Upper wing skins - Twin Commander Aircraft LLC

Upper wing skins - Twin Commander Aircraft LLC

[Federal Register: December 4, 2009 (Volume 74, Number 232)]
[Rules and Regulations]
[Page 63565-63568]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr04de09-7]
––––––––––––––––––––––––––––––––––
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2009-0778; Directorate Identifier 2009-CE-040-AD; Amendment 39-16119;
AD 2009-25-02]
RIN 2120-AA64
Airworthiness Directives; Twin Commander Aircraft LLC Models 690, 690A, and 690B
Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
––––––––––––––––––––––––––––––––––
SUMMARY: We are adopting a new airworthiness directive (AD) for certain Twin Commander
Aircraft LLC Models 690, 690A, and 690B airplanes. This AD requires you to inspect between the
surface of the left-hand (LH) and right-hand (RH) upper wing skins and the engine mount beam
support straps for any signs of corrosion, replace the upper steel straps with parts of improved design,
and modify both wings. This AD results from reports that corrosion was found between the mating
surfaces of the wing upper skin surface and the engine mount beam support straps. We are issuing
this AD to detect and correct corrosion on the engine mount beam support straps and the upper wing
skins, which could result in failure of the engine mount beam support straps. This failure could lead
to loss of the engine and possible loss of control of the airplane.
DATES: This AD becomes effective on January 8, 2010.
On January 8, 2010, the Director of the Federal Register approved the incorporation by reference
of certain publications listed in this AD.
ADDRESSES: To get the service information identified in this AD, contact Twin Commander
Aircraft LLC, 18933-59th Avenue, NE., Suite 115, Arlington, WA 98223, telephone: (360) 435-
9797; fax: (360) 435-1112; Internet: http://www.twincommander.com.
To view the AD docket, go to U.S. Department of Transportation, Docket Operations, M-30,
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC
20590, or on the Internet at http://www.regulations.gov. The docket number is FAA-2009-0778;
Directorate Identifier 2009-CE-040-AD.
1

FOR FURTHER INFORMATION CONTACT: Vince Massey, Aerospace Engineer, FAA, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone:
(425) 917-6475; fax: (425) 917-6590; e-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
SUPPLEMENTARY INFORMATION:
Discussion
On August 21, 2009, we issued a proposal to amend part 39 of the Federal Aviation Regulations
(14 CFR part 39) to include an AD that would apply to certain Twin Commander Aircraft LLC
Models 690, 690A, and 690B airplanes. This proposal was published in the Federal Register as a
notice of proposed rulemaking (NPRM) on August 28, 2009 (74 FR 44308). The NPRM proposed to
require you to inspect between the surface of the LH and RH upper wing skins and the engine mount
beam support straps for any signs of corrosion, replace the upper steel straps with parts of improved
design, and modify both wings.
Comments
We provided the public the opportunity to participate in developing this AD. The following
presents the comments received on the proposal and FAA's response to each comment:
Comment Issue: Extend Compliance Time
Michael Curtis Pidek, William I. Smith, and Tom Bayer all state that with 275 airplanes affected
by this AD and only 15 service centers available to do the actions required in this AD, there is not
enough time to comply with the AD.
All three commenters request an extension of the compliance time to allow enough time for the
service centers to schedule the work without grounding airplanes until the work can be done.
We do not agree with the commenters. Over 65 airplanes are already in compliance with this
AD. We have consulted with Twin Commander Aircraft LLC and they have covered this issue with
the service centers. The service centers know how much work is required since they have already
done the work on over 65 of the affected airplanes. The service centers plan on using multiple teams
to work on several airplanes at the same time. They have confirmed they can perform the actions
required in this AD in the compliance time as proposed.
Part of the alternative method of compliance (AMOC) provisions of 14 CFR 39.19 is an
extension of the compliance time provided a level of safety acceptable to the FAA is met. The FAA
will review any AMOCs of this nature on a case-by-case basis. If we determine the proposal presents
an acceptable level of safety, we will approve it as an AMOC to the AD.
We are not changing the final rule AD action based on these comments.
Conclusion
We have carefully reviewed the available data and determined that air safety and the public
interest require adopting the AD as proposed except for minor editorial corrections. We have
determined that these minor corrections:
• Are consistent with the intent that was proposed in the NPRM for correcting the unsafe condition;
and
• Do not add any additional burden upon the public than was already proposed in the NPRM.
Costs of Compliance
We estimate that this AD will affect 275 airplanes in the U.S. registry.
2

