Document ID: FAA-2008-1244-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; MD Helicopters, Inc. Model 500N and 600N Helicopters
Posted Date: 2008-11-28T05:00Z

[Federal Register: November 28, 2008 (Volume 73, Number 230)]
[Rules and Regulations]               
[Page 72326-72328]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr28no08-8]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-1244; Directorate Identifier 2008-SW-59-AD; 
Amendment 39-15752; AD 2008-22-52]
RIN 2120-AA64

 
Airworthiness Directives; MD Helicopters, Inc. Model 500N and 
600N Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This document supersedes AD 2008-18-52 and publishes in the 
Federal Register an amendment adopting Emergency Airworthiness 
Directive (AD) 2008-22-52 which was sent previously to all known U.S. 
owners and operators of MD Helicopters, Inc. (MDHI) Model 500N and 600N 
helicopters by individual letters. This AD requires turning OFF the Yaw 
Stability Augmentation System (YSAS); installing a placard that limits 
airspeed to 100 KTS or VNE, whichever is less; and revising 
the limitations section of the Rotorcraft Flight Manual (RFM) to 
reflect that limitation. Finally, replacing the adapter tubes with 
airworthy adapter tubes that have a production date code stamp is 
required. This AD is prompted by several occurrences of failed adapter 
tubes on the Model MD900 helicopter which uses the same adapter tubes. 
The actions specified by this AD are intended to prevent loss of yaw 
control and subsequent loss of control of the helicopter.

DATES: Effective December 15, 2008, to all persons except those persons 
to whom it was made immediately effective by Emergency AD 2008-22-52, 
issued on October 23, 2008, which contained the requirements of this 
amendment.
    Comments for inclusion in the Rules Docket must be received on or 
before January 27, 2009.

ADDRESSES: Use one of the following addresses to submit comments on 
this 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 AD 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.
    Examining the Docket: You may examine the docket that contains the 
AD, any comments, and other information on the Internet at http://
www.regulations.gov, or 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.

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: On August 20, 2008, we issued Emergency AD 
2008-18-51 for 500N, 600N, and MD900 helicopters. Emergency AD 2008-18-
51 was prompted by reports that 2 MD900 helicopters experienced failed 
vertical stabilizer control system (VSCS) adapter tubes. In one case, 
the helicopter experienced an uncommanded yaw, resulting in loss of a 
window and a door. The Emergency AD required several actions related to 
the YSAS for the Model 500N and 600N helicopters and to the vertical 
stabilizer control system (VSCS) for the Model MD900 helicopters.
    After we issued Emergency AD 2008-18-51, we discovered that pulling 
the circuit breaker per the Emergency AD caused impaired directional 
control, which could result in loss of control of the helicopter. 
Therefore, on August 27, 2008, we issued superseding Emergency AD 2008-
18-52, which requires, 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, 
limiting flight to VFR, prohibiting use of the autopilot, and making 
changes to the Emergency Procedures and Airworthiness (sic) Limitations 
sections of the RFM are also required. For all of the helicopter 
models, Emergency AD 2008-18-52 requires, within 45 days, terminating 
action by replacing the adapter tube with an airworthy adapter tube 
that has a date stamp of August 15, 2008 or later, and then removing 
the placards, removing the AD limitation changes from the RFM, and 
returning all switches and circuit breakers to their normal positions.
    Since the issuance of Emergency AD 2008-18-52, we have had 
additional occurrences of failed adapter tubes on the MD900 
helicopters. The replacement adapter tube that was terminating action 
for the requirements of Emergency AD 2008-18-52 failed on 2 of the 
MD900 helicopters. Furthermore, adapter tubes without a production date 
code stamp remain a safety concern on the 500N and 600N helicopters 
because they may not conform to the FAA-approved design. Therefore, we 
separated the AD actions and issued 2 superseding Emergency ADs; 2008-
22-52 for the 500N and 600N helicopters, and 2008-22-53 for the MD900 
helicopters.
    Emergency AD 2008-22-52 applies to the 500N and 600N helicopters 
and continues to require the same actions as Emergency AD 2008-18-52; 
however,

[[Page 72327]]

we made minor editorial changes as well as the following changes:
     We do not include any serial numbers in the applicability 
because this unsafe condition can occur on any helicopter with the 
affected adapter tube installed.
     We require that the limitations section of the RFM be 
revised to reflect the airspeed limitation required by the placard.
     We require that replacement adapter tubes have a 
production date code stamped on them to determine that the parts are 
airworthy (e.g., 08-08 indicates a production date of August 2008).
    We have reviewed MDHI Service Bulletin (SB) SB500N-040R1/SB600N-
047R1 dated August 27, 2008. The SB specifies de-energizing the YSAS, 
installing a placard that limits the airspeed, and replacing the YSAS 
adapter.
    Since the unsafe condition described is likely to exist or develop 
on other MDHI Model 500N and 600N helicopters of the same type designs, 
we issued superseding Emergency AD 2008-22-52 to prevent loss of yaw 
control and subsequent loss of control of the helicopter. The Emergency 
AD requires the following before further flight:
     Turning OFF the YSAS switch.
     Installing a placard on the instrument panel as close as 
practicable to the airspeed indicator that states:

    ``YSAS SYSTEM IS OFF. AIRSPEED LIMIT 100 KIAS or VNE, 
WHICHEVER IS LESS.''

