[Federal Register Volume 71, Number 120 (Thursday, June 22, 2006)]
[Proposed Rules]
[Page 35843]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-9846]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2004-SW-16-AD]
RIN 2120-AA64


Airworthiness Directives; MD Helicopters, Inc., Model 600N 
Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Proposed rule; withdrawal.

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SUMMARY: The FAA withdraws a notice of proposed rulemaking (NPRM) 
proposing a new Airworthiness Directive (AD) for MD Helicopters, Inc. 
(MDHI) Model 600N helicopters. The NPRM proposed adding six more 
inspection holes in the aft fuselage skin panels and inspecting the 
upper and lower tailboom attachment fittings, the upper longerons, and 
the angles and nutplates for cracks. Also, the NPRM proposed a 
terminating action of modifying the fuselage aft section to strengthen 
the tailboom attachments and longerons. Since issuing the NPRM, we have 
received a report of an in-flight separation of the tailboom in the 
inspection area. Based on that accident and due to the critical unsafe 
condition, we issued a final rule; request for comments that addressed 
the actions proposed in the NPRM. Accordingly, we withdraw the proposed 
AD.

ADDRESSES: This information may be examined at the FAA, Office of the 
Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort 
Worth, Texas.

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:

Discussion

    A proposal to amend 14 CFR part 39 by superseding AD 2001-24-51, 
Docket 2001-SW-57-AD, Amendment 39-12706 (67 FR 17934, April 12, 2002), 
for the MDHI Model 600N helicopters was published in the Federal 
Register on February 10, 2005 (70 FR 7063). In addition to retaining 
various requirements of AD 2001-24-51, the action proposed installing 
six more inspection holes in the aft fuselage skin panels and 
inspecting the upper and lower tailboom attachment fittings, the upper 
longerons, and the angles and nutplates for cracks. Also, the action 
proposed a terminating action of modifying the fuselage aft section to 
strengthen the tailboom attachments and longerons. That actions was 
prompted by analysis that shows that certain tailboom attachments and 
longerons may develop cracks. The proposed actions were intended to 
prevent failure of a tailboom attachment, loss of the tailboom, and 
subsequent loss of control of the helicopter.
    Since issuing the NPRM, we have received an additional report of an 
in-flight separation of the tailboom in the inspection area. After 
reviewing the data, we issued a final rule; request for comments (AD 
2006-08-12, 71 FR 24808, April 27, 2006) to correct a critical unsafe 
condition. That AD, 2006-08-12, requires the necessary actions proposed 
in the NPRM as well as other actions necessary to correct the unsafe 
condition.

FAA's Conclusion

    Since we issued AD 2006-08-12, which includes the necessary actions 
that were previously proposed, we are withdrawing the NPRM.
    Withdrawal of the NPRM does not preclude the FAA from issuing 
another notice in the future nor does it commit the agency to any 
course of action in the future.

Regulatory Impact

    Since this action only withdraws an NPRM, it is neither a proposed 
nor a final rule and therefore is not covered under Executive Order 
12866, the Regulatory Flexibility Act, or DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Withdrawal

    Accordingly, we withdraw the NPRM, Docket No. 2004-SW-16-AD, 
published in the Federal Register on February 10, 2005, 70 FR 7063, FR 
Doc. 05-2608, filed February 9, 2005.

    Issued in Fort Worth, Texas, on June 9, 2006.
Mark R. Schilling,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
 [FR Doc. E6-9846 Filed 6-21-06; 8:45 am]
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