[Federal Register Volume 71, Number 78 (Monday, April 24, 2006)]
[Proposed Rules]
[Pages 20915-20919]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-6054]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-23578; Directorate Identifier 2006-CE-01-AD]
RIN 2120-AA64


Airworthiness Directives; Mitsubishi Heavy Industries MU-2B 
Series Airplanes

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

ACTION: Supplemental notice of proposed rulemaking (NPRM); Reopening of 
the comment period.

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SUMMARY: The FAA proposes to revise an earlier proposed airworthiness 
directive (AD) that applies to all Mitsubishi Heavy Industries MU-2B 
series airplanes. The earlier NPRM would have required you to do the 
following: Remove and visually inspect the wing attach barrel nuts, 
bolts, and retainers for cracks, corrosion, and fractures; replace any 
cracked, corroded, or fractured parts; inspect reusable wing attach 
barrel nuts and bolts for deformation and irregularities in the 
threads; replace any deformed or irregular parts; and install new or 
reusable parts and torque to the correct value. The earlier NPRM 
resulted from a recent safety evaluation that used a data-driven 
approach to evaluate the design, operation, and maintenance of the MU-
2B series airplanes in order to determine their safety and define what 
steps, if any, are necessary for their safe operation. This proposed AD 
would retain the actions from the earlier NPRM, add airplanes to the 
applicability, revise the serial numbers of the affected airplanes, and 
update the manufacturer's contact information. This proposed AD results 
from the manufacturer revising the service information to include two 
additional airplane models. Since these actions impose an additional 
burden over that proposed in the NPRM, we are reopening the comment 
period to allow

[[Page 20916]]

the public the chance to comment on these additional actions.

DATES: We must receive comments on this proposed AD by May 25, 2006.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD:
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-0001.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
Mitsubishi Heavy Industries America, Inc., 4951 Airport Parkway, Suite 
800, Addison, Texas 95001; telephone: (972) 934-5480; fax: (972) 934-
5488, or Turbine Aircraft Services, Inc., 4550 Jimmy Doolittle Drive, 
Addison, Texas 75001; telephone: (972) 248-3108; facsimile: (972) 248-
3321.

FOR FURTHER INFORMATION CONTACT: Andrew McAnaul, Aerospace Engineer, 
ASW-150 (c/o MIDO-43), 10100 Reunion Place, Suite 650, San Antonio, 
Texas 78216; telephone: (210) 308-3365; facsimile: (210) 308-3370.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments regarding this proposed airworthiness directive (AD). Send 
your comments to an address listed under the ADDRESSES section. Include 
the docket number, ``FAA-2006-23578; Directorate Identifier 2006-CE-01-
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://dms.dot.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

    Recent accidents and the service history of the Mitsubishi Heavy 
Industries (MHI) MU-2B series airplanes prompted the Federal Aviation 
Administration (FAA) to conduct an MU-2B Safety Evaluation. This 
evaluation used a data-driven approach to evaluate the design, 
operation, and maintenance of MU-2B series airplanes in order to 
determine their safety and define what steps, if any, are necessary for 
their safe operation.
    The safety evaluation provided an in-depth review and analysis of 
MU-2B incidents, accidents, safety data, pilot training requirements, 
engine reliability, and commercial operations. In conducting this 
evaluation, the team employed new analysis tools that provided a much 
more detailed root cause analysis of the MU-2B problems than was 
previously possible.
    Part of that evaluation was to identify unsafe conditions that 
exist or could develop on the affected type design airplanes. One of 
these conditions is the discovery of the right wing upper forward and 
lower forward barrel nuts found cracked during routine maintenance on 
one of the affected airplanes. The manufacturer conducted additional 
investigations of the wing attach barrel nuts on other affected 
airplanes. The result of this investigation revealed no other cracked 
barrel nuts. However, it was discovered that several airplanes had 
over-torqued barrel nuts, which could result in cracking.
    This condition, if not detected and corrected, could result in 
failure of the wing barrel nuts and/or associated wing attachment 
hardware. This failure could lead to in-flight separation of the outer 
wing from the center wing section and result in loss of controlled 
flight.
    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 all 
MHI MU-2B series airplanes. This proposal was published in the Federal 
Register as a notice of proposed rulemaking (NPRM) on January 25, 2006 
(71 FR 4072). The NPRM proposed to require you to do the following:
     Remove and visually inspect the wing attach barrel nuts, 
bolts, and retainers for cracks, corrosion, and fractures;
     Replace any cracked, corroded, or fractured wing attach 
barrel nuts, bolts, and retainers with new parts;
     Inspect reusable barrel nuts and bolts for deformation and 
irregularities in the threads;
     Replace any deformed or irregular wing attach barrel nuts 
or bolts with new parts; and
     Install new or reusable parts and torque to the correct 
value.

