[Federal Register: March 25, 2008 (Volume 73, Number 58)]
[Proposed Rules]
[Page 15682-15685]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr25mr08-14]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2008-0356; Directorate Identifier 2008-NM-042-AD]
RIN 2120-AA64
Airworthiness Directives; Bombardier Model DHC-8-400 Series
Airplanes
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
[[Page 15683]]
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to supersede an existing airworthiness
directive (AD) that applies to certain Bombardier Model DHC-8-400
series airplanes. The existing AD currently requires inspecting all
barrel nuts to determine if the barrel nuts have a certain marking,
inspecting affected bolts to determine if the bolts are pre-loaded
correctly, and replacing all hardware if the pre-load is incorrect. For
airplanes on which the pre-load is correct, the existing AD requires
doing repetitive visual inspections for cracking of the barrel nuts and
cradles and replacing all hardware for all cracked barrel nuts. The
existing AD also requires replacement of all hardware for certain
affected barrel nuts that do not have cracking, which would end the
repetitive inspections for those airplanes. The existing AD also
provides an optional replacement for all affected barrel nuts. This
proposed AD would require replacement of all affected barrel nuts. This
proposed AD results from reports of cracking in the barrel nuts at the
four primary front spar wing-to-fuselage attachment joints. We are
proposing this AD to detect and correct cracking of the barrel nuts at
the wing front spar wing-to-fuselage joints, which could result in
reduced structural integrity of the wing-to-fuselage attachments and
consequent detachment of the wing.
DATES: We must receive comments on this proposed AD by April 24, 2008.
ADDRESSES: You may send comments by any of the following methods:
Federal eRulemaking Portal: Go to http://
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: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
For service information identified in this AD, contact Bombardier,
Inc., Bombardier Regional Aircraft Division, 123 Garratt Boulevard,
Downsview, Ontario M3K 1Y5, Canada.
Examining the AD Docket
You may examine the AD docket on the Internet at http://
www.regulations.gov; 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 proposed AD, the regulatory
evaluation, any comments received, and other information. The street
address for the Docket Office (telephone 800-647-5527) is in the
ADDRESSES section. Comments will be available in the AD docket shortly
after receipt.
FOR FURTHER INFORMATION CONTACT: Pong Lee, 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) 228-7324; fax (516) 794-5531.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include ``Docket No. FAA-2008-0356;
Directorate Identifier 2008-NM-042-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this proposed AD. We
will consider all comments received by the closing date and may amend
this proposed AD because of those comments.
We will post all comments we receive, without change, to http://
www.regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.
Discussion
On February 7, 2008, we issued AD 2008-04-02, amendment 39-15374
(73 FR 8187, February 13, 2008), for certain Bombardier Model DHC-8-400
series airplanes. That AD requires inspecting all barrel nuts to
determine if the barrel nuts have a certain marking, inspecting
affected bolts to determine if the bolts are pre-loaded correctly, and
replacing all hardware if the pre-load is incorrect. For airplanes on
which the pre-load is correct, that AD requires doing repetitive visual
inspections for cracking of the barrel nuts and cradles and replacing
all hardware for all cracked barrel nuts. That AD also requires
replacement of all hardware for certain affected barrel nuts that do
not have cracking, which would end the repetitive inspections for those
airplanes. That AD also provides an optional replacement for all
affected barrel nuts. That AD resulted from reports of cracking in the
barrel nuts at the four primary front spar wing-to-fuselage attachment
joints. We issued that AD to detect and correct cracking of the barrel
nuts at the wing front spar wing-to-fuselage joints, which could result
in reduced structural integrity of the wing-to-fuselage attachments and
consequent detachment of the wing.
Actions Since Existing AD Was Issued
The preamble to AD 2008-04-02 explains that we consider the
requirements ``interim action'' and were considering further rulemaking
to require the replacement of all hardware for all barrel nuts
identified with a marking of LH7940T SPS 01. We now have determined
that further rulemaking is indeed necessary, and this proposed AD
follows from that determination.
FAA's Determination and Requirements of the Proposed AD
These airplanes are manufactured in Canada and are 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, Transport Canada Civil Aviation
(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 AD action is necessary for airplanes of this type
design that are certificated for operation in the United States.
This proposed AD would supersede AD 2008-04-02 and would retain the
requirements of the existing AD. This proposed AD would also require
replacement of all affected barrel nuts.
