[Federal Register Volume 59, Number 225 (Wednesday, November 23, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-28884]


[[Page Unknown]]

[Federal Register: November 23, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-CE-51-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 supersede Airworthiness Directive 
(AD) 83-26-05 and AD 86-15-08, which currently require repetitively 
inspecting the horizontal stabilizer attachment fittings for cracks or 
looseness on certain de Havilland DHC-6 series airplanes, and, if a 
cracked or loose part is found, modifying the horizontal stabilizer. 
The proposed action would incorporate an improved modification that, 
when incorporated, provides terminating action for the existing AD's. 
Reports of loose horizontal stabilizer attachment fittings on airplanes 
with the existing inspection-terminating modification incorporated 
prompted the proposed action. The actions specified by the proposed AD 
are intended to prevent separation of the horizontal stabilizer from 
the airplane caused by a cracked attachment fitting, and subsequent 
loss of control of the airplane.

DATES: Comments must be received on or before January 27, 1995.

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-51-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-51-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-51-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 attachment fittings have cracked on several of 
the above referenced airplanes that were in compliance with AD 83-26-
05, Amendment 39-4793, and AD 86-15-08, Amendment 39-5362.
    AD 83-26-05 currently requires repetitively inspecting the 
horizontal stabilizer attachment fittings on de Havilland DHC-6 series 
airplanes, and replacing any cracked fitting with a new fitting of the 
same part number or incorporating Modification 6/1808 and 6/1809.
    AD 86-15-08 currently requires incorporating improved modifications 
(Modifications 6/1855 and 6/1856) for de Havilland DHC-6 series 
airplanes that have Modifications 6/1808 and 6/1809 incorporated.
    De Havilland has issued Service Bulletin (SB) No. 6/512, dated 
October 25, 1991, which specifies procedures for (1) inspecting the 
horizontal stabilizer attachment fittings for cracks; and (2) replacing 
these fittings. This service bulletin replaces de Havilland SB No. 6/
475, which included procedures for incorporating Modifications 6/1855 
and 6/1856. Transport Canada classified de Havilland SB No. 6/512 as 
mandatory and issued Transport Canada AD CF-92-04, dated January 30, 
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 (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, 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 supersede both AD 83-26-05 and 
AD 86-15-08 with a new AD that would require repetitively inspecting 
the horizontal stabilizer attachment fittings for cracks; and, if a 
cracked fitting is found, replacing with a serviceable fitting, part 
number (P/N) C6TPM1049-27 (forward fitting) or C6TPM1050-27 (rear 
fitting), and incorporating Modifications 6/1890, 6/1891, and 6/1892. 
The proposed action would also require the eventual incorporation of 
the above-referenced modifications for airplanes that have 
Modifications 6/1808 and 6/1809 incorporated. 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 it 
would take approximately 10 workhours to accomplish the modification 
for those airplanes having Modifications 6/1808 and 6/1809 
incorporated, and that the average labor rate is $60 per hour. The FAA 
has no way of knowing how many airplanes have incorporated these 
modifications. In estimating the total cost impact of the proposed AD 
on U.S. operators, the FAA is only using the inspection criteria (1 
workhour). With this in mind and based on those figures above, the 
total cost impact of the proposed AD upon U.S. operators of the 
affected airplanes is estimated to be $10,140. This figure only 
includes the cost for the initial inspection and does not include 
replacement costs if an attachment fitting was found cracked nor does 
it include repetitive inspection costs. The FAA has no way of 
determining how many horizontal stabilizer attachment fittings 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 
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. 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 removing AD 83-26-05, Amendment 39-
4793, and AD 86-15-08, Amendment 39-5362, and by adding a new AD to 
read as follows:

De Havilland: Docket No. 93-CE-51-AD; Supersedes AD 83-26-05, 
Amendment 39-4793, and AD 86-15-08, Amendment 39-5362.

    Applicability: Models DHC-6-1, DHC-6-100, DHC-6-200, and DHC-6-
300 airplanes, serial number 3 through 820, certificated in any 
category.
    Compliance: Required as indicated, unless already accomplished.
    To prevent separation of the horizontal stabilizer from the 
airplane caused by a cracked attachment fitting, and subsequent loss 
of control of the airplane, accomplish the following:
    (a) For airplanes without Modification Nos. 6/1808 and 6/1809 
incorporated, accomplish the following:
    (1) Within the next 50 hours time-in-service (TIS) after the 
effective date of this AD or 800 hours TIS after the last inspection 
required by superseded AD 83-26-05, whichever occurs later, and 
thereafter at intervals not to exceed 800 hours TIS, inspect the 
horizontal stabilizer forward and rear attachment fittings for 
cracks in accordance with de Havilland Service Bulletin (SB) No. 6/
438, Revision D, dated March 28, 1986.
    (2) If any cracks are found, prior to further flight, replace 
the cracked fitting with a serviceable fitting, part number (P/N) 
C6TPM1049-27 (forward fitting) or P/N C6TPM1050-27 (rear fitting), 
and incorporate Modifications 6/1890, 6/1891, and 6/1892 at each 
replacement fitting location in accordance with and as specified in 
de Havilland SB No. 6/513, dated October 25, 1991.
    (b) For airplanes that have Modifications 6/1808 and 6/1809 
incorporated, accomplish the following:
    (1) Within the next 400 hours time-in-service after the 
effective date of this AD, and thereafter at intervals not to exceed 
800 hours TIS, inspect the rivets attaching the fittings to the 
horizontal stabilizer forward and rear spars for looseness in 
accordance with the III. ACCOMPLISHMENT INSTRUCTIONS A. INSPECTION 
section of de Havilland SB No. 6/513, dated October 25, 1993.
    (2) If rivets are found loose, prior to further flight, 
incorporate Modifications 6/1890, 6/1891, and 6/1892 in accordance 
with the ACCOMPLISHMENT INSTRUCTIONS section of de Havilland SB No. 
6/513, dated October 25, 1993.
    (3) Within the next 2,400 hours TIS after the effective date of 
this AD, unless already accomplished as required by paragraph (b)(2) 
of this AD, incorporate Modifications 6/1890, 6/1891, and 6/1892 on 
all four horizontal stabilizer fittings in accordance with the 
ACCOMPLISHMENT INSTRUCTIONS section of de Havilland SB No. 6/513, 
dated October 25, 1993.
    (c) Incorporating Modifications 6/1890, 6/1891, and 6/1892 on 
all four horizontal stabilizer fittings in accordance with the 
ACCOMPLISHMENT INSTRUCTIONS section of de Havilland SB No. 6/513, 
dated October 25, 1993, is considered terminating action for the 
repetitive inspection requirements of this AD.
    (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.
    (e) 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: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the New York ACO.

    (f) 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.
    (g) This amendment supersedes AD 83-26-05, Amendment 39-4793, 
and AD 86-15-08, Amendment 39-5362. Issued in Kansas City, Missouri, 
on November 16, 1994.
Henry A. Armstrong,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-28884 Filed 11-22-94; 8:45 am]
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