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CFR Citation: 14 CFR Part 39

Docket ID: [Docket No. 2002-SW-25-AD]

RIN ID: RIN 2120-AA64

NOTICE: PROPOSED RULES

ACTION: Airworthiness directives:

DOCUMENT ACTION: Notice of proposed rulemaking (NPRM).

SUBJECT CATEGORY: Airworthiness Directives; Schweizer Aircraft Corporation Model 269A, 269A-1, 269B, 269C, and TH-55A Helicopters

DATES: Comments must be received by April 19, 2004.

DOCUMENT SUMMARY: This document proposes to revise an existing airworthiness directive (AD) for Schweizer Aircraft Corporation (Schweizer) Model 269A, 269A1, 269B, 269C, and TH55A helicopters. That AD currently requires inspecting the lugs on certain aft cluster fittings and each aluminum end fitting on certain tailboom struts. Modifying or replacing each strut assembly within a specified time period and serializing certain strut assemblies is also required. Additionally, a onetime inspection and repair, if necessary, of certain additional cluster fittings, and replacement and modification of certain cluster fittings within 150 hours timeinservice (TIS) or 6 months, whichever occurs first, is required. This action would require the same actions as the existing AD, but would revise the Applicability section of the AD. This proposal is prompted by the discovery of an error in the Applicability section of the existing AD. The actions specified by the proposed AD are intended to prevent failure of a tailboom support strut or a cluster fitting, which could cause rotation of a tailboom into the main rotor blades, and subsequent loss of control of the helicopter.

SUMMARY: Schweizer Aircraft Corp.,

SUPPLEMENTAL INFORMATION

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 FAApublic 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. 2002SW25AD.'' The postcard will be date stamped and returned to the commenter.

Discussion

On June 24, 2003, the FAA issued AD 20031315, Amendment 3913217 (68 FR 40478, July 8, 2003), to require owners and operators of the affected helicopters to:
[sbull] Within 10 hours TIS and thereafter at intervals not to exceed 50 hours TIS, dyepenetrant inspect the lugs and replace any cracked cluster fitting;
[sbull] Within 150 hours TIS or 6 months, whichever occurs first, replace or modify, using kit, part number (P/N) SA269K1061, each cluster fitting, P/N 269A2234 and P/N 269A2235;
[sbull] For strut assemblies, P/N 269A2015 or P/N 269A20155, at intervals not to exceed 50 hours TIS, visually inspect the strut aluminum end fittings for deformation or damage, dyepenetrant inspect the strut aluminum end fittings for a crack, and replace deformed, damaged, or cracked parts. Within 500 hours TIS or one year, whichever occurs first, modify or replace certain partnumbered strut assemblies; [sbull] Within 100 hours TIS, for Model 269C helicopters, serialize each strut assembly, P/N 269A20155 and 269A201511;
[sbull] Within 25 hours TIS or 60 days, whichever occurs first, inspect and repair cluster fittings, P/N 269A22343 and P/N 269A22353; and [sbull] Before further flight, replace any cluster fitting that is cracked or has a surface defect beyond rework limits.
That action was prompted by the need to expand the applicability to include certain Hughesmanufactured cluster fittings and to provide a terminating action for the repetitive dyepenetrant inspections of the cluster fittings. That condition, if not corrected, could result [[Page 7711]]
in failure of a tailboom support strut or a cluster fitting, which could cause rotation of a tailboom into the main rotor blades, and subsequent loss of control of the helicopter.

Since issuing that AD, we have discovered an error in the Applicability section that should be changed. The AD currently excepts helicopters that have Hughesmanufactured cluster fittings installed and that were originally sold by Hughes after June 1, 1988. We intended that this exception apply to all cluster fittings, P/N 269A22343 or P/ N 269A22353, that are installed, regardless of the manufacturer, if there was written documentation in the aircraft or manufacturer's records that shows the cluster fitting was originally sold by the manufacturer after June 1, 1988. Therefore, we are now proposing to expand the exception to all cluster fittings originally sold after June 1, 1988, regardless of the manufacturer.

The previously described unsafe condition is likely to exist or develop on other helicopters of the same type designs. Therefore, the proposed AD would revise AD 20031315 to retain the current requirements but revise the Applicability to exclude all cluster fittings with appropriate written documentation showing that the cluster fitting was originally sold by the manufacturer after June 1, 1988.

The FAA estimates that 1,000 helicopters of U.S. registry would be affected by the proposed AD. It would take approximately 2.5 work hours for each dyepenetrant inspection, 12 work hours to replace one cluster fitting, 4 work hours to modify or replace the strut assembly, 0.25 work hours to serialize the strut assembly, and 16 work hours to modify a cluster fitting. The average labor rate is $65 per work hour. Required parts would cost approximately $5 for each fitting inspection, $1,635 to replace a cluster fitting, $1,500 to modify or replace the strut assembly, and $1,688 for each cluster fitting modification kit (2 cluster fittings). Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $2,369,248 (assuming 2,000 cluster fittings are inspected, 50 cluster fittings are replaced, 6 strut assemblies are modified or replaced, 6 strut assemblies are serialized, and 1,010 cluster fittings are modified).

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 39AIRWORTHINESS DIRECTIVES

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

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

Sec. 39.13 [Amended]

2. Section 39.13 is amended by removing Amendment 3913217 (68 FR 40478, July 8, 2003), and by adding a new airworthiness directive (AD), to read as follows:
Schweizer Aircraft Corporation: Docket No. 2002SW25AD. Revises AD 20031315, Amendment 3913217.

Applicability: Model 269A, 269A1, 269B, 269C, and TH55A helicopters, certificated in any category, with a tailboom support strut (strut) assembly, part number (P/N) 269A2015 or 269A20155; or with a center frame aft cluster fitting, P/N 269A2234 or 269A2235, and an aft cluster fitting listed in the following table:
Helicopter model number Helicopter serial number With aft cluster fitting, P/N Model 269C......................... 0570 through 1165.......... 269A22343. Model 269C......................... 0500 through 1165.......... 269A22353. Model 269A, A1, B, or C, or TH55A All........................ 269A22343 or 269A22353. Exception: For the Model 269A, A1, B, or C or TH55A helicopters with cluster fittings, P/N 269A22343 or P/N 269A22353, installed, if there is written documentation in the aircraft or manufacturer's records that shows the cluster fitting was originally sold by the manufacturer after June 1, 1988, the requirements of this AD are not applicable.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of a tailboom support strut or lug on a cluster fitting, which could cause rotation of a tailboom into the main rotor blades, and subsequent loss of control of the helicopter, accomplish the following:
(a) Within 10 hours timeinservice (TIS), and thereafter at intervals not to exceed 50 hours TIS, for helicopters with cluster fittings, P/N 269A2234 or P/N 269A2235:
(1) Using paint remover, remove paint from the lugs on each cluster fitting. Wash with water and dry. The tailboom support strut must be removed prior to the paint stripping.
(2) Dyepenetrant inspect the lugs on each cluster fitting. See the following Figure 1:

FOR FURTHER INFORMATION CONTACT George Duckett, Aviation Safety Engineer, FAA, New York Aircraft Certification Office, Airframe and Propulsion Branch, 10 Fifth Street, 3rd Floor, Valley Stream, New York, telephone (516) 2567525, fax (516) 5682716.