Costs of Compliance
This proposed AD would affect about 48 airplanes of U.S. registry.
The actions that are required by AD 2008-04-02 and retained in this
proposed AD take about 3 work hours per airplane, at an average labor
rate of $80 per work hour. Based on these figures, the estimated cost
of the currently required actions is $11,520, or $240 per airplane, per
inspection cycle.
Replacement of the hardware of a barrel nut, if required, will take
about 12 work hours per airplane, at an average labor rate of $80 per
work hour. Required parts will cost about $800 per airplane. Based on
these figures, we estimate the cost of a replacement to be $1,760 per
barrel nut.
[[Page 15684]]
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 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
removing amendment 39-15374 (73 FR 8187, February 13, 2008) and adding
the following new airworthiness directive (AD):
Bombardier, Inc. (Formerly de Havilland, Inc.): Docket No. FAA-2008-
0356; Directorate Identifier 2008-NM-042-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by April 24,
2008.
Affected ADs
(b) This AD supersedes AD 2008-04-02.
Applicability
(c) This AD applies to Bombardier Model DHC-8-400, DHC-8-401,
and DHC-8-402 airplanes, certificated in any category; serial
numbers 4001 and 4003 through 4176 inclusive.
Unsafe Condition
(d) This AD results from reports of cracking in the barrel nuts
at the four primary front spar wing-to-fuselage attachment joints.
We are issuing this AD to detect and correct cracking of the barrel
nuts at the wing front spar wing-to-fuselage joints, which could
result in reduced structural integrity of the wing-to-fuselage
attachments and consequent detachment 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.
Restatement of Requirements of AD 2008-04-02
Inspections and Corrective Actions
(f) Within 50 flight hours after February 13, 2008 (the
effective date of AD 2008-04-02), inspect all barrel nuts, part
number DSC228-16, to determine if the barrel nuts are identified
with a marking of LH7940T SPS 01. Inspect in accordance with the
Accomplishment Instructions of Bombardier Alert Service Bulletin
A84-57-19, Revision A, dated February 6, 2008.
(1) If no barrel nuts are identified with a marking of LH7940T
SPS 01, no further actions are required by this paragraph.
(2) If any barrel nut is found that is identified with a marking
of LH7940T SPS 01, before further flight, inspect the inboard and
outboard bolts to determine if the bolts are pre-loaded correctly.
Inspect in accordance with the Accomplishment Instructions of
Bombardier Alert Service Bulletin A84-57-19, Revision A, dated
February 6, 2008.
(i) If the pre-load is incorrect (i.e., the ring can be
rotated), before further flight, replace all hardware at that
location in accordance with the Accomplishment Instructions of the
alert service bulletin.
(ii) If the pre-load is correct, before further flight, do a
visual inspection for cracking of the barrel nuts and cradles in
accordance with the Accomplishment Instructions of the alert service
bulletin.
(A) If no cracking of the barrel nut and cradle is found, do the
applicable action required by paragraph (g) of this AD.
(B) If no cracking of the barrel nut is found and only cracking
of the cradle is found, no action is required by this paragraph
provided that the applicable corrective action specified in
paragraph (g) of this AD is done.
(C) If any cracking of the barrel nut is found, before next
flight, replace all hardware only at that location in accordance
with the Accomplishment Instructions of the alert service bulletin.
(g) For any barrel nuts on which no cracking of the barrel nut
was found during the inspection required by paragraph (f)(2)(ii) of
this AD, do the applicable corrective action specified in paragraph
(g)(1), (g)(2), (g)(3), (g)(4), or (g)(5) of this AD at the
compliance time specified in the applicable paragraph.
(1) If four barrel nuts having no cracking are found, do the
actions specified in paragraphs (g)(1)(i), (g)(1)(ii), and
(g)(1)(iii) of this AD.
(i) Within 50 flight hours after doing the inspection required
by paragraph (f)(2)(ii) of this AD, repeat the inspection specified
in paragraph (f)(2) of this AD. Thereafter, repeat the inspection at
intervals not to exceed 50 flight hours until the replacement
specified in paragraph (g)(1)(ii) of this AD is done.
(ii) Within 100 flight hours after doing the inspection required
by paragraph (f)(2)(ii) of this AD, replace all hardware at the
left-hand outboard location and the right-hand outboard location in
accordance with the Accomplishment Instructions of Bombardier Alert
Service Bulletin A84-57-19, Revision A, dated February 6, 2008.
