[Federal Register Volume 65, Number 28 (Thursday, February 10, 2000)]
[Proposed Rules]
[Pages 6565-6566]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-3133]



[[Page 6565]]

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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: 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-
100, -200, and -300 series airplanes. This proposal would 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. This 
proposal is prompted by issuance of mandatory continuing airworthiness 
information by a foreign civil airworthiness authority. The actions 
specified by the 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 March 13, 2000.

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.
    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 FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Engine and 
Propeller Directorate, New York Aircraft Certification Office, 10 Fifth 
Street, Third Floor, Valley Stream, New York.

FOR FURTHER INFORMATION CONTACT: James E. Delisio, Aerospace Engineer, 
Airframe and Propulsion Branch, ANE-171, FAA, Engine and Propeller 
Directorate, 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 notice may be changed in 
light of the comments received.
    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 notice 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

    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-8-100, -200, and -300 series 
airplanes. TCCA advises that, during maintenance, a sealing problem was 
detected in the access panels of the upper wing fuel tanks. 
Investigation revealed that the diameter of the O-ring seals installed 
during manufacture on certain airplanes may be too large for the 
grooves of the access panels of the upper wing fuel tanks. The large 
diameter O-ring seals can prevent the fuel tank access panels from 
fitting properly to the upper wing ladder plates. This improper fit 
could lead to fretting and corrosion damage of the upper wing ladder 
plates. Such damage, if not detected and corrected, could result in 
displacement of the adjacent channel seals and consequent reduced 
lightning strike protection of the fuel tanks.

Explanation of Relevant Service Information

    The manufacturer has issued Bombardier Service Bulletin S.B. 8-57-
41, Revision `A', dated July 28, 1999, which describes procedures for 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. The service bulletin also describes 
procedures for installing new 0.103 inch diameter O-ring seals. 
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-99-20, dated July 20, 1999, 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.

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 bulletin described previously, 
except as discussed below.

Differences Between Proposed AD and Service Bulletin

    Operators should note that, although the Bombardier service 
bulletin specifies that the manufacturer may be

[[Page 6566]]

contacted for disposition of certain conditions, this proposal would 
require the repair of those conditions to be accomplished in accordance 
with a method approved by the FAA.
    Additionally, operators should note that, the Bombardier service 
bulletin does not provide procedures for repair of damage within 
certain limits. However, this proposed AD would require the repair of 
damage that is determined to be within certain limits; the repair would 
be required to be accomplished in accordance with the Structure Repair 
Manual (SRM).

Cost Impact

    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 inspection and 
installation 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.

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:
    (a) Within 60 days after the effective date of this AD, 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 in accordance with paragraph 
III.A., III.B., or III.C., as applicable, of the Accomplishment 
Instructions of Bombardier Service Bulletin S.B. 8-57-41, Revision 
`A', dated July 28, 1999.

    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 in accordance with 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 the Structure Repair Manual (SRM), prior to further 
flight, repair the damage in accordance with the SRM, and install 
new 0.103-inch diameter O-ring seals in accordance with 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 the SRM, prior to further flight, repair in accordance 
with a method approved by the Manager, New York Aircraft 
Certification Office (ACO), FAA, Engine and Propeller Directorate, 
and install new 0.103-inch diameter O-ring seals.

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. 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 3: 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 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 4: The subject of this AD is addressed in Canadian 
airworthiness directive CF-99-20, dated July 20, 1999.


    Issued in Renton, Washington, on February 4, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-3133 Filed 2-9-00; 8:45 am]
BILLING CODE 4910-13-U