2036 Federal Register / Vol. 60, No. 4 / Friday, January 6, 1995 / Proposed Rules

Issued in Renton, Washington, on

December 30, 1994.

S.R. Miller,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 95–307 Filed 1–5–95; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 94–NM–28–AD]

Airworthiness Directives; Boeing

Model 767 Series Airplanes Equipped

With General Electric CF6–80C2 Series

Engines

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes the

supersedure of an existing airworthiness

directive (AD), applicable to certain

Boeing Model 767 series airplanes, that

currently requires tests, inspections, and

adjustments of the thrust reverser

system. This action would add

requirements for installation of a

terminating modification on airplanes

equipped with General Electric CF6–

80C2 series engines, and repetitive

operational checks of the electromechanical brake and the cone brake of

the center drive unit following

accomplishment of the modification.

This action also would remove airplanes

equipped with Rolls-Royce RB211–524

series engines from the applicability of

the existing AD. This proposal is

prompted by the identification of a

modification that ensures that the level

of safety inherent in the original type

design of the thrust reverser system is

further enhanced. The actions specified

by the proposed AD are intended to

prevent possible discrepancies that exist

in the current thrust reverser control

system, which could result in an

inadvertent deployment of a thrust

reverser during flight.

DATES: Comments must be received by

March 3, 1995.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 94–NM–

28–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

Boeing Commercial Airplane Group,

P.O. Box 3707, Seattle, Washington

98124–2207. This information may be

examined at the FAA, Transport

Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Lanny Pinkstaff, Aerospace Engineer,

Propulsion Branch, ANM–140S, FAA,

Transport Airplane Directorate, Seattle

Aircraft Certification Office, 1601 Lind

Avenue, SW., Renton, Washington

98055–4056; telephone (206) 227–2684;

fax (206) 227–1181.

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 94–NM–28–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.

94–NM–28–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

On October 7, 1991, the FAA issued

AD 91–22–02, amendment 39–8062 (56

FR 51638, October 15, 1991), applicable

to Boeing Model 767 series airplanes

equipped with Rolls-Royce RB211–524

series engines or General Electric CF6–

80C2 series engines, to require tests,

inspections, and adjustments of the

thrust reverser system. That action was

prompted by an ongoing design review,

resulting from an accident investigation

from which it had been determined that,

prior to the accident, the airplane

apparently experienced an

uncommanded in-flight deployment of a

thrust reverser. Deployment of a thrust

reverser in flight could result in reduced

controllability of the airplane. The

requirements of that AD are intended to

ensure the integrity of the fail-safe

features of the thrust reverser system by

preventing possible discrepancies in the

thrust reverser control system that can

result in the inadvertent deployment of

a thrust reverser during flight.

Since the issuance of AD 91–22–02,

the FAA issued AD 94–17–03,

amendment 39–8998 (59 FR 41647,

August 15, 1994). AD 94–17–03 was

issued to require inspections,

adjustments, and functional checks of

the thrust reverser system; installation

of a terminating modification; and

repetitive operational checks of the

gearbox locks and the air motor brake

following accomplishment of the

terminating modification on Model 767

series airplanes equipped with RollsRoyce RB211–524 series engines. In the

preamble to AD 94–17–03, the FAA

stated it would consider superseding

AD 91–22–02 to remove the

requirements for Model 767 series

airplanes equipped with Rolls-Royce

RB211–524 series engines from that AD,

to specify that those requirements are

contained in AD 94–17–03, and to

require accomplishment of a

terminating modification for Model 767

series airplanes equipped with General

Electric CF6–80C2 series engines. This

action proposes such requirements.

Explanation of Relevant Service

Information

Since the issuance of AD 91–22–02,

the FAA has reviewed and approved

Boeing Service Bulletin 767–78–0047,

Revision 3, dated July 28, 1994. The

original issue of the service bulletin was

cited in AD 91–22–02 as the appropriate

source of service information for

performing various tests, inspections,

and adjustments required by that AD.

Revision 3 of the service bulletin revises

certain procedures specified in the

Accomplishment Instructions of earlier

revisions of the service bulletin. (The

FAA has referenced this latest revision

of the service bulletin as the appropriate

source of service information for

accomplishment of those actions after

the effective date of this proposed AD.)

