[Federal Register Volume 62, Number 236 (Tuesday, December 9, 1997)]
[Proposed Rules]
[Pages 64787-64789]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-32120]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-228-AD]
RIN 2120-AA64


Airworthiness Directives; Aerospatiale Model ATR-42 and ATR-72 
Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to all Aerospatiale Model ATR-42 and 
ATR-72 series airplanes. This proposal would require revising the 
Airplane Flight Manual (AFM) to modify the limitation that prohibits 
positioning the power levers below the flight idle stop during flight, 
and to provide a statement of the consequences of positioning the power 
levers below the flight idle stop during flight. This proposal is 
prompted by incidents and accidents involving airplanes equipped with 
turboprop engines in which the ground propeller beta range was used 
improperly during flight. The actions specified by the proposed AD are 
intended to prevent loss of airplane controllability, or engine 
overspeed and consequent loss of engine power caused by the power 
levers being positioned below the flight idle stop while the airplane 
is in flight.

DATES: Comments must be received by January 8, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-228-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Mark Quam, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone (425) 
227-2145; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 97-NM-228-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules 
Docket No. 97-NM-228-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    In recent years, the FAA has received reports of 14 incidents and/
or accidents involving intentional or inadvertent operation of the 
propellers in the ground beta range during flight on airplanes equipped 
with turboprop engines. (For the purposes of this proposal, beta is 
defined as the range of propeller operation intended for use during 
taxi, ground idle, or reverse operations as controlled by the power 
lever settings aft of the flight idle stop.)

[[Page 64788]]

    Five of the fourteen in-flight beta occurrences were classified as 
accidents. In each of these five cases, operation of the propellers in 
the beta range occurred during flight. Operation of the propellers in 
the beta range during flight, if not prevented, could result in loss of 
airplane controllability, or engine overspeed with consequent loss of 
engine power.
    Communication between the FAA and the public during a meeting held 
on June 11-12, 1996, in Seattle, Washington, revealed a lack of 
consistency of the information on in-flight beta operation contained in 
the FAA-approved Airplane Flight Manual (AFM) for airplanes that are 
not certificated for in-flight operation with the power levers below 
the flight idle stop. (Airplanes that are certificated for this type of 
operation are not affected by the above-referenced conditions.)

U.S. Type Certification of the Airplane

    These airplane models 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 and the applicable 
bilateral airworthiness agreement. The FAA has reviewed all available 
information, and determined that AD action is necessary for products of 
these type designs that are certificated for operation in the United 
States.

FAA's Determinations

    The FAA has examined the circumstances and reviewed all available 
information related to the incidents and accidents described 
previously. The FAA finds that the Limitations Section of the AFM's for 
certain airplanes must be revised to prohibit positioning the power 
levers below the flight idle stop while the airplane is in flight, and 
to provide a statement of the consequences of positioning the power 
levers below the flight idle stop. The FAA has determined that the 
affected airplanes include those that are equipped with turboprop 
engines and that are not certificated for in-flight operation with the 
power levers below the flight idle stop.
    The FAA notes that both Model ATR-42 and ATR-72 series airplanes 
are equipped with an electro-mechanical gate device that is designed to 
protect against the positioning of power levers below the flight idle 
stop in flight. The gate device has an override feature that allows 
access to beta during a landing roll, in the event of certain system 
failures. If a certain type of failure occurs, access to beta is 
available in flight. A pilot who is accustomed to protection that the 
electro-mechanical gate device provides may inadvertently access beta 
in flight. Further, a pilot may deliberately access beta in flight 
using the override feature.
    In light of this, the FAA considers that the revision of the AFM is 
necessary to ensure that pilots are reminded that positioning of power 
levers below the flight idle stop while the airplane is in flight is 
prohibited, even though an electro-mechanical gate device is installed. 
The FAA further considers this to be a minimum action to ensure that 
pilots do not carry over certain flight habits from an airplane design 
that mitigates the effects of beta in flight to an airplane design that 
does not.

Explanation of the Requirements of the Proposed AD

    Since an unsafe condition has been identified that is likely to 
exist or develop on Model ATR-42 and ATR-72 series airplanes of the 
same type design, the proposed AD would require revising the 
Limitations Section of the AFM to modify the limitation that prohibits 
the positioning of the power levers below the flight idle stop while 
the airplane is in flight, and to add a statement of the consequences 
of positioning the power levers below the flight idle stop while the 
airplane is in flight.

Cost Impact

    The FAA estimates that 144 Aerospatiale Model ATR-42 and ATR-72 
series airplanes of U.S. registry would be affected by this proposed 
AD, that it would take approximately 1 work hour per airplane to 
accomplish the proposed actions, and that the average labor rate is $60 
per work hour. Based on these figures, the cost impact of the proposed 
AD on U.S. operators is estimated to be $8,640, or $60 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed requirements of 
this AD action, and that no operator would accomplish those actions in 
the future if this AD were not adopted.

Regulatory Impact

    The regulations proposed herein would not have substantial direct 
effects 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. Therefore, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this 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) if promulgated, 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. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Aerospatiale: Docket 97-NM-228-AD.

    Applicability: All Model ATR-42 and ATR-72 series airplanes, 
certificated in any category.
    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (b) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent loss of airplane controllability, or engine overspeed 
and consequent loss of engine power caused by the power levers being 
positioned below the flight idle stop

[[Page 64789]]

while the airplane is in flight, accomplish the following:
    (a) Within 30 days after the effective date of this AD, revise 
the Limitations Section of the FAA-approved Airplane Flight Manual 
(AFM) to include the following statements. This action may be 
accomplished by inserting a copy of this AD into the AFM.
    ``Positioning of power levers below the flight idle stop while 
the airplane is in flight is prohibited. Such positioning may lead 
to loss of airplane control or may result in an overspeed condition 
and consequent loss of engine power.''
    (b) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Standardization Branch, ANM-113, 
FAA, Transport Airplane Directorate. Operators shall submit their 
requests through an appropriate FAA Principal Maintenance Inspector, 
who may add comments and then send it to the Manager, 
Standardization Branch, ANM-113.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (c) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.

    Issued in Renton, Washington, on December 2, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-32120 Filed 12-8-97; 8:45 am]
BILLING CODE 4910-13-U