[Federal Register Volume 72, Number 220 (Thursday, November 15, 2007)]
[Proposed Rules]
[Pages 64172-64173]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-22330]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-0157; Directorate Identifier 2001-NE-23-AD]
RIN 2120-AA64


Airworthiness Directives; Turbomeca Makila 1 A and 1 A1 
Turboshaft Engines

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede an existing airworthiness 
directive (AD) for Turbomeca Makila 1 A, 1 A1, and 1 A2 turboshaft 
engines. That AD currently requires replacing certain digital 
electronic control units (DECUs) and electronic control units (ECUs) 
with modified DECUs and ECUs. This proposed AD would apply only to 
Makila 1 A and 1 A1 turboshaft engines, and would require replacing the 
selector-comparator board in the ECU with a board incorporating 
Turbomeca modification TU 250. This proposed AD results from recent 
unexplained reversions of the ECU to the 65% N1 back-up mode. We are 
proposing this AD to prevent dual-engine reversion of the ECU to the 
65% N1 back-up mode, which could lead to inability to continue safe 
flight, emergency autorotation landing, or an accident.

DATES: We must receive any comments on this proposed AD by January 14, 
2008.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD.
     Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 1200 New Jersey Avenue, SE., West Building Ground 
Floor, Room W12-140, Washington, DC 20590-0001.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
     Fax: (202) 493-2251.
    Contact Turbomeca, 40220 Tarnos, France; telephone (33) 05 59 74 40 
00; fax (33) 05 59 74 45 15 for the service information identified in 
this proposed AD.

FOR FURTHER INFORMATION CONTACT: Christopher Spinney, Aerospace 
Engineer, Engine Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803; e-
mail: [email protected]; telephone (781) 238-7175; fax (781) 
238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send us any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2007-0157; Directorate 
Identifier 2001-NE-23-AD'' in the subject line 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 AD. Using the search 
function of the Web site, anyone can find and read the comments in any 
of our dockets, including, if provided, the name of the individual who 
sent the comment (or signed the comment on behalf of an association, 
business, labor union, etc.). 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 AD Docket

    You may examine the AD docket 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 AD docket contains this proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Operations office (telephone (800) 647-5527) is 
the same as the Mail address provided in the ADDRESSES section. 
Comments will be available in the AD docket shortly after receipt.

Discussion

    On July 23, 2002, we issued AD 2002-15-05, Amendment 39-12833 (67 
FR 49859, August 1, 2002). That AD requires replacing certain DECUs and 
ECUs with modified DECUs and ECUs, on Turbomeca Makila 1 A, 1 A1, and 1 
A2 turboshaft engines. The Direction Generale De L'Aviation Civile, 
which is the airworthiness authority for France, advised that 
incorporating Turbomeca Modification TU 203 to the ECUs that are used 
on the Makila 1 A and 1 A1 turboshaft engines, and incorporating 
Turbomeca Modification TU 205C to the DECUs used on the Makila 1 A2 
turboshaft engines, improves failure detection of the ECU and simulates 
a fixed power turbine speed (Npt) if two of the three channels fail.

Actions Since AD 2002-15-05 Was Issued

    Since AD 2002-15-05 was issued, The European Aviation Safety Agency 
(EASA), which is the Technical Agent for the Member States of the 
European Community, notified us that an unsafe condition may exist on 
Turbomeca Makila 1 A and 1 A1 turboshaft engines. EASA advises that 
recent unexplained reversions of the ECU to the 65% N1 back-up mode 
have occurred on these engines. Turbomeca postulates that these events 
can be caused by corruption of the engine N2 speed signals by short 
disturbances, such as electromagnetic interference, which can threaten 
both engines at the same time. The replacement of the selector-
comparator board will allow recovery from the ECU 65% N1 back-up mode 
for temporary interruptions of the N2 signal.