Comments

    The FAA encouraged interested persons to participate in developing 
this amendment. The following presents the comments received on the 
proposal and FAA's response to each comment:

Comment Issue No. 1: Incorporate Revised Service Bulletin

    The manufacturer revised the MU-2 Service Bulletin referenced as 
FAA T.C.: No. 103/57-004, dated August 2, 2004, to add two airplane 
models to the effectivity. The change in the model effectivity 
accurately reflects the airplanes for that service bulletin.
    The manufacturer requests the revised service bulletin, MU-2 
Service Bulletin referenced as FAA T.C.: No. 103/57-004A, dated March 
10, 2006, be incorporated into the NPRM.
    We agree with the commenter and will incorporate the revised 
service bulletin into the supplemental NPRM.

Comment Issue No. 2: Revise the Manufacturer Contact Information

    The manufacturer requests that we revise the manufacturer contact 
information from Mitsubishi Heavy Industries in Nagoya, Japan, to 
Mitsubishi Heavy Industries America, Inc. in Addison Texas.
    We agree with the commenter and will incorporate the change into 
the supplemental NPRM.

Comment Issue No. 3: Revise the Serial Numbers of the Affected 
Airplanes

    The manufacturer requests that we revise the serial numbers of the 
affected airplanes based on additional information submitted for 
clarification.
    We agree with the commenter and will incorporate the change into 
the supplemental NPRM.

Comment Issue No. 4

    The manufacturer requests that we revise the proposed requirement 
in the NPRM for ``replacing any bolts or barrel nuts with deformation 
or irregularities in the threads'' to include a ``or that do not meet 
the minimum breakaway torque check.''
    We agree with the commenter and will incorporate the change into 
the supplemental NPRM.

Events That Caused FAA To Issue a Supplemental NPRM

    The manufacturer revised the service information to include two 
additional airplane models.

[[Page 20917]]

Relevant Service Information

    We have reviewed Mitsubishi Heavy Industries, Ltd. MU-2 Service 
Bulletin referenced as JCAB T.C.: No. 241, dated July 14, 2004, and MU-
2 Service Bulletin referenced as FAA T.C.: No. 103/57-004A, dated March 
10, 2006.
    These service bulletins describe procedures for:
     Removing and inspecting the wing attach barrel nuts and 
retainer for cracks, corrosion, and fractures;
     Replacing any wing attach barrel nuts and retainer with 
cracks, corrosion, or fractures;
     Inspecting reusable wing attach barrel nuts and bolts for 
deformation or irregularities in the threads;
     Checking the minimum breakaway torque of the wing attach 
barrel nuts;
     Replacing any bolts or wing attach barrel nuts with 
deformation or irregularities in the threads or that do not meet the 
minimum breakaway torque check; and
     Reinstalling the wing attach barrel nuts and hardware to 
the correct torque value.

Foreign Airworthiness Authority Information

    The MU-2B series airplane was initially certificated in 1965 and 
again in 1976 under two separate type certificates (TC) that consist of 
basically the same type design. Japan is the State of Design for TC No. 
A2PC, and the United States is the State of Design for TC No. A10SW. 
The affected models are as follows (where models are duplicated, 
specific serial numbers are specified in the individual TCs):

------------------------------------------------------------------------
       Type certificate                      Affected models
------------------------------------------------------------------------
A10SW.........................  MU-2B-25, MU-2B-26, MU-2B-26A, MU-2B-35,
                                 MU-2B-36, MU-2B-36A, MU-2B-40, and MU-
                                 2B-60.
A2PC..........................  MU-2B, MU-2B-10, MU-2B-15, MU-2B-20, MU-
                                 2B-25, MU-2B-26, MU-2B-30, MU-2B-35,
                                 and MU-2B-36.
------------------------------------------------------------------------

    The Japan Civil Airworthiness Board (JCAB), which is the 
airworthiness authority for Japan, approved Mitsubishi Heavy 
Industries, Ltd. MU-2 Service Bulletin referenced as JCAB T.C.: No. 
241, dated July 14, 2004, and MU-2 Service Bulletin referenced FAA 
T.C.: No. 103/57-004A, dated March 10, 2006, to ensure the continued 
airworthiness of these airplanes in Japan.

