[Federal Register Volume 62, Number 193 (Monday, October 6, 1997)]
[Proposed Rules]
[Pages 52051-52053]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-26376]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-120-AD]
RIN 2120-AA64


Airworthiness Directives; De Havilland 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 de Havilland Model DHC-8-
100, -200, and -300 series airplanes. This proposal would require 
repetitive inspections of certain refuel/defuel tube assemblies in the 
engine nacelles for fuel leakage, and corrective action, if necessary. 
It would also require eventual modification of all tube assemblies, 
which would terminate the repetitive inspections. 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 fuel leaks and consequent 
increased risk of engine fires.

DATES: Comments must be received by November 5, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-120-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.
    The service information referenced in the proposed rule may be 
obtained from Bombardier, Inc., Bombardier Regional Aircraft Division, 
Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada.

[[Page 52052]]

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, Engine and Propeller 
Directorate, 10 Fifth Street, Third Floor, Valley Stream, New York.

FOR FURTHER INFORMATION CONTACT: Richard Fiesel, Aerospace Engineer, 
Airframe and Propulsion Branch, ANE-171, FAA, New York Aircraft 
Certification Office, Engine and Propeller Directorate, 10 Fifth 
Street, Third Floor, Valley Stream, New York 11581; telephone (516) 
256-7504; fax (516) 256-2716.

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 97-NM-120-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-103, Attention: Rules 
Docket No. 97-NM-120-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    Transport Canada Aviation (TCA), which is the airworthiness 
authority for Canada, notified the FAA that an unsafe condition may 
exist on certain de Havilland Model DHC-8-100, -200, and -300 series 
airplanes. TCA advises that it received reports of fuel leaks from the 
shroud drain line located adjacent to the refuel/defuel adapter in the 
engine nacelles. Investigation has revealed that some of the welds 
between the outer shroud and the inner tube of the refuel/defuel 
assemblies may be of poor quality. Relative motion between the shroud 
and the tube can result in cracking of both the tube and the shroud. 
This condition, if not corrected, could result in fuel leaks and 
consequent increased risk of engine fires.

Explanation of Relevant Service Information

    Bombardier has issued Alert Service Bulletin S.B. A8-28-20, 
Revision `A,' dated September 10, 1996, which describes procedures for 
repetitive inspections of the refuel/defuel tube assemblies in the 
engine nacelles for fuel leakage, and replacement of tube assemblies 
that leak with improved tube assemblies.
    The alert service bulletin also describes procedures for eventual 
modification of all tube assemblies to prevent potential future 
leakage, which would eliminate the need for the repetitive inspections. 
Part 2 of the Accomplishment Instructions of the alert service bulletin 
describes replacement of the tube assembly located in the most critical 
area of the engine nacelle. Part 3 of the Accomplishment Instructions 
of the alert service bulletin describes replacement of the remaining 
tube assemblies. Accomplishment of the actions specified in the alert 
service bulletin are intended to adequately address the identified 
unsafe condition.
    TCA classified this alert service bulletin as mandatory and issued 
Canadian airworthiness directive CF-96-14, dated August 20, 1996, 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 
Sec. 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the 
applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, TCA has kept the FAA informed of the 
situation described above. The FAA has examined the findings of TCA, 
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 alert service bulletin described 
previously.

Cost Impact

    The FAA estimates that 95 de Havilland Model DHC-8-100, -200, and -
300 series airplanes of U.S. registry would be affected by this 
proposed AD.
    The proposed inspection would take approximately 6 work hours per 
airplane to accomplish, at an average labor rate of $60 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 $34,200, or $360 per 
airplane, per inspection cycle.
    The proposed modification (specified in Part 2 of the 
Accomplishment Instructions in the referenced alert service bulletin), 
would take approximately 15 work hours per airplane to accomplish, at 
an average labor rate of $60 per work hour. Required parts would cost 
approximately $500. Based on these figures, the cost impact of this 
modification as proposed by this AD on U.S. operators is estimated to 
be $133,000, or $1,400 per airplane.
    The proposed modification (specified in Part 3 of the 
Accomplishment Instructions in the referenced service bulletin), would 
take approximately 36 work hours per airplane to accomplish, at an 
average labor rate of $60 per work hour. Required parts would cost 
approximately $1,600 per airplane. Based on these figures, the cost 
impact of this modification proposed by this AD on U.S. operators is 
estimated to be $357,200, or $3,760 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 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 substantial direct 
effects 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, in 
accordance with Executive Order

[[Page 52053]]

12612, it is determined that this proposal would not have sufficient 
federalism implications to warrant the preparation of a Federalism 
Assessment.
    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:

De Havilland, Inc.: Docket 97-NM-120-AD.

    Applicability: Model DHC-8-100, -200, and -300 series airplanes; 
as listed in Bombardier Alert Service Bulletin S.B. A8-28-20, 
Revision `A,' dated September 10, 1996; certificated in any 
category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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 (f) 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 fuel leaks and consequent increased risk of engine 
fires, accomplish the following:
    (a) Within 30 days after the effective date of this AD, inspect 
the five refuel/defuel tube assemblies in the engine nacelles to 
detect fuel leaks, in accordance with Part 1 of the Accomplishment 
Instructions of Bombardier Alert Service Bulletin S.B. A8-28-20, 
Revision `A', dated September 10, 1996. If any fuel leak is found, 
prior to further flight, replace the refuel/defuel tube assembly 
with an improved assembly, in accordance with the alert service 
bulletin. Thereafter, repeat the inspection at intervals not to 
exceed 6 months.
    (b) Within 12 months after the effective date of this AD, modify 
the refuel/defuel tube assembly located under the exhaust fingernail 
on the engine nacelle, as specified in Part 2 of the Accomplishment 
Instructions of Bombardier Alert Service Bulletin S.B. A8-28-20, 
Revision `A,' dated September 10, 1996, in accordance with the 
procedures specified in the alert service bulletin.
    (c) Within 24 months after the effective date of this AD, modify 
the remaining refuel/defuel tube assemblies, as specified in Part 3 
of the Accomplishment Instructions of Bombardier Alert Service 
Bulletin S.B. A8-28-20, Revision `A,' dated September 10, 1996, in 
accordance with the procedures specified in the alert service 
bulletin.
    (d) Accomplishment of the modifications required by paragraphs 
(b) and (c) of this AD constitutes terminating action for the 
repetitive inspections required by paragraph (a) of this AD.
    (e) As of the effective date of this AD, no person shall install 
a refuel/defuel tube assembly having part number 82820107-007, 
82821015-003, 82820108-005, 82820245-001, 82820246-001, 82820247-
001, or 82821014-001, on any airplane.
    (f) 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, Engine and Propeller Directorate. 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.

    (g) Special flight permits may be issued in accordance with 
Sec. 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-96-14, dated August 20, 1996.

    Issued in Renton, Washington, on September 30, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-26376 Filed 10-3-97; 8:45 am]
BILLING CODE 4910-13-U