63288 Federal Register / Vol. 62, No. 229 / Friday, November 28, 1997 / Proposed Rules

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the International Branch,

ANM–116.

(d) 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.

Note 3: The subject of this AD is addressed

in German airworthiness directive 96–320,

dated November 7, 1996.

Issued in Renton, Washington, on

November 20, 1997.

Stewart R. Miller,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–31157 Filed 11–26–97; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97–NM–231–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).

SUMMARY: This document proposes the

adoption of a new airworthiness

directive (AD) that is applicable to

certain EMBRAER Model EMB–120

series airplanes. This proposal would

require deactivation of certain circuit

breakers, and a revision to the Airplane

Flight Manual (AFM) to provide

operational procedures to prevent loss

of electrical power following an engine

flameout. This proposal also would

require modifications of the electrical

system, which would terminate the

requirement for the AFM revision and

allow reactivation of the circuit

breakers. This proposal is prompted by

the issuance of mandatory continued

airworthiness information by a foreign

civil airworthiness authority. The

actions specified by the proposed AD

are intended to prevent generator

overload conditions that could result in

loss of electrical power and failure of

certain flight and landing control

systems, and to prevent power

interruption to the attitude heading

reference system (AHRS) that could

result in the display of erroneous

heading information.

DATES: Comments must be received by

December 29, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 97–NM–

231–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.

The service information referenced in

the proposed rule may be obtained from

Empresa Brasileira de Aeronautica S/A,

Sao Jose dos Campos, Brazil. This

information may be examined at the

FAA, Transport Airplane Directorate,

1601 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: John

W. McGraw, Aerospace Engineer,

Systems and Flight Test Branch, ACE–

116A, FAA, Atlanta Aircraft

Certification Office, One Crown Center,

1895 Phoenix Boulevard, suite 450,

Atlanta, Georgia 30349; telephone (770)

703–6098; 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–231–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–231–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The Departamento de Aviacao Civil

(DAC), which is the airworthiness

authority for Brazil, notified the FAA

that an unsafe condition may exist on

certain EMBRAER Model EMB–120

series airplanes. The DAC advises that

it received a report of one instance of

substantial electrical power loss after

flameout of the number 1 engine. The

power loss was caused by activation of

the system overload protection due to

excessive loads on the remaining

number 2 engine generator, which led to

loss of certain flight and landing control

systems. The DAC also advises that, due

to power interruption for a few

milliseconds to the attitude heading

reference system (AHRS), erroneous

heading information in both electronic

horizontal situation indicators (EHSI)

may be provided, without warning to

the pilots, during an electrical

emergency or when the electrical

emergency switch is set to the

‘‘EMERGENCY’’ position. This

condition, if not corrected, could result

in generator overload conditions that

could result in loss of electrical power

and failure of certain flight and landing

control systems, and power interruption

to the AHRS that could result in display

of erroneous heading information.

Explanation of Relevant Service

Information

EMBRAER has issued Service Bulletin

120–24–0008, Change 04, dated October

3, 1995, which describes procedures for

modification of the electrical system.

This modification involves revising

the electrical connections and wiring in

the relay boxes and circuit breaker

panels.

EMBRAER has also issued Service

Bulletin 120–24–0051, Change 04, dated

March 8, 1995, which also describes

procedures for modification of the

electrical system. This modification

involves electrical load redistribution

and introduction of a contactor to

connect a direct current (DC) bus to the

emergency bus.

Accomplishment of the actions

specified in these service bulletins is
Federal Register / Vol. 62, No. 229 / Friday, November 28, 1997 / Proposed Rules 63289

intended to adequately address the

identified unsafe condition.

The DAC classified these service

bulletins as mandatory and issued

Brazilian airworthiness directives (DAE)

93–24–01, dated December 31, 1993;

94–03–01R1, dated December 10, 1994,

and 93–12–01R1, dated December 12,

1994, in order to assure the continued

airworthiness of these airplanes in

Brazil.

FAA’s Conclusions

This airplane model is manufactured

in Brazil and is 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. Pursuant to

this bilateral airworthiness agreement,

the DAC has kept the FAA informed of

the situation described above. The FAA

has examined the findings of the DAC,

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.

Explanation of Requirements of

Proposed Rule

Since an unsafe condition has been

identified that is likely to exist or

develop on other airplanes of the same

type design registered in the United

States, the proposed AD would require

accomplishment of the actions specified

in the service bulletins described

previously.

The proposed AD also would require

a revision to the FAA-approved

Airplane Flight Manual (AFM) to

provide operational procedures in the

event of loss of electrical power

following an engine flameout.