FAA's Determination and Requirements of the Proposed AD

    After examining the circumstances and reviewing all available 
information related to the incidents described above, we have 
determined that:
     The unsafe condition referenced in this document exists or 
could develop on other Mitsubishi MU-2B series airplanes of the same 
type design that are on the U.S. registry;
     We should change the NPRM to incorporate the concerns 
addressed by the commenters and incorporate the revised service 
information; and
     We should take AD action to correct this unsafe condition.

The Supplemental NPRM

    Adding airplanes to the applicability section of the NPRM goes 
beyond the scope of what was originally proposed in the NPRM. 
Therefore, we are reopening the comment period and allowing the public 
the chance to comment on these additional actions.
    This proposed AD would require you to do the following:
     Remove and visually inspect the wing attach barrel nuts, 
bolts, and retainers for cracks, corrosion, and fractures;
     Replace any cracked, corroded, or fractured wing attach 
barrel nuts, bolts, and retainers with new parts;
     Inspect reusable wing attach barrel nuts and bolts for 
deformation and irregularities in the threads;
     Check the minimum breakaway torque of the wing attach 
barrel nuts;
     Replace any deformed or irregular wing attach barrel nuts 
or bolts with new parts; and
     Install new or reusable parts and torque to the correct 
value.
    The FAA is committed to updating the aviation community of expected 
costs associated with the MU-2B series airplane safety evaluation 
conducted in 2005. As a result of that commitment, the accumulating 
expected costs of all ADs related to the MU-2B series airplane safety 
evaluation may be found in the Final Report section at the following 
Web site: http://www.faa.gov/aircraft/air_cert/design_approvals/small_airplanes/cos/mu2_foia_reading_library/.

Costs of Compliance

    We estimate that this proposed AD affects 399 airplanes in the U.S. 
registry.
    We estimate the following costs to do the proposed inspection:

----------------------------------------------------------------------------------------------------------------
                                                         Total cost per
            Labor cost                  Parts cost          airplane           Total cost on U.S. operators
----------------------------------------------------------------------------------------------------------------
12 workhours x $80 per hour =      N/A.................           $960   $960 x 399 = $383,040
 $960.
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary 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 replacement:

------------------------------------------------------------------------
                                                         Total cost per
                                                           airplane to
          Labor cost                  Parts cost          replace all 8
                                                           wing attach
                                                           barrel nuts
------------------------------------------------------------------------
No additional labor cost. Any   $60 for each barrel                 $480
 necessary replacements will     nut. There are 8
 be done at the time of          barrel nuts on each
 inspection.                     airplane. Possible
                                 total cost of: $60 x
                                 8 = $480.
------------------------------------------------------------------------


[[Page 20918]]

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://dms.dot.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) 647-5227) 
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, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the Federal Aviation Administration 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 Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

Mitsubishi Heavy Industries, Ltd.: Docket No. FAA-2006-23578; 
Directorate Identifier 2006-CE-01-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by May 25, 
2006.

Affected ADs

    (b) None.

Applicability

    (c) This AD affects the following Mitsubishi Heavy Industries, 
Ltd. airplane models and serial numbers that are certificated in any 
category:

--------------------------------------------------------------------------------------------------------------------------------------------------------
                 Model                                                                    Serial numbers
--------------------------------------------------------------------------------------------------------------------------------------------------------
MU-2B-10...............................  101 through 120 (Except 102, 114, 115, and 118).
MU-2B-15...............................  114, 115, and 118.
MU-2B-20...............................  102, and 121 through 238.
MU-2B-25...............................  239 through 318 (Except 313), and 313SA.
MU-2B-26...............................  319 through 347 (Except 321), and 349SA.
MU-2B-26A..............................  321SA, 348SA, and 350SA through 394SA (Except 365SA).
MU-2B-30...............................  502 through 547.
MU-2B-35...............................  548 through 654 (Except 652), and 652SA.
MU-2B-36...............................  501, and 655 through 696 (Except 661).
MU-2B-36A..............................  661SA, and 697SA through 730SA (Except 700SA).
MU-2B-40...............................  365SA.
MU-2B-60...............................  700SA.
--------------------------------------------------------------------------------------------------------------------------------------------------------

Unsafe Condition

    (d) This AD results from a recent safety evaluation that used a 
data-driven approach to evaluate the design, operation, and 
maintenance of the MU-2B series airplanes in order to determine 
their safety and define what steps, if any, are necessary for their 
safe operation. Part of that evaluation was to identify unsafe 
conditions that exist or could develop on the affected type design 
airplanes. The actions specified in this AD are intended to detect 
and correct cracks, corrosion, fractures, and incorrect torque 
values in the wing attach barrel nuts, which could result in failure 
of the wing attach barrel nuts and/or associated wing attachment 
hardware. This failure could lead to in-flight separation of the 
outer wing from the center wing section and result in loss of 
controlled flight.

