[Federal Register Volume 66, Number 223 (Monday, November 19, 2001)]
[Proposed Rules]
[Pages 57905-57908]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-28797]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-140-AD]
RIN 2120-AA64


Airworthiness Directives; Bombardier Model DHC-8-400 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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[[Page 57906]]

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Bombardier Model DHC-8-400 
series airplanes. This proposal would require two actions--a 
modification and a replacement--affecting the fuel tanks in the wings. 
All affected airplanes would require modification of the clearance of 
the fuel tank vent lines to the left and the right wing fuel tanks. 
Some affected airplanes would also require replacement of three 
existing fuel probes from the center fuel tank on the left and right 
wings with new production fuel probes. This action is prompted by 
mandatory continuing airworthiness information from a foreign 
airworthiness authority. This action is necessary to prevent inadequate 
clearance between the fuel tank vent lines and the adjacent rib 
structures of the wings or failure of certain temporary, reworked fuel 
probes in the center fuel tanks in the wings. Either condition could 
compromise the airplane's lightning protection system, possibly 
resulting in a fire or explosion if the airplane were hit by lightning. 
This action is intended to address the identified unsafe condition.

DATES: Comments must be received by December 19, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket Number 2001-NM-140-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. 2001-NM-140-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 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: James Delisio, Aerospace Engineer, 
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 2001-NM-140-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. 2001-NM-140-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-8-400 series airplanes. TCCA 
advises that two problems have been identified with the wing fuel tanks 
which, if not corrected, could compromise the lightning protection of 
the airplanes. The first problem is a possible lack of clearance 
between the fuel tank vent lines and the adjacent wing rib structures. 
The second is possible failure of temporary, re-worked fuel probes in 
the wing center fuel tanks. Either condition, if not corrected, could 
compromise the airplane's lightning protection system, possibly 
resulting in a fire or explosion if the airplane were hit by lightning.

Explanation of Relevant Service Information

    Bombardier has issued Alert Service Bulletin A84-28-02, dated 
February 7, 2001, which describes procedures for modification of the 
fuel tank vent lines by adding Teflon tubing and band clamps to 
insulate and separate the fuel tank vent lines from the adjacent wing 
rib structures. Bombardier has also issued Service Bulletin 84-28-01, 
Revision `A', dated February 8, 2001, which describes procedures for 
replacement of existing fuel probes numbers 1, 2, and 5 with new 
production fuel probes. The existing fuel probes were previously 
reworked as a temporary solution to potential inadequate clearance 
between the fuel probes and the structure of the center fuel tanks in 
the wings. Accomplishment of the actions specified in the service 
bulletins is intended to adequately address the identified unsafe 
condition. TCCA classified these service bulletins as mandatory and 
issued Canadian airworthiness directive CF-2001-14, dated March 21, 
2001, in order to assure the continued airworthiness of these airplanes 
in Canada.

FAA's Conclusions

    This airplane model is manufactured in Canada and is 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 the FAA informed of 
the situation described above. The FAA has 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.

[[Page 57907]]

Explanation of Requirements of Proposed Rule

    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 bulletins described previously.

Cost Impact

    There are approximately 32 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 15 airplanes of U.S. registry 
would be affected by the proposed AD with 13 airplanes affected by the 
proposed modification of the clearance of the fuel tank vent line and 7 
airplanes affected by the proposed replacement of the numbers 1, 2, and 
5 fuel probes.
    It would take approximately 12 work hours to accomplish the 
proposed modification of the clearance of the fuel tank vent line, at 
an average labor rate of $60 per work hour. Required parts would cost 
approximately $440 per airplane. Based on these figures, the cost 
impact of the proposed modification on U.S. operators is estimated to 
be $15,080, or $1,160 per airplane.
    It would take approximately 2 work hours to accomplish the proposed 
replacement of fuel probes numbers 1, 2, and 5, at an average labor 
rate of $60 per work hour. The required parts would be provided by the 
manufacturer at no cost to the operators. Based on these figures, the 
cost impact of the proposed replacement on U.S. operators is estimated 
to be $840, or $120 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the proposed requirements 
of this AD, and that no operator would accomplish those actions in the 
future if this proposed 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.

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 2001-NM-140-
AD.

    Applicability: Model DHC-8-400 series airplanes; certificated in 
any category; serial numbers 4005, 4006, 4008 through 4010 
inclusive, 4012 through 4015 inclusive, and 4018 through 4040 
inclusive.

    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 (c) 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 inadequate clearance between the fuel tank vent line 
and the adjacent rib structures of the wings or failure of certain 
temporary, reworked fuel probes in the center fuel tanks in the 
wings, either of which could compromise the airplane's lightning 
protection system, possibly resulting in a fire or explosion if the 
airplane were hit by lightning, accomplish the following:

Modification of Clearance of Fuel Tank Vent Lines

    (a) For airplanes having serial numbers 4005, 4006, 4008 through 
4010 inclusive, 4012 through 4015 inclusive, and 4018 through 4040 
inclusive: Within 120 days after the effective date of this AD, 
modify the clearance of the fuel tank vent lines to the left and the 
right wing fuel tanks by wrapping 1 piece of Teflon tube around the 
vent line at each of 10 stations (2 pieces at station 191.200) and 
securing it with a clamping band (2 clamping bands at station 
191.200), in accordance with the Accomplishment Instructions 
(including Table 1) and Figure 1 of Bombardier Alert Service 
Bulletin A84-28-02, dated February 7, 2001.

Replacement of Fuel Probes Numbers 1, 2, and 5

    (b) For airplanes having serial numbers 4006, 4008, 4012 through 
4015 inclusive, and 4018 through 4027 inclusive: Prior to the 
accumulation of 4,000 flight hours after the effective date of this 
AD, or within 120 days after the effective date of this AD, 
whichever occurs later: Replace existing fuel probes numbers 1, 2, 
and 5 from the center fuel tank on the left and the right wings with 
new production fuel probes, in accordance with Bombardier Service 
Bulletin 84-28-01, Revision ``A,'' dated February 8, 2001.

Alternative Methods of Compliance

    (c) 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 Aircraft Certification 
Office (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 2: 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

    (d) Special flight permits may be issued in accordance with 
sections 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 3: The subject of this AD is addressed in Canadian 
airworthiness directive CF-2001-14, dated March 21, 2001.



[[Page 57908]]


    Issued in Renton, Washington, on November 9, 2001.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-28797 Filed 11-16-01; 8:45 am]
BILLING CODE 4910-13-P