Airworthiness Directives; Eurocopter Deutschland Model EC135 P1 and T1 Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD) for Eurocopter Deutschland Model EC135 P1 and T1 helicopters that currently requires visual and dye-penetrant inspections for a cracked stator blade of the fenestron tail rotor (tail rotor). That AD also requires either stop drilling a cracked blade or, as necessary, replacing an unairworthy stator blade with an airworthy stator blade. This action would require replacing the existing stator blade assembly with a new stator blade assembly that incorporates a reinforced base and modified riveting and limits the applicability to certain serial numbered tail booms. This proposal is prompted by additional reports of cracked stator blades of the tail rotor. The actions specified by the proposed AD are intended to prevent failure of the tail rotor and subsequent loss of control of the helicopter.

DATES:

Comments must be received on or before November 17, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2000-SW-19-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. You may also send comments electronically to the Rules Docket at the following address: 9-asw-adcomments@faa.gov. Comments may be inspected at the Office of the Federal Register between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT:

Richard Monschke, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, 2601 Meacham Blvd., Fort Worth, Texas 76137, telephone (817) 222-5116, fax (817) 222-5961.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their mailed comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket No. 2000-SW-19-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2000-SW-19-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

Discussion

On December 2, 1997, the FAA issued AD 97-20-13, Amendment 39-10240; (62 FR 65198, dated December 11, 1997), to require visual and dye-penetrant inspections for a cracked stator blade of the tail rotor. That AD also requires that a cracked stator blade be stop-drilled or replaced with an airworthy stator blade if the crack is 15mm or longer or if more than three stator blades are affected. That action was prompted by the discovery of cracks on the stator blades of the fenestron tail rotor. The requirements of that AD are intended to prevent failure of the tail rotor and subsequent loss of control of the helicopter.

Since the issuance of that AD, additional cracks have been reported on the stator blades of the fenestron tail rotor. The manufacturer has developed a stator blade assembly that incorporates a reinforced base and modified riveting.

We have identified an unsafe condition that is likely to exist or develop on other Eurocopter Deutschland Model EC135 P1 and T1 helicopters of the same type design. The proposed AD would supersede AD 97-20-13 to require replacing any stator blade assembly, part number (P/N) L 535A4201 052, with a stator blade assembly, P/N L 535A4201 053, that incorporates a reinforced base and modified riveting. The proposed AD would also limit the applicability to certain serial numbered tail booms.

The FAA estimates that 25 helicopters of U.S. registry would be affected by this proposed AD, that it would take approximately 12 work hours per helicopter to accomplish the proposed actions, and that the average labor rate is $60 per work hour. The manufacturer states in its service bulletin that parts and labor will be furnished at no cost. Based on that information, there would be no cost impact from the proposed AD on U.S. operators.

The regulations proposed herein 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this 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) if promulgated, 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. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

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.