Airworthiness Directives; Eurocopter Deutschland GmbH (Eurocopter) Model EC 135 Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Eurocopter Model EC 135 helicopters. This proposal would require replacing a certain oil cooler fan splined drive shaft (shaft) with a different airworthy shaft and re-identifying the part numbers on the oil cooler fans. This proposal is prompted by two incidents in which the shaft broke. The actions specified by the proposed AD are intended to prevent failure of the shaft, loss of oil cooling, and a subsequent engine shutdown during flight.

DATES:

Comments must be received on or before April 11, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 99-SW-05-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT:

Shep Blackman, Aerospace Engineer, FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, 2601 Meacham Blvd., Fort Worth, Texas 76137, telephone (817) 222-5125, 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, 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 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. 99-SW-05-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. 99-SW-05-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

Discussion

The Luftfahrt-Bundesamt (LBA), which is the airworthiness authority for the Federal Republic of Germany, notified the FAA that an unsafe condition may exist on Eurocopter Model EC 135 helicopters. The LBA advises that breakage of fan drive shafts, which occurred on two helicopters, resulted in failure of the fan and reduced oil cooling.

Eurocopter has issued Eurocopter Alert Service Bulletin No. EC 135-79A-001, dated January 23, 1998 (ASB), which specifies replacing the “shafts with spline” with new reinforced shafts. The LBA classified this ASB as mandatory and issued AD No. 1998-109, dated February 26, 1998, in order to assure the continued airworthiness of these helicopters in the Federal Republic of Germany.

This helicopter model is manufactured in the Federal Republic of Germany and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the LBA has kept the FAA informed of the situation described above. The FAA has examined the findings of the LBA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Since an unsafe condition has been identified that is likely to exist or develop on other Eurocopter Model EC 135 helicopters of the same type design registered in the United States, the proposed AD would require replacing each shaft, part number (P/N) L 792M3004 225, with an airworthy shaft, P/N L 792M3004 235; re-identifying the left oil cooler fan, P/N L792M3004 102 with P/N L 792M3004 103, and right oil cooler fan, P/N L792M3005 102 with P/N L 792M3005 103, and reflecting these changes in the gearbox component history card or equivalent record. Replacing, re-identifying, and recording these changes would be considered terminating actions for the requirements of this AD.

The FAA estimates that 9 helicopters of U.S. registry would be affected by this proposed AD, that it would take approximately 4 work hours per helicopter to replace and re-identify the affected parts and record these actions in the gearbox history card or equivalent record, and that the average labor rate is $60 per work hour. The manufacturer has stated in Alert Service Bulletin EC 135-79A-001, dated January 23, 1998, that required parts would be provided at no cost. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $2,160 to accomplish the proposed actions on all the U.S. 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 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.