[Federal Register Volume 74, Number 166 (Friday, August 28, 2009)]
[Proposed Rules]
[Pages 44308-44311]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-20789]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0778; Directorate Identifier 2009-CE-040-AD]
RIN 2120-AA64


Airworthiness Directives; Twin Commander Aircraft Corporation 
Models 690, 690A, and 690B Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain Twin Commander Aircraft Corporation Models 690, 690A, and 690B 
airplanes. This proposed AD would require 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 proposed 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 proposing 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: We must receive comments on this proposed AD by October 13, 
2009.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: (202) 493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
Twin Commander Aircraft, LLC, 19010 59th Drive, NE., Arlington, WA 
98223, telephone: (360) 435-9797; fax: (360) 435-1112; Internet: 
www.twincommander.com.

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: [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include the docket number, ``FAA-
2009-0778; Directorate Identifier 2009-CE-040-AD'' at the beginning of 
your comments. We specifically invite comments on the overall 
regulatory, economic, environmental, and energy aspects of the proposed 
AD. We will consider all comments received by the closing date and may 
amend the proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://

[[Page 44309]]

www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive concerning this proposed AD.

Discussion

    We have received a report that corrosion was found between the 
mating surfaces of the wing upper skin surface and the engine mount 
beam support straps. These straps carry engine loads from the support 
beams into the upper wing skins and wing internal support structure. 
Severe corrosion of the straps can lead to inability to carry engine 
loads.
    This condition, if not corrected, 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.

Relevant Service Information

    We have reviewed Twin Commander Aircraft LLC Alert Service Bulletin 
No. 237, dated May 13, 2005. The service information describes 
procedures for inspecting the surface of the LH and RH upper wing skins 
and the engine mount beam support straps for any signs of corrosion, 
replacing the upper steel straps with parts of improved design, and 
modifying both wings.
    We have reviewed Twin Commander Aircraft Corporation Custom Kit No. 
150, dated July 8, 1994. The service information describes procedures 
for installing inspection access holes in the LH and RH upper wing 
skins.
    We have reviewed Gulfstream American Corporation Service Bulletin 
No. 182, dated March 2, 1981. The service information describes 
procedures for installing additional wing fasteners on the LH and RH 
wing.

FAA's Determination and Requirements of the Proposed AD

    We are proposing this AD because we evaluated all information and 
determined the unsafe condition described previously is likely to exist 
or develop on other products of the same type design. This proposed AD 
would 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.

Costs of Compliance

    We estimate that this proposed AD would affect 275 airplanes in the 
U.S. registry.
    We estimate the following costs to do the proposed inspection:

----------------------------------------------------------------------------------------------------------------
                                                                                      Total cost
                   Labor cost                                Parts cost                  per       Total cost on
                                                                                       airplane   U.S. operators
----------------------------------------------------------------------------------------------------------------
80 work-hours x $80 per hour = $6,400..........  Not applicable....................       $6,400      $1,760,000
----------------------------------------------------------------------------------------------------------------

     We estimate the following costs to do any necessary repairs/
replacements that would be required based on the results of the 
proposed inspection. We have no way of determining the number of 
airplanes that may need this repair/replacement:

                      Short Modification--Option A*
------------------------------------------------------------------------
                                                              Total cost
                                                                 per
             Labor cost                    Parts cost          airplane
                                                               per side
------------------------------------------------------------------------
250 work-hours x $80 per hour =      $9,170 per kit per          $29,170
 $20,000 per side.                    side.
------------------------------------------------------------------------


                     Middle Modification--Option B*
------------------------------------------------------------------------
                                                              Total cost
                                                                 per
             Labor cost                    Parts cost          airplane
                                                               per side
------------------------------------------------------------------------
280 work-hours x $80 per hour =      $9,170 per kit per          $31,570
 $22,400 per side.                    side.
------------------------------------------------------------------------


                      Long Modification--Option C*
------------------------------------------------------------------------
                                                              Total cost
                                                                 per
             Labor cost                    Parts cost          airplane
                                                               per side
------------------------------------------------------------------------
320 work-hours x $80 per hour =      $9,170 per kit per          $34,770
 $25,600 per side.                    side.
------------------------------------------------------------------------


    Note: *Depending on airplane configuration, airplanes with 
rectangular plates would 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.