$6,400
$1,015,575
$3,693
$1,293
30 work-hours X $80 per hour = $2,400
Total Cost on U.S.
Operators
Total Cost Per
Airplane
Parts Cost
Labor Cost
We estimate the following costs to do the installation of access holes:
$12,190
$6,190 per
strap per side
75 work-hours X $80 per hour =
$6,000 per side
Total Cost Per Airplane Per Side
Parts Cost
Labor Cost
Strap Only Replacement – Option D
Note: * Depending on airplane configuration, airplanes with rectangular plates will need the
Plate and Hardware Kit (SB237-4) at $2,090 per side. Labor to install this kit is included in Options
A, B, and C.
$34,770
$9,170 per kit
per side
320 work-hours X $80 per hour =
$25,600 per side
Total Cost Per Airplane Per Side
Parts Cost
Labor Cost
Long Modification – Option C*
$31,570
$9,170 per kit
per side
280 work-hours X $80 per hour =
$22,400 per side
Total Cost Per Airplane Per Side
Parts Cost
Labor Cost
Middle Modification – Option B*
$29,170
$9,170 per kit
per side
We estimate the following costs to do the inspection:
Labor Cost
Parts Cost
Total Cost Per
Airplane
Total Cost on U.S.
Operators
80 work-hours X $80 per
hour = $6,400
Not applicable
3
$1,760,000
We estimate the following costs to do any necessary repairs/replacements that will be required
based on the results of the inspection. We have no way of determining the number of airplanes that
may need this repair/replacement:
Short Modification – Option A*
Labor Cost
Parts Cost
Total Cost Per Airplane Per Side
250 work-hours X $80 per hour =
$20,000 per side

$930
Authority: 49 U.S.C. 106(g), 40113, 44701.
1. The authority citation for part 39 continues to read as follows:
PART 39–AIRWORTHINESS DIRECTIVES
Accordingly, under 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:
Adoption of the Amendment
We estimate the following costs to do the wing fastener modification:
Labor Cost
Parts Cost
Total Cost Per
Airplane
Total Cost on U.S.
Operators
8.5 work-hours X $80 per hour = $680
$250
4
$255,750
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety.
Subtitle I, Section 106 describes the authority of the FAA Administrator. Subtitle VII, Aviation
Programs, describes in more detail the scope of the agency's authority.
We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III,
Section 44701, ''General requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices,
methods, and procedures the Administrator finds necessary for safety in air commerce. This
regulation is within the scope of that authority because it addresses an unsafe condition that is likely
to exist or develop on products identified in this AD.
Regulatory Findings
We have determined that this AD will not have federalism implications under Executive Order
13132. This AD will not have a substantial direct effect 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.
For the reasons discussed above, I certify that this AD:
1. Is not a ''significant regulatory action'' under Executive Order 12866;
2. Is not a ''significant rule'' under the 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.
We prepared a summary of the costs to comply with this AD (and other information as included
in the Regulatory Evaluation) and placed it in the AD Docket. You may get a copy of this summary
by sending a request to us at the address listed under ADDRESSES. Include ''Docket No. FAA-2009-
0778; Directorate Identifier 2009-CE-040-AD'' in your request.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

2. FAA amends § 39.13 by adding a new AD to read as follows:
5
§ 39.13 [Amended]

Affected ADs
(e) To address this problem, you must do the following, unless already done:
Compliance
(d) This AD results from reports that corrosion was found between the mating surfaces of the
wing upper skin surface and the engine mount beam support straps. We are issuing this AD to detect
and correct corrosion on the engine mount beam support straps and upper wing skins, which could
result in failure of the engine mount beam support straps. This failure could lead to loss of the engine
and possible loss of control of the airplane.
Unsafe Condition
All S/Ns except 11361, 11383, 11527, and 11536.
690B
All S/Ns except 11195 and 11279.
690A
S/Ns
AIRWORTHINESS DIRECTIVE
FAA
Aircraft Certification Service
www.faa.gov/aircraft/safety/alerts/
www.gpoaccess.gov/fr/advanced.html
2009-25-02 Twin Commander Aircraft LLC: Amendment 39-16119; Docket No. FAA-2009-0778;
Directorate Identifier 2009-CE-040-AD.
Effective Date
(a) This AD becomes effective on January 8, 2010.
6
(b) None.
Applicability
(c) This AD applies to the following airplane models and serial numbers that are certificated in
any category:
Models Serial
Nos. (S/Ns)
690 All