     Revising the limitations section of the RFM to limit the 
airspeed to 100 KIAS or VNE, whichever is less.
    The Emergency AD also requires replacing adapter tubes without a 
production date code stamp with adapter tubes that have a production 
date code stamp within 45 days and is terminating action for the 
requirements of the Emergency AD. After replacing the affected adapter 
tubes, the Emergency AD requires removing the placards, removing the 
revisions that were made to the RFM because of the Emergency AD, and 
returning the YSAS system to its normal position. The short compliance 
time involved is required because the previously described critical 
unsafe condition can adversely affect the controllability of the 
helicopter. Therefore, the actions described previously are required 
before further flight and within 45 days, and this AD must be issued 
immediately.
    Since it was found that immediate corrective action was required, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual letters 
issued on October 23, 2008 to all known U.S. owners and operators of 
MDHI Model 500N and 600N helicopters. These conditions still exist, and 
the AD is hereby published in the Federal Register as an amendment to 
14 CFR 39.13 to make it effective to all persons.
    We estimate that this AD will affect 65 helicopters of U.S. 
registry. The required actions will take about 6 work hours per 
helicopter, at an average labor rate of $80 per work hour. Required 
parts will cost about $920 per helicopter. Based on these figures we 
estimate the total cost impact of the AD on U.S. operators to be 
$91,000 ($1,400 per helicopter). However, MDHI states in their service 
information that required YSAS adapters will be supplied at no cost and 
labor costs of 5.7 hours will be covered under labor warranty. Assuming 
operators take advantage of these credits, we estimate that this AD 
will have a negligible cost impact on U.S. operators.

Comments Invited

    This AD is a final rule that involves requirements that affect 
flight safety and was not preceded by notice and an opportunity for 
public comment; however, we invite you to submit any written data, 
views, or arguments regarding this AD. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2008-1244; Directorate 
Identifier 2008-SW-59-AD'' at the beginning of your comments. We 
specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of the AD. We will consider all 
comments received by the closing date and may amend the 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 AD. 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 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).

Regulatory Findings

    We have determined that 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.
    For the reasons discussed above, I certify that the 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 an economic evaluation of the estimated costs to comply 
with this AD. See the AD docket to examine the 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.

Adoption of the Amendment

0
Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration 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. Section 39.13 is amended by adding a new airworthiness directive to 
read as follows:

[[Page 72328]]

2008-22-52 MD Helicopters, Inc.: Amendment 39-15752. Docket No. FAA-
2008-1244; Directorate Identifier 2008-SW-59-AD. Supersedes 
Emergency AD 2008-18-52, Directorate Identifier 2008-SW-52-AD.

     Applicability: Model 500N and 600N helicopters, with a Yaw 
Stability Augmentation System (YSAS) adapter tube, part number 
500N7218-1, installed, certificated in any category. Adapter tubes 
that have a production date code stamp are not included in the 
applicability of this AD.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent loss of yaw control and subsequent loss of control of 
the helicopter, do the following:
    (a) Before further flight:
    (1) Turn OFF the YSAS switch.
    (2) Install a placard on the instrument panel as close as 
practicable to the airspeed indicator that states:

    ``YSAS SYSTEM IS OFF. AIRSPEED LIMIT 100 KIAS or VNE, 
WHICHEVER IS LESS.''

    Note: MDHI Service Bulletin SB500N-040R1/SB600N-047R1, dated 
August 27, 2008, and maintenance manual CSP-HMI-3, Section 96-00-00, 
pertain to the subject of this AD.

    (3) Make pen and ink changes or place a copy of this AD in 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.''
    (b) Within 45 days, replace each affected adapter tube with an 
airworthy adapter tube that has a production date code stamp. This 
replacement is terminating action for the requirements of this AD. 
Once this replacement has been done, remove the placards, remove the 
airspeed restriction revisions that were made to the RFM, and return 
the YSAS system to its normal position.
    (c) 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.
    (d) 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.
    (e) This amendment becomes effective on December 15, 2008, to 
all persons except those persons to whom it was made immediately 
effective by Emergency AD 2008-22-52, issued October 23, 2008, which 
contained the requirements of this amendment.

    Issued in Fort Worth, Texas, on November 14, 2008.
Scott A. Horn,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
 [FR Doc. E8-28110 Filed 11-26-08; 8:45 am]

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