[Federal Register Volume 71, Number 90 (Wednesday, May 10, 2006)]
[Proposed Rules]
[Pages 27212-27215]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-7092]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-24631; Directorate Identifier 2005-SW-01-AD]
RIN 2120-AA64


Airworthiness Directives; MD Helicopters, Inc. Model MD900 
Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes superseding an existing airworthiness 
directive (AD) for MD Helicopters, Inc. (MDHI) Model MD900 helicopters. 
That AD currently requires reducing the life limit of certain Notar fan 
system tension-torsion (TT) straps. That AD also requires, at a 
specified time interval, removing each affected TT strap from the 
helicopter, doing a visual and X-ray inspection, and replacing any 
unairworthy part before further flight. This AD would require the same 
actions as the existing AD, but would also require revising the life 
limit on the component history card or equivalent record, doing 
repetitive visual and X-ray inspections, and would remove reporting 
requirements. This proposal is prompted by two in-flight TT strap 
failures. The actions specified by the proposed AD are intended to 
prevent failure of a TT strap, loss of directional control, and 
subsequent loss of control of the helicopter.

DATES: Comments must be received on or before July 10, 2006.

ADDRESSES: Use one of the following addresses to submit comments 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;
     Fax: 202-493-2251; or
     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.
    You may get the service information identified in this proposed AD 
from MD Helicopters Inc., Attn: Customer Support Division, 4555 E. 
McDowell Rd., Mail Stop M615, Mesa, Arizona 85215-9734, telephone 1-
800-388-3378, fax 480-346-6813, or on the Web at http://www.mdhelicopters.com.
    You may examine the comments to this proposed AD in the AD docket 
on the Internet at http://dms.dot.gov.

FOR FURTHER INFORMATION CONTACT: Roger Durbin, Aviation Safety 
Engineer, FAA, Los Angeles Aircraft Certification Office, Airframe 
Branch, 3960 Paramount Blvd., Lakewood, California 90712, telephone 
(562) 627-5233, fax (562) 627-5210.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any written data, views, or arguments 
regarding this proposed AD. Send your comments to the address listed 
under the caption ADDRESSES. Include the docket number ``FAA-2006-
24631, Directorate Identifier 2005-SW-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 with FAA 
personnel concerning this proposed rulemaking. Using the search 
function of our docket Web site, you can find and read the comments to 
any of our dockets, including the name of the individual who sent or 
signed the comment. You may review the DOT's complete Privacy Act 
Statement in the Federal Register published on April 11, 2000 (65 FR 
19477-78) or you may visit http://dms.dot.gov.

Examining the Docket

    You may examine the docket that contains the proposed AD, any 
comments, and other information in person at the Docket Management 
System (DMS) Docket Office between 9 a.m. and 5 p.m., Monday through 
Friday, except Federal holidays. The Docket Office (telephone 1-800-
647-5227) is located at the plaza level of the Department of 
Transportation Nassif Building in Room PL-401 at 400 Seventh Street, 
SW., Washington, DC. Comments will be available in the AD docket 
shortly after the DMS receives them.

Discussion

    On November 10, 2004, we issued a Final Rule; Request for Comments. 
That AD, 2004-23-15, Amendment 39-13870 (69 FR 67805, November 22, 
2004), requires reducing the life limit of certain TT straps. At a 
specified time interval, that AD also requires removing each affected 
TT strap from the helicopter, doing a visual and X-ray inspection, and 
replacing any unairworthy part before further flight. Reporting the 
discovery of any unairworthy TT strap is also required. That action was 
prompted by two in-flight TT strap failures. The requirements of that 
AD are intended to prevent failure of a TT strap resulting in loss of 
directional control and subsequent loss of control of the helicopter.
    At the time we issued AD 2004-23-15, the cause of the failures was 
not known, and that AD was considered interim action. These proposals 
also are interim actions because the cause of the failures is still 
unknown and the investigation is ongoing. We will consider further 
rulemaking once our investigation is complete.
    Before issuing that AD, we reviewed MD Helicopters Service Bulletin 
SB-900-095, dated November 3, 2004. The service bulletin advises of the 
reduction of the TT strap life limit and describes procedures for 
performing an inspection of each TT strap for nicks, cuts, cracks, or 
wear. Procedures for a Level II or higher X-Ray technician to do and 
interpret an X-ray inspection of each TT strap for progressive fiber 
fractures are also included in the service bulletin.
    Since issuing AD 2004-23-15, we received several comments from the 
manufacturer and have given them due consideration. The following table 
lists requested changes and comments and our responses:

