Airworthiness Directives; Eurocopter Deutschland GmbH Model EC135 P1, P2, T1, and T2 Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes superseding an existing airworthiness directive (AD) for Eurocopter Deutschland GmbH (Eurocopter) Model EC135 P1, P2, T1, and T2 helicopters. That AD currently requires adding the AD or a statement to the Rotorcraft Flight Manual (RFM) informing the pilot to reduce power and land as soon as practicable if a thump-like sound followed by an unusual vibration occurs during flight. That AD also requires visually inspecting the main rotor drive torque strut assembly (strut) for a crack or a break, recording the inspections in the historical or equivalent record, re-marking and relocating the strut, as appropriate, and replacing any unairworthy strut with an airworthy strut. Also, that AD establishes life limits for certain struts and revises the life limit for other struts. This action would require the same actions as the existing AD except that it proposes to change the visual inspection from a one-time inspection to daily inspections; reduces the life limit for aluminum struts; and eliminates the once-only transfer and remarking of certain struts. This proposal is prompted by an incident in which a pilot felt an in-flight increase in vibration and subsequent discovery of a failed strut. The actions specified by the proposed AD are intended to prevent failure of a strut and subsequent loss of control of the helicopter.

DATES:

Comments must be received on or before August 2, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2003-SW-39-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 Regional Counsel 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, Fort Worth, Texas 76193-0110, 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 will be considered before taking action on the proposed rule. The proposals contained in this document 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, both before and after the closing date for comments, 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 proposal must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket No. 2003-SW-39-AD.” The postcard will be date stamped and returned to the commenter.

Discussion

On September 29, 2003, the FAA issued AD 2003-20-11, Amendment 39-13329 (68 FR 58581, October 10, 2003), Docket 2003-SW-08-AD, to require adding the AD or a statement to the RFM informing the pilot to reduce power and land as soon as practicable if a thump-like sound followed by an unusual vibration occurs during flight. That AD also requires visually inspecting the strut for a crack or a break within 10 hours time-in-service, recording the inspections in the historical or equivalent record, re-marking and relocating the strut, as appropriate, and replacing any unairworthy strut with an airworthy strut. Also, that AD establishes life limits for certain struts and revises the life limit for other struts.

Since issuing that AD, there has been another incident in which a pilot felt an in-flight increase in vibration. Post-flight examinations revealed a fractured aluminum strut.

The Luftfahrt-Bundesamt (LBA), the airworthiness authority for the Federal Republic of Germany, notified the FAA that an unsafe condition may exist on Eurocopter Model EC135 P1, P2, T1, and T2 helicopters. The LBA advises that the holders of affected aircraft registered in the Federal Republic of Germany must carry out the inspection for a crack, marking, replacement, and reduction of life limit of struts in accordance with the manufacturer's alert service bulletin.

Eurocopter has issued Alert Service Bulletin EC135-63A-002, Revision 4, dated July 7, 2003 (ASB), concerning reduction in life limit for the strut, and visual inspections of the strut and emergency stop. The ASB contains errors—in paragraph 1.A., the abbreviation “S/N” should be “P/N” and in paragraphs 1.C., 1.E.(1), and 1.E.(2), it incorrectly states that the ASB is Revision 3 rather than Revision 4. The LBA classified this ASB as mandatory and issued AD No. 2001-107/3, dated August 21, 2003, to ensure the continued airworthiness of these helicopters in the Federal Republic of Germany.

This previously described unsafe condition is likely to exist or develop on other helicopters of the same type designs. Therefore, the proposed AD would supersede AD 2003-20-11 and require: adding the AD or a statement to the RFM informing the pilot to reduce power and land as soon as practicable if a thump-like sound followed by unusual vibration occurs during flight; visually inspecting the strut for a crack or a break before the first flight of each day; replacing any unairworthy strut with an airworthy strut; replacing all aluminum struts with titanium struts on or before accumulating 500 hours TIS or no later than December 31, 2004, whichever occurs first; installing the struts in pairs; and canceling the once-only transfer and remarking of certain struts.

The FAA estimates that this proposed AD would affect 50 helicopters of U.S. registry, and would take approximately 92.25 work hours per helicopter to accomplish the inspections and parts replacement at an average labor rate of $65 per work hour. Required parts would cost approximately $7,296 per helicopter. Based on these figures, we estimate the total cost impact of the proposed AD on U.S. operators to be $664,612 to replace the aluminum struts on the entire fleet.

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 economic 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.