AD 2011-12-16

We are superseding an existing emergency airworthiness directive (EAD) for the specified Schweizer model helicopters that was previously sent to all known U.S. owners and operators. That EAD currently requires removing each locknut and verifying sufficient drag torque and retorquing, or if the locknut does not have sufficient drag torque, replacing the locknut with an airworthy locknut. This AD retains the existing EAD requirements but also requires within a specified time, modifying the expandable bolts and installing a cotter pin. This AD is prompted by a locknut working loose from a bolt attaching the tailboom support strut at the aft cluster fitting because the locknut installed on the expandable bolt did not have the proper threads. We are issuing this AD to modify each expandable bolt to allow adding a cotter pin to prevent the strut and driveshaft separating from the helicopter and subsequent loss of control of the helicopter.

Final rule; request for comments.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends Part 39 of the Federal Aviation Regulations (14 CFR Part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0 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]

0 2. The FAA amends Sec. 39.13 by adding the following new AD:

2011-12-16 Schweizer Aircraft Corporation (Schweizer): Amendment 39- 16723; Docket No. FAA-2011-0593; Directorate Identifier 2011-SW-002- AD.

Effective Date

(a) This AD is effective July 21, 2011.

Affected ADs

(b) This AD supersedes Emergency AD 2011-01-52, issued December 20, 2010; Directorate Identifier 2010-SW-111-AD.

Applicability

(c) Schweizer Model 269A, A-1, B, C helicopters (serial number (S/N) 1846 and larger); C-1 helicopters (S/N 0156 and larger); and TH-55 series helicopters with an Aft Cluster Fitting Modification Kit, part number (P/N) SA-269K-106, installed; certificated in any category.

Unsafe Condition

(d) This AD was prompted by a locknut working loose on the tailboom aft cluster fitting strut because the locknut installed on one expandable bolt did not have the proper threads. This AD contains terminating action to require modifying each expandable bolt to allow installing a cotter pin to prevent the strut and driveshaft separating from the helicopter and subsequent loss of control of the helicopter.

Compliance

(e) Required as indicated, unless already done.
(1) Before further flight, remove both the left-hand and right- hand locknuts, P/N MS21043-3. Reinstall the locknuts while determining the locknut drag torque. If the drag torque is a minimum of 2 in-lbs., retorque the locknut to 23 in-lbs. If the drag torque is not at least 2 in-lbs, replace the locknut with an airworthy locknut.
(2) Within 10 hours time-in-service, modify each expandable bolt, P/N ADB221-1A, torque locknut, P/N MS21043-3, and install cotter pin, P/N MS24665-132 or MS24665-151, in accordance with the Procedure Section, Part II, of Schweizer Service Bulletin (SB) No. B-295, dated December 21, 2010, for Model 269A, A-1, B, C, and TH-55 series helicopters or SB No. C1B-032, dated December 21, 2010, for Model 269C-1 helicopters.
(3) Before installing an expandable bolt, P/N ADB221-1A, to secure the tailboom support strut to the tailboom aft cluster fitting, modify the expandable bolt in accordance with paragraph (e)(2) of this AD.
(f) Modifying both expandable bolts by torquing the locknuts and installing the cotter pins as required by this AD is terminating action for the requirements of paragraph (e)(1) and (e)(2) of this AD.

Special Flight Permit

(g) Special flight permits will not be issued.

Alternative Methods of Compliance (AMOCs)

(h) The Manager, New York Aircraft Certification Office (NYACO), FAA, has the authority to approve AMOCs for this AD if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the NYACO, send it to the attention of the Program Manager, Continuing Operational Safety.

Note: Before using any approved AMOC, we request that you notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office or certificate holding district office.

Related Information

(i) For more information about this AD, contact Stephen Kowalski, Aviation Safety Engineer, FAA, Airframe and Propulsion Branch, ANE-171, 1600 Stewart Ave., Suite 410, Westbury, New York 11590, telephone (516) 228-7327, fax (516) 794-5531.

Subject

(j) Joint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code 5302: Rotorcraft Tailboom.