Differences Between the Proposal and

Related Brazilian AD

This proposed AD differs from the

parallel Brazilian airworthiness

directives in the following four respects:

1. It would not require (as DAE 93–

24–01 and DAE 93–12–01R1 require)

that the electrical emergency switch be

set to the ‘‘EMERGENCY’’ position prior

to takeoff for operations without

auxiliary power units (APU); rather, it

would require electrical loads to be

reduced to below 400 amps. The FAA

has determined that reduction of loads

to below 400 amps prevents the unsafe

generator overload condition.

2. It would require that the APU be

operational for all flights into known or

forecast icing conditions and during

takeoff and landing. DAE 93–12–01R1

makes no limitation with respect to

such icing conditions. The FAA has

determined that the APU must be

operational for flights into known or

forecast icing conditions to ensure

adequate electrical power for systems

that are necessary for operation in such

conditions.

3. It would extend the proposed

compliance time for accomplishment of

the modifications beyond that specified

by DAE 93–12–01R1 and DAE 94–03–

01R1. The FAA has determined that the

compliance time specified in this

proposed AD would allow the

modifications to be accomplished

during regularly scheduled

maintenance.

4. It would not require the

accomplishment of PART C of DAE 94–

03–01R1, which requires revision of

Section 4 (‘‘Normal Procedures’’) of the

AFM. The FAA has determined that Part

C has been incorporated by a previously

approved change to the AFM and need

not be mandated.

Cost Impact

The FAA estimates that 227 airplanes

of U.S. registry would be affected by this

proposed AD.

It would take approximately 1 work

hour per airplane to accomplish the

proposed AFM revisions, at an average

labor rate of $60 per work hour. Based

on these figures, the cost impact of the

AFM revisions proposed by this AD on

U.S. operators is estimated to be

$13,620, or $60 per airplane.

It would take approximately 90 work

hours per airplane to accomplish the

proposed modifications at an average

labor rate of $60 per work hour.

Required parts would cost

approximately $4,150 per airplane.

Based on these figures, the cost impact

of the modifications proposed by this

AD on U.S. operators is estimated to be

$2,167,850, or $9,550 per airplane.

The cost impact figures discussed

above are 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. However, the

FAA has been advised that 43 U.S.-

registered airplanes are in compliance

in accordance with the requirements of

this proposed AD. Therefore, the future

economic cost impact of this rule on

U.S. operators is now $11,040 for

accomplishment of the AFM revisions,

and $1,757,200 for accomplishment of

the modifications.

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.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

Empresa Brasileira de Aeronautica, S.A.

(EMBRAER): Docket 97–NM–231–AD.

Applicability: Model EMB–120, EMB–

120RT, and EMB–120ER series airplanes; up

to and including serial number 120291;

certificated in any category.

Note 1: This AD applies to each airplane

identified in the preceding applicability

provision, regardless of whether it has been

otherwise 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 (d) 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
63290 Federal Register / Vol. 62, No. 229 / Friday, November 28, 1997 / Proposed Rules

been eliminated, the request should include

specific proposed actions to address it.

Compliance: Required as indicated, unless

accomplished previously.

To prevent generator overload conditions

that could result in loss of electrical power

and failure of certain flight and landing

control systems, and to prevent power

interruption to the attitude heading reference

system (AHRS) that could result in the

display of erroneous heading information,

accomplish the following:

(a) For airplanes not equipped with an

auxiliary power unit (APU); except serial

numbers 120004, 120006 through 120024

inclusive, 120026 through 120030 inclusive,

120033 through 120035 inclusive, 120037,

and 120040; on which Part I, II, or III of

EMBRAER Service Bulletin 120–24–0008,

Change 03, dated August 19, 1994, or Change

04, dated October 3, 1995, has not been

accomplished: Within 3 days after the

effective date of this AD, accomplish

paragraphs (a)(1), (a)(2), and (a)(3) of this AD.

(1) Trip (pull open) circuit breakers (CB)

534 (auxiliary generator 2 bus control) and

CB 535 (auxiliary generator 1 bus control)

located in the right-hand direct current (DC)

relay box and left-hand DC relay box,

respectively.

(2) Install circuit breaker collars to prevent

the circuit breakers from closing.

(3) Install, near CB 534 and CB 535, a

placard or tag with the following wording:

‘‘Do not close CB 534 or CB 535.’’

(b) For all airplanes: Within 30 days after

the effective date of this AD, accomplish

paragraphs (b)(1), (b)(2), and (b)(3) of this AD.

(1) Revise the Abnormal Procedures

section of the FAA-approved Airplanese Gen

Flight Manual (AFM) to include the

following. This may be accomplished by

inserting a copy of this AD into the AFM.

‘‘Section III—Abnormal Procedures:

Engine Failure

One Engine Inoperative Approach and

Landing

If auxiliary power unit (APU) is not

available

Electrical Load—Reduce to Below 400 Amps

At least the following systems should be

turned off: windshield heating, propeller deice, gasper fans, recirculation fans, logotype

lights, and taxi lights.

