[Federal Register Volume 66, Number 4 (Friday, January 5, 2001)]
[Proposed Rules]
[Pages 1057-1059]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-342]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-371-AD]
RIN 2120-AA64


Airworthiness Directives; Bombardier Model DHC-8-100, -200, and -
300 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

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SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to certain Bombardier Model DHC-8-100, -200, 
and -300 series airplanes, that continues to require a one-time 
detailed visual inspection to detect damage of the ladder plates and 
access cover areas of the upper surface of the wings, repair, if 
necessary, and installation of new O-ring seals. That proposal was 
prompted by issuance of mandatory continuing airworthiness information 
by a foreign civil airworthiness authority. This new action revises the 
inspection requirements of the proposed rule by correcting a reference 
to a repair manual. The actions specified by this new proposed AD are 
intended to prevent damage of the upper wing ladder plates, which could 
result in displacement of the adjacent channel seals and consequent 
reduced lightning strike protection of the fuel tanks.

DATES: Comments must be received by January 30, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-371-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 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. 99-NM-371-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 for Windows or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Bombardier, Inc., Bombardier Regional Aircraft Division, 
123 Garrett Boulevard, Downsview, Ontario M3K 1Y5, Canada. This 
information may be examined at the Federal Aviation Administration 
(FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, 
SW., Renton, Washington; or at the FAA, New York Aircraft Certification 
Office, 10 Fifth Street, Third Floor, Valley Stream, New York; or at 
the Office of the Federal Register, 800 North Capitol Street, NW., 
suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: James E. Delisio, 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) 256-7521; 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:
     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.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    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 99-NM-371-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. 99-NM-371-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to add an airworthiness directive (AD), applicable to 
certain Bombardier Model DHC-8-100, -200, and -300 series airplanes, 
was

[[Page 1058]]

published as a notice of proposed rulemaking (NPRM) in the Federal 
Register on February 10, 2000 (65 FR 6565). That NPRM would have 
required a one-time detailed visual inspection to detect damage of the 
ladder plates and access cover areas of the upper surface of the wings, 
repair, if necessary, and installation of new O-ring seals. That NPRM 
was prompted by issuance of mandatory continuing airworthiness 
information by a foreign civil airworthiness authority.

Comments

    Due consideration has been given to the comments received in 
response to the original NPRM:

Requests to Correct a Reference to a Bombardier Repair Manual

    One commenter requests correcting a reference to a repair manual in 
the original NPRM. That commenter states that the limits for correcting 
fretting corrosion are included in the Generic Structural Repair 
Schemes Manual PSM 1-8-3RS instead of in the Structural Repair Manual, 
as cited in paragraphs (a)(2) and (a)(3) of the original NPRM. A second 
commenter agrees with the first commenter's statements.
    The FAA concurs that Generic Structural Repair Schemes Manual PSM 
1-8-3RS is one of the correct references for specifying the limits for 
correcting fretting and corrosion. A second appropriate reference is 
Generic Structural Repair Schemes Manual PSM 1-82-3RS (Chapter 57 
Contents and Repair Index). We point out that Bombardier Service 
Bulletin 8-57-41, Revision `C' dated August 4, 2000, cites both of 
those references. In light of this, we have added both references in 
paragraphs (a)(2) and (a)(3) of this supplemental NPRM.

Requests To Change the Revision Level of the Service Bulletin

    Two commenters state that the original NPRM should cite Bombardier 
Service Bulletin 8-57-41, Revision ``B'', dated December 22, 1999, 
instead of Revision ``A'', dated July 28, 1999. One of the commenters 
adds that Revision ``B'' includes procedures for inspecting the long-
range fuel tanks.
    Although the FAA does not concur that Revision ``B'' of the service 
bulletin should be cited, we have cited a later revision of the service 
bulletin, Revision ``C'', in this supplemental NPRM. Revision ``C'' 
includes additional changes and corrections to earlier revisions of the 
service bulletin, adds additional work for the operators, and revises 
the inspection and installation procedures for long-range fuel tanks. 
We have changed the reference in paragraph (a) of this supplemental 
NPRM to cite Revision ``C'' of the service bulletin.

Requests To Extend the Compliance Time

    Two commenters request extending the compliance time for the one-
time detailed visual inspection and the corrective actions specified by 
the original NPRM. Both commenters state that the compliance time of 60 
days is too restrictive and will result in airplanes being removed from 
service for an extended downtime. They also consider that a 60-day 
compliance time would cause particular problems for U.S. operators with 
large fleets of Model DHC-8 series airplanes. One of the commenter 
suggests extending the compliance time to 12 months, and adds that its 
10-year service history shows that no significant instances of 
corrosion or fretting occurred on its airplanes with the larger O-ring 
seals installed. That same commenter adds that Canadian airworthiness 
directive CF-99-20 specified a compliance time of 5 months for a much 
smaller fleet. The second commenter suggests that the action specified 
by the original NPRM be accomplished at the next maintenance period 
when the fuel tanks are accessed.
    The FAA partially concurs with the commenters' requests to extend 
the compliance time. Analysis of the data sent by both commenters, 
which includes long-term service history, shows that the use of larger 
O-ring seals has not presented a serious problem in the U.S. fleet. For 
these reasons, we have extended the compliance time from 60 days to 9 
months after the effective date of this AD, or at the next maintenance 
period during which the fuel tanks are accessed, whichever occurs 
earlier.
    We consider that such an extension will avoid grounding airplanes 
unnecessarily, while ensuring timely replacement of the seals. We have 
revised paragraph (a) of this proposed AD accordingly.

