[Federal Register Volume 70, Number 177 (Wednesday, September 14, 2005)]
[Proposed Rules]
[Pages 54316-54318]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-18208]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-20403; Directorate Identifier 2005-NM-144-AD]
RIN 2120-AA64


Airworthiness Directives; Bombardier Model DHC-8-400 Series 
Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (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 Model DHC-8-400 series airplanes. This proposed 
AD would require an inspection of the laminated shims for cracks, 
damage, or extrusion between the forward attachment fittings of the 
horizontal stabilizer and the top rib of the vertical stabilizer; a 
torque check of the attachment bolts in the attachment fittings of the 
front, middle, and rear spars; and corrective actions if necessary. 
This proposed AD results from a report indicating that delaminated 
shims extruded from the interface between the forward attaching 
fittings of horizontal stabilizer and the top rib of the vertical 
stabilizer, and that inadequate torque values of some bolts were found. 
We are proposing this AD to prevent reduced structural integrity of the 
horizontal stabilizer, and consequent loss of controllability of the 
airplane.

DATES: We must receive comments on this proposed AD by October 14, 
2005.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401, 
Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. 
and 5 p.m., Monday through Friday, except Federal holidays.
    Contact Bombardier, Inc., Bombardier Regional Aircraft Division, 
123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada, for service 
information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT: George Duckett, Aerospace Engineer, 
Airframe and Propulsion Branch, ANE-171, FAA, New York Aircraft 
Certification Office, 1600 Stewart Avenue, suite 410, Westbury, New 
York 11590; telephone (516) 256-7525; fax (516) 794-5531.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed in the ADDRESSES section. Include the docket number ``FAA-2005-
20403; Directorate Identifier 2005-NM-144-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that Web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You may review the DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit http://dms.dot.gov.

[[Page 54317]]

Examining the Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the Docket Management System 
receives them.

Discussion

    Transport Canada Civil Aviation (TCCA), which is the airworthiness 
authority for Canada, notified us that an unsafe condition may exist on 
certain Bombardier Model DHC-8-400 series airplanes. TCCA advises that 
delaminated shims extruded from the interface between the forward 
attaching fittings of horizontal stabilizer and the top rib of the 
vertical stabilizer. In addition, during removal of the horizontal 
stabilizer for replacing the laminated shims with solid shims, 
inadequate torque values of some bolts at the six attachment locations 
(two each at the front, middle, and rear spars) were found on some 
airplanes. This can cause increased load on the bolts and consequent 
reduction in fatigue life of the bolts. These conditions, if not 
corrected, could result in reduced structural integrity of the 
horizontal stabilizer, and consequent loss of controllability of the 
airplane.

Relevant Service Information

    Bombardier has issued Service Bulletin 84-55-02, Revision ``A,'' 
dated January 12, 2005. The service bulletin describes doing the 
following procedures:
     A detailed inspection of the laminated shims for cracks, 
damage, or extrusion between the forward attachment fittings of the 
horizontal stabilizer and the top rib of the vertical stabilizers;
     A breakaway torque check of the six attachment bolts in 
the attachment fittings of the front, middle, and rear spars; and
     Corrective actions if necessary. The corrective actions 
include replacing the laminated shims, between the forward attachment 
fittings of the horizontal stabilizer and the top rib of the vertical 
stabilizer, with solid shims and replacing the corresponding barrel nut 
and retainer with new parts.
    Accomplishing the actions specified in the service information is 
intended to adequately address the unsafe condition. TCCA mandated the 
service information and issued Canadian airworthiness directive CF-
2005-07, issued March 21, 2005, to ensure the continued airworthiness 
of these airplanes in Canada.

FAA's Determination and Requirements of the Proposed AD

    This airplane model is manufactured in Canada and is type 
certificated for operation in the United States under the provisions of 
section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and 
the applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, TCCA has kept the FAA informed of 
the situation described above. We have examined TCCA's findings, 
evaluated all pertinent information, and determined that we need to 
issue an AD for airplanes of this type design that are certificated for 
operation in the United States.
    Therefore, we are proposing this AD, which would require 
accomplishing the actions specified in the service information 
described previously, except as discussed under ``Difference Between 
the Proposed AD and the Service Bulletin.''

Difference Between the Proposed AD and Service Bulletin

    Operators should note that, although the Accomplishment 
Instructions of the referenced service bulletin describe procedures for 
submitting a sheet recording torque values to the airplane 
manufacturer, this proposed AD would not require that action. We do not 
need this information from operators.

Costs of Compliance

    The following table provides the estimated costs for U.S. operators 
to comply with this proposed AD.

