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

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.

ration (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

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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.)

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

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

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

s 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

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

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.''

e 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