Requests To Allow the Use of Alternative Solvents

    One commenter states that the previously referenced service 
bulletin specifies the use of solvents that typically are not available 
[or are not approved] for use in the United States. The commenter 
suggests that the original NPRM should allow operators to use other 
appropriate solvents that do not pose significant safety hazards for 
maintenance personnel. This would avoid requiring operators to request 
an alternative method of compliance (AMOC) for using other appropriate 
solvents. A second commenter agrees with the first commenter's 
statements.
    The FAA concurs with the commenters' suggestions to allow operators 
to make repairs using alternative solvents that are approved per 
standard industry maintenance practices without having to request an 
AMOC. We have added Note 3 in this proposed AD to notify operators of 
such an alternative.

Explanation of Applicability

    The Canadian airworthiness directive specifies, for certain Model 
DHC-8 series airplanes, serial numbers 003 through 543. However, the 
service bulletin specifies serial numbers 003 through 528 and 531, and 
clarifies that the specified modification will be incorporated before 
delivery on applicable Model DHC-8 series airplanes, having serial 
numbers 529, 530, and 532 through 543. For this reason, the 
applicability of this supplemental NPRM parallels the effectivity of 
the service bulletin.

Conclusion

    Since the scope of the originally proposed rule has been expanded, 
the FAA has determined that it is necessary to reopen the comment 
period to provide additional opportunity for public comment.

Cost Impact

    There are approximately 516 Model DHC-8-100, -200, and -300 series 
airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 235 airplanes of U.S. registry would be affected by this 
proposed AD, that it would take approximately 6 work hours per airplane 
to accomplish the proposed actions, and that the average labor rate is 
$60 per work hour. Based on these figures, the cost impact of the 
proposed AD on U.S. operators is estimated to be $84,600, or $360 per 
airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed requirements of 
this AD action, and that no operator would accomplish 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 
perform 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.

[[Page 1059]]

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 99-NM-371-AD.

    Applicability: Model DHC-8-100, -200, and -300 series airplanes, 
having serial numbers 003 through 528 inclusive and 531; 
certificated in any category.


    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (b) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent damage of the upper wing ladder plates, which could 
result in displacement of the adjacent channel seals and consequent 
reduced lightning strike protection of the fuel tanks, accomplish 
the following:

Inspection and Repair

    (a) Within 9 months or at the next maintenance period during 
which the fuel tanks are accessed after the effective date of this 
AD, whichever occurs earlier: Perform a one-time detailed visual 
inspection to detect damage (i.e., fretting and/or corrosion) of the 
ladder plates and access cover areas of the upper surface of the 
wings per paragraph III.A., III.B., or III.C., as applicable, of the 
Accomplishment Instructions of Bombardier Service Bulletin 8-57-41, 
Revision `C', dated August 4, 2000.

    Note 2: For the purposes of this AD, a detailed visual 
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.''

    (1) If no damage is detected, prior to further flight, install 
new 0.103-inch-diameter O-ring seals per paragraph III.A., III.B., 
or III.C., as applicable, of the Accomplishment Instructions of the 
service bulletin.
    (2) If any damage is detected that is within the limits 
specified in Generic Structural Repair Schemes Manual PSM 1-8-3RS or 
PSM 1-82-3RS (Chapter 57 Contents and Repair Index), before further 
flight, repair the damage per Generic Structural Repair Schemes 
Manual PSM 1-8-3RS or PSM 1-82-3RS (Chapter 57 Contents and Repair 
Index), and install new 0.103-inch-diameter O-ring seals per 
paragraph III.A., III.B., or III.C., as applicable, of the 
Accomplishment Instructions of the service bulletin.
    (3) If any damage is detected that is outside the limits 
specified in Generic Structural Repair Schemes Manual PSM 1-8-3RS or 
PSM 1-82-3RS (Chapter 57 Contents and Repair Index), before further 
flight, repair per a method approved by the Manager, New York 
Aircraft Certification Office (ACO), FAA, and install new 0.103-
inch-diameter O-ring seals.

    Note 3: Although the Bombardier service bulletin includes 
references to solvents that are not available for use in the United 
States, operators may use appropriate substitute solvents per 
standard industry maintenance practices.

Alternative Methods of Compliance

    (b) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, New York ACO, FAA. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, New York ACO.

    Note 4: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the New York ACO.

Special Flight Permits

    (c) Special flight permits may be issued per Secs. 21.197 and 
21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 
21.199) to operate the airplane to a location where the requirements 
of this AD can be accomplished.

    Note 5: The subject of this AD is addressed in Canadian 
airworthiness directive CF-99-20, dated July 20, 1999.



    Issued in Renton, Washington, on December 29, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-342 Filed 1-4-01; 8:45 am]
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