
[Federal Register Volume 81, Number 236 (Thursday, December 8, 2016)]
[Rules and Regulations]
[Pages 88623-88627]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-28210]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-4224; Directorate Identifier 2015-NM-170-AD; 
Amendment 39-18720; AD 2016-24-03]
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 adopting a new airworthiness directive (AD) for certain 
Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted 
by reports of cracked and corroded barrel nuts found at the mid-spar 
location of the horizontal-stabilizer-to-vertical-stabilizer attachment 
joint. This AD requires repetitive detailed

[[Page 88624]]

inspections of each barrel nut and cradle, a check of the bolt torque 
of the preload indicating (PLI) washers, and corrective action if 
necessary. We are issuing this AD to address the unsafe condition on 
these products.

DATES: This AD is effective January 12, 2017.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of January 12, 
2017.

ADDRESSES: For service information identified in this final rule, 
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. It is also available on the 
Internet at http://www.regulations.gov by searching for and locating 
Docket No. FAA-2016-4224.

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-2016-
4224; 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 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 Branch, ANE-171, FAA, New York Aircraft 
Certification Office (ACO), 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 by adding an AD that would apply to certain Bombardier, Inc. 
Model DHC-8-400 airplanes. The NPRM published in the Federal Register 
on March 14, 2016 (81 FR 13298) (``the NPRM''). The NPRM was prompted 
by reports of cracked and corroded barrel nuts found at the mid-spar 
location of the horizontal-stabilizer-to-vertical-stabilizer attachment 
joint. The NPRM proposed to require repetitive detailed inspections of 
each barrel nut and cradle, a check of the bolt torque of the PLI 
washers, and corrective action if necessary. We are issuing this AD to 
detect and correct cracked and corroded barrel nuts, which could 
compromise the structural integrity of the vertical-stabilizer 
attachment joints and lead to loss of control of the airplane.
    Transport Canada Civil Aviation (TCCA), which is the aviation 
authority for Canada, issued Canadian Airworthiness Directive CF-2015-
13, dated June 25, 2015 (referred to after this as the Mandatory 
Continuing Airworthiness Information, or ``the MCAI''), to correct an 
unsafe condition for certain Bombardier, Inc. Model DHC-8-400 series 
airplanes. The MCAI states:

    There has been one in-service report of a cracked and corroded 
barrel nut, part number (P/N) DSC228-12, found at the mid-spar 
location of the horizontal stabilizer to vertical stabilizer 
attachment joint. There have also been two other reports of corroded 
barrel nuts found at mid-spar locations.
    Preliminary investigation determined that the cracking is 
initiated by corrosion. The corrosion may have been caused by 
inadequate cadmium plating on the barrel nut. Failure of the barrel 
nuts could compromise the structural integrity of the joint and 
could lead to loss of control of the aeroplane.
    This [Canadian] AD mandates initial and repetitive inspections 
of the barrel nuts [and cradles for cracks and corrosion] at each 
horizontal stabilizer to vertical stabilizer attachment joints.

    Required actions include a bolt preload check of the PLI washers 
and applicable corrective actions (retorque of the bolts and 
replacement of the barrel nut), a detailed inspection of cracked or 
broken barrel nuts for damaged bores of the fittings, replacement of 
barrel nuts, and repair of damage and corrosion.
    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-2016-
4224.

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.

Support for the NPRM

    The Air Line Pilots Association, International, and a commenter, 
Lara Gabrys, supported the intent of the NPRM.

Request To Specify Revised Service Information

    The source of service information in the NPRM--Bombardier Alert 
Service Bulletin A84-55-04, Revision A, dated June 2, 2015--has been 
revised. Horizon Air requested that we revise the NPRM to refer to the 
latest version of the service information.
    We agree and have revised this final rule to identify Bombardier 
Alert Service Bulletin A84-55-04, Revision C, dated May 3, 2016, as the 
appropriate source of service information. The revised service 
information clarifies certain conditional actions; the major actions 
remain essentially unchanged. We have also revised paragraph (m) of 
this AD to include all earlier revisions as credit for prior 
accomplishment of the corresponding actions specified in this AD.

Request for Terminating Action

    Commenter Lara Gabrys expressed concern about the unsafe condition 
and the lack of a permanent solution to address it.
    We acknowledge the commenter's concern, and point out that this 
final rule (as also specified in the NPRM) requires that operators 
submit their inspection findings to Bombardier. Then, based on those 
findings, Bombardier plans to develop a permanent solution to address 
the unsafe condition. If terminating action is developed, approved, and 
available, we might consider additional rulemaking. At this time, 
however, we are issuing this final rule as proposed.

