[Federal Register Volume 59, Number 33 (Thursday, February 17, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-3576]


[[Page Unknown]]

[Federal Register: February 17, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-CE-52-AD]

 

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 
(AD) that would apply to de Havilland DHC-6 series airplanes. The 
proposed action would require repetitively inspecting the horizontal 
stabilizer center hinge bracket for cracks, and replacing any cracked 
center hinge bracket. Several reports of cracks in the horizontal 
stabilizer center hinge bracket flange on the affected airplanes 
prompted the proposed action. The actions specified by the proposed AD 
are intended to prevent separation of the elevator control support from 
the airplane as a result of a cracked horizontal stabilizer center 
hinge bracket, which could result in reduced controllability of the 
airplane.

DATES: Comments must be received on or before April 22, 1994.

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-52-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, 181 South Franklin Avenue, room 
202, Valley Stream, New York 11581; telephone (516) 791-6220; facsimile 
(516) 791-9024.

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-52-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-52-AD, room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.

Discussion

    Transport Canada, which is the airworthiness authority for Canada, 
recently notified the FAA that an unsafe condition may exist on de 
Havilland DHC-6 series airplanes. Transport Canada reports that the 
horizontal stabilizer center hinge bracket has cracked on several of 
the above referenced airplanes.
    De Havilland has issued Service Bulletin (SB) 6/512, dated October 
25, 1991, which specifies procedures for (1) inspecting the horizontal 
stabilizer center hinge bracket for cracks; and (2) replacing this 
center hinge bracket. Transport Canada classified this service bulletin 
as mandatory and issued Transport Canada AD CF-92-05, dated February 7, 
1992, in order to assure the continued airworthiness of these airplanes 
in Canada.
    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 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, and determined 
that AD action is necessary for products of this type design that are 
certificated for operation in the United States.
    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, the proposed AD would require repetitively inspecting 
the horizontal stabilizer center hinge bracket for cracks, and 
replacing any cracked center hinge bracket. The proposed action would 
be accomplished in accordance with the ACCOMPLISHMENT INSTRUCTIONS 
section of de Havilland SB 6/512, dated October 25, 1991.
    The FAA estimates that 169 airplanes in the U.S. registry would be 
affected by the proposed AD, that it would take approximately 1 
workhour per airplane to accomplish the proposed inspection, and that 
the average labor rate is approximately $55 an hour. Based on these 
figures, the total cost impact of the proposed AD on U.S. operators is 
estimated to be $9,295. This figure only includes the cost for the 
initial inspection and does not include replacement costs if a center 
hinge bracket was found cracked nor does it include repetitive 
inspection costs. The FAA has no way to determine how many center hinge 
brackets may be cracked or how many repetitive inspections each owner/
operator may incur.
    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 14 
CFR part 39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new AD to read 
as follows:


De Havilland: Docket No. 93-CE-52-AD.

    Applicability: Models DHC-6-1, DHC-6-100, DHC-6-200, and DHC-6-
300 airplanes (all serial numbers), certificated in any category.
    Compliance: Required within the next 250 hours time-in-service 
(TIS), unless already accomplished, and thereafter at intervals not 
to exceed 1,200 hours TIS.
    To prevent separation of the elevator control support from the 
airplane as a result of a cracked horizontal stabilizer center hinge 
bracket, which could result in reduced controllability of the 
airplane, accomplish the following:
    (a) Inspect the horizontal stabilizer center hinge bracket for 
cracks in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of 
de Havilland Service Bulletin 6/512, dated October 25, 1991, except 
that where dye penetrant inspections are specified, accomplish 
visual inspections with a strong light source and 10X magnifying 
glass. If any cracks are found, prior to further flight, replace the 
center hinge bracket in accordance with the referenced service 
bulletin.

    Note 1: The repetitive inspection requirement of this AD still 
applies if the center hinge bracket is replaced.

    (b) Special flight permits may be issued in accordance with 14 
CFR 21.197 and 21.199 to operate the airplane to a location where 
the requirements of this AD can be accomplished.
    (c) An alternative method of compliance or adjustment of the 
initial or repetitive compliance times that provides an equivalent 
level of safety may be approved by the Manager, New York Aircraft 
Certification Office (ACO), FAA, 181 South Franklin Avenue, room 
202, 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 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) 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 February 11, 1994.
Michael K. Dahl,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Office.
[FR Doc. 94-3576 Filed 2-16-94; 8:45 am]
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