[Federal Register Volume 61, Number 193 (Thursday, October 3, 1996)]
[Proposed Rules]
[Pages 51619-51621]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-25304]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 93-CE-45-AD]
RIN 2120-AA64
Airworthiness Directives, de Havilland DHC-6 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes to adopt a new airworthiness directive
[[Page 51620]]
(AD) that would apply to de Havilland DHC-6 series airplanes that do
not have a certain wing strut modification (Modification 6/1581)
incorporated. The proposed action would require inspecting the wing
struts for cracks or damage (chafing, etc.), replacing wings struts
that are found damaged beyond certain limits or are found cracked, and
incorporating Modification No. 6/1581 to prevent future chafing damage.
Several reports of wing strut damage caused by the upper fairing
rubbing against the wing strut prompted the proposed action. The
actions specified by the proposed AD are intended to prevent failure of
the wing struts, which could result in loss of control of the airplane.
DATES: Commens must be received on or before December 5, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Central Region, Office of the Assistant Chief
Counsel, Attention: Rules Docket No. 93-CE-45-AD, Room 1558, 601 E.
12th Street, Kansas City, Missouri 64106. Comments may be inspected at
this location between 8 a.m. and 4 p.m., Monday through Friday,
holidays excepted.
Service information that applies to the proposed AD may be obtained
from de Havilland, Inc., 123 Garratt Boulevard, Downsview, Ontario,
Canada, M3K 1Y5. This information also may be examined at the Rules
Docket at the address above.
FOR FURTHER INFORMATION CONTACT: Jon Hjelm, Aerospace Engineer, FAA,
New York Aircraft Certification Office, 10 Fifth Street, 3rd Floor,
Valley Stream, New York 11581; telephone (516) 256-7523; facsimile
(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 should 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 that summarizes 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 No. 93-CE-45-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, Central Region, Office of the Assistant Chief Counsel,
Attention: Rules Docket No. 93-CE-45-AD, Room 1558, 601 E. 12th Street,
Kansas City, Missouri 64106.
Discussion
Transport Canada, which is the airworthiness authority for Canada,
has notified the FAA that an unsafe condition may exist on de Havilland
DHC-6 series airplanes. Transport Canada reports that the upper fairing
has rubbed against the wing struts on several of the above referenced
airplanes, which has resulted in wing strut damage.
Explanation of the Relevant Service Information
De Havilland has issued Service Bulletin (SB) No. 6/342, dated
February 23, 1976, which specifies procedures for (1) inspecting the
wing struts for cracks and damage (chafing, etc.); and (2)
incorporating Modification No. 6/1581 to prevent further chafing
damage. Modification No. 6/1581 consists of installing a preformed
nylon shield around the area of each wing strut at the upper end
closest to the wing. Transport Canada classified this service bulletin
as mandatory and issued Transport Canada AD CF-91-30, dated August 8,
1991, in order to assure the continued airworthiness of these airplanes
in Canada.
Evaluation of all Applicable Information
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, Transport Canada has kept the FAA
informed of the situation described above. The FAA has examined the
findings of Transport Canada; reviewed all available information,
including the service information referenced above; and determined that
AD action is necessary for products of this type design that are
certificated for operation in the United States.
Explanation of the Provisions of the Proposed AD
Since an unsafe condition has been identified that is likely to
exist or develop in other de Havilland DHC-6 series airplanes of the
same type design that do not have Modification 6/1581 incorporated, the
proposed AD would require inspecting the wing struts for cracks or
damage (chafing, etc.), replacing wing struts that are found damaged
beyond certain limits or are found cracked, and incorporating
Modification No. 6/1581 to prevent future chafing damage.
Accomplishment of the proposed inspection and modification would be
required in accordance with de Havilland SB No. 6/342, dated February
23, 1976.
FAA's Aging Commuter Aircraft Policy
This action is consistent with the FAA/s aging commuter airplane
policy. This policy simply states that reliance on repetitive
inspection of critical areas on airplanes utilized in commuter service
carries an unnecessary safety risk when a design change exists that
could eliminate or, in certain instances, reduce the number of those
critical inspections. The alternative to incorporating Modification No.