                    Strap Only Replacement--Option D
------------------------------------------------------------------------
                                                              Total cost
                                                                 per
             Labor cost                    Parts cost          airplane
                                                               per side
------------------------------------------------------------------------
75 work-hours x $80 per hour =       $6,190 per strap per        $12,190
 $6,000 per side.                     side.
------------------------------------------------------------------------


[[Page 44310]]

    We estimate the following costs to do the proposed installation of 
access holes:

------------------------------------------------------------------------
                                              Total cost
          Labor cost             Parts cost      per       Total cost on
                                               airplane   U.S. operators
------------------------------------------------------------------------
30 work-hours x $80 per hour =       $1,293       $3,693      $1,015,575
 $2,400.......................
------------------------------------------------------------------------

    We estimate the following costs to do the proposed wing fastener 
modification:

------------------------------------------------------------------------
                                              Total cost
          Labor cost             Parts cost      per       Total cost on
                                               airplane   U.S. operators
------------------------------------------------------------------------
8.5 work-hours x $80 per hour          $250         $930        $255,750
 = $680.......................
------------------------------------------------------------------------

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 
rulemaking action.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 the proposed 
regulation:
    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 regulatory evaluation of the estimated costs to 
comply with this proposed AD and placed it in the AD docket.

Examining the AD Docket

    You may examine the AD docket that contains the proposed AD, the 
regulatory evaluation, any comments received, and other information on 
the Internet at http://www.regulations.gov; or in person at the Docket 
Management Facility between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The Docket Office (telephone (800) 647-5527) 
is located at the street address stated in the ADDRESSES section. 
Comments will be available in the AD docket shortly after receipt.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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. The FAA amends Sec.  39.13 by adding the following new AD:

Twin Commander Aircraft Corporation: Docket No. FAA-2009-0778; 
Directorate Identifier 2009-CE-040-AD.

Comments Due Date

    (a) We must receive comments on this airworthiness directive 
(AD) action by October 13, 2009.

Affected ADs

    (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 S/Ns.
690A......................................  All S/N except 11195 and
                                             11279.
690B......................................  All S/Ns except 11361,
                                             11383, 11527, and 11536.
------------------------------------------------------------------------

Unsafe Condition

    (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.

Compliance

    (e) To address this problem, you must do the following, unless 
already done:

[[Page 44311]]



------------------------------------------------------------------------
           Actions                 Compliance            Procedures
------------------------------------------------------------------------
(1) Inspect between the       Within the next 150   Follow Twin
 surface of the left-hand      hours time-in-        Commander Aircraft
 (LH) and right-hand (RH)      service after the     LLC Alert Service
 upper wing skins and the      effective date of     Bulletin No. 237,
 engine mount beam support     this AD or within     dated May 13, 2005,
 straps for any signs of       the next 12 months    pages 1 through 14.
 corrosion and determine the   after the effective
 extent of any corrosion       date of this AD,
 found.                        whichever occurs
                               first.
(2) Install modification      Before further        Follow the
 access holes in the LH and    flight after the      Accomplishment
 RH lower wing skins.          inspection required   Instructions, steps
                               in paragraph (e)(1)   1 through 4 and 6
                               of this AD.           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    Before further        Follow Twin
 found during the inspection   flight after the      Commander Aircraft
 required in paragraph         inspection required   LLC Alert Service
 (e)(1) of this AD, perform    in paragraph (e)(1)   Bulletin No. 237,
 necessary modification.       of this AD.           dated May 13, 2005,
                                                     Part II, Options A,
                                                     B, or C, on pages
                                                     15 through 29, and
                                                     31.
(4) If corrosion damage is    Before further        Follow Twin
 not found during the          flight after the      Commander Aircraft
 inspection required in        inspection required   LLC Alert Service
 paragraph (e)(1) of this      in paragraph (e)(1)   Bulletin No. 237,
 AD, do the upper steel        of this AD.           dated May 13, 2005,
 strap replacements.                                 Part II, Option D,
                                                     on pages 30 and 31.
(5) Install additional wing   Before further        Follow Gulfstream
 fasteners on the LH and RH    flight after the      American
 wing.                         inspection required   Corporation Service
                               in paragraph (e)(1)   Bulletin No. 182,
                               of the AD.            dated March 2,
                                                     1981.
------------------------------------------------------------------------


    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.

Alternative Methods of Compliance (AMOCs)

    (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; e-mail: [email protected]. 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.

Related Information

    (g) To get copies of the service information referenced in this 
AD, contact Twin Commander Aircraft, LLC, 19010 59th Drive, NE., 
Arlington, WA 98223, telephone: (360) 435-9797; fax: (360) 435-1112; 
Internet: 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.

    Issued in Kansas City, Missouri, on August 21, 2009.
Kim Smith,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. E9-20789 Filed 8-27-09; 8:45 am]
BILLING CODE 4910-13-P