[Federal Register Volume 60, Number 209 (Monday, October 30, 1995)]
[Rules and Regulations]
[Pages 55187-55189]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-26403]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-CE-51-AD; Amendment 39-9415; AD 95-22-07]


Airworthiness Directives; de Havilland DHC-6 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes 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. This action retains 
the repetitive inspection requirement of the existing AD's, requires 
incorporating an improved modification for airplanes with a certain 
modification design as terminating action for the repetitive 
inspections, and making these inspection-terminating modifications 
optional for other affected airplanes. Reports of loose horizontal 
stabilizer attachment fittings on airplanes incorporating the 
inspection-terminating modifications required by AD 83-26-05 prompted 
this action. The actions specified by this 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: Effective December 27, 1995.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of December 27, 1995.

ADDRESSES: Service information that applies to this AD may be obtained 
from de Havilland, Inc., 123 Garratt Boulevard, Downsview, Ontario, 
Canada, M3K 1Y5. This information may also be examined at the Federal 
Aviation Administration (FAA), Central Region, Office of the Assistant 
Chief Counsel, Attention: Rules Docket 93-CE-51-AD, Room 1558, 601 E. 
12th Street, Kansas City, Missouri 64106; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, Washington, 
DC.

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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an AD that would apply 
to certain de Havilland DHC-6 series airplanes was published in the 
Federal Register on November 23, 1994 (59 FR 60337). The action 
proposed to 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. Accomplishment of the proposed inspections would be in 
accordance with de Havilland Service Bulletin (SB) No. 6/438, Revision 
D, dated March 28, 1986. Accomplishment of the proposed modifications 
would be in accordance with de Havilland SB 6/513, dated October 25, 
1991.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were received on the 
proposed rule or the FAA's determination of the cost to the public. 

[[Page 55188]]

    After careful review of all available information related to the 
subject presented above, the FAA has determined that air safety and the 
public interest require the adoption of the rule as proposed except for 
minor editorial corrections. The FAA has determined that these minor 
corrections will not change the meaning of the AD and will not add any 
additional burden upon the public than was already proposed.
    The FAA estimates that 169 airplanes in the U.S. registry will be 
affected by this AD, that it will take approximately 1 workhour per 
airplane to accomplish the required inspection, that it will 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 this 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 this 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 is found cracked and 
does not 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 over the life of the airplane.
    The regulations adopted herein will 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 final 
rule does 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) 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 final 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, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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), 40101, 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Airworthiness Directive 
(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:

95-22-07  De Havilland: Amendment 39-9415; Docket No. 93-CE-51-AD.

    Applicability: Models DHC-6-1, DHC-6-100, DHC-6-200, and DHC-6-
300 airplanes (serial numbers 3 through 820), certificated in any 
category, that do not have Modifications 6/1890, 6/1891, and 6/1892 
incorporated on all four horizontal stabilizer fittings in 
accordance with the ACCOMPLISHMENT INSTRUCTIONS section of de 
Havilland Service Bulletin (SB) No. 6/513, dated October 25, 1991.

    Note 1: 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 (e) 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 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 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. Accomplishing 
these modifications terminates the repetitive inspection requirement 
of this AD.
    (b) For airplanes that have Modifications 6/1808 and 6/1809 
incorporated, accomplish the following:
    (1) Within the next 400 hours TIS after the effective date of 
this AD, and thereafter at intervals not to exceed 800 hours TIS 
until the modifications required by paragraph (b)(3) of this AD are 
incorporated, 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, 1991.
    (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, 1991.
    (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, 1991.
    (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, 1991, 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, 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 2: Information concerning the existence of approved 
alternative methods of 

[[Page 55189]]
compliance with this AD, if any, may be obtained from the New York ACO.
    Note 3: Alternative methods of compliance approved in accordance 
with AD 83-26-05 or AD 86-15-08 (both superseded by this action) are 
not considered approved as alternative methods of compliance with 
this AD.

    (f) The inspections required by this AD shall be done in 
accordance with de Havilland Service Bulletin No. 6/438, Revision D, 
dated March 28, 1986. The modifications required by this AD shall be 
done in accordance with de Havilland Service Bulletin No. 6/513, 
dated October 25, 1991. This incorporation by reference was approved 
by the Director of the Federal Register in accordance with 5 U.S.C. 
552(a) and 1 CFR part 51. Copies may be obtained from de Havilland, 
Inc., 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5 Canada. 
Copies may be inspected at the FAA, Central Region, Office of the 
Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, 
Missouri, or at the Office of the Federal Register, 800 North 
Capitol Street, NW., 7th Floor, suite 700, Washington, DC.
    (g) This amendment (39-9415) supersedes AD 83-26-05, Amendment 
39-4793, and AD 86-15-08, Amendment 39-5362.
    (h) This amendment (39-9415) becomes effective on December 27, 
1995.

    Issued in Kansas City, Missouri, on October 18, 1995.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 95-26403 Filed 10-27-95; 8:45 am]
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