DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0987; Product Identifier 2019-NM-144-AD]
RIN 2120-AA64

Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain Bombardier, Inc., Model CL-600-2B19 (Regional Jet Series
100 & 440) airplanes. This proposed AD was prompted by reports that
during airplane wing fatigue testing, fatigue cracks were found on the
lower right-hand-side wing plank at the end of the integrally machined
stringers, which led to a determination that new or more restrictive
airworthiness limitations are necessary. This proposed AD would
require, for certain airplanes, revising the existing maintenance or
inspection program, as applicable, to incorporate new or more
restrictive airworthiness limitations. The FAA is proposing this
AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by February
10, 2020.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:

Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow
the instructions for submitting comments.

Fax: 202-493-2251.

Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.

Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this NPRM, contact
Bombardier, Inc., 400 C[ocirc]te-Vertu Road West, Dorval, Qu[eacute]bec
H4S 1Y9, Canada; Widebody Customer Response Center North America toll-
free telephone 1-866-538-1247 or direct-dial telephone 1-514-855-2999;
fax 514-855-7401; email ac.yul@aero.bombardier.com; internet
http://www.bombardier.com. You may view this 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.

Examining the AD Docket

You may examine the AD docket on the internet at https://www.regulations.gov
by searching for and locating Docket No. FAA-2019-
0987; 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 NPRM, the regulatory evaluation, any comments received, and other
information. The street address for Docket Operations is listed above.
Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Aziz Ahmed, Aerospace Engineer,
Airframe and Propulsion Section, FAA, New York ACO Branch, 1600 Stewart
Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7329; fax 516-
794-5531; email 9-avs-nyaco-cos@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under the ADDRESSES section. Include "Docket No. FAA-2019-0987;
Product Identifier 2019-NM-144-AD" at the beginning of your comments.
The FAA specifically invites comments on the overall regulatory,
economic, environmental, and energy aspects of this NPRM. The FAA will
consider all comments received by the closing date and may amend this
NPRM because of those comments.

The FAA will post all comments, without change, to https://www.regulations.gov,
including any personal information you provide. The FAA will also post a report
summarizing each substantive verbal contact the agency receives about this NPRM.

Discussion

Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued Canadian AD CF-2019-21, dated May 15,
2019 (referred to after this as the Mandatory Continuing Airworthiness
Information, or "the MCAI"), to correct an unsafe condition for
certain Bombardier, Inc., Model CL-600-2B19 (Regional Jet Series 100 &
440) airplanes. You may examine the MCAI in the AD docket on the
internet at https://www.regulations.gov by searching for and locating
Docket No. FAA-2019-0987.

This proposed AD was prompted by reports that during airplane wing
fatigue testing, fatigue cracks were found on the lower right-hand-side
wing plank at the end of the integrally machined stringers, which led
to a determination that new or more restrictive airworthiness
limitations are necessary. The FAA is proposing this AD to address
undetected cracks on the lower wing plank at the stringer run-out,
which could affect the structural integrity of the wing. See the MCAI
for additional background information.

Related Service Information Under 1 CFR Part 51

Bombardier has issued Nondestructive Testing Manual, CSP A-010,
Revision 40, dated November 10, 2018. This service information
describes airworthiness limitations for doing a special detailed
inspection of the lower wing skin splice joints at buttock line (BL)
45.00, wing station (WS) 65.75, and WS148.00. Bombardier has also
issued Temporary Revision 2B-2273, dated October 31, 2019, to Appendix
B--Airworthiness Limitations, of Part 2 of the Bombardier CL-600-2B19
Maintenance Requirements Manual. This service information describes
airworthiness limitations for doing an inspection for cracking on the
lower wing plank at the stringer run-out. 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.

FAA's Determination

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 the State of Design Authority,
the FAA has been notified of the unsafe condition described in the MCAI
and service information referenced above. The FAA is proposing this AD
because the FAA evaluated all the relevant information and determined
the unsafe condition described previously is likely to exist or develop
on other products of the same type design.

Proposed Requirements of This NPRM

This proposed AD would require revising the existing maintenance or
inspection program, as applicable, to incorporate new or more
restrictive airworthiness limitations.

This proposed AD would require revisions to certain operator
maintenance documents to include new actions (e.g., inspections).
Compliance with these actions is required by 14 CFR 91.403(c). For
airplanes that have been previously modified, altered, or repaired in
the areas addressed by this proposed AD, the operator may not be able
to accomplish the actions described in the revisions. In this
situation, to comply with 14 CFR 91.403(c), the operator must request
approval for an alternative method of compliance according to paragraph
(j)(1) of this proposed AD.

Differences Between This Proposed AD and the MCAI

Paragraph (h) of this proposed AD would require revising the
maintenance/inspection program to incorporate Airworthiness Limitations
(AWL) Task 57-21-169 for certain airplanes. The corresponding MCAI
requirement specifies incorporating this task using Bombardier
Temporary Revision 2B-2269, dated July 18, 2018, to Appendix B--
Airworthiness Limitations, of Part 2 of the Bombardier CL-600-2B19
Maintenance Requirements Manual. However, since the MCAI was issued,
that service information has been revised to Temporary Revision 2B-
2273, dated October 31, 2019 ("Temporary Revision 2B-2273").
Temporary Revision 2B-2273 defines the compliance time threshold, which
begins from the time the airplane entered into service. This
proposed AD would require incorporating Temporary Revision 2B-2273.

Costs of Compliance

The FAA estimates that this proposed AD affects 464 airplanes of
U.S. registry. The FAA estimates the following costs to comply with
this proposed AD:

The FAA has determined that revising the existing maintenance or
inspection program takes an average of 90 work-hours per operator,
although the FAA recognizes that this number may vary from operator to
operator. In the past, the FAA has estimated that this action takes 1
work-hour per airplane. Since operators incorporate maintenance or
inspection program changes for their affected fleet(s), the FAA has
determined that a per-operator estimate is more accurate than a per-
airplane estimate. Therefore, the FAA estimates the total cost per
operator to be $7,650 (90 work-hours x $85 per work-hour).

According to the manufacturer, some or all of the costs of this
proposed AD may be covered under warranty, thereby reducing the cost
impact on affected individuals. The FAA does not control warranty
coverage for affected individuals. As a result, the FAA has included
all known costs in the 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.

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 proposed 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 and associated appliances to the
Director of the System Oversight Division.

Regulatory Findings

The FAA determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 this proposed regulation:

(1) Is not a "significant regulatory action" under Executive
Order 12866,

(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
reference, Safety.

The Proposed Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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
directive (AD):