Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB-120 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-304-AD]

RIN 2120-AA64

Airworthiness Directives; Empresa Brasileira de Aeronautica S.A.

(EMBRAER) Model EMB-120 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 EMBRAER Model EMB-120 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 May 27, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-114,

Attention: Rules Docket No. 97-NM-30-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, 601 Lind Avenue, SW., Renton, Washington; or at the FAA,

Small Airplane Directorate, Atlanta Aircraft Certification Office, One

Crown Center, 1895 Phoenix Boulevard, suite 450, Atlanta, Georgia.

FOR FURTHER INFORMATION CONTACT: Wayne A. Shade, Aerospace Engineer,

Airframe and Propulsion Branch, ACE-117A , the FAA, Small Airplane

Directorate, Atlanta Aircraft Certification Office, One Crown Center,

1895 Phoenix Boulevard, suite 450, Atlanta, Georgia 30349; telephone

(770) 703-7337; fax (770) 703-6097.

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-304-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-114, Attention: Rules

Docket No. 97-NM-304-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.

Communications 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

This airplane model is manufactured in Brazil and is type

certificated for operation in the United States under the provisions of

Sec. 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 EMBRAER Model EMB-120 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 the protection that

the electro-mechanical gate device provides may inadvertently access

beta in flight. Further, a pilot may deliberately access beta in flight

by using the override feature.

In light of this, the FAA considers that revision of the AFM is

necessary to ensure that pilots are reminded that positioning 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 minimal action necessary 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 EMBRAER Model EMB-120 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 positioning

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.

Interim Action

This is considered interim action until final action is identified,

at which time the FAA may consider further rulemaking.

Cost Impact

The FAA estimates that 235 EMBRAER Model EMB-120 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 $14,100,

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:

Embraer: Docket 97-NM-304-AD.

Applicability: All Model EMB-120 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 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 in

flight is prohibited. Such positioning may result in an engine

overspeed condition with consequent loss of engine and potential

excessive asymmetric propeller drag reducing aircraft

controllability.''

(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, FAA, Small Airplane Directorate,

Atlanta Aircraft Certification Office (ACO). Operators shall submit

their requests through an appropriate FAA Principal Operations

Inspector, who may add comments and then send it to the Manager,

Atlanta ACO.

Note 2: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Atlanta ACO.

(c) Special flight permits may be issued in accordance with

Secs. 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 April 21, 1998.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 98-11101 Filed 4-24-98; 8:45 am]

BILLING CODE 4910-13-U