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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2010-1301; Directorate Identifier 2010-SW-008-AD]
          - RIN 2120-AA64

# AGENCY:

Federal Aviation Administration, DOT.

# ACTION:

Notice of proposed rulemaking (NPRM).

# SUMMARY:

This document proposes superseding an existing airworthiness directive (AD) for MDHI Model MD900 helicopters. That AD currently requires turning on both Vertical Stabilizer Control System (VSCS) switches and turning off the autopilot (AP/SAS) switch; pulling certain AP/SAS circuit breakers; installing a placard near the AP/SAS master switch; installing an airspeed limitation placard on the instrument panel; and making changes to the Rotorcraft Flight Manual (RFM). This action would retain those requirements and would provide an option of replacing each affected tube adapter with a newly-designed tube adapter, which would provide terminating action for the unsafe condition. This proposal is prompted by the manufacturer introducing an improved, newly-designed tube adapter. The actions specified by this AD are intended to prevent loss of yaw control and subsequent loss of control of the helicopter.

# DATES:

Comments must be received on or before March 15, 2011.

# ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD:
      -  Federal eRulemaking Portal:                          Go to                          http://www.regulations.gov.                          Follow the instructions for submitting comments.                    
      -  Fax:                          202-493-2251.                    
      -  Mail:                          U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.                    
      -  Hand Delivery:                          U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.                    

                        You may get the service information identified in this proposed AD from MD Helicopters, Inc., Attn: Customer Support Division, 4555 E. McDowell Rd., Mail Stop M615, Mesa, AZ 85215-9734, telephone 1-800-388-3378, fax 480-346-6813, or at                         *http://www.mdhelicopters.com*.                    

                        You may examine the comments to this proposed AD in the AD docket on                               ( print page 2608)                            the Internet at                         *http://www.regulations.gov.*

# FOR FURTHER INFORMATION CONTACT:

Eric D. Schrieber, FAA, Los Angeles Aircraft Certification Office, Aviation Safety Engineer, Airframe Branch, 3960 Paramount Blvd., Lakewood, California 90712, telephone 562-627-5348, fax 562-627-5210.

# 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-2010-1301, Directorate Identifier 2010-SW-008-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://www.regulations.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 the 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).                

## Examining the Docket

                    You may examine the docket that contains the proposed AD, any comments, and other information in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Operations office (telephone (800) 647-5527) is located in Room W12-140 on the ground floor of the West Building at the street address stated in the                     **ADDRESSES**                     section. Comments will be available in the AD docket shortly after receipt.                

## Discussion

On August 20, 2008, we issued Emergency AD (EAD) 2008-18-51, Directorate Identifier 2008-SW-50-AD, for Model 500N, 600N, and MD900 helicopters. That EAD required several actions related to the Yaw Stability Augmentation System (YSAS) for the Model 500N and 600N helicopters and to the VSCS for the Model MD900 helicopters.

                    We issued superseding EAD 2008-18-52, Directorate Identifier 2008-SW-52-AD, on August 27, 2008. That EAD required, for Model 500N, 600N and MD900 helicopters, turning OFF the VSCS or YSAS switches instead of pulling the circuit breakers and installing placards that limit airspeed to 100 KIAS or VNE,                     whichever is less. For the Model MD900 helicopters, the EAD also required limiting flight to VFR, prohibiting use of the autopilot, and making changes to the RFM. For all helicopters, the EAD required a terminating action of replacing each tube adapter with an airworthy tube adapter stamped with a date stamp of August 15, 2008, or later.                

                    After issuing EAD 2008-18-52, the replacement tube adapter failed on 2 of the Model MD900 helicopters. Therefore, we separated the AD actions and issued two superseding EADs: 2008-22-52 for the Model 500N and 600N helicopters and 2008-22-53 for the Model MD900 helicopters. Those EADS were published in the                     **Federal Register**                     as final rules; request for comments. AD 2008-22-52 (73 FR 72326) was published on November 28, 2008. AD 2008-22-53 (73 FR 73165) was published on December 2, 2008.                

AD 2008-22-53 does not include specific serial numbers in the applicability section because the unsafe condition can occur on any helicopter with an affected tube adapter installed. The AD also requires turning ON both VSCS switches to reduce pilot workload and to help control the helicopter if a tube adapter fails under normal flight conditions until the helicopter is on final approach. Also, AD 2008-22-53 did not include a terminating action because the manufacturer had not determined the cause of the failures.

Since issuing AD 2008-22-53, the manufacturer has designed a VSCS tube adapter to replace the existing tube adapter. Installing the newly designed tube adapter is optional but, if installed, would constitute terminating action for the requirements of this AD.

We have reviewed MDHI Service Bulletin No. SB900-110R1, dated December 3, 2008 (SB), which specifies replacing each VSCS tube adapter, part number (P/N) 500N7218-1, with an improved tube adapter, P/N 900C2010303-101, to prevent an uncommanded yaw of the helicopter. The SB specifies operating at a decreased speed until the newly designed tube adapters are installed.

