[Federal Register: November 28, 2003 (Volume 68, Number 229)]
[Proposed Rules]
[Page 66765-66768]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr28no03-22]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2003-NM-154-AD]
RIN 2120-AA64
Airworthiness Directives; Bombardier Model DHC-8-102, -103, -106,
-201, -202, -301, -311, and -315 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to certain Bombardier Model DHC-8-
102, -103, -106, -201, -202, -301, -311, and -315 series airplanes.
This proposal would require repetitive inspections for discrepancies of
certain rear spar fittings between the flex shaft of the flap secondary
drive and the wing-to-fuselage structure, and corrective action if
necessary. This proposal also provides for an optional modification of
the flex shaft installation, which would terminate the repetitive
inspections. This action is necessary to find and fix
[[Page 66766]]
damage and subsequent failure of the rear spar fittings, which could
result in loss of the wing. This action is intended to address the
identified unsafe condition.
DATES: Comments must be received by December 29, 2003.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 2003-NM-154-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. Comments may be inspected at this
location between 9 a.m. and 3 p.m., Monday through Friday, except
Federal holidays. Comments may be submitted via fax to (425) 227-1232.
Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must
contain ``Docket No. 2003-NM-154-AD'' in the subject line and need not
be submitted in triplicate. Comments sent via the Internet as attached
electronic files must be formatted in Microsoft Word 97 or 2000 or
ASCII text.
The service information referenced in the proposed rule may be
obtained from Bombardier, Inc., Bombardier Regional Aircraft Division,
123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. This
information may be examined at the FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington; or at the FAA, New York
Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley
Stream, New York.
FOR FURTHER INFORMATION CONTACT: Jon Hjelm, Aerospace Engineer,
Airframe and Propulsion Branch, ANE-171, FAA, New York Aircraft
Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New
York 11581; telephone (516) 256-7523; fax (516) 568-2716.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed rule by submitting such written data, views, or arguments as
they may desire. Communications shall identify the Rules Docket number
and be submitted in triplicate to the address specified above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this action may be changed in
light of the comments received.
Submit comments using the following format:
[sbull] Organize comments issue-by-issue. For example, discuss a
request to change the compliance time and a request to change the
service bulletin reference as two separate issues.
[sbull] For each issue, state what specific change to the proposed
AD is being requested.
[sbull] Include justification (e.g., reasons or data) for each
request.
[sbull] Comments are specifically invited on the overall
regulatory, economic, environmental, and energy aspects of the proposed
rule. All comments submitted will be available, both before and after
the closing date for comments, in the Rules Docket for examination by
interested persons. A report summarizing each FAA-public contact
concerned with the substance of this proposal will be filed in the
Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this action must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 2003-NM-154-AD.'' The postcard will be date stamped
and returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules
Docket No. 2003-NM-154-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
Transport Canada Civil Aviation (TCCA), which is the airworthiness
authority for Canada, notified the FAA that an unsafe condition may
exist on certain Bombardier Model DHC-8 series airplanes. TCCA has
informed the FAA that discrepancies (chafing, wear damage, cracking)
have been found on the rear spar fittings (part numbers (P/N) 85320053,
85322060, and 85334180), located between the flex shaft of the flap
secondary drive and the wing-to-fuselage structure. These discrepancies
are due to inadequate clearance between the fittings and the flex shaft
of the flap secondary drive mechanism, caused by vibration of the flex
drive during flap extension/retraction. Such discrepancies could affect
the fatigue life of the fittings, which could result in failure of the
fittings and consequent loss of the wing.
Explanation of Relevant Service Information
Bombardier has issued Service Bulletin 8-27-83, Revision `A', dated
February 8, 2002, which describes procedures for repetitive inspections
for discrepancies (chafing, wear damage, cracking) of certain rear spar
fittings between the flex shaft of the flap secondary drive and the
wing-to-fuselage structure, and corrective action if necessary. The
service bulletin also provides procedures for an optional modification
of the flex shaft, which would eliminate the need for the repetitive
inspections. The inspections and corrective action are as follows:
[sbull] A visual inspection to determine the wear damage of each
rear spar fitting, which includes the following actions:
If wear damage is found, measure the depth of the wear; and if wear
depth is less than the limits specified in Table 1 of the service
bulletin, continued operation is allowed for 4,000 flight cycles
without blending out the wear; when 4,000 flight cycles have been
accumulated, the wear damage must be blended out and must be within the
limits specified in Table 3 of the service bulletin. After blending the
fitting must be re-inspected (high frequency eddy current (HFEC)
inspection) for any remaining discrepancies (wear, cracking).
