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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 99-SW-57-AD] 

# 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 Schweizer Aircraft Corporation (Schweizer) Model 269A, 269A-1, 269B, 269C, 269C-1, and 269D helicopters. That AD currently requires inspecting the tail rotor swashplate shaft (shaft) nut for looseness and, if loose, inspecting the shaft for proper size; subsequently inspecting the shafts not previously inspected; and replacing any undersized shaft prior to further flight. This new action would reduce the applicability by specifying certain serial number tail rotor pitch control (pitch control) assemblies and shipping dates but would add the Schweizer Model TH-                              ( print page 26782)                            55A helicopter to the applicability. This proposal is prompted by the discovery of an undersized replacement shaft during routine maintenance. The actions specified by this proposed AD are intended to prevent failure of the shaft, loss of the tail rotor, and subsequent loss of control of the helicopter.                     

# DATES:

Comments must be received on or before July 10, 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-57-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:

George J. Duckett, Aviation Safety Engineer, New York Aircraft Certification Office, FAA, 10 Fifth Street, 3rd Floor, Valley Stream, New York 11581, telephone (516) 256-7525, fax (516) 568-2716. 

# 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-57-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-57-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. 

## Discussion 

The FAA issued AD 99-17-10, Amendment 39-11258, on August 4, 1999 (64 FR 44823, August 18, 1999), to require inspecting the shaft nut for looseness and, if loose, inspecting the shaft, part number (P/N) 269A6049-3, for proper size; subsequently inspecting the shafts not previously inspected; and replacing any undersized shaft prior to further flight. That action was prompted by the discovery of an undersized replacement shaft during routine maintenance. The requirements of that AD are intended to prevent failure of the shaft and subsequent loss of control of the helicopter. 

Since the issuance of that AD, the FAA has determined that the TH-55A model helicopter could have an undersized shaft installed and should have been included in the applicability of AD 99-17-10. Additionally, we have received reports of undersized shafts shipped from the factory as spares between September 1 and December 1, 1998. This action requires inspecting each shaft nut for looseness and each shaft for improper size, replacing each shaft, as necessary, and adding Schweizer Model TH-55A to the applicability requirements. 

The FAA has reviewed Schweizer Service Bulletins B-271.1 for Schweizer Models 269A, 269A-1, 269B, 269C, and TH-55A; C1B-009.1 for the Model 269C-1; and DB-007.1 for the Model 269D, all dated October 14, 1999. These service bulletins describe procedures for inspecting the shaft nut, P/N 269A6258, for looseness by using a firm hand pressure and inspecting the shaft, P/N 269A6049-3, for proper size. 

Since an unsafe condition has been identified that is likely to exist or develop on other Schweizer Model 269A, 269A-1, 269B, 269C, 269C-1, 269D and TH-55A helicopters of these same type designs, the proposed AD would supersede AD 99-17-10 to require inspecting the shaft nut, P/N 269A6258, for looseness; inspecting the shaft, P/N 269A6049-3, for proper size; and replacing any undersized shaft with an airworthy shaft of the proper size for helicopters with equipment installed as follows: 
    - Shaft, P/N 269A6049-3, shipped from the factory between September 1 and December 1, 1998, and installed after the helicopter was manufactured, or
    - Pitch control assembly, P/N 269A6050-5, with serial number with an “S” prefix and number 1047 through 1061.

The FAA estimates that 28 helicopters would be affected by this AD. For each helicopter, it would take 0.25 work hour to accomplish the 10-hour inspection and 3.6 work hours to accomplish the inspection and replacement, if necessary, at the 100-hour or annual inspection interval. The average labor rate is $60 per work hour. Required parts would cost approximately $1400 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $45,668. 

The regulations proposed herein would not have substantial direct effects 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 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 proposed 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: 

      ( print page 26783)    Authority:49 U.S.C. 106(g), 40113, 44701. 

§ 39.13 

2. Section 39.13 is amended by removing Amendment 39-11258 and by adding a new airworthiness directive to read as follows: 

**Schweizer Aircraft Corporation:**                                 Docket No. 99-SW-57-AD. Supersedes AD 99-17-10, Amendment 39-11258, Docket No. 99-SW-31-AD.                            

*Applicability:*                                 Model 269A, 269A-1, 269B, 269C, 269C-1, 269D and TH-55A helicopters, with a tail rotor swashplate shaft (shaft), part number (P/N) 269A6049-3, or a tail rotor pitch control assembly (pitch control), P/N 269A6050-5, with a serial number (S/N) with an “S” prefix and number 1047 through 1061, installed, 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 (c) 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 failure of the shaft, loss of the tail rotor, and subsequent loss of control of the helicopter, accomplish the following: 

(a) Within 10 hours time-in-service (TIS); 

(1) Determine whether the factory-installed shaft, part number (P/N) 269A6049-3, has been replaced with a shaft shipped from the factory between September 1 and December 1, 1998, inclusive, or if a pitch control, P/N 269A6050-5, with a S/N with an “S” prefix and numbers 1047 through 1061 is installed. 

(2) If the factory ship date for a replacement shaft cannot be positively determined, if the shipping date was between September 1 and December 1, 1998, inclusive, or if the pitch control S/N has an “S” prefix and number 1047 through 1061, 

(i) Before further flight and thereafter at intervals not to exceed 10 hours TIS, accomplish “Procedure, Part I,” of Schweizer Service Bulletins B-271.1 for Models 269A, 269A-1, 269B, 269C and TH-55A helicopters; C1B-009.1 for the Model 269C-1, or DB-007.1 for the Model 269D, all dated October 14, 1999 (SB), as applicable. 

(ii) At the next scheduled 100-hour or annual inspection, whichever occurs first, accomplish Part II, paragraphs a. through d., of the applicable SB. Shafts not meeting the requirements of paragraph d. of the applicable SB must be replaced with an airworthy shaft prior to further flight. 

(b) Before installing a replacement shaft, determine the date the shaft was shipped from the factory. If the date was between September 1 and December 1, 1998, inclusive, or cannot be determined, accomplish the inspections required by Part II, paragraph d., of the applicable SB prior to installation. Replace any unairworthy shaft with an airworthy shaft. 

(c) 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, New York Aircraft Certification Office. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, New York Aircraft Certification Office. 

# Note 2:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York Aircraft Certification Office.

(d) 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.

Issued in Fort Worth, Texas, on April 28, 2000. 

Eric Bries, 

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. 

[FR Doc. 00-11523 Filed 5-8-00; 8:45 am] 

BILLING CODE 4910-13-P