The FAA also has reviewed and

approved Boeing Service Bulletin 767–

78–0063, Revision 2, dated April 28,
Federal Register / Vol. 60, No. 4 / Friday, January 6, 1995 / Proposed Rules 2037

1994, which describes procedures for

installation of a third locking system on

the thrust reversers on Model 767 series

airplanes equipped with General

Electric CF6–80C2 series engines to

minimize the possibility of an

uncommanded in-flight deployment of

the thrust reversers. This modification

involves the following:

1. installing fuselage-to-wing pressure

seal doublers;

2. routing and installing new ships

wiring;

3. installing the tray assembly and

thrust reverser relay module on the E1–

4 or E2–6 shelf;

4. installing circuit breakers, filler

patches, bus bars, and a relay in the P11

panel;

5. removing, reworking, and installing

the M966 autothrottle microswitch

pack;

6. Installing the left and right thrust

reverser locks with associated wire

bundles on both engines; and

7. Performing a functional test of the

thrust reverser system.

The FAA has determined that

accomplishing this modification in

accordance with the service bulletin

will positively address the identified

unsafe condition with regard to those

airplanes equipped with General

Electric CF6–80C2 series engines.

Explanation of the Proposed

Requirements

Since an unsafe condition has been

identified that is likely to exist or

develop on other products of this same

type design, the proposed AD would

supersede AD 91–22–02 to continue to

require tests, inspections, and

adjustments of the thrust reverser

system on Model 767 series airplanes

equipped with General Electric CF6–

80C2 series engines. This proposed AD

would add a requirement to install the

terminating modification, described

above. The tests, inspections,

adjustments, and terminating

modification would be required to be

accomplished in accordance with the

Boeing service bulletins described

previously.

In addition, the FAA has determined

that operational checks of the electromechanical brake and the cone brake of

the center drive unit are necessary to

provide an adequate level of safety and

to ensure the effectiveness of the

terminating modification following its

installation in addressing the unsafe

condition identified in this proposed

AD. Procedures for accomplishment of

the proposed operational checks are

specified in Appendix 1 (including

Figure 1) of this proposed AD.

Accomplishment of the terminating

modification and operational checks

would constitute terminating action for

the tests, inspections, and adjustments

currently required by AD 91–22–02.

This proposed AD also would remove

airplanes equipped with Rolls-Royce

RB211–524 series engines from the

applicability of AD 91–22–02.

As a result of recent communications

with the Air Transport Association

(ATA) of America, the FAA has learned

that, in general, some operators may

misunderstand the legal effect of AD’s

on airplanes that are identified in the

applicability provision of the AD, but

that have been altered or repaired in the

area addressed by the AD. The FAA

points out that all airplanes identified in

the applicability provision of an AD are

legally subject to the AD. If an airplane

has been altered or repaired in the

affected area in such a way as to affect

compliance with the AD, the owner or

operator is required to obtain FAA

approval for an alternative method of

compliance with the AD, in accordance

with the paragraph of each AD that

provides for such approvals. A note has

been included in this notice to clarify

this requirement.

Cost Impact

There are approximately 135 Boeing

Model 767 series airplanes equipped

with General Electric CF6–80C2 series

engines in the worldwide fleet. The

FAA estimates that 39 airplanes of U.S.

registry would be affected by this

proposed AD.

The tests, inspections, and

adjustments that were previously

required by AD 91–22–02, and retained

in this AD, take approximately 30 work

hours per airplane to accomplish, at an

average labor rate of $60 per work hour.

Based on these figures, the total cost

impact on U.S. operators of the

currently required tests, inspections,

and adjustments that would be retained

in AD is estimated to be $70,200, or

$1,800 per airplane, per inspection

cycle.

The terminating modification

proposed by this AD would take

approximately 786 work hours per

airplane to accomplish, at an average

labor rate of $60 per work hour.

Required parts would be provided by

the manufacturer at no cost to the

operator. The repetitive operational

checks proposed by this AD would take

approximately 2 work hours per

airplane to accomplish at an average

labor rate of $60 per work hour. Based

on these figures, the total cost impact of

the terminating modification and

repetitive operational checks proposed

in this AD on U.S. operators is

estimated to be $1,843,920, or $47,280

per airplane.

The number of required work hours

for each requirement of this proposed

AD, as indicated above, is presented as

if the accomplishment of the actions

were to be conducted as ‘‘stand alone’’

actions. However, in actual practice,

these actions for the most part would be

accomplished coincidentally or in

combination with normally scheduled

airplane inspections and other

maintenance program tasks. Therefore,

the actual number of necessary

additional work hours will be minimal

in many instances. Additionally, any

costs associated with special airplane

scheduling will be minimal.