Request To Limit Required Actions

    Paragraphs (g)(1), (g)(2), (h)(1)(i), (h)(1)(ii), (i), and (k) of 
the proposed AD specified that certain actions be done in accordance 
with ``the Accomplishment Instructions'' of the referenced service 
information. Noting that ``the Accomplishment Instructions'' include 
paragraphs 3.A., ``Job Set-Up,'' and 3.C., ``Close Out,'' Horizon Air 
requested that the compliance method instead be limited to paragraph 
3.B., ``Procedures''--the only section that corrects the unsafe 
condition. Horizon Air objected to the inclusion of the specified set-
up and close-out procedures, which would restrict the operators' 
ability to perform other maintenance in conjunction with the 
incorporation of the service information.

[[Page 88625]]

    We agree with the request, for the reasons provided by the 
commenter. We have revised paragraphs (g)(1), (g)(2), (h)(1)(i), 
(h)(1)(ii), (i), and (k) of this AD, as well as paragraph (h)(1) of 
this AD, to refer to paragraph 3.B., ``Procedures.''

Clarification of Applicability

    This AD affects Model DHC-8-400, -401, and -402 airplanes. The 
SUMMARY of the NPRM and paragraph (c) of the proposed AD identified the 
affected airplanes as ``Model DHC-8-400 airplanes.'' Model DHC-8-400 
series airplanes consist of Model DHC-8-400, -401, and -402 airplanes 
and correspond to the affected airplanes identified in the MCAI. We 
have therefore revised the SUMMARY to identify the affected airplanes 
as certain ``Model DHC-8-400 series airplanes.'' We also revised 
paragraph (c) of this AD to identify the applicability as ``Model DHC-
8-400, -401, and -402 airplanes'' with serial numbers 4001 and 
subsequent.

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 for correcting the unsafe condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM.
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this AD.

Related Service Information Under 1 CFR Part 51

    Bombardier, Inc. has issued Alert Service Bulletin A84-55-04, 
Revision C, dated May 3, 2016. The service information describes 
procedures for a detailed inspection and repair for cracks and 
corrosion of the barrel nuts and cradles, a bolt preload check of the 
PLI washers, applicable corrective actions, a detailed inspection and 
repair for corrosion and damage of the bores of the fittings, and 
replacement of the barrel nuts.
    Bombardier, Inc. has also issued Bombardier Repair Drawing (RD) 8/
4-55-1143, Issue 1, dated May 21, 2015. The service information 
describes procedures for repairing corrosion and damage of the fitting 
bore.
    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 76 airplanes of U.S. registry.
    We also estimate that it will take about 6 work-hours per product 
to comply with the basic requirements of this AD and 1 work-hour per 
product for reporting. The average labor rate is $85 per work-hour. 
Required parts will cost about $0 per product. Based on these figures, 
we estimate the cost of this AD on U.S. operators to be $45,220, or 
$595 per product.
    In addition, we estimate that any necessary follow-on actions would 
take about 4 work-hours, and require parts costing $8,881, for a cost 
of $9,221 per product. We have no way of determining the number of 
aircraft that might need this action.

Paperwork Reduction Act

    A federal agency may not conduct or sponsor, and a person is not 
required to respond to, nor shall a person be subject to penalty for 
failure to comply with a collection of information subject to the 
requirements of the Paperwork Reduction Act unless that collection of 
information displays a current valid OMB control number. The control 
number for the collection of information required by this AD is 2120-
0056. The paperwork cost associated with this AD has been detailed in 
the Costs of Compliance section of this document and includes time for 
reviewing instructions, as well as completing and reviewing the 
collection of information. Therefore, all reporting associated with 
this AD is mandatory. Comments concerning the accuracy of this burden 
and suggestions for reducing the burden should be directed to the FAA 
at 800 Independence Ave. SW., Washington, DC 20591, ATTN: Information 
Collection Clearance Officer, AES-200.

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.

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

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

2016-24-03 Bombardier, Inc.: Amendment 39-18720; Docket No. FAA-
2016-4224; Directorate Identifier 2015-NM-170-AD.

(a) Effective Date

    This AD is effective January 12, 2017.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Bombardier, Inc. Model DHC-8-400, -401, and -
402 airplanes, certificated in any category, serial numbers 4001 and 
subsequent.

[[Page 88626]]

(d) Subject

    Air Transport Association (ATA) of America Code 55, Stablizers.