6/1581 on de Havilland DHC-6 series airplanes would be relying on
repetitive inspection to detect damaged wing struts.
Cost Impact
The FAA estimates that 169 airplanes in the U.S. registry would be
affected by the proposed AD, that it would take approximately 8
workhours per airplane to accomplish the proposed action, and that the
average labor rate is approximately $60 an hour. Parts cost
approximately $150 per airplane. Based on these figures, the total cost
impact of the proposed AD on U.S. operators is estimated to be
$106,470. This figure is based upon the assumption that no affected
airplane owner/operator has incorporated Modification No. 6/1581.
De Havilland has informed the FAA that enough parts have been
distributed to equip approximately 11 of the affected airplanes.
Assuming that each set of parts is incorporated on an effected
airplane, the cost impact upon U.S. operators/owners would be reduced
by $6,930 from $106,470 to $99,540.
[[Page 51621]]
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 action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under 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 has been placed 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 USC 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
to read as follows:
de Havilland: Docket No. 93-CE-45-AD.
Applicability: Models DHC-6-1, DHC-6-100, DHC-6-200, and DHC-6-
300 airplanes (all serial numbers), certificated in any category,
that do not have Modification No. 6/1581 incorporated.
Note 1: Modification No. 6/1581 consists of installing a
preformed nylon shield around the area of each wing strut at the
upper end closet to the wing.
Note 2: 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 (d) 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 already accomplished.
To prevent failure of the wing struts, which could result in
loss of control of the airplane, accomplish the following:
(a) Within the next 100 hours time-in-service (TIS) after the
effective date of this AD, inspect the wing struts, part number (P/
N) C6W1005, for cracks or damage (chafing, etc.) in accordance with
the ACCOMPLISHMENT INSTRUCTIONS section of de Havilland Service
Bulletin (SB) No. 6/342, dated February 23, 1976.
(1) If damage is found on a wing strut that exceeds 0.025-inch
in depth, exceeds a total length of 5 inches, or where any two
places of damage are separated by less than 10 inches of undamaged
surface over the length of the strut, prior to further flight,
replace the wing strut with an airworthy FAA-approved part in
accordance with the applicable maintenance manual.
(2) If any crack is found, prior to further flight, replace the
wing strut with an airworthy FAA-approved part in accordance with
the applicable maintenance manual.
(3) If damage is found on a wing strut that exceeds 0.010-inch
in depth, but does not exceed 0.25-inch in depth, does not exceed a
total length of 5 inches, and where any two places of damage are
separate by a minimum of 10 inches undamaged surface over the length
of the strut, within 500 hours TIS after the inspection specified in
paragraph (a) of this AD, replace the wing strut with an airworthy
FAA-approved part in accordance with the applicable maintenance
manual.
(b) Within the next 600 hours TIS after the effective date of
this AD, incorporate Modification No. 6/1581 in accordance with the
ACCOMPLISHMENT INSTRUCTIONS section of de Havilland SB No. 6/342,
dated February 23, 1976.
(1) Incorporating Modification No. 6/1581 eliminates the
repetitive inspection requirement of this Ad.
(2) Incorporating Modification No. 6/1581 may be accomplished at
any time prior to 600 hours TIS after the effective date of this AD,
at which time it must be incorporated.
(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.
(d) An alternative method of compliance or adjustment of the
compliance times that provides an equivalent level of safety may be
approved by the Manager, New York Aircraft Certification Office
(ACO), FAA, 10 Fifth Street, 3rd Floor, Valley Stream, New York
11581. The request shall be forwarded through an appropriate FAA
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.
(e) All persons affected by this directive may obtain copies of
the document referred to herein upon request to de Havilland, Inc.,
123 Garratt Boulevard, Downsview, Ontario M3K 1Y5 Canada; or may
examine this document at the FAA, Central Region, Office of the
Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City,
Missouri 64106.
Issued in Kansas City, Missouri, on September 26, 1996.
James E. Jackson,
Acting Manager, Small Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-25304 Filed 10-2-96; 8:45 am]
BILLING CODE 4910-13-M