The FAA recognizes the large number

of work hours required to accomplish

the proposed modification. However,

the 3-year compliance time proposed in

paragraph (c) of this AD should allow

the modification to be accomplished

coincidentally with scheduled major

airplane inspection and maintenance

activities, thereby minimizing the costs

associated with special airplane

scheduling.

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
2038 Federal Register / Vol. 60, No. 4 / Friday, January 6, 1995 / Proposed Rules

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. App. 1354(a), 1421

and 1423; 49 U.S.C. 106(g); and 14 CFR

11.89.

§ 39.13 [Amended]

2. Section 39.13 is amended by

removing amendment 39–8062 (56 FR

51638, October 15, 1991), and by adding

a new airworthiness directive (AD), to

read as follows:

Boeing: Docket 94–NM–28–AD. Supersedes

AD 91–22–02, Amendment 39–8062.

Applicability: Model 767 series airplanes

equipped with General Electric CF6–80C2

series engines, 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 use the authority

provided in paragraph (f) to request approval

from the FAA. This approval may address

either no action, if the current configuration

eliminates the unsafe condition; or different

actions necessary to address the unsafe

condition described in this AD. Such a

request should include an assessment of the

effect of the changed configuration on the

unsafe condition addressed by this AD. In no

case does the presence of any modification,

alteration, or repair remove any airplane from

the applicability of this AD.

Compliance: Required as indicated, unless

accomplished previously.

To ensure the integrity of the fail-safe

features of the thrust reverser system,

accomplish the following:

(a) Within 30 days after October 15, 1991

(the effective date of AD 91–22–02,

amendment 39–8062), perform tests,

inspections, and adjustments of the thrust

reverser system in accordance with Boeing

Service Bulletin 767–78–0047, dated August

22, 1991; Revision 1, dated March 26, 1992;

Revision 2, dated January 21, 1993; or

Revision 3, dated July 28, 1994. After the

effective date of this AD, those actions shall

be accomplished only in accordance with

Revision 3 of the service bulletin.

(1) Except as provided by paragraph (a)(2)

of this AD, repeat all tests and inspections

thereafter at intervals not to exceed 3,000

flight hours until the modification required

by paragraph (c) of this AD is accomplished.

(2) Repeat the check of the grounding wire

for the Directional Pilot Valve (DPV) of the

thrust reverser in accordance with the service

bulletin at intervals not to exceed 1,500 flight

hours, and whenever maintenance action is

taken that would disturb the DPV grounding

circuit, until the modification required by

paragraph (c) of this AD is accomplished.

(b) If any of the tests and/or inspections

required by paragraph (a) of this AD cannot

be successfully performed, or if those tests

and/or inspections result in findings that are

unacceptable in accordance with Boeing

Service Bulletin 767–78–0047, dated August

22, 1991; Revision 1, dated March 26, 1992;

Revision 2, dated January 21, 1993; or

Revision 3, dated July 28, 1994; accomplish

paragraphs (b)(1) and (b)(2) of this AD. After

the effective date of this AD, the actions

required by paragraphs (b)(1) and (b)(2) shall

be accomplished only in accordance with

Revision 3 of the service bulletin.

(1) Prior to further flight, deactivate the

associated thrust reverser in accordance with

Section 78–31–1 of Boeing Document

D630T002, ‘‘Boeing 767 Dispatch Deviation

Guide,’’ Revision 9, dated May 1, 1991; or

Revision 10, dated September 1, 1992. After

the effective date of this AD, this action shall

be accomplished only in accordance with

Revision 10 of the Boeing document. No

more than one reverser on any airplane may

be deactivated under the provisions of this

paragraph.

(2) Within 10 days after deactivation of any

thrust reverser in accordance with this

paragraph, the thrust reverser must be

repaired in accordance with Boeing Service

Bulletin 767–78–0047, dated August 22,

1991; Revision 1, dated March 26, 1992;

Revision 2, dated January 21, 1993; or

Revision 3, dated July 28, 1994. After the

effective date of this AD, the repair shall be

accomplished only in accordance with

Revision 3 of the service bulletin.

Additionally, the tests and/or inspections

required by paragraph (a) of this AD must be

successfully accomplished; once this is

accomplished, the thrust reverser must then

be reactivated.

(c) Within 3 years after the effective date

of this AD, install a third locking system on

the left- and right-hand engine thrust

reversers in accordance with Boeing Service

Bulletin 767–78–0063, Revision 2, dated

April 28, 1994.

