Document ID: FAA-2007-29342-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; MD Helicopters, Inc. Model 600N Helicopters
Posted Date: 2007-10-19T04:00Z

[Federal Register: October 19, 2007 (Volume 72, Number 202)]
[Proposed Rules]               
[Page 59227-59229]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr19oc07-19]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-29342; Directorate Identifier 2007-SW-08-AD]
RIN 2120-AA64

 
Airworthiness Directives; MD Helicopters, Inc. Model 600N 
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 600N helicopters. 
That AD currently requires interim initial and repetitive inspections 
of tailboom parts, installing six inspection holes in the aft fuselage 
skin panels, installing tailboom attachment bolt washers, modifying 
both access covers, and replacing broken attachment bolts. The current 
AD also provides for modifying the fuselage aft section as an optional 
terminating action. This proposal would mandate modifying the fuselage 
aft section within the next 24 months to strengthen the tailboom 
attachment fittings and upper longerons. The actions specified by the 
proposed AD are intended to prevent failure of the tailboom attachment 
fittings, separation of the tailboom from the helicopter, and 
subsequent loss of control of the helicopter.

DATES: Comments must be received on or before December 18, 2007.

ADDRESSES: Use one of the following addresses to submit comments 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.
    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://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Jon Mowery, Aviation Safety Engineer, 
FAA, Los Angeles Aircraft Certification Office, Airframe Branch, 3960 
Paramount Blvd., Lakewood, California 90712, telephone (562) 627-5322, 
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-2007-
29342, Directorate Identifier 2007-SW-08-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of

[[Page 59228]]

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://www.regulations.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://www.regulations.gov.

Examining the Docket

    You may examine the docket that contains the proposed AD, any 
comments, and other information in person at the Docket Operations 
Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Operations office (telephone (800) 647-5527) is 
located in Room W12-140 on the ground floor of the West Building at the 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after receipt.

Discussion

    On April 20, 2006, we issued AD 2006-08-12, Amendment 39-14569 (71 
FR 24808, April 27, 2006), which superseded AD 2001-24-51, Amendment 
39-12706 (67 FR 17934, April 12, 2002). AD 2001-24-51 required 
inspecting both the upper tailboom attachment fittings, nut plates, and 
both angles for a crack or thread damage, and repairing or replacing 
any cracked or damaged part. That AD also required replacing the upper 
right tailboom attachment bolt with a new bolt. That AD required if the 
attachment bolt was broken replacing the three remaining attachment 
bolts with airworthy attachment bolts. Adding a washer to each bolt and 
modifying both access covers was also required. Thereafter, inspecting 
the upper tailboom attachments at intervals not to exceed 25 hours 
time-in-service and repairing or replacing any cracked part was 
required. Superseding AD 2006-08-12 requires installing six inspection 
holes in the aft fuselage skin panels, inspecting the tailboom 
attachment fittings and parts, and replacing or modifying certain parts 
as necessary. That action was prompted by an accident involving a Model 
600N helicopter. The requirements of that AD are intended to prevent 
failure of the tailboom and subsequent loss of control of the 
helicopter.
    On January 12, 2004, MDHI issued Technical Bulletin (TB) TB600N-007 
specifying procedures, tooling, replacement parts, and supplies needed 
for modifying the fuselage aft section and tailboom. TB600N-007R1, 
dated April 13, 2006, superseded TB600N-007 to correct some tooling, 
replacement parts, and supplies. TB600N-007R2, dated October 5, 2006, 
superseded TB600N-007R1 to correct tooling part numbers and re-sequence 
some assembly steps. These TBs specify that any aircraft complying with 
any of these revisions meets the intent of the other TBs.
    In AD 2006-08-12, we incorporated by reference TB600N-007R1, dated 
April 13, 2006. Since issuing that AD, MDHI has issued TB600N-007R2, 
dated October 5, 2006 (TB), which updates previous issues by further 
specifying procedures for modifying the fuselage aft section to 
strengthen the tailboom attachment fittings and upper longerons. This 
latest revision continues to caution that a high level of sheet metal 
expertise and experience is required to perform this modification.
    This 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 2006-08-12 to require within the next 24 
months, modifying the fuselage aft section to strengthen tailboom 
attach fittings and upper longerons, which would constitute terminating 
action for this unsafe condition.
    We estimate that this proposed AD would affect 18 helicopters of 
U.S. registry, and the proposed actions would take about 322 work hours 
to modify each helicopter at an average labor rate of $80 per work 
hour. Required parts would cost about $14,960 per helicopter. The 
manufacturer states in its TB that those complying with the TB within 3 
years of the issue date are eligible for special pricing and technical 
assistance. Based on these figures, we estimate the total cost impact 
of the proposed AD on U.S. operators to be $732,960, assuming no 
special pricing from the manufacturer.

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 39-14569, AD 
2006-08-12, (71 FR 24808, April 27,

[[Page 59229]]

2006), and by adding a new airworthiness directive (AD), to read as 
follows:

MD Helicopter, Inc.: Docket No. FAA-2007-29342, Directorate 
Identifier 2007-SW-08-AD. Supersedes AD 2006-08-12, Amendment 39-
14569, Docket No. FAA-2006-24518, Directorate Identifier 2006-SW-10-
AD.
    Applicability: Model 600N helicopters, serial numbers with a 
prefix ``RN'' and 003 through 058, that have not been modified in 
the fuselage aft section to strengthen the tailboom attachments and 
longerons per MD Helicopters (MDHI) Technical Bulletin (TB) TB600N-
007, dated January 12, 2004; TB600N-007R1, dated April 13, 2006, or 
TB600N-007R2, dated October 5, 2006, certificated in any category.
    Compliance: Required within the next 24 months, unless 
accomplished previously.
    To prevent failure of the tailboom attachment fittings, 
separation of the tailboom from the helicopter, and subsequent loss 
of control of the helicopter, do the following:
    (a) Modify the fuselage aft section to strengthen the tailboom 
attach fittings and upper longerons by following paragraph 2, 
Accomplishment Instructions, of MDHI TB600N-007R2, dated October 5, 
2006, except you are not required to contact the manufacturer. This 
modification to the fuselage aft section is terminating action for 
the requirements of this AD.
    (b) 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 Manager, Los Angeles Aircraft Certification Office, FAA, 
ATTN: Jon Mowery, Aviation Safety Engineer, Airframe Branch, 3960 
Paramount Blvd., Lakewood, California 90712, telephone (562) 627-
5322, fax (562) 627-5210, for information about previously approved 
alternative methods of compliance.

    Issued in Fort Worth, Texas, on October 10, 2007.
Scott A. Horn,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
 [FR Doc. E7-20680 Filed 10-18-07; 8:45 am]

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