[[Page 27213]]



------------------------------------------------------------------------
        Requested change/comment                   FAA response
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1. Change the comments due date from     We agree with this change and
 January 21, 2004, to January 21, 2005.   published a correction for
                                          this typographical error in
                                          the Federal Register on
                                          December 23, 2004 (69 FR
                                          76979).
2. Correct the manufacturer's address    We have corrected the address
 and the fax number.                      and fax number. This proposed
                                          AD contains the correct
                                          address and fax number.
3. The commenter suggests we clarify     The suggestion of first
 when the initial visual and X-ray        describing the part affected
 inspections should begin. For example,   followed by the compliance
 instead of stating ``within 10 hours     time is an acceptable method
 TIS for any TT strap that has            of organizing an AD. The FAA
 accumulated 1190 or more hours TIS,''    has used that method. However,
 write it as: ``For any TT strap that     we believe that after
 has accumulated 1190 or more hours       determining if the AD applies
 TIS, within 10 hours TIS * * *'' The     to their product, operators
 commenter suggests this change be made   generally want to know when
 in the preamble as well as paragraphs    they have to comply with the
 (b) and (c) of the AD language.          AD. Therefore, in general, we
                                          attempt to place the
                                          compliance times at the
                                          beginning of a paragraph. Each
                                          organizational approach has
                                          its merits. However, we have
                                          chosen to continue to use the
                                          same organization in this
                                          proposal as we used in AD 2004-
                                          23-15.
4. The commenter suggests that we use    Although these words have the
 the word ``complete'' instead of         same meaning, under plain-
 ``do'' or ``doing'' in the AD where we   language concepts, the
 state the compliance requirements.       shorter, simpler word is
                                          preferred. Therefore, we are
                                          continuing to use ``do''
                                          instead of ``accomplish'' or
                                          ``complete,''
5. The commenter suggests that we add    We agree that the 300-hour TIS
 the following language to the preamble   repetitive inspection needs to
 discussion of the AD as well as add it   be mandated by AD. We issued
 as a note to the AD language:            AD 2004-23-15 as a Final Rule;
 ``Although not part of this AD, the      Request for comments (an
 FAA has required a 300 repetitive hour   immediately adopted rule
 visual and x-ray inspection of the       (IAR)) without prior public
 straps after the initial inspection      notice and comment because the
 required by this AD. This requirement    inspections mandated by that
 can be found as a note for each of the   AD were required within a very
 TT straps Part Numbers listed in the     short time period. An IAR is
 FAA Approved Airworthiness Limitations   an exception to the normal
 Section of the Maintenance Manual.''     prior public notice and
                                          comment procedures of the
                                          Administrative Procedures Act
                                          (5 U.S.C. 553) and is based on
                                          a good-cause finding of
                                          impracticable, unnecessary, or
                                          contrary to the public
                                          interest. Likewise, 14 CFR
                                          part 11 and DOT Regulatory
                                          Policies and Procedures guide
                                          our rulemaking.
                                         Based on these rulemaking
                                          constraints, we could not
                                          justify inserting a long-term
                                          requirement, such as a 300-
                                          hour TIS inspection, into an
                                          IAR. However, we should have
                                          discussed our plan to
                                          implement the long-term
                                          repetitive requirements in the
                                          preamble discussions of the
                                          IAR.
                                         We plan to add the recurring
                                          300-hour TIS inspection after
                                          issuing an NPRM and seeking
                                          public comments. We are doing
                                          that with this proposal.
                                         As to the comment that we add
                                          language to the AD in a note
                                          requiring a repetitive 300-
                                          hour TIS visual and X-ray
                                          inspection, it is
                                          inappropriate to place a
                                          mandatory requirement in an AD
                                          note. Notes in ADs are
                                          appropriate for providing
                                          helpful information, not
                                          required actions, to AD users.
                                          Thus far, we have not required
                                          a repetitive 300-hour TIS
                                          inspection of these affected
                                          TT strap part numbers.
                                         As to the comment that this
                                          requirement can be found as a
                                          note for each appropriate part
                                          number listed in the
                                          Limitation section of the
                                          maintenance manual, changes to
                                          the Airworthiness Limitations
                                          Section of the Instructions
                                          for Continued Airworthiness or
                                          Maintenance Manuals, even if
                                          FAA-approved, require
                                          compliance only if implemented
                                          through an AD. This action
                                          proposes to require the
                                          repetitive 300-hour TIS
                                          inspection sought by the
                                          commenter.
6. The commenter suggests the following  We do not agree that any
 editorial changes to the following       editorial changes are
 sentence from paragraph (g) of the       necessary.
 existing AD:
``This AD revises the Airworthiness
 Limitations section of the maintenance
 * * *'' to
``This AD revises the Airworthiness
 Limitations Section (ALS) of the
 maintenance * * *''
7. The commenter suggests that the new   We agree that the new life
 life limits be recorded on the           limit should be recorded and
 Assembly Component Historical Record     propose that change.
 (CSP-RLB-L16 form).
8. The commenter requests that the       We agree that the repetitive
 existing AD be superseded as soon as     inspection is important. The
 possible, but no later than February     comment period for AD 2004-23-
 7, 2005 ``due to the critical nature     15 that we are proposing to
 of the recommended AD changes'' and to   supersede in this NPRM closed
 ensure that operators do not overlook    January 21, 2005. Thus, the
 the 300-hour repetitive inspection.      February 7, 2005, compliance
                                          date requested by the
                                          commenter was unrealistically
                                          short and has already past.
                                          Since the comment period
                                          closed, the FAA has been
                                          processing this NPRM that
                                          proposes requiring an
                                          additional 300-hour TIS
                                          inspection to the other
                                          requirements currently in AD
                                          2004-23-15.
------------------------------------------------------------------------