(e) Reason

    This AD was prompted by reports of cracked and corroded barrel 
nuts found at the mid-spar location of the horizontal-stabilizer-to-
vertical-stabilizer attachment joint. We are issuing this AD to 
detect and correct cracked and corroded barrel nuts, which could 
compromise the structural integrity of the vertical-stabilizer 
attachment joints and lead to loss of control of the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Detailed Inspection of Barrel Nuts for Cracks and Corrosion

    (1) For airplanes that have accumulated 5,400 flight hours or 
more, or have been in service 32 months or more since the date of 
issuance of the original certificate of airworthiness or the date of 
issuance of the original export certificate of airworthiness, as of 
the effective date of this AD: Within 600 flight hours or 4 months, 
whichever occurs first after the effective date of this AD, do a 
detailed visual inspection for signs of cracks and corrosion of the 
barrel nut and cradle, in accordance with paragraph 3.B., 
``Procedures,'' of the Accomplishment Instructions of Bombardier 
Alert Service Bulletin A84-55-04, Revision C, dated May 3, 2016.
    (2) For airplanes that have less than 5,400 flight hours, and 
have been in-service for less than 32 months since the date of 
issuance of the original certificate of airworthiness or the date of 
issuance of the original export certificate of airworthiness, as of 
the effective date of this AD: Before the accumulation of 6,000 
total flight hours or 36 months since the date of issuance of the 
original certificate of airworthiness or the date of issuance of the 
original export certificate of airworthiness, whichever occurs 
first, do a detailed visual inspection of the barrel nut for signs 
of cracks and corrosion of the barrel nut and cradle, in accordance 
with paragraph 3.B., ``Procedures,'' of the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A84-55-04, 
Revision C, dated May 3, 2016.

(h) Corrective Actions, Detailed Inspection, and Repetitive Inspections

    Depending on the findings of any inspection required by 
paragraphs (g) and (j) of this AD, do the applicable actions in 
paragraphs (h)(1), (h)(2), and (h)(3) of this AD.
    (1) If any barrel nut or cradle is found cracked or broken, 
before further flight, replace the barrel nut and associated 
hardware, in accordance with paragraph 3.B., ``Procedures,'' of the 
Accomplishment Instructions of Bombardier Alert Service Bulletin 
A84-55-04, Revision C, dated May 3, 2016.
    (i) Concurrently with the replacement of any barrel nut, do a 
detailed inspection for corrosion and damage of the bore of the 
fitting, in accordance with paragraph 3.B., ``Procedures,'' of the 
Accomplishment Instructions of Bombardier Alert Service Bulletin 
A84-55-04, Revision C, dated May 3, 2016, and, before further 
flight, repair all corrosion and damage, in accordance with 
Bombardier Repair Drawing (RD) 8/4-55-1143, Issue 1, dated May 21, 
2015. If the bore of the fitting cannot be repaired in accordance 
with Bombardier RD 8/4-55-1143, Issue 1, dated May 21, 2015, 
accomplish corrective actions in accordance with the procedures 
specified in paragraph (n)(2) of this AD.
    (ii) Within 600 flight hours or 4 months, whichever occurs 
first, after the replacement of a cracked barrel nut, replace the 
remaining barrel nuts and their associated hardware at the 
horizontal-stabilizer-to-vertical-stabilizer attachment joints, in 
accordance with paragraph 3.B., ``Procedures,'' of the 
Accomplishment Instructions of Bombardier Alert Service Bulletin 
A84-55-04, Revision C, dated May 3, 2016.
    (2) If any corrosion is found on any barrel nut on the front or 
rear-spar joints, before further flight, replace the barrel nut 
accomplish corrective actions in accordance with the procedures 
specified in paragraph (n)(2) of this AD.
    (3) If any corrosion above level 1, as defined in Bombardier 
Alert Service Bulletin A84-55-04, Revision C, dated May 3, 2016, is 
found on a barrel nut at the mid-spar joint, before further flight, 
replace the barrel nut and accomplish corrective actions in 
accordance with the procedures specified in paragraph (n)(2) of this 
AD.
    (4) If all corrosion found is at level 1 or below, as defined in 
Bombardier Alert Service Bulletin A84-55-04, Revision C, dated May 
3, 2016, on a barrel nut at the mid-spar joint, repeat the 
inspection specified in paragraph (g) of this AD at intervals not to 
exceed 600 flight hours or 4 months, whichever occurs first, until 
completion of the actions required by paragraph (k) of this AD.

(i) Preload Indicating (PLI) Washer Check

    For airplanes with PLI washers installed at the front and rear-
spar joints, before further flight after accomplishing any 
inspection required by (g) of this AD and all applicable corrective 
actions required by paragraph (h) of this AD, check the bolt 
preload, and do all applicable corrective actions, in accordance 
with paragraph 3.B., ``Procedures,'' of the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A84-55-04, 
Revision C, dated May 3, 2016. Do all applicable corrective actions 
before further flight.

(j) Repetitive Inspection Interval

    Repeat the inspection and preload check required by paragraphs 
(g) and (i) of this AD at intervals not to exceed 3,600 flight hours 
or 18 months, whichever occurs first, except as provided by 
paragraph (k) of this AD.

