
[Federal Register Volume 76, Number 136 (Friday, July 15, 2011)]
[Rules and Regulations]
[Pages 41662-41665]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-17421]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0695; Directorate Identifier 2011-SW-001-AD; 
Amendment 39-16740; AD 2011-14-05]
RIN 2120-AA64


Airworthiness Directives; MD Helicopters, Inc. Model MD900 
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD) for MD Helicopters, Inc. (MDHI) Model MD900 helicopters. That AD 
currently requires visually inspecting the main rotor lower hub 
assembly (lower hub) for a crack, and if you find a crack, before 
further flight, replacing the unairworthy lower hub with an airworthy 
lower hub. Additionally, within 10 days of finding a cracked lower hub, 
the existing AD requires reporting the finding to the Los Angeles 
Aircraft Certification Office (LAACO). That AD was prompted by two 
reports of cracks detected in the hub in the area near the flex beam 
bolt hole locations during maintenance on two MDHI Model MD900 
helicopters. Since we issued that AD, we determined that one 
manufacturer had incorrectly inserted flanged bushings into the lower 
hub bore that resulted in local corrosion, leading to fatigue cracking. 
Examination of lower hubs from the other manufacturer shows correct 
bushing installation. Therefore, this amendment limits the 
applicability to the affected lower hubs; retains the visual inspection 
but at a different compliance time; adds an eddy current inspection; 
retains the requirement to replace a cracked lower hub with an 
airworthy lower hub before further flight; and removes the requirement 
to report to the LAACO. The actions specified by this AD are intended 
to detect a crack in the lower hub and prevent failure of the lower hub 
and subsequent loss of control of the helicopter.

DATES: This AD is effective August 1, 2011.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of August 1, 
2011.
    We must receive any comments on this AD by September 13, 2011.

ADDRESSES: You may send comments by any of the following methods:
     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 AD, contact MD 
Helicopters Inc., Attn: Customer Support Division, 4555 E. McDowell 
Rd., Mail Stop M615, Mesa, AZ 85215-9734, telephone 1-800-388-3378, fax 
480-346-6813, or at http://www.mdhelicopters.com.

[[Page 41663]]

Examining the AD Docket

    You may examine the AD docket 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 AD docket contains this AD, the regulatory evaluation, 
any comments received, and other information. The street address for 
the Docket Office (telephone (800) 647-5527) is in the ADDRESSES 
section. Comments will be available in the AD docket shortly after 
receipt.

FOR FURTHER INFORMATION CONTACT: Eric Schrieber, Aviation Safety 
Engineer, FAA, Los Angeles Aircraft Certification Office, Airframe 
Branch, 3960 Paramount Blvd., Lakewood, California 90712-4137, 
telephone (562) 627-5348, fax (562) 627-5210.

SUPPLEMENTARY INFORMATION:

Discussion

    On August 19, 2010, we issued Emergency AD (EAD) 2010-18-51. That 
EAD was prompted by two reports of cracks detected in the lower hub 
near the flex beam bolt hole location during maintenance. That EAD 
required, within 4 hours time-in-service (TIS), visually inspecting the 
lower hub for a crack and, if you find a crack, before further flight, 
replacing the lower hub with an airworthy lower hub and, within 10 
days, reporting a cracked lower hub to the LAACO. We superseded EAD 
2010-18-51 with EAD 2010-18-52, issued August 23, 2010, upon 
discovering a typographical error in the ``Applicability'' section of 
the EAD in the lower hub part number (P/N). EAD 2010-18-52 contained 
the same requirements as EAD 2010-18-51 but corrected the P/N for the 
lower hub.

Actions Since That AD Was Issued

    Since we issued the AD, 5 additional lower hubs were found cracked. 
We determined that one manufacturer of lower hubs with serial numbers 
(S/Ns) beginning with 5009 (e.g., 5009-XXXX) had incorrectly inserted 
flanged bushings into the lower hub bore. This condition resulted in 
local corrosion leading to fatigue cracking. Examination of lower hubs 
from the other manufacturer shows correct bushing installation.