Caution

Should an unexpected electrical power

loss occur during a rejected takeoff or landing

run, remember:

—Emergency brake will be available

—Below 45 knots (KT), turn anti-skid off to

recover one normal brake pair (inboard or

outboard).

Electrical Failure

Short Circuit in the Relay Box Direct Current

(DC) Bus 1

—Gen 1 off Bus, Bus 1 off. Emerg Bus off,

Central Bus off, Batt off Bus and inverter

2 INOP lights illuminated on the electrical

panel.

Note: In some cases, the Central Bus off

light may not illuminate.

—ELEC light illuminated on the multiple

alarm panel.

—CAUTION light flashing.

Caution: Do not try to Reset the Electrical

System.

Electrical Emergency Switch—Emerg

Altitude—At or Below 25,000 FT

Airplane is limited to 25,000 ft since the

left engine bleed is closed due to loss of the

electrical power.

The engines or APU airstart and electrical

crossfeed are not possible.

The equipment connected to the relay box

DC BUS 1, DC BUS 1, radio master DC buses

1B and 1C are out. Land as soon as practical.

Note:

• For airplanes Pre-Mod SB 120–24–0008,

the AHRS 1 and the equipment connected to

the radio master DC BUS 1A are out too.

• For airplanes Post-Mod SB 120–33–0033

or S/N 120.273 and on:

—The emergency lights will be automatically

turned on when the electrical system is in

emergency operating mode.

—The emergency lights must be turned off,

in order to save the emergency light

batteries.

—The emergency lights must be turned on

during approach or when necessary.’’

(2) Revise the Normal Procedures section

of the FAA-approved AFM to include the

following. This may be accomplished by

inserting a copy of this AD into the AFM.

‘‘Section IV—Normal Procedures: Before

Takeoff

If APU is available:

APU Generator ............................................ON

Takeoff must be carried out with APU

generator connected to the central DC bus,

thus providing another source to avoid

overload should one engine flame out.

If APU is not available:

Electrical Load.....Reduce to Below 400 Amps

At least the following systems should be

turned off: windshield heating, propeller deice, gasper fans, recirculation fans, logotype

lights, and taxi lights.

After Takeoff

If APU is available:

APU...............................................As Required

If APU is not available:

Electrical load—RESTORE

Windshield heating—AS REQUIRED

Emergency lights switch—OFF, then

ARM

Approach

If APU is available:

APU Generator ............................................ON

Approach and landing must be carried out

with APU generator connected to the central

DC bus.

Before Landing

If APU is not available:

Electrical Load.....Reduce to Below 400 Amps

At least the following systems should be

turned off: windshield heating, propeller deice, gasper fans, recirculation fans, logotype

lights, and taxi lights.

Caution:

Do not set electrical emergency switch to

emergency position during approach or

landing.’’

(3) Revise the Limitations section (Section

II) of the FAA-approved AFM to include the

following. This may be accomplished by

inserting a copy of this AD into the AFM.

‘‘Both starter/generators must operate

normally prior to flight. The APU generator

must operate normally prior to flight in

known or forecast icing conditions. [Note:

This supersedes any relief provided by the

Master Minimum Equipment List (MMEL).]’’

(c) Within 12 months after the effective

date of this AD, accomplish paragraph (c)(1)

and (c)(2) of this AD, as applicable.

(1) For all airplanes except serial numbers

120004, 120006 through 120024 inclusive,

120026 through 120030 inclusive, 120033

through 120035 inclusive, 120037, and

120040; on which Part I, II, or III of

EMBRAER Service Bulletin 120–24–0008,

Change 03, dated August 19, 1994, or Change

04, dated October 3, 1995; has not been

accomplished: Modify the electrical system

in accordance with Part IV of EMBRAER

Service Bulletin 120–24–0008, Change 04,

dated October 3, 1995. After this

modification is accomplished, the

modification required by paragraph (a) of this

AD may be removed and the affected circuit

breakers reactivated.

(2) For all airplanes: Modify the electrical

system in accordance with EMBRAER

Service Bulletin 120–24–0051, Change 04,

dated March 8, 1995. After this modification

is accomplished, the AFM revisions required

by paragraph (b) of this AD may be removed

from the AFM.

(d) 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, Atlanta

Aircraft Certification Office (ACO), FAA,

Small 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, 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.

(e) 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.

Note 3: The subject of this AD is addressed

in Brazilian airworthiness directives 93–24–

01, dated December 31, 1993; 94–03–01R1,

dated December 10, 1994; and 93–12–01R1,

dated December 12, 1994.

Issued in Renton, Washington, on

November 20, 1997.

Stewart R. Miller,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–31156 Filed 11–26–97; 8:45 am]

BILLING CODE 4910–13–U