This previously described unsafe condition is likely to exist or develop on other helicopters of this same type design. Therefore, the proposed AD would supersede AD 2008-22-53, retain the current requirements, and require continuing to operate at a reduced speed until you replace each tube adapter with an improved tube adapter.

We estimate that this proposed AD would affect 39 helicopters of U.S. registry. It would take about 5.5 hours to install the newly designed tube adapters and 0.5 hours for all other required modifications at an average labor rate of $85 per work hour. Required parts would cost about $244 for 2 tube adapters. Based on these figures, we estimate the total cost impact of the proposed AD on U.S. operators to be $29,406, assuming both tube adapters are replaced on the entire fleet of helicopters.

## 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 AD docket 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                           ( print page 2609)                        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 

2. Section 39.13 is amended by removing Amendment 39-15756 (73 FR 73165, December 2, 2008), and by adding a new airworthiness directive (AD), to read as follows:

**MD Helicopters, Inc.:**                                 Docket No. FAA-2010-1301; Directorate Identifier 2010-SW-008-AD. Supersedes AD 2008-22-53, Amendment 39-15756, Docket No. FAA-2008-1251, Directorate ID 2008-SW-61-AD.                            

*Applicability:*                                 Model MD900 helicopters with a Vertical Stabilizer Control System (VSCS) tube adapter, part number (P/N) 500N7218-1, installed, certificated in any category.                            

*Compliance:*                                 Required before further flight, unless done previously.                            

To prevent loss of yaw control and subsequent loss of control of the helicopter, do the following:

(a) Turn ON both VSCS switches.

(b) If installed, de-energize the autopilot (AP/SAS) as follows:

(1) Determine if the AP/SAS trim actuators are centered. If the AP/SAS trim actuators are not centered, center them.

(2) After the AP/SAS trim actuators are centered:

(i) Turn the AP/SAS MSTR switch to the OFF position.

(ii) Pull the following AP circuit breakers located on the A601 Essential Bus Circuit Breaker Panel, mounted in the cockpit console, and install a plastic cable tie on each circuit breaker to prevent accidental energizing of the circuit:

(A) AP/SAS CMPTR (CB28),

(B) AP/SAS DISC (CB29), and

(C) AP/SAS ACCEL (CB30).

(3) Install a placard next to the AP Mode Select panel that contains the AP/SAS MSTR switch stating “AP/SAS DEACTIVATED.”

(c) Install a placard on the instrument panel as close as practicable to the airspeed indicator that states:

                                “AIRSPEED LIMIT 100 KIAS or VNE, WHICHEVER IS LESS. VFR FLIGHT ONLY, AUTOPILOT OFF.”                            

                                (d) Make pen and ink changes or insert a copy of this AD into the Limitations section of the rotorcraft flight manual (RFM) to revise the limitations as follows: “VNE                                 is limited to 100 KIAS or less as determined by referring to the airspeed VNE                                 placard already installed on the helicopter. VFR Flight Only, Autopilot OFF.”                            

(e) Make pen and ink changes or insert a copy of this AD into the Limitations section of the RFM to revise the emergency procedures as follows: “If you experience an anti-torque system malfunction, turn both VSCS switches to OFF during final approach for a run-on landing.”

(f) Instead of complying with paragraphs (a) through (e) of this AD, you may replace both VSCS tube adapters, P/N 500N7218-1, with airworthy VSCS tube adapters, P/N 900C2010303-101. If you install VSCS tube adapters, P/N 900C2010303-101, and previously have complied with AD 2008-22-53, return the helicopter to its normal configuration by returning the switches and circuit breakers to their normal operating position, operationally testing the auto-pilot system, removing the two placards, and removing the revisions to the RFM pertaining to the airspeed limitation. Replacing both VSCS tube adapters, P/N 500N7218-1, with airworthy VSCS tube adapters, P/N 900C2010303-101, and returning the helicopter to its normal operating configuration constitutes terminating action for the requirements of this AD.

# Note:

 MD Helicopters Service Bulletin SB900-110R1, dated December 3, 2008, which is not incorporated by reference containing additional information about the subject of this AD.

                                (g) 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 Manager, Los Angeles Aircraft Certification Office, FAA,                                 *Attn:*                                 Eric D. Schrieber, Aviation Safety Engineer, Airframe Branch, 3960 Paramount Blvd., Lakewood, California 90712, telephone 562-627-5348, fax 562-627-5210, for information about previously approved alternative methods of compliance.                            

                                (h) Copies of the applicable service information may be obtained from MD Helicopters, Inc.,                                 *Attn:*                                 Customer Support Division, 4555 E. McDowell Rd., Mail Stop M615, Mesa, Arizona 85215-9734, telephone 1-800-388-3378, fax 480-346-6813, or on the Web at                                 *http://www.mdhelicopters.com*.                            

(i) The Joint Aircraft System/Component (JASC) Code is 6720: Tail Rotor Control System.

Issued in Fort Worth, Texas, on December 28, 2010.

Stefany James,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 2011-726 Filed 1-13-11; 8:45 am]

BILLING CODE 4910-13-P