DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2013-1029; Directorate Identifier 2013-NM-177-AD;
Amendment 39-18042; AD 2014-25-01]
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) 2010-13-04 for
certain Bombardier, Inc. Model DHC-8-400 series airplanes. AD 2010-13-
04 required modifying the nose landing gear (NLG) trailing arm. This
new AD requires installing a new pivot pin retention mechanism. This
new AD also adds airplanes to the applicability. This AD was prompted
by a report of several missing or damaged pivot pin retention bolts. We
are issuing this AD to prevent failure of the pivot pin retention bolt,
which could result in a loss of directional control or loss of a NLG
tire during take-off or landing.

DATES: This AD becomes effective January 16, 2015.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of January 16,
2015.
The Director of the Federal Register approved the incorporation by
reference of a certain other publication listed in this AD as of July
28, 2010 (75 FR 35622, June 23, 2010).

ADDRESSES: You may examine the AD docket on the Internet at http://www.regulations.gov/#!docketDetail;D=FAA-2013-1029; or in person at
the 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.
For service information identified in this AD, contact Bombardier,
Inc., Q-Series Technical Help Desk, 123 Garratt Boulevard, Toronto,
Ontario M3K 1Y5, Canada; telephone 416-375-4000; fax 416-375-4539;
email thd.qseries@aero.bombardier.com; Internet http://www.bombardier.com.
You may view this referenced service information at
the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton,
WA. For information on the availability of this material at the FAA,
call 425-227-1221.

FOR FURTHER INFORMATION CONTACT: Ricardo Garcia, Aerospace Engineer,
Airframe and Mechanical Systems Branch, ANE-171, FAA, New York Aircraft
Certification Office, 1600 Stewart Avenue, Suite 410, Westbury, NY
11590; telephone 516-228-7331; fax 516-794-5531.

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to supersede AD 2010-13-04, Amendment 39-16335 (75 FR 35622,
June 23, 2010). AD 2010-13-04 applied to certain Bombardier, Inc. Model
DHC-8-400 series airplanes. The NPRM published in the Federal Register
on December 24, 2013 (78 FR 77615).

Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued Canadian Airworthiness Directive CF-
2009-29R1, dated August 14, 2013 (referred to after this as the
Mandatory Continuing Airworthiness Information, or ``the MCAI''), to
correct an unsafe condition on certain Bombardier, Inc. Model DHC-8-400
series airplanes. The MCAI states:

Two in-service incidents have been reported on DHC-8 Series 400
aircraft in which the nose landing gear (NLG) trailing arm pivot pin
retention bolt (part number NAS6204-13D) was damaged. One incident
involved the left hand NLG tire which ruptured on take-off.
Investigation determined that the retention bolt failure was due to
repeated contact of the castellated nut with the towing device
including both the towbar and the towbarless rigs. The loss of the
retention bolt allowed the pivot pin to migrate from its normal
position and resulted in contact with and rupture of the tire. The
loss of the pivot pin could compromise retention of the trailing arm
and could result in a loss of directional control due to loss of
nose wheel steering. The loss of an NLG tire or the loss of
directional control could adversely affect the aircraft during take
off or landing.
To prevent the potential failure of the pivot pin retention
bolt, Bombardier Aerospace has developed a modification which
includes a new retention bolt, a reverse orientation of the
retention bolt and a rework of the weight on wheel (WOW) proximity
sensor cover to provide clearance for the re-oriented retention
bolt.
Since the original issue of this [Canadian] AD [which
corresponds to AD 2010-13-04, Amendment 39-16335 (75 FR 35622, June
23, 2010)], there have been several reports of pivot pin retention
bolts found missing or damaged. Additional investigation determined
that the failures were caused by high contact stresses on the
retention bolt due to excessive frictional torque on the pivot pin
and an adverse tolerance condition at the retention bolt.
Revision 1 of this [Canadian] AD mandates the installation of a
new pivot pin retention mechanism.

You may examine the MCAI in the AD docket on the Internet at http://www.regulations.gov/#!documentDetail;D=FAA-2013-1029-0002.

Comments

We gave the public the opportunity to participate in developing
this AD. The following presents the comments received on the NPRM (78
FR 77615, December 24, 2013) and the FAA's response to each comment.

