AD Amdt-39-10437

[Federal Register Volume 63, Number 65 (Monday, April 6, 1998)]
[Rules and Regulations]
[Pages 16679-16681]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 98-8579]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-CE-69-AD; Amendment 39-10437; AD 98-07-17]
RIN 2120-AA64


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 supersedes Airworthiness Directive (AD) 94-04-
17, which currently requires the following on Twin Commander Aircraft 
Corporation (Twin Commander) 500, 520, 560, 680, 681, 685, 690, 695, 
and 720 series airplanes: inspecting (one-time) 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. This AD requires inspecting all flap system 
cable grooves for the correct width, inspecting all flap system pulleys 
for rubbing on the support brackets, inspecting all flap pulley cable 
assemblies for frayed wires, and reworking or replacing any parts with 
discrepancies. This AD results from several reports of worn and frayed 
flap system cables attributed to flap pulley grooves that are too 
narrow. The actions specified by this AD are intended to prevent 
failure of a flap system cable caused by fatigue, which could result in 
loss of control of the airplane.

DATES: Effective May 29, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 29, 1998.

ADDRESSES: Service information that applies to this AD may be obtained 
from the Twin Commander Aircraft Corporation, 19003 59th Drive, NE, 
Arlington, Washington 98223-7832. This information may also be examined 
at the Federal Aviation Administration (FAA), Central Region, Office of 
the Regional Counsel, Attention: Rules Docket No. 97-CE-69-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: Mr. Jeffrey Morfitt, Aerospace 
Engineer, FAA, Northwest Mountain Region, 1601

[[Page 16680]]

Lind Avenue S.W., Renton, Washington 98055-4056; telephone: (425) 227-
2595; facsimile: (425) 227-1181.

SUPPLEMENTARY INFORMATION:

Events Leading to the Issuance of This AD

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to include an AD that would apply all models of Twin 
Commander 500, 520, 560, 680, 681, 685, 690, 695, and 720 series 
airplanes was published in the Federal Register as a notice of proposed 
rulemaking (NPRM) on October 31, 1997 (62 FR 58925). The NPRM proposed 
to supersede AD 94-04-17 with a new AD that requires inspecting all 
flap system cable grooves for the correct width, inspecting all flap 
system pulleys for rubbing on the support brackets, inspecting all flap 
pulley cable assemblies for frayed wires, and reworking or replacing 
any parts with discrepancies. Accomplishment of the proposed action as 
specified in the NPRM would be in accordance with Twin Commander 
Mandatory Service Bulletin No. 226, dated April 14, 1997 (Revision No. 
1 Release Date: July 15, 1997).
    The NPRM was the result of several reports of worn and frayed flap 
system cables attributed to flap pulley grooves that are too narrow.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the one comment received.

Comment Disposition

    The commenter expresses concern over the availability of the parts 
necessary to comply with the proposed AD. The commenter states that, if 
the proposed AD would become a final rule with the proposed compliance 
time of ``within the next 100 hours time-in-service (TIS) after the 
effective date of the AD'', then the commenter's fleet of the affected 
airplanes would be grounded because of parts unavailability. The 
commenter requests that the FAA re-examine the compliance time of the 
proposed AD before issuing a final rule.
    The FAA has re-examined the compliance time, checked with the 
manufacturer about the availability of parts, and has determined that a 
more realistic compliance time would be ``within the next 300 hours TIS 
after the effective date of this AD''. The final rule reflects this 
change.

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 the rule as proposed except for 
the compliance time change discussed above and minor editorial 
corrections. The FAA has determined that this change and 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.

Cost Impact

    The FAA estimates that 1,230 airplanes in the U.S. registry will be 
affected by this AD, that it will take approximately 22 workhours per 
airplane to accomplish the inspection required by this AD, and that the 
average labor rate is approximately $60 an hour. Based on these 
figures, the total cost impact of this AD on U.S. operators is 
estimated to be $1,623,600, or $1,320 per airplane. These figures only 
take into account the inspection costs of this AD and do not reflect 
the costs of any repairs or replacements that may be required if 
discrepancies are found during the inspection. The FAA has no way of 
determining how many parts will need to be repaired or replaced after 
accomplishing the inspection.