Replacing the barrel nuts on the outboard locations terminates the
requirement to do the repetitive inspections specified in paragraph
(g)(1)(i) of this AD.
(iii) Within 100 flight hours after doing the replacement
required by paragraph (g)(1)(ii) of this AD, repeat the inspection
specified in paragraph (f)(2) of this AD for the remaining barrel
nuts identified with a marking of LH7940T SPS 01. Thereafter, repeat
the inspection at intervals not to exceed 100 flight hours until the
replacement of all hardware at those locations is done. Do the
inspection and replacement in accordance with the Accomplishment
Instructions of Bombardier Alert Service Bulletin A84-57-19,
Revision A, dated February 6, 2008.
(2) If three barrel nuts having no cracking are found, do the
actions specified in paragraphs (g)(2)(i), (g)(2)(ii), and
(g)(2)(iii) of this AD.
(i) Within 50 flight hours after doing the inspection required
by paragraph (f)(2)(ii) of this AD, repeat the inspection specified
in paragraph (f)(2) of this AD. Thereafter, repeat the inspection at
intervals not to exceed 50 flight hours until the replacement
specified in paragraph (g)(2)(ii) of this AD is done.
(ii) Within 100 flight hours after doing the inspection required
by paragraph (f)(2)(ii) of this AD, replace all hardware for one
affected barrel nut at the outboard location, on the side with two
affected barrel nuts, in
[[Page 15685]]
accordance with the Accomplishment Instructions of Bombardier Alert
Service Bulletin A84-57-19, Revision A, dated February 6, 2008.
Replacing the barrel nut on the outboard location terminates the
requirement to do the repetitive inspections specified in paragraph
(g)(2)(i) of this AD.
(iii) Within 100 flight hours after doing the replacement
required by paragraph (g)(2)(ii) of this AD, repeat the inspection
specified in paragraph (f)(2) of this AD for the remaining barrel
nuts identified with a marking of LH7940T SPS 01. Thereafter, repeat
the inspection at intervals not to exceed 100 flight hours until the
replacement of all hardware at those locations is done. Do the
inspection and replacement in accordance with the Accomplishment
Instructions of Bombardier Alert Service Bulletin A84-57-19,
Revision A, dated February 6, 2008.
(3) If two barrel nuts having no cracking are found and both
nuts are on the same side, do the actions specified in paragraphs
(g)(3)(i), (g)(3)(ii), and (g)(3)(iii) of this AD.
(i) Within 100 flight hours after doing the inspection required
by paragraph (f)(2)(ii) of this AD, repeat the inspection specified
in paragraph (f)(2) of this AD. Thereafter, repeat the inspection at
intervals not to exceed 100 flight hours until the replacement
specified in paragraph (g)(3)(ii) of this AD is done.
(ii) Within 500 flight hours after doing the inspection required
by paragraph (f)(2)(ii) of this AD, replace all hardware for one
affected barrel nut at the outboard location that has two affected
barrel nuts in accordance with the Accomplishment Instructions of
Bombardier Alert Service Bulletin A84-57-19, Revision A, dated
February 6, 2008. Replacing the barrel nut on the outboard location
terminates the requirement to do the repetitive inspections
specified in paragraph (g)(3)(i) of this AD.
(iii) Within 100 flight hours after doing the replacement
required by paragraph (g)(3)(ii) of this AD, repeat the inspection
specified in paragraph (f)(2) of this AD for the remaining barrel
nut identified with a marking of LH7940T SPS 01. Thereafter, repeat
the inspection at intervals not to exceed 100 flight hours until the
replacement of all hardware at that location is done. Do the
inspection and replacement in accordance with the Accomplishment
Instructions of Bombardier Alert Service Bulletin A84-57-19,
Revision A, dated February 6, 2008.
(4) If two barrel nuts having no cracking are found and are on
opposite sides, within 100 flight hours after doing the inspection
required by paragraph (f)(2)(ii) of this AD, repeat the inspection
specified in paragraph (f)(2) of this AD. Thereafter, repeat the
inspection at intervals not to exceed 100 flight hours until the
replacement of all hardware at those locations is done. Do the
inspection and replacement in accordance with the Accomplishment
Instructions of Bombardier Alert Service Bulletin A84-57-19,
Revision A, dated February 6, 2008.
