Note: An ``M'' or an ``I'' painted on the root of the T/R blade indicates compliance to an Alternate Method of Compliance (AMOC) to AD 20030851, (Docket No. 2003SW17AD, Amendment 3913215 (68 FR 39449, July 2, 2008), corrected at 68 FR 47447, August 11, 2003, issued by the FAA, Los Angeles Aircraft Certification Office (LAACO) on June 13, 2003 to HTC. The AMOC addressed shot peening of the pitch horn of the T/R assembly.

The proposed AD would require, within 25 hours timeinservice (TIS), and thereafter at intervals not to exceed 25 hours TIS, tap inspections of the upper and lower surfaces of each T/R blade abrasion strip using a coin (United States 25cent piece or equivalent), or a small brass, mild steel, or aluminum hammer, to detect bonding voids that exceed 0.2 square inch in size with a minimum of 1.0 inch between voids, at least 75 percent of the bonded area of the abrasion strip being free from voids, and no voids at the edge of the abrasion strip. Modifying each T/R blade in accordance with FAAapproved data by installing a titanium rivet in the tip of the outboard end of each T/R blade and painting a ``T'' in the rootend of the T/R blade would be considered terminating action for the AD. This proposal is prompted by an incident in which an abrasion strip separated from a T/R blade during flight. The actions specified by the proposed AD are intended to prevent disbonding and subsequent separation of an abrasion strip from a T/R blade, which could result in vibration, loss of the T/R, and subsequent loss of control of the helicopter.

We have reviewed the following service information:

This unsafe condition is likely to exist or develop on other helicopters of the same type designs. Therefore, the proposed AD would require, within 25 hours TIS, unless accomplished previously, and thereafter at intervals
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not to exceed 25 hours TIS, tap inspections of the upper and lower surfaces of each T/R blade abrasion strip using a coin (United States 25 cent piece or equivalent) or a small brass, mild steel, or aluminum hammer, to detect bonding voids in accordance with Part 1Inspection of the HTC Mandatory Service Bulletin Notice No. 31004R4, dated May 10, 2006. Modifying each T/R blade by installing a titanium rivet, P/N 500P312413, in the tip of the T/R blade and painting a ``T'' in the rootend of the T/R blade would be a terminating action for this AD. The actions would be required to be accomplished by following the specified portions of the HTC service bulletin described previously.

We estimate that this proposed AD would affect 718 helicopters of U.S. registry.

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 AD Docket 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 39AIRWORTHINESS 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 adding a new airworthiness directive to read as follows:
MD Helicopters, Inc. (MDHI): Docket No. FAA20080287; Directorate Identifier 2006SW15AD.

Applicability

Model 369A, OH6A, 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, and 369HS, certificated in any category, with a tail rotor (T/R) blade installed as follows including all serial numbers and those T/ R blades with an ``M'' or an ``I'' painted on the T/R blade root:

Note 1: An ``M'' or an ``I'' painted on the root of the T/R blade indicates compliance to an Alternate Method of Compliance (AMOC) to Emergency AD 20030851 (Docket No. 2003SW17AD,
Amendment 3913215, April 15, 2003), issued by the FAA, Los Angeles Aircraft Certification Office (LAACO) on June 13, 2003 to HTC. The AMOC addressed shot peening of the pitch horn of the T/R assembly. Compliance

Required as indicated.

To prevent disbonding and subsequent separation of an abrasion strip from a T/R blade, which could result in vibration, loss of the T/R, and subsequent loss of control of the helicopter, accomplish the following:
(a) Within 25 hours timeinservice (TIS), unless accomplished previously, and thereafter at intervals not to exceed 25 hours TIS, inspect the abrasion striptoskin bond integrity on each T/R blade using a tap test method in accordance with Part 1Inspection, in Helicopter Technology Company, LLC (HTC) Mandatory Service Bulletin Notice No. 31004R4, dated May 10, 2006 (SB).

Note 2: MD Helicopters Service Bulletin SB369D203R1, SB369E 097R1, SB369F082R1, and SB369H246R1, dated January 23, 2006, pertain to the subject of this AD.
(b) Modifying each T/R blade in accordance with FAAapproved data by installing a titanium rivet at the outboard end and painting the letter ``T'' on the rootend of the T/R blade to indicate the modification has been accomplished is considered a terminating action for the requirements of this AD.
(c) 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,

FOR FURTHER INFORMATION CONTACT John Cecil, Aviation Safety Engineer, FAA, Los Angeles Aircraft Certification Office, Airframe Branch, 3960 Paramount Blvd., Lakewood, California 907124137, telephone (562) 627 5228, fax (562) 6275210.