Note 2: The Boeing service bulletin

references General Electric Service Bulletin

78–135 as an additional source of service

information for accomplishment of the third

locking system on the thrust reversers.

However, the Boeing service bulletin does

not specify the appropriate revision level for

the General Electric service bulletin. The

appropriate revision level for the General

Electric service bulletin to be used in

conjunction with the Boeing service bulletin

is Revision 3, dated August 2, 1994.

(d) Within 4,000 flight hours after

accomplishing the modification required by

paragraph (c) of this AD, or within 4,000

flight hours after the effective date of this AD,

whichever occurs later; and thereafter at

intervals not to exceed 4,000 flight hours;

perform operational checks of the electromechanical brake and the cone brake of the

center drive unit in accordance with

Appendix 1 (including Figure 1) of this AD.

(e) Accomplishment of the modification

and periodic operational checks required by

paragraphs (c) and (d) of this AD constitutes

terminating action for the tests, inspections,

and adjustments required by paragraph (a) of

this AD.

(f) 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, Seattle

Aircraft Certification Office (ACO), 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, Seattle ACO.

Note 3: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Seattle ACO.

(g) 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.

Appendix—Thrust Reverser ElectroMechanical Brake and CDU Cone Brake Test

1. General

A. This procedure contains steps to do two

checks:

(1) A check of the holding torque of the

electro-mechanical brake

(2) A check of the holding torque of the

CDU cone brake.

2. Electro-Mechanical Brake and CDU Cone

Brake Torque Check (Fig. 1)

A. Prepare to do the checks:

(1) Open the fan cowl panels.

B. Do a check of the torque of the electromechanical brake:

(1) Do a check of the running torque of the

thrust reverser system:

(a) Manually extend the thrust reverser six

inches and measure the running torque.

(1) Make sure the torque is less than 10

pounds-inches.

(2) Do a check of the elctro-mechanical

brake holding torque:

(a) Make sure the thrust reverser translating

cowl is extended at least one inch.

(b) Make sure the CDU lock handle is

released.

(c) Pull down on the manual release handle

on the electro-mechanical brake until the

handle fully engages the retaining clip.

Note: This will lock the electro-mechanical

brake.

(d) With the manual drive lockout cover

removed from the CDU, install a 1/4-inch

extension tool and dial-type torque

wrench into the drive pad.

Note: You will need a 24-inch extension to

provide adequate clearance for the torque

wrench.

(e) Apply 90 pound-inches of torque to the

system.

(1) The electro-mechanical brake system is

working correctly if the torque is reached

before you turn the wrench 450 degrees

(1-1⁄4 turns).

(2) If the flexshaft turns more than 450

degrees before you reach the specified

torque, you must replace the long

flexshaft between the CDU and the upper

angle gearbox.
Federal Register / Vol. 60, No. 4 / Friday, January 6, 1995 / Proposed Rules 2039

(3) If you do not get 90 pound-inches of

torque, you must replace the electromechanical brake.

(f) Release the torque by turning the

wrench in the opposite direction until

you read zero pound-inches.

(1) If the wrench does not return to within

30 degrees of initial starting point, you

must replace the long flexshaft between

the CDU and upper angle gearbox.

(3) Fully retract the thrust reverser.

C. Do a check of the torque of the CDU cone

brake:

(1) Pull up on the manual release handle

to unlock the electro-mechanical brake.

(2) Pull the manual brake release lever on

the CDU to release the cone brake.

Note: This will release the pre-load tension

that may occur during a stow cycle.

(3) Return the manual brake release lever

to the locked position to engage the cone

brake.

(4) Remove the two bolts that hold the

lockout plate to the CDU and remove the

lockout plate.

(5) Install a 1⁄4-inch drive and a dial-type

torque wrench into the CDU drive pad.

CAUTION: DO NOT USE MORE THAN

130 POUND-INCHES OF TORQUE WHEN

YOU DO THIS CHECK. EXCESSIVE

TORQUE WILL DAMAGE THE CDU.

(6) Turn the torque wrench to try to

manually extend the translating cowl

until you get at least 15 pound-inches.

Note: The cone brake prevents movement

in the extend direction only. If you try to

measure the holding torque in the retract

direction, you will get a false reading.

(a) If the torque is less than 15 poundinches, you must replace the CDU.

D. Return the airplane to its usual condition:

(1) Fully retract the thrust reverser.

(2) Pull down on the manual release

handle on the electro-mechanical brake

until the handle fully engages the

retaining clip.

