[Federal Register: March 15, 2005 (Volume 70, Number 49)]
[Proposed Rules]
[Page 12614-12616]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr15mr05-12]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2005-20595; Directorate Identifier 2004-NM-149-AD]
RIN 2120-AA64
Airworthiness Directives; Bombardier Model DHC-7 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-7 series airplanes. This proposed AD
would require revising the Airworthiness Limitations section of the
Instructions of Continued Airworthiness to include a new lower life
limit for lower wing skins. This proposed AD is prompted by the
discovery that during the manufacture of the lower wing skins, score
marks may have been accidentally inscribed around the edge of the lower
wing skin doublers. We are proposing this AD to prevent fatigue cracks
from developing at the score marks in the lower wing skins, which could
result in the structural failure of the wing.
DATES: We must receive comments on this proposed AD by April 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.
By 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.
For service information identified in this proposed AD, contact
Bombardier, Inc., Bombardier Regional Aircraft Division, 123 Garratt
Boulevard, Downsview, Ontario M3K 1Y5, Canada.
You can examine the contents of this AD docket on the Internet at
http://dms.dot.gov, or in person at the Docket Management Facility,
U.S. Department of Transportation, 400 Seventh Street SW., room PL-401,
on the plaza level of the Nassif Building, Washington, DC. This docket
number is FAA-2005-20595; the directorate identifier for this docket is
2004-NM-149-AD.
FOR FURTHER INFORMATION CONTACT: David Lawson, 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) 228-7327; 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 under ADDRESSES. Include ``Docket No. FAA-2005-20595;
Directorate Identifier 2004-NM-149-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 submitted 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 our
docket 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 can review the DOT's complete Privacy Act Statement in the
Federal Register published on April 11, 2000 (65 FR 19477-78), or you
can visit http://dms.dot.gov.
Examining the Docket
You can 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 DMS 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-7 series airplanes. TCCA advises that
during the manufacture of the wing bottom skins, score marks may have
been accidentally inscribed around the edge of the lower wing skin
doublers. Wing stations YW180 to YW375 were identified as the locations
where these scores could result in a reduced wing life. Bombardier
evaluated the lower wing skin with score marks 0.003 inch in depth and
determined that a wing life of 60,000 flights must be introduced. This
condition, if not corrected, could result in fatigue cracks developing
at the score marks and could result the structural failure of the wing.
Relevant Service Information
Bombardier has issued Temporary Revision (TR) 5-103 to Chapter 5-
10-11 of the DHC-7 Maintenance Manual (PSM 1-7-2), dated March 26,
2004, which adds a new life limit of 60,000 flights for the DHC-7 lower
wing skins to prevent a structural failure of the wing. 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-2004-12,
dated June 28, 2004, 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
[[Page 12615]]
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 the TCCA's findings,
evaluated all pertinent information, and determined that we need to
issue an AD for products of this type design that are certificated for
operation in the United States.
Therefore, we are proposing this AD, which would require revising
the Airworthiness Limitations section of the Instructions of Continued
Airworthiness to include a new lower life limit for certain lower wing
skins. The proposed AD would require you to use the service information
described previously to perform these actions.
Clarification of Actions in the Canadian Airworthiness Directive and
the Proposed AD
The Canadian airworthiness directive specifies that the operator's
maintenance schedule be revised to incorporate a new life limit for the
lower skins and that, before reaching the life limit, wings having
lower wing skins be removed from service. This proposed AD would only
require revising the Airworthiness Limitations section of the
Instructions of Continued Airworthiness to require the new life limit.
Once that document is revised, as required, and the proposed AD has
been fully complied with, the life limit remains enforceable as a part
of the Airworthiness Limitations section in accordance with 14 CFR
91.403(c). As no lower wing skin is near the life limit, only the
revision to the Airworthiness Limitation section is necessary to
address the unsafe condition.
Costs of Compliance
This proposed AD would affect about 3 airplanes of U.S. registry.
The proposed revision of the Airworthiness Limitations section would
take about 1 work hour per airplane, at an average labor rate of $65
per work hour. Based on these figures, the estimated cost of the
proposed AD for U.S. operators is $195, or $65 per airplane.
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. 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 FAA amends Sec. 39.13 by adding the following new
airworthiness directive (AD):
Bombardier, Inc. (Formerly de Havilland, Inc.): Docket No. FAA-2005-
20595; Directorate Identifier 2004-NM-149-AD.
Comments Due Date
(a) The Federal Aviation Administration must receive comments on
this AD action by April 14, 2005.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Bombardier Model DHC-7 series airplanes,
serial numbers 3 through 10 inclusive, 12 through 14 inclusive, and
16 through 27 inclusive; certificated in any category.
Note 1: This AD requires revision to a certain operator
maintenance document to include a new replacement time. Compliance
with this replacement time is required by 14 CFR 91.403(c). For
airplanes that have been previously modified, altered, or repaired
in the areas addressed by this replacement time, the operator may
not be able to accomplish the replacement described in the revision.
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 (i) of this AD. The request should include a
description of changes to the required replacement time that will
ensure the continued damage tolerance of the affected structure. The
FAA has provided guidance for this determination in Advisory
Circular (AC) 25-1529.
Unsafe Condition
(d) This AD is prompted by the discovery that during the
manufacture of the lower wing skins, score marks may have been
accidentally inscribed around the edge of the lower wing skin
doublers. We are issuing this AD to prevent fatigue cracks from
developing at the score marks in the lower wing skins, which could
result in the structural failure of the wing.
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.
Revise the Airworthiness Limitations (AWL) Section--New Life Limit
(f) Within 30 days after the effective date of this AD, revise
the AWL section of the Instructions for Continued Airworthiness to
incorporate new life limits for the lower wing skins by
incorporating Bombardier Temporary Revision (TR) 5-103, dated March
26, 2004, to the Bombardier DHC-7 Maintenance Manual (PSM 1-7-2),
into the AWL section.
(g) When the contents of TR 5-103 have been included in the
general revisions of the AWL section, the general revisions may be
incorporated into the AWL section, and the TR may be removed from
the AWL section.
(h) After the actions specified in paragraphs (f) of this AD
have been accomplished, no alternative life limits may be approved
for the lower wing skins, except as provided in paragraph (i) of
this AD.
Alternative Methods of Compliance (AMOCs)
(i) The Manager, New York Aircraft Certification Office, FAA,
has the authority to
[[Page 12616]]
approve AMOCs for this AD, if requested in accordance with the
procedures found in 14 CFR 39.19.
Related Information
(j) Canadian airworthiness directive CF-2004-12, dated June 28,
2004, also addresses the subject of this AD.
Issued in Renton, Washington, on March 7, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 05-5012 Filed 3-14-05; 8:45 am]
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