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Proposed Rule

Airworthiness Directives; Eurocopter Deutschland GmbH Model EC 135 Helicopters

Document Details

Information about this document as published in the Federal Register.

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AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to Eurocopter Deutschland GmbH (ECD) Model EC-135 helicopters. The existing AD requires conducting a tail rotor drive shaft vibration survey (survey), installing a Fenestron Shaft Retrofit Kit, inspecting each tail rotor drive shaft bearing (bearing) attaching lock plate for bent-open tabs and broken or missing slippage marks, and visually inspecting each bearing support for cracks. This action would require conducting the survey and installing the Fenestron Shaft Retrofit Kit. This AD would also require installing double bearing supports and struts, revising the required compliance time for the repetitive inspections of the bearing attach hardware and supports, and removing the requirement to contact the FAA if a lock plate tab is bent open or if slippage marks are broken or missing. This proposal is prompted by continued reports of misaligned or cracked bearing supports and loose bearing attachment bolts. The actions specified by the proposed AD are intended to prevent loss of drive to the tail rotor and subsequent loss of control of the helicopter.

DATES:

Comments must be received on or before June 5, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 98-SW-74-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. Comments may be inspected at this location between 9 am and 3 pm, Monday through Friday, except Federal holidays.

The service information referenced in the proposed rule may be obtained from American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 75053-4005, telephone (972) 641-3460, fax (972) 641-3527. This information may be examined at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas.

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FOR FURTHER INFORMATION CONTACT:

Shep Blackman, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, Fort Worth, Start Printed Page 18011Texas 76137, telephone (817) 222-5296, fax (817) 222-5961.

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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. 98-SW-74-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. 98-SW-74-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

Discussion

On October 27, 1998, the FAA issued AD 98-15-25, Amendment 39-10866 (63 FR 59206, November 3, 1998), requiring the following:

  • Before further flight, conduct a survey and install a Fenestron Shaft Retrofit Kit L 535M3002 882.
  • Before further flight and thereafter at intervals not to exceed 15 hours time-in-service (TIS), inspect the bearing attaching lock plate for bent-open tabs and broken or missing slippage marks. If found, the FAA must be notified.
  • Before further flight and thereafter at intervals not to exceed 3 hours TIS, using a 6-power or higher magnifying glass and a bright light, visually inspect the bearing supports for cracks.

That action was prompted by reports of loose bearings and attachment bolts. The actions of that AD were intended to prevent loss of drive to the tail rotor and subsequent loss of control of the helicopter.

Since the issuance of AD 98-15-25, additional reports of misaligned, cracked, or corroded bearing supports, and loose bearing attachment bolts have been received. The original bearing supports have been redesigned to enable more precise alignment with the tail rotor driveshaft and have been strengthened to prevent cracking. In addition, they are now fabricated of corrosion-resistant material. Struts have been added to the tail boom to improve airframe vibration characteristics and further minimize bearing support cracking.

The Luftfahrt-Bundesamt (LBA), the airworthiness authority for the Federal Republic of Germany, notified the FAA that an unsafe condition may exist on ECD Model EC 135 helicopters. The LBA advises that misaligned, corroded, or cracked bearing supports and loose bearing attachment bolts may lead to a tail rotor failure and subsequent loss of the helicopter.

Since those cited in AD 98-15-25, ECD has issued the following Alert Service Bulletins (ASB's):

  • EC 135-53A-004, dated August 14, 1998, to specify replacing the current single bearing supports with double bearing supports made of corrosion-resistant material and to provide instructions for aligning these double bearing supports with the drive shaft axis for improved tail rotor drive shaft support.
  • EC 135-53A-005, Revision 3, dated September 2, 1998, to extend the time interval for compliance with the repetitive bearing attach hardware inspection and to identify the required tail rotor driveshaft vibration measurement procedure.
  • EC 135-53A-002, Revision 2, dated September 2, 1998, to extend the time interval for compliance with the repetitive bearing support crack inspection contingent on accomplishing Alert Service Bulletin EC 135-53A-004.

The LBA classified these ASB's as mandatory and issued AD's 1998-033/7 and 1998-389, both dated September 14, 1998, to ensure 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 ECD Model EC 135 helicopters of the same type design, the proposed AD would supersede AD 98-15-25. The proposed AD would require the following:

  • Conducting a vibration survey and installing the Fenestron Shaft Retrofit Kit L535M3002 882;
  • Installing double bearing supports and struts;
  • Replacing bearing attach hardware if necessary; and
  • Increasing the repetitive inspection interval for the bearing supports and attach hardware to 50 hours TIS.

The FAA estimates that 16 helicopters of U.S. registry would be affected by this proposed AD. The 50-hour inspection would take approximately 2 work hours to complete. The average labor rate is $60 per work hour. ECD has stated in its ASB's that the baseline vibration measurements and initial installation of all new parts are provided at no charge to the owner/operator. Assuming the helicopters are operated 900 hours TIS per year, the total cost impact of the proposed AD on U.S. operators is estimated to be $34,560.

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 Start Printed Page 18012location provided under the caption ADDRESSES.

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List of Subjects in 14 CFR Part 39

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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:

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PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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[Amended]

2. Section 39.13 is amended by removing Amendment 39-10866; AD 98-15-25, Docket No. 98-SW-35-AD, and by adding a new airworthiness directive (AD), to read as follows:

Eurocopter Deutschland GmbH: Docket No. 98-SW-74-AD. Supersedes AD 98-15-25, Amendment 39-10866, Docket No. 98-SW-35-AD.

Applicability: Model EC 135 helicopters, certificated in any category.

Note 1:

This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent loss of drive to the tail rotor and subsequent loss of control of the helicopter, accomplish the following:

(a) Before further flight, conduct a tail rotor drive shaft vibration survey and install a Fenestron Shaft Retrofit Kit L535M3002 882 in accordance with Eurocopter Deutschland GmbH Alert Service Bulletin (ASB) EC 135-53A-005, Revision 3, dated September 2, 1998.

(b) Before further flight, install double bearing supports for the tail rotor driveshaft and tail boom struts in accordance with ASB EC 135-53A-004, dated August 14, 1998.

Note 2:

ASB EC 135-53A-002, Revision 2, dated September 2, 1998, pertains to the subject of this AD.

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(c) Before further flight and thereafter at intervals not to exceed 50 hours time-in-service, perform the following:

(1) Clean each tail rotor drive shaft bearing support. Using a 6-power or higher magnifying glass and a bright light, visually inspect the attach lugs of the bearing supports B and C (shown in Figure 1) for cracks, particularly in the area extending from the bend radius to the attaching screws and rivets connecting the bearing supports to the tail boom. Before further flight, replace each cracked bearing support with an airworthy bearing support.

(2) Inspect each bearing attach hardware lock plate for bent-open tabs and slippage marks for attach hardware looseness or rotation. Before further flight, replace any loose bearing attach hardware (including lock plates found bent or open due to bolt rotation) with airworthy hardware.

(d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Regulations Group, Rotorcraft Directorate, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Regulations Group.

Note 3:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Regulations Group.

(e) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the helicopter to a location where the requirements of this AD can be accomplished.

Note 4:

The subject of this AD is addressed in Luftfahrt-Bundesamt (Federal Republic of Germany) AD's 1998-033/7 and 1998-389, both dated September 14, 1998.

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Issued in Fort Worth, Texas, on March 29, 2000.

Henry A. Armstrong,

Manager, Rotorcraft Directorate, Aircraft Certification Service.

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[FR Doc. 00-8520 Filed 4-5-00; 8:45 am]

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