Request To Revise Required Actions of Paragraph (h) of the Proposed AD
(78 FR 77615, December 24, 2013)

Horizon Air requested that we revise paragraph (h) of the proposed
AD (78 FR 77615, December 24, 2013) to refer to only the specific
section of the Accomplishment Instructions of the service information
that specifies the steps that correct the unsafe condition and exclude
the steps related to the set-up and close-out actions. Horizon Air
stated that only Part B. of the Accomplishment Instructions of
Bombardier Service Bulletin 84-32-110, Revision A, dated April 8, 2013,
contains any corrective actions.
We agree with the commenter's request and rationale for excluding
the ``Job Set-Up'' and ``Close Out'' sections of Bombardier Service
Bulletin 84-32-110, Revision A, dated April 8, 2013. We have revised
paragraph (h) of this AD to require accomplishment of paragraph 3.B.,
``Procedure,'' of the Accomplishment Instructions of Bombardier Service
Bulletin 84-32-110, Revision A, dated April 8, 2013.

Request To Provide Credit for Certain Actions

Horizon Air requested that we revise the proposed AD (78 FR 77615,
December 24, 2013) to provide credit for accomplishing Goodrich Service
Bulletin 47100-32-96. Horizon Air stated that a nose landing gear
repaired by Goodrich Landing Gear (or other repair station) using the
Goodrich service information would not have any Bombardier service
bulletin entered into the maintenance record as the service information
that was incorporated.
We do not agree. Paragraph (h) of this AD requires incorporating
Bombardier Modsum 4-113749, which is entirely contained in Bombardier
Service Bulletin 84-32-110, dated December 21, 2012; or Revision A,
dated April 8, 2013; but not in Goodrich Service Bulletin 47100-32-96.
The full contents of Bombardier Modsum 4-113749 must be incorporated
and noted in the maintenance records. Goodrich Service Bulletin 47100-
32-96 is considered to be a portion of the Bombardier Modsum.
Bombardier developed the Modsum in consideration of the overall
structure and airworthiness of the system. Paragraph (i)(2) of this AD
addresses the acceptable service information that we have determined
may be used as credit for complying with the requirements of paragraph
(h) of this AD to incorporate the Modsum. In addition, operators may
apply for an alternative method of compliance (AMOC) under the
provisions of paragraph (j)(1) of this AD. We have not changed this
final rule in this regard.

