E6-6586. Airworthiness Directives; Sikorsky Aircraft Corporation Model S-76A, B, and C Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes adopting a new airworthiness directive (AD) for Sikorsky Aircraft Corporation (Sikorsky) Model S-76A, B, and C helicopters. The AD would require inspecting all installed HR Textron main rotor servo actuators (servo actuators) for a high rate of leakage and also inspecting for contaminated hydraulic fluid. The AD would also require reducing the time-in-service (TIS) interval for overhauling the servo actuators. This proposal is prompted by a National Transportation Safety Board (NTSB) Safety Recommendation written in response to an accident involving a Model S-76 helicopter in which the performance of an HR Textron servo actuator was questioned as a result of piston head seal leakage and piston head plasma spray flaking. The actions specified by the proposed AD are intended to detect a high rate of leaking from a servo actuator and contamination of the hydraulic fluid, which could lead to degraded ability to maneuver the cyclic and collective controls and could result in subsequent loss of control of the helicopter.

DATES:

Comments must be received on or before July 3, 2006.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD:

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically;
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically;
• Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590;
• Fax: [phone]; or
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

You may examine the comments to this proposed AD in the AD docket on the Internet at http://dms.dot.gov.

FOR FURTHER INFORMATION CONTACT:

Terry Fahr, Aviation Safety Engineer, Boston Aircraft Certification Office, 12 New England Executive Park, Burlington, MA 01803, telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any written data, views, or arguments regarding this proposed AD. Send your comments to the address listed under the caption ADDRESSES. Include the docket number “FAA-2006-24587, Directorate Identifier 2006-SW-05-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed rulemaking. Using the search function of our docket Web site, you can find and read the comments to any of our dockets, including the name of the individual who sent or signed the comment. You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78) or you may visit http://dms.dot.gov.

Examining the Docket

You may examine the docket that contains the proposed AD, any comments, and other information in person at the Docket Management System (DMS) Docket Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone [phone]) is located at the plaza level of the Department of Transportation Nassif Building in Room PL-401 at 400 Seventh Street, SW., Washington, DC. Comments will be available in the AD docket shortly after the DMS receives them.

Discussion

This document proposes adopting a new AD for Sikorsky Model S-76A, B, and C helicopters with an HR Textron servo actuator, part number (P/N) 76650-09805, installed. The AD would require inspecting all installed HR Textron servo actuators for leakage that exceeds 700 cc per minute by installing a test line in the servo actuator return port, and inspecting the hydraulic fluid for contamination using a patch test kit or an independent laboratory analysis method. If leakage in excess of 700 cc per minute is detected in any servo actuator, the proposed AD would require replacing that servo actuator with an airworthy servo actuator. If the hydraulic fluid is found to be contaminated, the proposed AD would require flushing the hydraulic system. The AD would also require reducing the TIS interval for overhauling an affected servo actuator from 3,000 to 2,000 hours TIS. This proposal is prompted by an NTSB Safety Recommendation written in response to an accident involving a Model S-76 helicopter in which the performance of an HR Textron servo actuator was questioned as a result of piston head seal leakage and piston head plasma spray flaking. The actions specified by the proposed AD are intended to detect a high rate of leaking from a servo actuator and contamination of the hydraulic fluid, which could lead to degraded ability to maneuver the cyclic and collective controls and could result in subsequent loss of control of the helicopter.

This unsafe condition is likely to exist or develop on other helicopters of the same type design. Therefore, the proposed AD would require, within 25 hours TIS and thereafter at intervals not to exceed 600 hours TIS, determining the leakage rate for the three servo actuators by installing a test line in each servo actuator return port and turning on the hydraulic power. If the leakage rate exceeds 700 cc per minute in any servo actuator, the proposed AD would require replacing that servo actuator with an airworthy servo actuator before further flight. The proposed AD would also require inspecting the hydraulic fluid for contamination using a patch test kit or an independent laboratory analysis method. If the hydraulic fluid is found to be contaminated, the proposed AD would require flushing the hydraulic system before further flight. The proposed AD would also require reducing the TIS interval for overhauling the servo actuator from 3,000 to 2,000 hours TIS.

We estimate that this proposed AD would affect 300 helicopters of U.S. registry, and that

• Determining the servo actuator leakage rate would take approximately 8 work hours,
• Inspecting the hydraulic fluid for contamination would take approximately 3 work hours,
• Replacing the servo actuator, if necessary, would take approximately 12 work hours, and
• Flushing the hydraulic system, if necessary, would take approximately 6 work hours per helicopter to accomplish at an average labor rate of $80 per work hour. Required parts would cost approximately $13,000 per helicopter for a servo actuator. Based on these figures, the total cost impact of the proposed AD on U.S. operators would be $4,596,000 ($15,320 per helicopter), assuming one leakage inspection and one hydraulic fluid inspection on each helicopter, and replacing one servo actuator and flushing the hydraulic system on each helicopter.

Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. Additionally, this proposed AD 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.

For the reasons discussed above, I certify that the 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. 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.

We prepared a draft economic evaluation of the estimated costs to comply with this proposed AD. See the DMS to examine the draft economic evaluation.

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.

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

[Amended]

2. Section 39.13 is amended by adding a new airworthiness directive to read as follows:

Sikorsky Aircraft Corporation: Docket No. FAA-2006-24587; Directorate Identifier 2006-SW-05-AD.

Applicability: Model S-76A, B, and C helicopters, with HR Textron main rotor servo actuator (servo actuator), part number (P/N) 76650-09805, installed, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To detect leaking in a servo actuator and contamination of the hydraulic fluid, which could lead to degraded ability to maneuver the cyclic and collective controls and could result in subsequent loss of control of the helicopter, accomplish the following:

(a) Within 25 hours time-in-service (TIS), and thereafter at intervals not to exceed 600 hours TIS:

(1) Determine the leakage rate of each of the three servo actuators by installing a test line in each servo actuator return port and turning on the hydraulic power.

(2) If the leakage rate exceeds 700 cc per minute in a servo actuator, before further flight, remove that servo actuator and replace it with an airworthy servo actuator.

(3) Inspect the hydraulic fluid for contamination using either a patch test kit or an independent laboratory analysis method.

(4) If contamination is found, before further flight, flush the hydraulic system and refill the system with uncontaminated hydraulic fluid.

(b) On or before reaching 2,000 hours TIS since the last overhaul, and thereafter at intervals not to exceed 2,000 hours TIS, overhaul each servo actuator, P/N part number 76650-09805, or replace it with an airworthy servo actuator.

(c) This AD revises the Airworthiness Limitations and Inspection Requirements manual by reducing the overhaul interval for the servo actuator, P/N 76650-09805, from 3,000 hours TIS to 2,000 hours TIS.

(d) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the FAA, ATTN: Terry Fahr, Aviation Safety Engineer, Boston Aircraft Certification Office, 12 New England Executive Park, Burlington, MA 01803, telephone [phone], fax [phone], for information about previously approved alternative methods of compliance.

Issued in Fort Worth, Texas, on April 21, 2006.

Mark R. Schilling,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.