(k) Optional Barrel Nut Replacement

    Inspection and replacement of all barrel nuts at the horizontal-
stabilizer-to vertical-stabilizer attachment joints, in accordance 
with paragraph 3.B., ``Procedures,'' of the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A84-55-04, 
Revision C, dated May 3, 2016, extends the next inspection required 
by paragraph (j) of this AD to within 6,000 flight hours or 36 
months, whichever occurs first, after accomplishing the replacement.

(l) Reporting Requirements

    At the applicable time specified in paragraph (l)(1) or (l)(2) 
of this AD, submit a report of the findings (both positive and 
negative) of each inspection required by this AD to Technical Help 
Desk--Q-series, telephone: 416-375-4000, fax: 416-375-4539, email: 
thd.qseries@aero.bombardier.com, using the inspection form in 
Bombardier Alert Service Bulletin A84-55-04, Revision C, dated May 
3, 2016.
    (1) If the inspection was done on or after the effective date of 
this AD: Submit the report within 30 days after the inspection.
    (2) If the inspection was done before the effective date of this 
AD: Submit the report within 30 days after the effective date of 
this AD.

(m) Credit for Previous Actions

    This paragraph provides credit for the corresponding actions 
specified in paragraphs (g)(1), (g)(2), (h)(1), (h)(1)(i), 
(h)(1)(ii), (h)(3), (h)(4), (i), (k), and (l) of this AD, if those 
actions were performed before the effective date of this AD using 
the service information identified in paragraphs (m)(1), (m)(2), and 
(m)(3) of this AD.
    (1) Bombardier Alert Service Bulletin A84-55-04, dated May 21, 
2015.
    (2) Bombardier Alert Service Bulletin A84-55-04, Revision A, 
dated June 2, 2015.
    (3) Bombardier Alert Service Bulletin A84-55-04, Revision B, 
dated July 30, 2015.

(n) Other FAA AD Provisions

    The following provisions also apply to this AD:
    (1) Alternative Methods of Compliance (AMOCs): The Manager, New 
York ACO, ANE-170, FAA, has the authority to approve AMOCs for this 
AD, if requested using the procedures found in 14 CFR 39.19. In 
accordance with 14 CFR 39.19, send your request to your principal 
inspector or local Flight Standards District Office, as appropriate. 
If sending information directly to the ACO, send it to ATTN: Program 
Manager, Continuing Operational Safety, FAA, New York ACO, 1600 
Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-
7300; fax 516-794-5531. Before using any approved AMOC, notify your 
appropriate principal inspector, or lacking a principal inspector, 
the manager of the local flight standards district office/
certificate holding district office. The AMOC approval letter must 
specifically reference this AD.
    (2) Contacting the Manufacturer: For any requirement in this AD 
to obtain corrective actions from a manufacturer, the action must be 
accomplished using a method approved by the Manager, New York ACO, 
ANE-170, FAA; or Transport Canada Civil Aviation (TCCA); or 
Bombardier, Inc.'s TCCA DAO. If approved by the DAO, the approval 
must include the DAO-authorized signature.
    (3) Reporting Requirements: A federal agency may not conduct or 
sponsor, and a person is not required to respond to, nor shall a 
person be subject to a penalty for

[[Page 88627]]

failure to comply with a collection of information subject to the 
requirements of the Paperwork Reduction Act unless that collection 
of information displays a current valid OMB Control Number. The OMB 
Control Number for this information collection is 2120-0056. Public 
reporting for this collection of information is estimated to be 
approximately 5 minutes per response, including the time for 
reviewing instructions, completing and reviewing the collection of 
information. All responses to this collection of information are 
mandatory. Comments concerning the accuracy of this burden and 
suggestions for reducing the burden should be directed to the FAA at 
800 Independence Ave. SW., Washington, DC 20591, Attn: Information 
Collection Clearance Officer, AES-200.

(o) Related Information

    (1) Refer to Mandatory Continuing Airworthiness Information 
(MCAI) Canadian Airworthiness Directive CF-2015-13, dated June 25, 
2015, for related information. This MCAI may be found in the AD 
docket on the Internet at http://www.regulations.gov by searching 
for and locating Docket No. FAA-2016-4224.
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (p)(4) and (p)(5) of this AD.

(p) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless this AD specifies otherwise.
    (i) Bombardier Alert Service Bulletin A84-55-04, Revision C, 
dated May 3, 2016.
    (ii) Bombardier Repair Drawing (RD) 8/4-55-1143, Issue 1, dated 
May 21, 2015.
    (3) 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.
    (4) You may view this 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.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, call 202-741-6030, or go to http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Renton, Washington, on November 15, 2016.
Paul Bernado,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-28210 Filed 12-7-16; 8:45 am]
 BILLING CODE 4910-13-P


