E7-11409. Airworthiness Directives; MD Helicopters, Inc., Model 369, YOH-6A, 369A, OH-6A, 369H, 369HM, 369HS, 369HE, 369D, 369E, 369F, and 369FF Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 2007-09-51, sent previously to all known U.S. owners and operators of the specified MD Helicopters, Inc. (MDHI), model helicopters by individual letters. This AD requires, before further flight, removing each affected tail rotor blade assembly and inspecting the bore of the tail rotor blade root fitting. If the blade assembly does not have a smooth radius, the AD requires replacing it. The AD also requires identifying each airworthy tail rotor blade assembly with the applicable helicopter model. This amendment is prompted by a report of an accident after the loss of a tail rotor blade. The actions specified by this AD are intended to prevent the failure of a tail rotor blade and subsequent loss of control of the helicopter.

DATES:

Effective July 5, 2007, to all persons except those persons to whom it was made immediately effective by Emergency AD 2007-09-51, issued on April 27, 2007, which contained the requirements of this amendment.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of July 5, 2007.

Comments for inclusion in the Rules Docket must be received on or before August 20, 2007.

ADDRESSES:

Use one of the following addresses to submit comments on this 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: 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: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays; or
• Fax: [phone].

You may get the service information identified in this AD from MD Helicopters Inc., Attn: Customer Support Division, 4555 E. McDowell Rd., Mail Stop M615, Mesa, Arizona 85215-9734, telephone [phone], fax [phone], or on the web at http://www.mdhelicopters.com.

Examining the Docket: You may examine the docket that contains the AD, any comments, and other information on the Internet at http://dms.dot.gov,, or in person at the Docket Management System (DMS) Docket Offices between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone [phone]) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the DMS receives them.

FOR FURTHER INFORMATION CONTACT:

John Cecil, Aviation Safety Engineer, FAA, Los Angeles Aircraft Certification Office, Airframe Branch, 3960 Paramount Blvd., Lakewood, California 90712-4137, telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

On April 27, 2007, the FAA issued Emergency AD 2007-09-51 (EAD) for the specified MDHI model helicopters. The EAD requires, before further flight, removing each affected tail rotor blade assembly and, using a bright light, inspecting the bore of the tail rotor blade root fitting. If the blade assembly does not have a smooth radius, the AD requires replacing it. The AD also requires identifying each airworthy tail rotor blade assembly with the applicable model of helicopter. That action was prompted by a report of an accident after the loss of a tail rotor blade. This condition, if not corrected, could result in the failure of a tail rotor blade and subsequent loss of control of the helicopter.

MDHI has issued Service Bulletin No. SB369H-247, SB369D-204, SB369E-099, and SB369F-084, dated April 26, 2007 (SB), which describes procedures for inspecting the tail rotor blade assembly. The SB states that reports from the field have shown that there are tail rotor blades in operation with a machining defect. The SB further states that these blades have a sharp transition in the tapered end of the root fitting bore that can cause the tail rotor blade root fitting to fail.

Since the unsafe condition described is likely to exist or develop on other MDHI model helicopters of these same type designs, the FAA issued EAD 2007-09-51 to prevent the failure of a tail rotor blade and subsequent loss of control of the helicopter. This AD requires the following, before further flight:

• Remove each affected tail rotor blade assembly. Using a bright light, inspect the bore of the tail rotor blade root fitting.
• Replace each blade assembly that does not have a smooth radius.
• Identify the airworthy tail rotor blade assembly with the applicable model of helicopter.

The actions must be done by following specified portions of the ASB described previously. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the controllability and structural integrity of the helicopter. Therefore, removing each affected blade assembly, inspecting the bore of the tail rotor blade root fitting, and replacing each blade assembly that does not have a smooth radius are required before further flight, and this AD must be issued immediately.