                                                                     Estimated Costs
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                                                                                                                          Number of U.S.-
               Action                   Work hours     Average labor                 Parts                   Cost per       registered      Fleet cost
                                                       rate per hour                                         airplane        airplanes
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Detailed inspection and torque check               2             $65  None..............................            $130              19          $2,470
Replacement.........................              30              65  Free of charge....................           1,950              19          37,050
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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 have 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 that the proposed 
regulation:
    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); 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD and placed it in the

[[Page 54318]]

AD docket. See the ADDRESSES section for a location to examine the 
regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, 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 Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

Bombardier, Inc. (Formerly de Havilland, Inc.): Docket No. FAA-2005-
20403; Directorate Identifier 2005-NM-144-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by October 
14, 2005.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Bombardier Model DHC-8-400 series 
airplanes, certificated in any category; serial numbers 4001, and 
4003 through 4081 inclusive.

Unsafe Condition

    (d) This AD results from a report indicating that laminated 
shims were delaminated and extruded from the interface between the 
forward attaching fittings of horizontal stabilizer and the top rib 
of the vertical stabilizer, and that inadequate torque values of 
some bolts were found. We are issuing this AD to prevent reduced 
structural integrity of the horizontal stabilizer, and consequent 
loss of controllability of the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Service Information

    (f) The term ``service bulletin,'' as used in this AD, means the 
Accomplishment Instructions of Bombardier Service Bulletin 84-55-02, 
Revision `A,' dated January 12, 2005.
    (g) Accomplishing a detailed inspection, a breakaway torque 
check, and corrective actions if necessary before the effective date 
of this AD in accordance with Bombardier Service Bulletin 84-55-02, 
dated December 11, 2003, is acceptable for compliance with the 
corresponding requirements of this AD.
    (h) Accomplishing the repair before the effective date of this 
AD in accordance with the Bombardier repair drawings in Table 1 of 
this AD is acceptable for compliance with the requirements of this 
AD.

                        Table 1.--Repair Drawings
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                                          RD
      Bombardier  repair drawing        issue             Dated
------------------------------------------------------------------------
RD 8/4-55-083........................        3  April 16, 2003.
RD 8/4-55-084........................        1  May 5, 2003.
RD 8/4-55-089........................        2  June 6, 2003.
RD 8/4-55-090........................        3  August 26, 2003.
RD 8/4-55-093........................        2  June 20, 2003.
RD 8/4-55-094........................        3  September 4, 2003.
RD 8/4-55-106........................        2  July 31, 2003.
RD 8/4-55-110........................        3  October 1, 2003.
RD 8/4-55-138........................        1  October 29, 2003.
------------------------------------------------------------------------

Detailed Inspection and Torque Check

    (i) Within 4,000 flight hours after the effective date of this 
AD, do the actions specified in paragraphs (i)(1) and (i)(2) of this 
AD in accordance with Part A of the service bulletin.
    (1) Do a detailed inspection of the laminated shims for cracks, 
damage, or extrusion between the forward attachment fittings of the 
horizontal stabilizer and the top rib of the vertical stabilizer.

    Note 1: For the purposes of this AD, a detailed inspection is: 
``An intensive examination of a specific item, installation, or 
assembly to detect damage, failure, or irregularity. Available 
lighting is normally supplemented with a direct source of good 
lighting at an intensity deemed appropriate. Inspection aids such as 
mirror, magnifying lenses, etc., may be necessary. Surface cleaning 
and elaborate procedures may be required.''

    (2) Do a breakaway torque check of the six attachment bolts in 
the attachment fittings of the front, middle, and rear spars.

Corrective Actions

    (j) If, during the inspection required by paragraph (i)(1) of 
this AD, any cracked, damaged, or extruded laminated shim is found, 
before further flight, replace the discrepant laminated shim with a 
solid shim, and replace the attachment bolts, barrel nuts, and 
retainers of both front spars with new parts, in accordance with 
Parts A and B of the service bulletin.
    (k) If, during the torque check required by paragraph (i)(2) of 
this AD, any attachment bolt is found with a breakaway torque value 
outside the limits specified in the service bulletin, before further 
flight, replace the attachment bolt and its corresponding barrel nut 
and retainer with new parts, in accordance with Part A of the 
service bulletin.

Replacement of Laminated Shims

    (l) Within 8,000 flight hours after the effective date of this 
AD, unless previously accomplished in accordance with paragraph (j) 
of this AD, replace the laminated shims, between the forward 
attachment fittings of the horizontal stabilizer and the top rib of 
the vertical stabilizer, with solid shims and replace the 
corresponding barrel nut and retainer with new parts, in accordance 
with Part B of the service bulletin.

No Reporting

    (m) Although the service bulletin referenced in this AD 
specifies to submit certain information to the manufacturer, this AD 
does not include that requirement.

Alternative Methods of Compliance (AMOCs)

    (n) The Manager, New York Aircraft Certification Office, FAA, 
has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.

Related Information

    (o) Canadian airworthiness directive CF-2005-07, issued March 
21, 2005, also addresses the subject of this AD.


    Issued in Renton, Washington, on September 6, 2005.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-18208 Filed 9-13-05; 8:45 am]
BILLING CODE 4910-13-P