Relevant Service Information

    We reviewed MDHI Service Bulletin SB900-117, dated January 14, 2011 
(SB). The SB specifies an initial 100-hour and recurring 300-hour 
visual and eddy current inspections of the lower hub for a crack and, 
if there is a crack, replacing the lower hub with an airworthy lower 
hub. The inspections would be done at the stated intervals or at the 
next annual inspection, whichever occurs first. The SB also specifies 
replacing an affected lower hub within 3 years after the date of the 
SB.

FAA's Determination

    We are issuing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other helicopters of this same type 
design.

AD Requirements

    This AD requires a visual inspection, and if necessary, an eddy 
current inspection of the lower hub for a crack. If there is a crack, 
the AD requires replacing the lower hub with an airworthy lower hub. 
This AD requires accomplishing these actions by following specified 
portions of the service information described previously, except as 
discussed under ``Differences Between the AD and the Service 
Information.''

Change to Existing AD

    This superseding AD changes the compliance time for the visual 
inspection and adds an eddy current inspection of the lower hub for a 
crack. This AD also removes the reporting requirement to the LAACO and 
the requirement for an OMB control number. This AD also reduces the 
applicability to only those helicopters with certain serial-numbered 
lower hubs installed.

Differences Between the AD and the Service Information

    This AD does not require contacting the manufacturer or returning 
the lower hub assembly with a certain report. This AD also does not 
require the 300-hour inspection or replacing the lower hub within 3 
years from the date of the SB because these actions do not fit our 
criteria for a Final rule, request for comments.

FAA's Justification and Determination of the Effective Date

    An unsafe condition exists that requires the immediate adoption of 
this AD. The FAA has found that the risk to the flying public justifies 
waiving notice and comment prior to adoption of this rule because the 
previously described unsafe condition can adversely affect the 
structural integrity and controllability of the helicopter. The 
inspection is required within 100 hours TIS or during the annual 
inspection, whichever occurs first, unless done within the last 200 
hours TIS. Since the affected helicopters could reach 100 hours TIS 
within 1 month, we find that notice and opportunity for prior public 
comment are impracticable and that good cause exists for making this 
amendment effective in less than 30 days.

Comments Invited

    This AD is a final rule that involves requirements affecting flight 
safety, and we did not provide you with notice and an opportunity to 
provide your comments before it becomes effective. However, we invite 
you to send any written data, views, or arguments about this AD. Send 
your comments to an address listed under the ADDRESSES section. Include 
the docket number FAA-2011-0695 and directorate identifier 2011-SW-001-
AD at the beginning of your comments. We specifically invite comments 
on the overall regulatory, economic, environmental, and energy aspects 
of this AD. We will consider all comments received by the closing date 
and may amend this AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this AD.

Costs of Compliance

    We estimate that this AD affects 12 helicopters of U.S. registry. 
We estimate the following costs to comply with this AD:

                                                                     Estimated Costs
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                                                                                                                   Cost per
                Action                          Labor cost                          Parts cost                      product      Cost on U.S. operators
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1 work hour to visually inspect the     1 work-hour x $85 per      N/A........................................             $85  $1,020.
 hub.                                    hour = $85.

[[Page 41664]]

 
1 work hour to eddy current inspect     1 work-hour x $85 per      N/A........................................             $85  $1,020.
 the lower hub [new action].             hour = $85.
Required parts and labor to replace a   11 work hours x 85 per     $12,480 per hub............................         $13,415  $160,980.
 lower hub.                              hour = $935.
                                       -----------------------------------------------------------------------------------------------------------------
    Total.............................  $1,105...................  $12,480....................................         $13,585  $163,020 assuming the
                                                                                                                                 lower hubs are replaced
                                                                                                                                 for the entire fleet.
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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

    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 DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends part 39 of the Federal Aviation 
Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by removing airworthiness directive (AD) 
2010-18-52, Amendment 39-16515 (75 FR 69862, November 16, 2010) and 
adding the following new AD:

2011-14-05 MD HELICOPTERS, INC.: Amendment 39-16740; Docket No. FAA-
2011-0695; Directorate Identifier 2011-SW-001-AD.