Since it was found that immediate corrective action was required, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest. Good cause existed to make the AD effective immediately by individual letters issued on April 27, 2007, to all known U.S. owners and operators of MD Helicopters, Inc., Model 369 (Army YOH-6A), 369A (Army OH-6A), 369H, 369HM, 369HS, 369HE, 369D, 369E, 369F, and 369FF helicopters. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to 14 CFR 39.13 to make it effective to all persons.

The FAA estimates that this AD will affect 980 helicopters of U.S. registry and will require about:

• 0.1 work hour to identify a blade,
• 2 work hours to remove, inspect, install and balance the tail rotor blade assemblies on each helicopter,
• $80 per work hour labor rate, and
• $8,862 for each replacement blade plus hardware.

Based on these figures, we estimate the total cost impact of the AD on U.S. operators to be $1,901,592, assuming 1 out of 10 blades are found defective for an estimated 196 blades that need replacing.

Comments Invited

This AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any written data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2007-28449; Directorate Identifier 2007-SW-18-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD. We will consider all comments received by the closing date and may amend the 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 AD. 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 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.

Regulatory Findings

We have determined that 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 the 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 an economic evaluation of the estimated costs to comply with this AD. See the DMS to examine the 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
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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.

§ 39.13

[Amended]

2. Section 39.13 is amended by adding a new airworthiness directive to read as follows:

2007-09-51 MD Helicopters, Inc.: Amendment 39-15103. Docket No. FAA-2007-28449; Directorate Identifier 2007-SW-28-AD.

Applicability

Model 369, YOH-6A, 369A, OH-6A, 369H, 369HM, 369HS, 369HE, 369D, 369E, 369F, and 369FF helicopters, with a tail rotor blade, part number (P/N) 369A1613, 369D21606, 369D21613, 369D21615, or 421-088, all dash numbers, installed, certificated in any category.

Compliance

Before further flight, unless accomplished previously.

To prevent the loss of a tail rotor blade and subsequent loss of control of the helicopter, do the following:

(a) Inspect each affected tail rotor blade for a smooth radius as follows:

(1) Remove the tail rotor blade assembly by following the Accomplishment Instructions, paragraphs 2.B.(1) through 2.B.(3), Part 2., of MD Helicopters, Inc., Service Bulletin SB369H-247, SB369D-204, SB369E-099, and SB369F-084 dated April 26, 2007 (SB).

(2) Using a bright light, inspect the bore of the tail rotor blade root fitting by following the Accomplishment Instructions, paragraphs 2.B.(4) and 2.B.(5), Part 2, and Figures 1 and 2 of the SB.

(b) Replace each blade assembly that does not have a smooth radius by following the Accomplishment Instructions, paragraphs 2.B.(6) and (7), Part 2, and Figure 2 of the SB.

(c) Identify the airworthy tail rotor blade assembly with the applicable model of helicopter by following the Identification, paragraphs 3.(1) through 3.(4) of the SB.

(d) 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: John Cecil, Aviation Safety Engineer, Airframe Branch, 3960 Paramount Blvd., Lakewood, California 90712-4137, telephone [phone], fax [phone], for information about previously approved alternative methods of compliance.

(e) Special flight permits will not be issued.

(f) Inspecting, replacing, and identifying the tail rotor blade assembly shall be done by following the specified portions of MD Helicopters, Inc., Service Bulletin SB369H-247, SB369D-204, SB369E-099, and SB369F-084, dated April 26, 2007. The Director of the Federal Register approved this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from MD Helicopters, Inc., Attn: Customer Support Division, 4555 E. McDowell Rd., Mail Stop M615, Mesa, Arizona 85215-9734, telephone [phone], fax [phone], or on the Web at http://www.mdhelicopters.com. 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 NARA, call 202-741-6030, or go to: http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

(g) This amendment becomes effective on July 5, 2007, to all persons except those persons to whom it was made immediately effective by Emergency AD 2007-09-51, issued April 27, 2007, which contained the requirements of this amendment.

Issued in Fort Worth, Texas, on June 5, 2007.

Mark R. Schilling,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.