Discrepancies must be repaired before further flight. If no
discrepancies are found the inspection is to be repeated at intervals
not to exceed 12 months.
If the wear depth is outside the limits specified in Table 1 of the
service bulletin, but is less than the limits specified in Table 2 of
the service bulletin, temporary operation is allowed for 400 flight
cycles without blending out the wear; when 400 flight cycles have been
accumulated, the wear must be blended out and within the limits
specified in Table 3. The inspection is to be repeated at intervals not
to exceed 12 months.
If the wear depth is greater than the limits specified in Table 2,
or after blending is greater than the limits specified in Table 3, or
cracking is found after temporary operation, the fitting must be
replaced before further flight.
[sbull] A HFEC inspection for cracking of damaged areas after
continued operation and after blending out wear damage. If no cracking
is found and the blended wear is within the limits specified in Table
3, permanent continued operation is allowed. If cracking is found or
blended wear exceeds the limits specified in Table 3, the fitting must
be replaced before further flight.
[sbull] Replacement of the rear spar fittings includes removal of
the existing fittings, removal of old sealant, inspection of each hole
through the rear spar and fuselage for damage, repair of any
[[Page 66767]]
damage before further flight, and application of new sealant,
installation of new fittings, and application of anti-corrosive
compound.
[sbull] The optional modification of the flex shaft includes
installation of new brackets on the rear spar, rework of the torque
tube support fittings in the flap primary drive, installation of a new
torque tube retainer tray assembly, and installation of additional
clamps to stabilize the flex shaft.
The service bulletin also describes procedures for functional tests
after doing all applicable actions.
Accomplishment of the actions specified in the service bulletin is
intended to adequately address the identified unsafe condition. TCCA
classified this service bulletin as mandatory and issued Canadian
airworthiness directive CF-2001-42, dated November 23, 2001, to ensure
the continued airworthiness of these airplanes in Canada.
FAA's Conclusions
These airplane models 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, TCCA has kept us informed of the
situation described above. We have examined the findings of TCCA,
reviewed all available information, and determined that AD action is
necessary for products of this type design that are certificated for
operation in the United States.
Explanation of Requirements of Proposed AD
Since an unsafe condition has been identified that is likely to
exist or develop on other airplanes of the same type design registered
in the United States, the proposed AD would require accomplishment of
the actions specified in the service bulletin described previously,
except as discussed below.
This AD allows flight with wear damage, provided that (1) the wear
damage is within the limits specified in the service bulletin, (2) no
cracking is found, and (3) established inspection procedures would find
wear damage in structure at intervals permitting repairs to be done
before reduced structural integrity of the fuselage could occur.
To be consistent with the findings of the TCCA, this proposed AD
allows operators to continue the repetitive inspections instead of
doing the terminating action. In making this determination, we consider
that, in the case of this AD, long-term continued operational safety is
adequately assured by doing the repetitive inspections to detect
discrepancies before they represent a hazard to the airplane, and by
doing repairs within the specified time limits.
Differences Between Proposed AD, Canadian Airworthiness Directive, and
Service Information
The service bulletin and Canadian airworthiness directive refer
only to a ``visual inspection'' for discrepancies of the rear spar
fittings. We have determined that the procedures in the service
bulletin should be described as a ``detailed inspection.'' Note 1 has
been included in this proposed AD to define this type of inspection.
Although the service bulletin specifies to submit certain
information to the manufacturer, this proposed AD does not include such
a requirement.
The applicability specified in the service bulletin and Canadian
airworthiness directive includes Model DHC-8-314 airplanes; however,
those airplanes are not U.S. type certificated and are not included in
the applicability in this proposed AD.
Cost Impact
The FAA estimates that 218 airplanes of U.S. registry would be
affected by this proposed AD.
It would take about 16 work hours per rear spar fitting (two
fittings per airplane) to accomplish the proposed inspection, at an
average labor rate of $65 per work hour. Based on these figures, the
cost impact of the inspection proposed by this AD on U.S. operators is
estimated to be $453,440, or $2,080 per airplane, per inspection cycle.
The cost impact figure discussed above is based on assumptions that
no operator has yet done any of the proposed requirements of this AD
action, and that no operator would do those actions in the future if
this AD were not adopted. The cost impact figures discussed in AD
rulemaking actions represent only the time necessary to do the specific
actions actually required by the AD. These figures typically do not
include incidental costs, such as the time required to gain access and
close up, planning time, or time necessitated by other administrative
actions.
The optional terminating modification, if done, would take about 16
work hours, at an average labor rate of $65 per work hour. Required
parts would cost about $365 per airplane. Based on these figures, we
estimate the cost of the optional terminating modification to be $1,405
per airplane.
Regulatory Impact
The regulations proposed herein 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. Therefore, it
is determined that this proposal would not have federalism implications
under Executive Order 13132.
For the reasons discussed above, I certify that this 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) if promulgated, 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. A copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting the Rules
Docket at the location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new
airworthiness directive:
Bombardier, Inc. (Formerly de Havilland, Inc.): Docket 2003-NM-154-
AD.
Applicability: Model DHC-8-102, -103, -106, -201, -202, -301, -
311, and -315 series airplanes; certificated in any category; as
listed in Bombardier Service Bulletin 8-27-83, Revision ``A'', dated
February 8, 2002.
Compliance: Required as indicated, unless accomplished
previously. To find and fix damage and prevent subsequent failure of
the rear spar fittings between the flex shaft of the flap secondary
drive and the wing-to-fuselage structure, which could result in loss
of the wing, accomplish the following:
Repetitive Inspections/Corrective Action
(a) For airplanes with rear spar fittings having part number (P/
N) 85320053,
[[Page 66768]]
85322060, or 85334180: Within 12 months after the effective date of
this AD; do a detailed inspection for discrepancies (chafing, wear
damage, cracking) of the rear spar fittings located between the flex
shaft of the flap secondary drive and the wing-to-fuselage
structure. Do the inspection as defined in Parts III.A., III.B., and
III.D. of the Accomplishment Instructions of Bombardier Service
Bulletin 8-27-83, Revision ``A'', dated February 8, 2002; except
where the service bulletin specifies to report inspection findings,
this AD does not require such reporting. Do the inspection per the
service bulletin, and repeat the inspection thereafter at the
applicable time specified in Part I.D. ``Compliance'' of the service
bulletin. Any applicable corrective action (high frequency eddy
current inspection for cracking, blending out wear damage,
replacement of rear spar fittings) must be done at the applicable
time specified in Part I.D. ``Compliance'' of the service bulletin.
Note 1: For the purposes of this AD, a detailed inspection is
defined as: ``An intensive visual examination of a specific
structural area, system, installation, or assembly to detect damage,
failure, or irregularity. Available lighting is normally
supplemented with a direct source of good lighting at intensity
deemed appropriate by the inspector. Inspection aids such as mirror,
magnifying lenses, etc., may be used. Surface cleaning and elaborate
access procedures may be required.''
Optional Terminating Modification
(b) Modification of the flex shaft of the flap secondary drive
per Part III.C. of the Accomplishment Instructions of Bombardier
Service Bulletin 8-27-83, Revision ``A'', dated February 8, 2002,
terminates the repetitive inspections required by paragraph (a) of
this AD.
Actions Done per Previous Issue of Service Bulletins
(c) Accomplishment of the inspections or the modification before
the effective date of this AD in accordance with Bombardier Service
Bulletin 8-27-83, dated October 19, 2001, is considered acceptable
for compliance with the applicable actions specified in this AD.
Alternative Methods of Compliance
(d) In accordance with 14 CFR 39.19, the Manager, New York
Aircraft Certification Office, FAA, is authorized to approve
alternative methods of compliance for this AD.
Note 2: The subject of this AD is addressed in Canadian
airworthiness directive CF-2001-42, dated November 23, 2001.
Issued in Renton, Washington, on November 21, 2003.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 03-29698 Filed 11-26-03; 8:45 am]
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