[Federal Register Volume 63, Number 63 (Thursday, April 2, 1998)]
[Proposed Rules]
[Pages 16169-16170]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-8576]
[[Page 16169]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-60-AD]
RIN 2120-AA64
Airworthiness Directives; de Havilland Model DHC-8-311 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 de Havilland Model DHC-8-
311 and -315 series airplanes. This proposal would require replacement
of the nitrogen cylinder assemblies that inflate the airplane's
ditching dams with improved nitrogen cylinder assemblies. 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 failure of the
ditching dams to inflate fully during an emergency water landing, which
could result in water entering the airplane.
DATES: Comments must be received by May 4, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 98-NM-60-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,
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, Engine and Propeller
Directorate, New York Aircraft Certification Office, 10 Fifth Street,
Third Floor, Valley Stream, New York.
FOR FURTHER INFORMATION CONTACT: Ezra Sasson, Aerospace Engineer,
Systems and Flight Test Branch, ANE-172, FAA, Engine and Propeller
Directorate, New York Aircraft Certification Office, 10 Fifth Street,
Third Floor, Valley Stream, New York 11581; telephone (516) 256-7520;
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 98-NM-60-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. 98-NM-60-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-8-311 and -315 series airplanes
on which the medium and high gross weight configuration is
incorporated. This airplane model is equipped with ditching dams to
prevent water from entering the airplane in the event of an emergency
water landing. A nitrogen cylinder assembly is intended to inflate the
ditching dams in fewer than six seconds. TCA advises that, during
functional testing of ditching dams on Model DHC-8-300 series
airplanes, some of the dams failed to inflate fully. The manufacturer
also reported several incidents in which the nitrogen cylinder assembly
failed to inflate the ditching dam. Such failures have been attributed
to a problem with the design of the nitrogen cylinder assembly, in
which excessive back pressure in the inflation valve assembly allows
some of the gas to escape during inflation of the ditching dam. This
condition, if not corrected, could lead to failure of the ditching dams
to inflate fully during an emergency water landing, which could result
in water entering the airplane.
Explanation of Relevant Service Information
The manufacturer has issued Bombardier Service Bulletin S.B. 8-25-
122, dated October 10, 1997, which describes procedures for replacing
the existing nitrogen cylinder assemblies on ditching dams with new
nitrogen cylinder assemblies that incorporate an improved valve
assembly. Accomplishment of the actions specified in the service
bulletin is intended to adequately address the identified unsafe
condition. TCA classified this service bulletin as mandatory and issued
Canadian airworthiness directive CF-97-21, dated November 13, 1997, 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, 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 service bulletin described previously.
Cost Impact
The FAA estimates that 2 airplanes of U.S. registry would be
affected by this proposed AD, that it would take approximately 4 work
hours per
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airplane to accomplish the proposed modification, and that the average
labor rate is $60 per work hour. Required parts would be provided by
the manufacturer of the nitrogen cylinder assembly at no cost to the
operator. Based on these figures, the cost impact of the proposed AD on
U.S. operators is estimated to be $480, or $240 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 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 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 98-NM-60-AD.
Applicability: Model DHC-8-311 and -315 series airplanes in the
medium and high gross weight configuration, on which Bombardier
Change Request CR803SO00001, CR803SO00002, CR803CH00046,
CR803CH00079, CR803CH00105, CR825CH00847, or CR803CH00051 has been
incorporated; 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 (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 failure of the ditching dams to inflate fully during
an emergency water landing, which could result in water entering the
airplane, accomplish the following:
(a) Within 6 months after the effective date of this AD, replace
the existing nitrogen cylinder assembly on the ditching dams with a
new nitrogen cylinder assembly that incorporates an improved valve
assembly (reference de Havilland Modification 8/3154), in accordance
with Bombardier Service Bulletin S.B. 8-25-122, dated October 10,
1997.
(b) As of the effective date of this AD, no person shall install
on any airplane any nitrogen cylinder assembly having part number
410870(BSC) or 410870-1.
(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, 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.
(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-97-21, dated November 13, 1997.
Issued in Renton, Washington, on March 25, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 98-8576 Filed 4-1-98; 8:45 am]
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