Effective Date

    (a) This AD is effective August 1, 2011.

Affected ADs

    (b) This AD supersedes AD 2010-18-52, Amendment 39-16515, Docket 
No. FAA-2010-1126; Directorate Identifier 2010-SW-078-AD.

Applicability

    (c) Model MD900 helicopters with main rotor lower hub assembly 
(lower hub), part number (P/N) 900R2101008-107, serial numbers (S/
Ns) that begin with 5009, certificated in any category.

Unsafe Condition

    (d) This amendment is prompted by the determination that a 
certain manufacturer had incorrectly inserted the flanged bushings 
into the lower hub bore. The actions specified by this AD are 
intended to detect a crack in the lower hub and prevent failure of 
the hub and subsequent loss of control of the helicopter.

Compliance

    (e) Within 100 hours time-in-service (TIS) or during the next 
annual inspection, whichever occurs first, unless done within the 
last 200 hours TIS:
    (1) Visually inspect the sides and bottom of the area between 
the arms for the centering bearing and the areas adjacent to the 
bushings of the lower hub assembly for a crack. If there is a crack, 
before further flight, replace the lower hub with an airworthy lower 
hub.
    (2) If the lower hub is not replaced as a result of the visual 
inspection required by paragraph (e)(1) of this AD, eddy current 
inspect the lower hub for a crack by following the Accomplishment 
Instructions, paragraphs 2.A(2) through 2.A.(10)., of MD Helicopters 
Inc. Service Bulletin SB900-117, dated January 14, 2011 (SB). If 
there is a crack, before further flight, replace the lower hub with 
an airworthy hub.
    (f) The eddy current inspection required by paragraph (e)(2) of 
this AD must be done by a Level II technician with ASNT-TC-1A, CEN 
EN 4179, MIL-STD-410, NAS410, or equivalent certification in eddy 
current inspections. The technician must have done an eddy current 
inspection in the last 12 months.

Alternative Methods of Compliance (AMOCs)

    (g)(1) The Manager, Los Angeles Aircraft Certification Office 
(LAACO), FAA, has the authority to approve AMOCs for this AD, if 
requested, using the procedures found in 14 CFR 39.19. In accordance 
with 14 CFR 39.19, send your request to your principal inspector or 
local Flight Standards District Office, as appropriate. If sending 
information directly to the manager of the LAACO, send it to the 
attention of the person identified in the Additional Information 
section of this AD.
    (2) Before using any approved AMOC, we request that you notify 
your appropriate principal inspector, or lacking a principal 
inspector, the manager of the local flight standards district 
office/certificate holding district office.

Additional Information

    (h) For more information about this AD, contact Eric Schrieber, 
Aviation Safety Engineer, FAA, Los Angeles Aircraft Certification 
Office, Airframe Branch, 3960 Paramount Blvd., Lakewood, California 
90712-4137, telephone (562) 627-5348, fax (562) 627-5210.

Material Incorporated by Reference

    (i)(1) Inspect the main rotor lower hub assembly for a crack by 
following the specified portions of MD Helicopter, Inc. Service 
Bulletin SB 900-117, dated January

[[Page 41665]]

14, 2011. The Director of the Federal Register approved the 
incorporation by reference of the service information, under 5 
U.S.C. 552(a) and 1 CFR part 51.
    (2) For service information identified in this AD, contact MD 
Helicopters Inc., Attn: Customer Support Division, 4555 E. McDowell 
Rd., Mail Stop M615, Mesa, AZ 85215-9734, telephone 1-800-388-3378, 
fax 480-346-6813, or at http://www.mdhelicopters.com.
    (3) Copies may be inspected at the FAA, Office of the Regional 
Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, 
Texas, or at the National Archives and Records Administration 
(NARA). For information on the availability of this material at an 
NARA facility, call 202-741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

Subject

    (j) The Joint Aircraft System Component (JASC)/Air Transport 
Association (ATA) of America Code is 6220: Main Rotor Head.

    Issued in Fort Worth, Texas, on June 21, 2011.
Kim Smith,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 2011-17421 Filed 7-14-11; 8:45 am]
BILLING CODE 4910-13-P