Material Incorporated by Reference

(k) You must use the specified portions of the service information contained in Schweizer Service Bulletins B-295 or C1B- 032, both dated December 21, 2010, for your model helicopter to do the actions required by this AD.
(2) For service information identified in this AD, contact Schweizer Aircraft Corporation, Elmira/Corning Regional Airport, 1250 Schweizer Road, Horseheads, NY 14845, telephone (607) 739-3821, fax: (607) 796-2488, e-mail address schweizer@sacusa.com, or at http://www.sacusa.com/support.
(3) You may also review copies of the service information that is incorporated by reference at the FAA, Office of the Regional Counsel, 2601 Meacham Blvd., Room 663, Fort Worth, Texas, or at the National Archives and Records Administration (NARA). For information on the availability of this material at an NARA facility, call 202- 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

Discussion

On December 20, 2010, we issued EAD 2011-01-52, Directorate Identifier 2010-SW-111-AD, for the specified Schweizer model helicopters. That EAD requires, before further flight, removing the locknut and reinstalling the locknut while determining the locknut drag torque. If the drag torque is a minimum of 2 in-lbs, retorquing the locknut to 23 in-lbs is required. If the drag torque is not at least 2 in-lbs, replacing the locknut with an airworthy locknut is required. That AD resulted from a locknut working loose from a bolt attaching the tailboom support strut at the aft cluster fitting. Further investigation revealed that the locknut installed on the expandable bolt did not have the proper threads. We issued that EAD to prevent the strut and driveshaft separating from the helicopter and subsequent loss of control of the helicopter.

Actions Since AD Was Issued

Since we issued AD 2011-01-52, the manufacturer has introduced a modification of the expandable bolts to allow the addition of a cotter pin.

Relevant Service Information

We reviewed Schweizer Service Bulletins No. B-295 for Model 269A, A-1, B, and C helicopters, and No. C1B-032 for Model 269C-1 helicopters, both dated December 21, 2010. The service information specifies verifying sufficient drag torque on each locknut and applying the proper torque to each locknut. The service information also specifies modifying both expandable bolts to allow the addition of a cotter pin.

FAA's Determination

We are issuing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop on other helicopters of these same type designs.

AD Requirements

This AD retains the requirements in the existing EAD. This AD also requires, within 10 hours time-in-service (TIS), modifying both expandable bolts by drilling a hole through each bolt to allow the addition of acotter pin. Thereafter, you may not install an expandable bolt unless that bolt has been modified in accordance with this AD. Modifying both expandable bolts in accordance with this AD is terminating action for the requirements of paragraphs (e)(1) and (e)(2) of this AD.

Differences Between the AD and the Service Information

We refer to flight hours as hours TIS.

FAA's Justification and Determination of the Effective Date

An unsafe condition exists that requires the immediate adoption of this AD. The FAA has found that the risk to the flying public justifies waiving notice and comment prior to adoption of this rule because this condition, if not corrected, could result in the strut and driveshaft separating from the helicopter and subsequent loss of control of the helicopter. Therefore, we find that notice and opportunity for prior public comment are impracticable because of the short compliance time and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited

This AD is a final rule that involves requirements affecting flight safety, and we did not provide notice and an opportunity to comment before it becomes effective. However, we invite you to send any written data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include the Docket Number FAA-2011-0593 and Directorate Identifier 2011-SW-002-AD at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this AD. We will consider all comments received by the closing date and may amend this AD because of those comments.
We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this AD.

Costs of Compliance

We estimate that this AD affects 585 helicopters of U.S. registry. We estimate the following costs to comply with this AD:

Estimated Costs ----------------------------------------------------------------------------------------------------------------
Cost per Cost on U.S.
Action Labor cost Parts cost helicopter operators ---------------------------------------------------------------------------------------------------------------- Inspection........................ .5 work-hour x $85 negligible........... $43 $25,155
per hour = $43. Modification...................... 1.5 work-hours x $85 negligible........... 128 74,880
per hour = $128. ----------------------------------------------------------------------------------------------------------------

We estimate the total cost impact of this AD to be $100,035.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, ``General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

This AD will not have federalism implications under Executive Order 13132. This AD will 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.

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For the reasons discussed above, I certify that this AD:
(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),
(3) Will not affect intrastate aviation in Alaska to the extent that it justifies making any regulatory distinctions, and
(4) 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.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.