    We have also received several reports from operators as required by 
AD 2004-23-13. We included this reporting requirement to obtain 
sufficient field data that would allow us to verify that the mandated 
inspection interval would be adequate to manage the immediate short-
term safety concern. Since issuing the AD, we have reviewed a 
sufficient number of reports to determine that the current interim 
inspection actions are adequate to ensure safety. Accordingly, we are 
proposing the remove the reporting requirements. However, this action 
is interim until the investigation is complete and final terminating 
action can be generated.

[[Page 27214]]

    The previously described unsafe condition is likely to exist or 
develop on other helicopters of the same type design. Therefore, the 
proposed AD would supersede AD 2004-23-15 and would require the 
following for MDHI Model MD900 helicopters with a TT strap, part number 
(P/N) 900R3442009-103, 900R6442009-103, 900R3442009-101, or 500N5311-5, 
installed:
     Before further flight, unless accomplished previously, for 
TT strap, P/N 900R3442009-103 and 900R6442009-103, reducing the life 
limit from 3,034 to 2,500 hours TIS and revising the life limit on the 
component history card or equivalent record;
     Within 10 hours TIS, unless accomplished previously, and 
then at intervals not to exceed 300 hours TIS, for any TT strap that 
has accumulated 1,190 or more hours TIS, doing a visual and X-ray 
inspection of each TT strap and replacing any unairworthy TT strap 
before further flight; and
     Before the TT strap accumulates 1,200 hours TIS, and then 
at intervals not to exceed 300 hours TIS, for any TT strap with less 
than 1,190 hours TIS, doing a visual and X-ray inspection of each strap 
and replacing any unairworthy TT strap before further flight.
    The inspections would have to be accomplished by following portions 
of the service information previously described.
    We estimate that this proposed AD would affect 31 helicopters of 
U.S. registry. It would take about 7 work hours for each visual 
inspection and replacement at an average labor rate of $65 per work 
hour. Because you must remove the TT strap to inspect it, there is no 
additional labor cost for replacing the TT strap. It would also cost 
$100 for each X-ray inspection. Required parts would cost about $757 to 
replace each strap. Based on these figures, we estimate the total cost 
impact of the proposed AD on U.S. operators to be $168,950 in the first 
year (assuming a total of 5 TT straps are replaced per helicopter and 3 
visual inspections and 3 X-ray inspections are conducted the first year 
for each helicopter).