Relevant Service Information

    We have reviewed and approved the technical contents of Turbomeca 
Mandatory Service Bulletin (MSB) No. 298 73 0250, dated March 23, 2007, 
that describes procedures for replacing the selector-comparator board 
in the ECU with a board incorporating Turbomeca modification TU 250. 
The replacement board makes the ECU less sensitive to electromagnetic 
interference. EASA classified this service bulletin as mandatory and 
issued AD 2007-0144,

[[Page 64173]]

dated May 18, 2007, in order to ensure the airworthiness of these 
Makila 1 A and 1 A1 turboshaft engines in Europe.

Makila 1 A2 Turboshaft Engines Excluded From This Proposed AD

    Although Makila 1 A2 turboshaft engines, which were also listed in 
the previous AD, are affected by this unsafe condition, they are 
addressed by a different EASA AD. We will address those engines in 
another proposed AD.

Bilateral Agreement Information

    These Makila 1 A and 1 A1 turboshaft engines are manufactured in 
France and are type certificated for operation in the United States 
under the provisions of Section 21.29 of the Federal Aviation 
Regulations (14 CFR 21.29) and the applicable bilateral airworthiness 
agreement. Under this bilateral airworthiness agreement, EASA kept us 
informed of the situation described above. We have examined the 
findings of EASA, reviewed all available information, and determined 
that AD action is necessary for products of this type design that are 
certificated for operation in the United States.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other products 
of this same type design. We are proposing this AD, which would require 
replacing the selector-comparator board in the ECU with a board 
incorporating Turbomeca Modification TU 250.

Costs of Compliance

    We estimate that this proposed AD would affect 10 Makila 1 A and 1 
A1 turboshaft engines installed on helicopters of U.S. registry. We 
also estimate that it would take about 1 work-hour per engine to 
perform the proposed actions, and that the average labor rate is $80 
per work-hour. Required parts would cost about $3,500 per engine. Based 
on these figures, we estimate the total cost of the proposed AD to U.S. 
operators to be $35,800.

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.

Docket Number Change

    We are transferring the docket for this AD to the Federal Docket 
Management System as part of our on-going docket management 
consolidation efforts. The new Docket No. is FAA-2007-0157. The old 
Docket No. became the Directorate Identifier, which is 2001-NE-23-AD.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. 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 AD:
    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. Would 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 regulatory evaluation of the estimated costs to 
comply with this proposed AD. See the ADDRESSES section for a location 
to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 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.


Sec.  39.13  [Amended]

    2. The FAA amends Sec.  39.13 by removing Amendment 39-12833 (67 FR 
49859, August 1, 2002) and by adding a new airworthiness directive, to 
read as follows:

Turbomeca: Docket No. FAA-2007-0157; Directorate Identifier 2001-NE-
23-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by January 14, 
2008.

Affected ADs

    (b) This AD supersedes AD 2002-15-05, Amendment 39-12833.

Applicability

    (c) This AD applies to Turbomeca Makila 1 A and 1 A1 turboshaft 
engines. These engines are installed on, but not limited to, 
Eurocopter France model AS 332C, AS 332L, and AS 332L1 helicopters.

Unsafe Condition

    (d) This AD results from recent unexplained reversions of the 
ECU to the 65% N1 back-up mode. The actions specified in this AD are 
intended to prevent dual-engine reversion of the ECU to the 65% N1 
back-up mode, which could lead to inability to continue safe flight, 
emergency autorotation landing, or an accident.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed before June 30, 2008, unless the actions have already 
been done.
    (f) Replace the Selector-Comparator board in the ECU with a 
board incorporating Turbomeca Modification TU 250. Information on 
Modification TU 250 can be found in Turbomeca Mandatory Service 
Bulletin No. 298 73 0250, dated March 23, 2007.

Alternative Methods of Compliance

    (g) The Manager, Engine Certification Office, FAA, has the 
authority to approve alternative methods of compliance for this AD 
if requested using the procedures found in 14 CFR 39.19.

Related Information

    (h) European Aviation Safety Agency AD 2007-0144, dated May 18, 
2007, also addresses the subject of this AD.
    (i) Contact Christopher Spinney, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
[email protected]; telephone (781) 238-7175; fax (781) 
238-7199, for more information about this AD.

    Issued in Burlington, Massachusetts, on November 8, 2007.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E7-22330 Filed 11-14-07; 8:45 am]
BILLING CODE 4910-13-P