of $85 per work-hour. Required
parts cost about $730 per product. Based on these figures, the
estimated cost of the on-condition actions that are required by AD
2016-25-18 is $900 per product.
We have received no definitive data that would enable us to provide
cost estimates for other retained on-condition actions specified in AD
2016-25-18.
We also estimate that it will take about 4 work-hours per product
to comply with the basic requirements of this AD. The average labor
rate is $85 per work-hour. Required parts will cost up to $14,940 per
product. Based on these figures, we estimate the cost of this AD on
U.S. operators to be up to $1,482,160, or up to $15,280 per product.
We have received no definitive data that would enable us to provide
cost estimates for the on-condition actions specified in this AD.
According to the manufacturer, some of the costs of this AD may be
covered under warranty, thereby reducing the cost impact on affected
individuals. We do not control warranty coverage for affected
individuals. As a result, we have included all available costs in our
cost estimate.

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)
2016-25-18, Amendment 39-18744 (81 FR 90961, December 16, 2016), and
adding the following new AD: