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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 2000-SW-17-AD] 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Notice of proposed rulemaking (NPRM). 

# SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD) for Societe Nationale Industrielle Aerospatiale (currently Eurocopter France) Model AS350 and AS355 series helicopters. That AD requires inspecting the fuselage frame (frame) for a crack at the fuselage-to-tailboom interface and replacing or repairing, as necessary. That AD also requires a fastener torque check and retorquing, as necessary. This action would retain the requirements of the existing AD but would increase the inspection interval from 1,200 hours time-in-service (TIS) to 2,500 hours or 6 years TIS, whichever occurs first. This proposal would revise the time interval for inspecting the frame at the fuselage-to-tailboom interface to coincide with the inspection interval specified in the maintenance manual. The actions specified by the proposed AD are intended to eliminate confusion and unnecessary costs and to prevent a cracked frame, tailboom failure, and subsequent loss of control of the helicopter. 

# DATES:

Comments must be received on or before February 6, 2001. 

# ADDRESSES:

                        Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2000-SW-17-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:

Jim Grigg, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Regulations Group, Fort Worth, Texas 76193-0111, telephone (817) 222-5490, 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 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. 2000-SW-17-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-17-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. 

## Discussion 

On June 28, 1985, the FAA issued AD 85-14-06, Amendment 39-5089 (50 FR 28561, July 15, 1985) to require repetitive inspections and to repair or replace the fuselage frame at the fuselage tailboom interface. On August 8, 1985, the FAA issued AD 85-14-06 R1, Amendment 39-5121 (50 FR 37173, September 12, 1985), to require repetitive visual inspections and to repair or replace the frame, as necessary. That AD also requires fastener torque checks and re-torquing, as necessary. That action was prompted by reports of cracked frames at the fuselage-to-tailboom interface. The requirements of that AD are intended to prevent a cracked frame, tailboom failure, and subsequent loss of control of the helicopter. 

Since the issuance of that AD, we have been notified that the inspection interval of the frame at the fuselage-to-tailboom interface in the current AD does not coincide with the maintenance manual. The FAA has determined that this may create confusion among operators as to when the inspections are required. 

We have identified an unsafe condition that is likely to exist or develop on other Eurocopter France Model AS350 and AS355 helicopters of these same type designs. The proposed AD would supersede AD 85-14-06 R1 and would require the same actions as the existing AD except to increase the inspection interval from 1,200 hours TIS to 2,500 hours or 6 years TIS, whichever occurs first, to coincide with the maintenance manual to eliminate confusion and unnecessary costs. To compensate for the increase in the inspection interval, we propose that the initial inspection interval be reduced from 100 hours TIS to 30 hours TIS and that the visual inspection be changed to a dye-penetrant inspection. 

                    The FAA estimates that 475 helicopters of U.S. registry would be affected by this proposed AD, that it would take approximately 8 work hours per helicopter to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Based on these figures, the total cost impact of the proposed AD on U.S. operators is                           ( print page 76954)                        estimated to be $228,000 assuming no cracked frames are discovered.                 

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. 

§ 39.13 

2. Section 39.13 is amended by removing Amendment 39-5089 (50 FR 28561, July 15, 1985) and Amendment 39-5121 (50 FR 37173, September 12, 1985), and by adding a new airworthiness directive (AD), to read as follows: 

**Eurocopter France:**                                 Docket No. 2000-SW-17-AD. Supersedes AD 85-14-06, Amendment 39-5089, and 85-14-06 R1, Amendment 39-5121, Docket No. 85-ASW-15.                             

*Applicability:*                                 Model AS350B, AS350B1, AS350B2, AS350B3, AS350BA, AS350C, AS350D, AS350D1, AS355E, AS355F, AS355F1, AS355F2, and AS355N 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 (e) 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 eliminate confusion and unnecessary costs and to prevent a cracked fuselage frame (frame), tailboom failure, and subsequent loss of control of the helicopter, accomplish the following: 

(a) Inspect the fuselage-to-tailboom attachment bolts in accordance with paragraph (d) within 30 hours time-in-service (TIS). 

(b) Inspect the fuselage-to-tailboom attachment bolts in accordance with paragraph (d) within 30 hours TIS of replacing or reinstalling a tailboom. 

(c) Repeat the inspection in accordance with paragraph (d) at intervals not to exceed 2500 hours or 6 years TIS, whichever occurs first. 

(d) Inspect the fuselage-to-tailboom attachment bolts for proper torque range and the frame, part number 350A21-1247-00, for a crack at the fuselage-to-tailboom interface. 

(1) Procedure for inspecting proper torque range: 

(i) Using a fine-point felt tip pen, mark the position of the nut relative to the assembly. 

(ii) One at a time, slightly loosen each nut. Do not allow the corresponding bolt to rotate relative to the assembly. 

(iii) Tighten the nut with a properly calibrated torque wrench until the mark on the nut lines up with the mark on the assembly. 

(iv) Record the torque value required to line up the two marks. 

(2) Interpretation of the recorded torque values for each nut: 

(i) If the torque value is less than 0.3 mdaN (26 in-lbs) on any nut: 

(A) Remove the tailboom. 

(B) Perform a dye-penetrant inspection for a crack in the bending radius of the frame. 

(C) If a crack is found, repair or replace the frame with an airworthy frame before further flight. 

(ii) If the torque value is between 0.3 mdaN and 1 mdaN (26 to 88 in-lbs), re-torque to 0.75 mdaN to 0.9 mdaN (67 to 79 in-lbs). 

(iii) If the torque value is equal to or greater than 1 mdaN (88 in-lbs), remove the nut and bolt and replace them with a new nut and bolt. Torque the nut to 0.75 mdaN to 0.9 mdaN (67-79 in-lbs). 

# Note 2:

Aerospatiale Service Bulletins AS 355 No. 05.14 and AS 350 No. 05.16 pertain to the subject of this AD.

(e) 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.

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

Issued in Fort Worth, Texas, on November 30, 2000. 

Larry M. Kelly, 

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. 

[FR Doc. 00-31319 Filed 12-7-00; 8:45 am] 

BILLING CODE 4910-13-U