Note: This will lock the electro-mechanical

brake.

(3) Close the fan cowl panels.

BILLING CODE 4910–13–U
2040 Federal Register / Vol. 60, No. 4 / Friday, January 6, 1995 / Proposed Rules

BILLING CODE 4910–13–C
Federal Register / Vol. 60, No. 4 / Friday, January 6, 1995 / Proposed Rules 2041

Issued in Renton, Washington, on

December 30, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 95–306 Filed 1–5–95; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 94–NM–175–AD]

Airworthiness Directives; McDonnell

Douglas Model MD–11 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 McDonnell Douglas MD–11

series airplanes. This proposal would

require the installation of an electrically

controlled slat system. This proposal is

prompted by numerous incidents of

inadvertent deployment of the slats

while the airplane was in flight at cruise

altitude. The actions specified by the

proposed AD are intended to prevent

inadvertent deployment of the slats

during flight, which could result in an

abrupt pitch up of the airplane and

consequent injury to crew and

passengers; it could also result in

significant vibrations and cause damage

to the elevators.

DATES: Comments must be received by

March 3, 1995.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 94–NM–

175–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

McDonnell Douglas Corporation, P.O.

Box 1771, Long Beach, California

90801–1771, Attention: Business Unit

Manager, Technical Administrative

Support, Dept. L51, M.C. 2–98. This

information may be examined at the

FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton,

Washington; or at the FAA, Los Angeles

Aircraft Certification Office, Transport

Airplane Directorate, 3960 Paramount

Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT:

Wahib Mina, Aerospace Engineer,

Airframe Branch, ANM–120L, Los

Angeles Aircraft Certification Office,

FAA, Transport Airplane Directorate,

3960 Paramount Boulevard, Lakewood,

California 90712–4137; telephone (310)

627–5324; fax (310) 627–5210.

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 94–NM–175–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.

94–NM–175–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The FAA previously has issued

several AD’s, applicable to McDonnell

Douglas Model MD–11 series airplanes,

whose requirements have addressed the

problems associated with inadvertent

deployment of the slats during flight:

1. AD 92–13–03, amendment 39–8273

(57 FR 27155, June 18, 1992), requires

either modification or replacement of

the flap control module quadrant. That

action was prompted by an incident in

which a flightcrew member

inadvertently bumped the flap/slat

handle, which then placed the handle in

an improper position that allowed the

slats to extend during cruise.

2. AD 92–14–51, amendment 39–8325

(57 FR 38264, August 24, 1992), requires

a one-time inspection of the slat

mechanical input system for proper

clearance and rigging, and adjustment of

the system, if necessary. That action was

prompted by two incidents in which the

slats extended during flight at cruise

altitude because the rigging of the slat

input system was out of tolerance in

three separate places in the extended

position

3. AD 92–26–03, amendment 39–8430

(57 FR 57906, December 8, 1992),

requires installing a cover on the flap/

slat control module quadrant in the

flight compartment. That action was

prompted by an incident in which a

flightcrew member inadvertently

initiated slat deployment by

unintentionally depressing the zero

degree detent gate while the flap/slat

handle was stowed in the retracted

detent and the handle was not in the

proper position within the detent.

4. AD 93–15–03, amendment 39–8649

(58 FR 41421, August 4, 1993), requires

installing a retainer assembly on the

upper pedestal flap/slat control module

quadrant in the flight compartment.

That action was prompted by several

incidents in which flightcrew members

accidentally bumped the flap/slat

handle and the slats deployed during

cruise.

Deployment of the slats during flight

at cruise altitude could result in abrupt

pitch up of the airplane and consequent

injury to crew and passengers; it could

also create significant vibrations and

cause damage to the elevators.

In the preambles to those AD’s, the

FAA stated that the requirements of

each of the AD’s were considered to be

interim action until final action was

identified. The manufacturer had

undertaken a design review of the flap/

slat system of the Model MD–11 in an

effort to positively address the problems

associated with it, and the FAA

indicated that it would consider further

rulemaking once that design review was

completed.

The manufacturer’s design review has

now been completed and the

manufacturer has developed an

electrically controlled slat system.

Installation of this new system will

reduce the possibility of uncommanded

operation of the slats and inadvertent

displacement of the flap/slat handle.

The FAA has determined that the

system positively addresses the unsafe

condition addressed in the previouslyissued AD’s. In light of this, the FAA

has determined that further rulemaking

action is indeed necessary, and this