[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