(5) If one barrel nut having no cracking is found, within 100
flight hours after doing the inspection required by paragraph
(f)(2)(ii) of this AD, repeat the inspection specified in paragraph
(f)(2) of this AD. Thereafter, repeat the inspection at intervals
not to exceed 100 flight hours until the replacement of all hardware
at that location is done. Do the inspection and replacement in
accordance with the Accomplishment Instructions of Bombardier Alert
Service Bulletin A84-57-19, Revision A, dated February 6, 2008.
Actions Accomplished According to Previous Issue of Alert Service
Bulletin
(h) Actions accomplished before February 13, 2008, in accordance
with Bombardier Alert Service Bulletin A84-57-19, dated February 1,
2008, are acceptable for compliance with the corresponding actions
specified in this AD.
Actions Accomplished According to Bombardier Alert Service Bulletin
A84-57-18
(i) For airplanes on which the actions specified in Bombardier
Alert Service Bulletin A84-57-18, dated January 16, 2008, were
accomplished before February 13, 2008 and on which no barrel nuts
were found that were identified with a marking of LH7940T SPS 01: No
further action is required by this AD.
Parts Installation
(j) As of February 13, 2008, no person may install a barrel nut,
part number DSC228-16, identified with a marking of LH7940T SPS 01,
on any airplane.
New Requirement of This AD
Replacement of All Affected Barrel Nuts
(k) For airplanes on which barrel nuts are inspected in
accordance with paragraph (g)(1)(iii), (g)(2)(iii), (g)(3)(iii),
(g)(4), or (g)(5) of this AD: Within 3,000 flight hours after the
effective date of this AD, replace all hardware for all remaining
barrel nuts, part number DSC228-16, identified with a marking of
LH7940T SPS 01. Do the replacement in accordance with the
Accomplishment Instructions of Bombardier Alert Service Bulletin
A84-57-19, Revision A, dated February 6, 2008. Replacement of all
hardware for all affected barrel nuts constitutes terminating action
for this AD.
Special Flight Permit
(l) Special flight permits, as described in Section 21.197 and
Section 21.199 of the Federal Aviation Regulations (14 CFR 21.197
and 21.199), may be issued to operate the airplane to a location
where the requirements of this AD can be accomplished but
concurrence by the Manager, New York Aircraft Certification Office,
FAA, is required prior to issuance of the special flight permit.
Before using any approved special flight permits, notify your
appropriate principal inspector (PI) in the FAA Flight Standards
District Office (FSDO), or lacking a PI, your local FSDO. Special
flight permits may be permitted provided that the conditions
specified in paragraph (l)(1), (l)(2), (l)(3), (l)(4), and (l)(5) of
this AD are met.
(1) Both the right-hand side and left-hand side of the airplane
must have at least one barrel nut that is not within the suspect
batch (i.e., barrel nut is not identified with a marking of LH7940T
SPS 01). The barrel nuts that are not within the suspect batch must
be in good working condition (i.e., no cracking of the barrel nut).
(2) No passengers and no cargo are onboard.
(3) Airplane must operate in fair weather conditions with a low
risk of turbulence.
(4) Airplane must operate with reduced airspeed. For further
information, contact Bombardier, Q Series 24 Hour Service Customer
Response Center, at: Tel: 1-416-375-4000; Fax: 1-416-375-4539; E-
mail: thd.qseries@aero.bombardier.com.
(5) All of the conditions specified in paragraphs (l)(1),
(1)(2), (l)(3), and (l)(4) of this AD are on a case by case basis.
Contact your appropriate principal inspector (PI) in the FAA Flight
Standards District Office (FSDO), or lacking a PI, your local FSDO,
for assistance.
Alternative Methods of Compliance (AMOCs)
(m)(1) 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.
(2) To request a different method of compliance or a different
compliance time for this AD, follow the procedures in 14 CFR 39.19.
Before using any approved AMOC on any airplane to which the AMOC
applies, notify your appropriate principal inspector (PI) in the FAA
Flight Standards District Office (FSDO), or lacking a PI, your local
FSDO.
Related Information
(n) Canadian emergency airworthiness directive CF-2008-11, dated
February 5, 2008.
Issued in Renton, Washington, on March 17, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E8-6054 Filed 3-24-08; 8:45 am]
BILLING CODE 4910-13-P