Compliance

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

------------------------------------------------------------------------
            Actions                 Compliance           Procedures
------------------------------------------------------------------------
(1) Remove each wing attach     Within the next    Follow Mitsubishi
 barrel nut, bolt, and           200 hours time-    Heavy Industries,
 retainer and do a detailed      in-service (TIS)   Ltd. MU-2 Service
 visual inspection for cracks,   or 12 months       Bulletins referenced
 corrosion, and fractures.       after the          as JCAB T.C.: No.
                                 effective date     241, dated July 14,
                                 of this AD,        2004, and FAA T.C.:
                                 whichever occurs   No. 103/57-004A,
                                 first, unless      dated March 10,
                                 already done.      2006, as applicable.

[[Page 20919]]

 
(2) If any signs of cracks,     Before further     Follow Mitsubishi
 corrosion, or fractures are     flight after the   Heavy Industries,
 found on any wing attach        inspection         Ltd. MU-2 Service
 barrel nut during the           required in        Bulletins referenced
 inspection required in          paragraph (e)(1)   as JCAB T.C.: No.
 paragraph (e)(1) of this AD,    of this AD,        241, dated July 14,
 replace that wing attach        unless already     2004, and FAA T.C.:
 barrel nut, bolt, and           done.              No. 103/57-004A,
 retainer with new parts and                        dated March 10,
 install to the correct torque                      2006, as applicable,
 value.                                             and the appropriate
                                                    maintenance manual.
(3) If no signs of cracks,      Before further     Follow Mitsubishi
 corrosion, or fractures are     flight after the   Heavy Industries,
 found during the inspection     inspection         Ltd. MU-2 Service
 required in paragraph (e)(1)    required in        Bulletins referenced
 of this AD, you may reuse the   paragraph (e)(1)   as JCAB T.C.: No.
 wing attach barrel nuts and     of this AD,        241, dated July 14,
 bolts if they have been         unless already     2004, and FAA T.C.:
 inspected and are free of       done.              No. 103/57-004A,
 deformation and                                    dated March 10,
 irregularities in the threads                      2006, as applicable,
 and meet the minimum                               and the appropriate
 breakaway torque requirement.                      maintenance manual.
 Reinstall inspected parts to
 the correct torque value. If
 the wing attach barrel nuts
 and bolts are not free of
 deformation and
 irregularities in the threads
 or do not meet the minimum
 breakaway torque requirement,
 install new parts to the
 correct torque value.
------------------------------------------------------------------------

Alternative Methods of Compliance (AMOCs)

    (f) The Manager, Fort Worth Airplane Certification Office, FAA, 
ATTN: Andrew McAnaul, Aerospace Engineer, ASW-150 (c/o MIDO-43), 
10100 Reunion Place, Suite 650, San Antonio, Texas 78216; telephone: 
(210) 308-3365; facsimile: (210) 308-3370, has the authority to 
approve alternative methods of compliance for this AD, if requested 
using the procedures found in 14 CFR 39.19.

Related Information

    (g) Mitsubishi Heavy Industries, Ltd. MU-2 Service Bulletins 
JCAB T.C.: No. 241, dated July 14, 2004, and FAA T.C.: No. 103/57-
004A, dated March 10, 2006, pertain to the subject of this AD. To 
get copies of the documents referenced in this AD, contact 
Mitsubishi Heavy Industries America, Inc., 4951 Airport Parkway, 
Suite 800, Addison, Texas 95001; telephone: (972) 934-5480; fax: 
(972) 934-5488, or Turbine Aircraft Services, Inc., 4550 Jimmy 
Doolittle Drive, Addison, Texas 75001; telephone: (972) 248-3108; 
facsimile: (972) 248-3321. To view the AD docket, go to the Docket 
Management Facility; U.S. Department of Transportation, 400 Seventh 
Street, SW., Nassif Building, Room PL-401, Washington, DC, or on the 
Internet at http://dms.dot.gov. The docket number is Docket No. FAA-
2006-23578; Directorate Identifier 2006-CE-01-AD.

    Issued in Kansas City, Missouri, on April 18, 2006.
William J. Timberlake,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-6054 Filed 4-21-06; 8:45 am]
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