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. Additionally, 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 draft economic evaluation of the estimated costs to 
comply with this proposed AD. See the DMS to examine the draft economic 
evaluation.

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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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 Amendment 39-13870 (69 FR 
67805, November 22, 2004), and by adding a new airworthiness directive 
(AD), to read as follows:

MD Helicopters, Inc.: Docket No. FAA-2006-24631; Directorate 
Identifier 2005-SW-01. Supersedes AD 2004-23-15, Amendment 39-13870, 
Docket No. FAA-2004-19613, Directorate Identifier 2004-SW-38-AD.

    Applicability: Model MD900 helicopters, with a Notar fan system 
that has a tension-torsion (TT) strap, part number (P/N) 
900R3442009-103, 900R6442009-103, 900R3442009-101, or 500N5311-5, 
installed, certificated in any category.
    Compliance: Required as indicated.
    To prevent failure of a TT strap in the Notar fan system, loss 
of directional control, and subsequent loss of control of the 
helicopter, accomplish the following:
    (a) Before further flight, unless accomplished previously, for 
TT Straps, P/N 900R3442009-103 and 900R6442009-103, reduce the life 
limit from 3,034 to 2,500 hours time-in-service (TIS) and revise the 
life limit on the component history card or equivalent record to 
reflect this reduced retirement life.
    (b) Within 10 hours TIS, unless accomplished previously, for any 
TT strap that has accumulated 1,190 or more hours TIS, and then at 
intervals not to exceed 300 hours TIS, remove the TT strap from the 
helicopter and do a visual and an X-ray inspection in accordance 
with the Inspection Instructions, paragraph 2.B.(1). through (5)., 
and Figures 1 and 2 of MD Helicopters Service Bulletin SB900-095, 
dated November 3, 2004 (SB). Replace any unairworthy TT strap before 
further flight.
    (c) Before the TT strap accumulates 1,200 hours TIS, for any TT 
strap with less than 1,190 hours TIS, and then at intervals not to 
exceed 300 hours TIS, remove the TT strap from the helicopter and do 
a visual and an X-ray inspection in accordance with the Inspection 
Instructions, paragraph 2.B.(1). through (5)., and Figures 1 and 2 
of the SB. Replace any unairworthy TT strap before further flight.
    (d) The X-ray inspection of the TT strap must be performed by a 
Level II or higher X-ray technician who is qualified under the 
guidelines established by MIL-STD- 410E, ATA Specification 105, AIA-
NAS-410, or an FAA-accepted equivalent for qualification standards.
    (e) This AD revises the Airworthiness Limitations section of the 
maintenance manual by reducing the life limit of the TT straps, P/N 
900R3442009-103 and 900R6442009-103, from 3,034 hours TIS to 2,500 
hours TIS. Additionally, this AD revises the Airworthiness 
Limitations section of the maintenance manual by adding repetitive 
inspection requirements at intervals not to exceed 300 hours TIS for 
TT straps, P/N 900R3442009-103, 900R6442009-103, 900R3442009-101, 
and 500N5311-5, that have 1,200 or more hours TIS until the TT strap 
reaches its retirement life.
    (f) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Contact the Los Angeles Aircraft Certification, Transport Airplane 
Directorate, FAA, for information about previously approved 
alternative methods of compliance.


[[Page 27215]]


    Issued in Fort Worth, Texas, on May 1, 2006.
Mark R. Schilling,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. E6-7092 Filed 5-9-06; 8:45 am]
BILLING CODE 4910-13-P