(2) Install modification
access holes in the LH and
RH lower wing skins.
(f) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve
AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to
ATTN: Vince Massey, Aerospace Engineer, FAA, Seattle ACO, 1601 Lind Avenue, SW, Renton,
Washington 98057-3356; telephone: (425) 917-6475; fax: (425) 917-6590; email:
This e-mail address is being protected from spambots. You need JavaScript enabled to view it . Before using any approved AMOC on any airplane to which the AMOC
applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office
(FSDO), or lacking a PI, your local FSDO.
Alternative Methods of Compliance (AMOCs)
Note: Although not required by this AD, we highly recommend compliance with Twin
Commander Aircraft Corporation Service Bulletin No. 217, Revision No. 1, dated May 26, 1993,
Engine Nacelle Firewall Reinforcement; and Twin Commander Aircraft LLC Alert Service Bulletin
No. 239, dated February 13, 2006, Outboard Flap–Inboard Hinge Inspection & Reinforcement.
Follow Gulfstream American
Corporation Service Bulletin No.
182, dated March 2, 1981.
Before further flight after the
inspection required in
paragraph (e)(1) of the AD.
(5) Install additional wing
fasteners on the LH and RH
wing.
Follow Twin Commander Aircraft
LLC Alert Service Bulletin No.
237, dated May 13, 2005, Part II,
Option D, on pages 30 and 31.
Before further flight after the
inspection required in
paragraph (e)(1) of this AD.
Actions Compliance
Procedures
(1) Inspect between the
surface of the left-hand (LH)
and right-hand (RH) upper
wing skins and the engine
mount beam support straps
for any signs of corrosion and
determine the extent of any
corrosion found.
Within the next 150 hours
time-in-service after January
8, 2010 (the effective date of
this AD) or within the next 12
months after January 8, 2010
(the effective date of this
AD), whichever occurs first.
Follow Twin Commander Aircraft
LLC Alert Service Bulletin No.
237, dated May 13, 2005, pages 1
through 14.
7
Before further flight after the
inspection required in
paragraph (e)(1) of this AD.
Follow the Accomplishment
Instructions, steps 1 through 4 and
6 through 9, of Twin Commander
Aircraft Corporation Custom Kit
No. 150, dated July 8, 1994, as
specified in Twin Commander
Aircraft LLC Alert Service
Bulletin No. 237, dated May 13,
2005.
(3) If corrosion damage is
found during the inspection
required in paragraph (e)(1)
of this AD, perform
necessary modification.
Before further flight after the
inspection required in
paragraph (e)(1) of this AD.
Follow Twin Commander Aircraft
LLC Alert Service Bulletin No.
237, dated May 13, 2005, Part II,
Options A, B, or C, on pages 15
through 29 and 31.
(4) If corrosion damage is not
found during the inspection
required in paragraph (e)(1)
of this AD, do the upper steel
strap replacements.

(g) You must use Twin Commander Aircraft LLC Alert Service Bulletin No. 237, dated May 13,
2005; Twin Commander Aircraft Corporation Custom Kit No. 150, dated July 8, 1994; and
Gulfstream American Corporation Service Bulletin No. 182, dated March 2, 1981, to do the actions
required by this AD, unless the AD specifies otherwise.
(1) The Director of the Federal Register approved the incorporation by reference of this service
information under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) For service information identified in this AD, contact Twin Commander Aircraft LLC,
18933–59th Avenue, NE., Arlington, WA 98223, telephone: (360) 435-9797; fax: (360) 435-1112;
Internet: http://www.twincommander.com.
(3) You may review copies of the service information incorporated by reference for this AD at
the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Kansas City, Missouri 64106.
For information on the availability of this material at the Central Region, call (816) 329-3768.
(4) You may also review copies of the service information incorporated by reference for this AD
at the National Archives and Records Administration (NARA). For information on the availability of
this material at NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal_register/code_
of_federal_regulations/ibr_locations.html.
Issued in Kansas City, Missouri, on November 20, 2009.
Margaret Kline,
Acting Manager, Small Airplane Directorate,
Aircraft Certification Service.
8
Material Incorporated by Reference

Dan Weiler
Executive Director of the Cessna Owner Organization
(715) 445-5000, ext. 116
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Daniel
Executive Director
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