[Federal Register Volume 62, Number 62 (Tuesday, April 1, 1997)]
[Rules and Regulations]
[Pages 15373-15375]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-8249]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 93-CE-45-AD; Amendment 39-9984; AD 97-07-10]
RIN 2120-AA64
Airworthiness Directives; De Havilland DHC-6 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: This amendment adopts a new airworthiness directive (AD) that
applies to de Havilland DHC-6 series airplanes that do not have a
certain wing strut modification (Modification 6/1581) incorporated.
This action requires 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. This AD results from several
reports of wing strut damage caused by the upper fairing rubbing
against the wing strut. The actions specified by this AD are intended
to prevent failure of the wing struts, which could result in loss of
control of the airplane.
DATES: Effective May 23, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of May 23, 1997.
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-45-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:
Discussion
A proposal to amend part 39 of the Federal Aviation Regulations (14
CFR part 39) to include an AD that would apply to de Havilland DHC-6
series airplanes that do not have a certain wing strut modification
(Modification 6/1581) incorporated was published in the Federal
Register as a notice of proposed rulemaking (NPRM) on October 3, 1996
(61 FR 51619). The NPRM proposed to 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.
Modification No. 6/1581 consists of installing a preformed nylon shield
around the area of each wing strut of the upper end closest to the
wing. Accomplishment of the proposed inspection and modification as
specified in the NPRM would be required in accordance with de Havilland
Service Bulletin No. 6/342, dated February 23, 1976.
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.
The FAA's Determination
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
[[Page 15374]]
the AD 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.
FAA's Aging Commuter Aircraft Policy
This AD is consistent with the FAA's aging commuter airplane
policy. This policy simply states that reliance on repetitive
inspections 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 inspections to detect damaged wing struts.
Cost Impact
The FAA estimates that 169 airplanes in the U.S. registry will be
affected by this AD, that it will take approximately 8 workhours per
airplane to accomplish the required 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 AD on
U.S. operators is estimated to be $106,470. This figure is based upon
the presumption 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.
Presuming that each set of parts is incorporated on an affected
airplane, the cost impact upon U.S. operators/owners would be reduced
by $6,930 from $106,470 to $99,540.
Regulatory Impact
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), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
(AD) to read as follows:
97-07-10 Dehavilland: Amendment 39-9984; 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 closest 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 (or FAA-approved equivalent), 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, provided the damage does not exceed 0.025-inch in depth,
the damage does not exceed a total length of 5 inches, and where any
two places of damage are separated 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) The inspections and modification required by this AD shall
be done in accordance de Havilland Service Bulletin No. 6/342, dated
February 23, 1976. 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,
[[Page 15375]]
Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the
Office of the Federal Register, 800 North Capitol Street, NW., suite
700, Washington, DC.
(f) This amendment (39-9984) becomes effective on May 23, 1997.
Issued in Kansas City, Missouri, on March 26, 1997.
James E. Jackson,
Acting Manager, Small Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 97-8249 Filed 3-31-97; 8:45 am]
BILLING CODE 4910-13-U