"Contacting the Manufacturer"' Paragraph in This AD

Since late 2006, we have included a standard paragraph titled
``Airworthy Product'' in all MCAI ADs in which the FAA develops an AD
based on a foreign authority's AD.
The MCAI or referenced service information in an FAA AD often
directs the owner/operator to contact the manufacturer for corrective
actions, such as a repair. Briefly, the Airworthy Product paragraph
allowed owners/operators to use corrective actions provided by the
manufacturer if those actions were FAA-approved. In addition, the
paragraph stated that any actions approved by the State of Design
Authority (or its delegated agent) are considered to be FAA-approved.
In the NPRM (78 FR 77615, December 24, 2013), we proposed to
prevent the use of repairs that were not specifically developed to
correct the unsafe condition, by requiring that the repair approval
provided by the State of Design Authority or its delegated agent
specifically refer to this FAA AD. This change was intended to clarify
the method of compliance and to provide operators with better
visibility of repairs that are specifically developed and approved to
correct the unsafe condition. In addition, we proposed to change the
phrase ``its delegated agent'' to include a design approval holder
(DAH) with State of Design Authority design organization approval
(DOA), as applicable, to refer to a DAH authorized to approve required
repairs for the proposed AD.
No comments were provided to the NPRM (78 FR 77615, December 24,
2013) about these proposed changes. However, a comment was provided for
an NPRM having Directorate Identifier 2012-NM-101-AD (78 FR 78285,
December 26, 2013). The commenter stated the following: ``The proposed
wording, being specific to repairs, eliminates the interpretation that
Airbus messages are acceptable for approving minor deviations
(corrective actions) needed during accomplishment of an AD mandated
Airbus service bulletin.''
This comment has made the FAA aware that some operators have
misunderstood or misinterpreted the Airworthy Product paragraph to
allow the owner/operator to use messages provided by the manufacturer
as approval of deviations during the accomplishment of an AD-mandated
action. The Airworthy Product paragraph does not approve messages or
other information provided by the manufacturer for deviations to the
requirements of the AD-mandated
actions. The Airworthy Product paragraph only addresses the requirement
to contact the manufacturer for corrective actions for the identified
unsafe condition and does not cover deviations from other AD
requirements. However, deviations to AD-required actions are addressed
in 14 CFR 39.17, and anyone may request the approval for an alternative
method of compliance to the AD-required actions using the procedures
found in 14 CFR 39.19.
To address this misunderstanding and misinterpretation of the
Airworthy Product paragraph, we have changed the paragraph and retitled
it ``Contacting the Manufacturer.'' This paragraph now clarifies that
for any requirement in this AD to obtain corrective actions from a
manufacturer, the actions must be accomplished using a method approved
by the FAA, the TCCA, or Bombardier, Inc.'s TCCA Design Approval
Organization (DAO).
The Contacting the Manufacturer paragraph also clarifies that, if
approved by the DAO, the approval must include the DAO-authorized
signature. The DAO signature indicates that the data and information
contained in the document are TCCA-approved, which is also FAA-
approved. Messages and other information provided by the manufacturer
that do not contain the DAO-authorized signature approval are not TCCA-
approved, unless TCCA directly approves the manufacturer's message or
other information.
This clarification does not remove flexibility previously afforded
by the Airworthy Product paragraph. Consistent with long-standing FAA
policy, such flexibility was never intended for required actions. This
is also consistent with the recommendation of the Airworthiness
Directive Implementation Aviation Rulemaking Committee to increase
flexibility in complying with ADs by identifying those actions in
manufacturers' service instructions that are ``Required for
Compliance'' with ADs. We continue to work with manufacturers to
implement this recommendation. But once we determine that an action is
required, any deviation from the requirement must be approved as an
alternative method of compliance.
Other commenters to the NPRM having Directorate Identifier 2012-NM-
101-AD (78 FR 78285, December 26, 2013) pointed out that in many cases
the foreign manufacturer's service bulletin and the foreign authority's
MCAI might have been issued some time before the FAA AD. Therefore, the
DOA might have provided U.S. operators with an approved repair,
developed with full awareness of the unsafe condition, before the FAA
AD is issued. Under these circumstances, to comply with the FAA AD, the
operator would be required to go back to the manufacturer's DOA and
obtain a new approval document, adding time and expense to the
compliance process with no safety benefit.
Based on these comments, we removed the requirement that the DAH-
provided repair specifically refer to this AD. Before adopting such a
requirement, the FAA will coordinate with affected DAHs and verify they
are prepared to implement means to ensure that their repair approvals
consider the unsafe condition addressed in this AD. Any such
requirements will be adopted through the normal AD rulemaking process,
including notice-and-comment procedures, when appropriate.
We also have decided not to include a generic reference to either
the ``delegated agent'' or ``DAH with State of Design Authority design
organization approval,'' but instead we have provided the specific
delegation approval granted by the State of Design Authority for the
DAH.

Conclusion

We reviewed the relevant data, considered the comments received,
and determined that air safety and the public interest require adopting
this AD with the changes described previously and minor editorial
changes. We have determined that these minor changes:
Are consistent with the intent that was proposed in the
NPRM (78 FR 77615, December 24, 2013) for correcting the unsafe
condition; and
Do not add any additional burden upon the public than was
already proposed in the NPRM (78 FR 77615, December 24, 2013).
We also determined that these changes will not increase the
economic burden on any operator or increase the scope of this AD.

Costs of Compliance

We estimate that this AD affects 383 airplanes of U.S. registry.
We estimate the following costs to comply with this AD:

Estimated Costs

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 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.

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.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov/#!docketDetail;D=FAA-2013-1029; 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 street address for the Docket Operations office (telephone 800-647-
5527) is in the ADDRESSES section.

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)
2010-13-04, Amendment 39-16335 (75 FR 35622, June 23, 2010), and adding
the following new AD: