[Federal Register Volume 68, Number 229 (Friday, November 28, 2003)]
[Proposed Rules]
[Pages 66765-66768]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-29698]


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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: 
[email protected]. 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]
BILLING CODE 4910-13-P