[Federal Register Volume 59, Number 37 (Thursday, February 24, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-4127]
[[Page Unknown]]
[Federal Register: February 24, 1994]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 92-CE-59-AD; Amendment 39-8837; AD 94-04-17]
Airworthiness Directives: Twin Commander Aircraft Corporation
500, 520, 560, 680, 681, 685, 690, 695, and 720 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD) that
applies to Twin Commander Aircraft Corporation (Twin Commander) 500,
520, 560, 680, 681, 685, 690, 695, and 720 series airplanes. This
action requires inspecting the flap system for cables with broken wires
or pulleys with worn cable clips, replacing any damaged parts, and
replacing the master pulley and cable with new parts of improved
design. Reports of cable fatigue, particularly the master pulley cable,
on several of the affected airplanes prompted this action. The actions
specified by this AD are intended to prevent flap system failure caused
by cable fatigue, which could result in loss of control of the
airplane.
DATES: Effective April 15, 1994. The incorporation by reference of
certain publications listed in the regulations is approved by the
Director of the Federal Register as of April 15, 1994.
ADDRESSES: Service information that applies to this AD may be obtained
from the Twin Commander Aircraft Corporation, 19003 59th Drive, NE.,
Arlington, Washington 98223. This information may also be examined at
the Federal Aviation Administration (FAA), Central Region, Office of
the Assistant Chief Counsel, 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: Mr. Mike Pasion, Aerospace Engineer,
FAA, Northwest Mountain Region, 1601 Lind Avenue SW., Renton,
Washington 98055-4056; telephone (206) 227-2594; facsimile (206) 227-
1181.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations to include an AD that would apply to certain Twin
Commander 500, 520, 560, 680, 681, 685, 690, 695, and 720 series
airplanes was published in the Federal Register on July 19, 1993 (58 FR
38540). The action proposed to require inspecting the flap system for
cables with broken wires and pulleys with worn clips, replacing any
damaged parts, and replacing the master pulley with a new part of
improved design. The proposed actions would be accomplished in
accordance with Twin Commander Service Bulletin No. 210, dated February
1, 1991.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the two comments received.
One commenter, the Twin Commander Aircraft Corporation, supports
the proposed rule, and recommends wording the proposed AD to more
closely coincide with Service Bulletin 210, dated February 1, 1991. The
FAA concurs and has reworded the proposal accordingly. This change does
not add any additional burden upon U.S. owners/operators of the
affected airplanes than was originally proposed.
The other commenter states that a parts availability problem may
occur if owners/operators of the affected airplanes find as many
damaged pulleys in the cable system as this owner/operator did on a
Model 690B airplane. This commenter feels that there is not sufficient
parts inventory to coincide with the 50-hour time-in-service (TIS)
compliance time, and recommends changing the compliance time to 12
months. The FAA does not concur. Twin Commander has assured the FAA
that there will be adequate parts available for all required repairs.
In addition, if a temporary delay in parts availability should occur,
then an owner/operator could request an extension of the compliance
time through instructions specified in paragraph (d) of the proposed
AD. The proposed AD is unchanged as a result of this comment.
After careful review of all available information, the FAA has
determined that air safety and the public interest require the adoption
of the rule as proposed except for the wording changes referenced above
and minor editorial corrections. The FAA has determined that these
minor changes and corrections will not change the meaning of the AD nor
add any additional burden upon the public than was already proposed.
The FAA estimates that 1,860 airplanes in the U.S. registry will be
affected by this AD, that it will take approximately 25 workhours per
airplane to accomplish the required action, and that the average labor
rate is approximately $55 an hour. Parts cost approximately $600 per
airplane. Based on these figures, the total cost impact of the AD on
U.S. operators is estimated to be $3,673,500. This figure is based upon
the assumption that none of the affected airplane operators have
accomplished the required actions.
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 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:
94-04-17 Twin Commander Aircraft Corporation: Amendment 39-8837;
Docket No. 92-CE-59-AD.
Applicability: Models 500, 500A, 500B, 500S, 500U, 520, 560,
560A, 560E, 560F, 680, 680E, 680F, 680FL, 680FL(P), 680FP, 680T,
680V, 680W, 681, 685, 690, 690A, 690B, 690C, 690D, 695, 695A, 695B,
and 720 airplanes (all serial numbers), certificated in any
category:
Compliance: Required within the next 50 hours time-in-service
after the effective date of this AD, unless already accomplished.
To prevent flap system failure caused by cable fatigue, which
could result in loss of control of the airplane, accomplish the
following:
(a) Accomplish the following inspections and parts replacements
(where applicable) of the flap system in accordance with the
Accomplishment Instructions section of Twin Commander Service
Bulletin (SB) No. 210, dated February 1, 1991.
(1) Rub each flap system cable over its length using a soft
cotton cloth. Where the cotton snags, visually inspect the cable for
broken wires. Prior to further flight, replace any cable having a
broken wire.
(2) Inspect the slave pulley groove width. If the groove is too
narrow as specified in Part I, paragraph C, of the Accomplishment
Instructions section of Twin Commander SB No. 210, prior to further
flight, replace the slave pulley and slave pulley cable.
(3) Visually inspect the flap system for pulleys with worn cable
clips or rubbing against the upper or lower support brackets. Prior
to further flight, replace any damaged pulleys, brackets, or clips.
(b) Replace the master pulley and the master pulley cable with
new parts of improved design in accordance with the Accomplishment
Instructions section of Twin Commander SB No. 210, dated February 1,
1991. The applicable master pulley and master cable pulley part
numbers are referenced in Table I of Twin Commander SB No. 210.
(c) 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.
(d) An alternative method of compliance or adjustment of the
compliance time that provides an equivalent level of safety may be
approved by the Manager, Seattle Aircraft Certification Office
(ACO), FAA, Northwest Mountain Region, 1601 Lind Avenue SW., Renton,
Washington 98055-4056. The request shall be forwarded through an
appropriate FAA Maintenance Inspector, who may add comments and then
send it to the Manager, Seattle ACO, FAA, Northwest Mountain Region.
Note: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO, FAA, Northwest Mountain Region.
(e) The inspection and replacement required by this AD shall be
done in accordance with Twin Commander Service Bulletin No. 210,
dated February 1, 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 the Twin
Commander Aircraft Corporation, 19003 59th Drive, NE., Arlington,
Washington 98223. 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., suite 700, Washington, DC.
(f) This amendment (39-8837) becomes effective on April 15,
1994.
Issued in Kansas City, Missouri, on February 15, 1994.
Barry D. Clements,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 94-4127 Filed 2-23-94; 8:45 am]
BILLING CODE 4910-13-U