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 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Airworthiness Directive 
(AD) 94-04-17, Amendment 39-8837, and by adding a new AD to read as 
follows:

98-07-17  Twin Commander Aircraft Corporation: Amendment 39-10437; 
Docket No. 97-CE-69-AD. Supersedes AD 94-04-17, Amendment 39-8837.

    Applicability: The following airplane models (all serial 
numbers), certificated in any category:


500            5500-A        5500-B        5500-S        5500-U         
520            5560          5560-A        5560-E        5560-F         
680            680-E         680-F         680FL         680FL(P)       
680FP          680T          680V          680W          681            
685            690           690A          690B          690C           
690D           695           695A          695B          720            
                                                                        


    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.


[[Page 16681]]


    Compliance: Required as indicated in the body of this AD, unless 
already accomplished.
    To prevent failure of a flap system cable caused by fatigue, 
which could result in loss of control of the airplane, accomplish 
the following:
    (a) Within the next 300 hours time-in-service (TIS) after the 
effective date of this AD, unless already accomplished, perform the 
following in accordance with the ACCOMPLISHMENT INSTRUCTIONS section 
of Twin Commander Aircraft Corporation (Twin Commander) Mandatory 
Service Bulletin No. 226, dated April 14, 1997 (Revision No. 1 
Release Date: July 15, 1997):
    (1) Inspect all flap system cable grooves for the correct width;
    (2) Inspect all flap system pulleys for rubbing on the support 
brackets;
    (3) Inspect all flap pulley cable assemblies for frayed wires; 
and
    (4) Mark pulleys that have been inspected and have the correct 
groove radius with two parallel lines as specified in the service 
bulletin.

    Note 2: Revision No. 1 Release Date: July 15, 1997, of Twin 
Commander Mandatory Service Bulletin No. 226, specifies changes in 
the workhours necessary to accomplish this action and makes 
reference to a gauge that is available from the manufacturer for use 
in accomplishing the inspection.

    (b) If any of the above discrepancies are found, prior to 
further flight after the inspections required by paragraph (a), 
including all subparagraphs, of this AD, rework or replace the 
affected part in accordance with Twin Commander Mandatory Service 
Bulletin No. 226, dated April 14, 1997 (Revision No. 1 Release Date: 
July 15, 1997).
    (c) As of the effective date of this AD, no person may install a 
pulley that does not have the criteria presented in either paragraph 
(c)(1), (c)(2), or (c)(3) of this AD:
    (1) A pulley that has been inspected, found acceptable, and 
marked with two parallel lines in accordance with paragraph (a), 
including all subparagraphs, of this AD;
    (2) A pulley that has been reworked in accordance with an FAA-
approved procedure and is marked ``SB 226''; or
    (3) A new pulley that is marked ``SB 226-NEW''.
    (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 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, Seattle Aircraft Certification Office 
(ACO), Northwest Mountain Region, FAA, 1601 Lind Avenue S.W., 
Renton, Washington 98055-4056.
    (1) The request shall be forwarded through an appropriate FAA 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Seattle ACO.
    (2) Alternative methods of compliance approved in accordance 
with AD 94-04-17 (superseded by this AD) are not considered approved 
as alternative methods of compliance for this AD.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (f) The inspections and replacements required by this AD shall 
be done in accordance with Twin Commander Mandatory Service Bulletin 
No. 226, dated April 14, 1997 (Revision No. 1 Release Date: July 15, 
1997). 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 98223-7832. 
Copies may be inspected at the FAA, Central Region, Office of the 
Regional 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.
    (g) This amendment supersedes AD 94-04-17, Amendment 39-8837.
    (h) This amendment becomes effective on May 29, 1998.

    Issued in Kansas City, Missouri, on March 24, 1998.
Carolanne L. Cabrini,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-8579 Filed 4-3-98; 8:45 am]
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