This section of the FEDERAL REGISTER

contains regulatory documents having general

applicability and legal effect, most of which

are keyed to and codified in the Code of

Federal Regulations, which is published under

50 titles pursuant to 44 U.S.C. 1510.

The Code of Federal Regulations is sold by

the Superintendent of Documents. Prices of

new books are listed in the first FEDERAL

REGISTER issue of each week.

Rules and Regulations Federal Register

1051

Vol. 65, No. 5

Friday, January 7, 2000

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99–NM–361–AD; Amendment

39–11502; AD 2000–01–05]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 747 Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule; request for

comments.

SUMMARY: This amendment supersedes

an existing airworthiness directive (AD)

applicable to certain Boeing Model 747

series airplanes. That AD currently

requires repetitive inspections and tests

of the thrust reverser control and

indication system on each engine, and

corrective actions, if necessary;

installation of a terminating

modification; and repetitive operational

checks of that installation, and repair, if

necessary. This amendment is prompted

by the results of a safety review, which

revealed that in-flight deployment of a

thrust reverser could result in

significant reduction in airplane

controllability. The actions specified in

this AD are intended to ensure the

integrity of the fail-safe features of the

thrust reverser system by preventing

possible failure modes, which could

result in inadvertent deployment of a

thrust reverser during flight, and

consequent reduced controllability of

the airplane. This action identifies

certain repetitive operational checks

that were inadvertently omitted from

the existing AD, and revises certain

procedures for accomplishment of the

operational checks and certain followon corrective actions.

DATES: Effective January 24, 2000.

The incorporation by reference of

certain publications as listed in the

regulations was approved previously by

the Director of the Federal Register as of

September 15, 1999 (64 FR 47365,

August 31, 1999).

Comments for inclusion in the Rules

Docket must be received on or before

March 7, 2000.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 99–NM–

361–AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055–4056.

The service information referenced in

this AD 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; or at the Office of

the Federal Register, 800 North Capitol

Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Ed

Hormel, Aerospace Engineer,

Propulsion Branch, ANM–140S, FAA,

Transport Airplane Directorate, Seattle

Aircraft Certification Office, 1601 Lind

Avenue, SW., Renton, Washington

98055–4056; telephone (206) 227–2681;

fax (206) 227–1181.

SUPPLEMENTARY INFORMATION: On August

19, 1999, the FAA issued AD 99–18–03,

amendment 39–11269 (64 FR 47365,

August 31, 1999), applicable to certain

Boeing Model 747 series airplanes. That

AD requires repetitive inspections and

tests of the thrust reverser control and

indication system on each engine, and

corrective actions, if necessary;

installation of a terminating

modification; and repetitive operational

checks of that installation, and repair, if

necessary. That AD was prompted by

the results of a safety review, which

revealed that in-flight deployment of a

thrust reverser could result in

significant reduction in airplane

controllability. The actions required by

that AD are intended to ensure the

integrity of the fail-safe features of the

thrust reverser system by preventing

possible failure modes, which could

result in inadvertent deployment of a

thrust reverser during flight, and

consequent reduced controllability of

the airplane.

Actions Since Issuance of Previous Rule

Since the issuance of AD 99–18–03,

the FAA finds that it inadvertently

omitted reference to the

accomplishment of repetitive

operational checks; however, the

Summary and Explanation of

Requirements of the Rule sections both

specified accomplishment of the

repetitive operational checks. The

FAA’s intent in paragraph (d) of that AD

was to require operators to perform

repetitive operational checks at intervals

not to exceed 3,000 flight hours

following accomplishment of the initial

operational check. Paragraph (d) of this

AD has been revised accordingly.

The FAA also has determined that the

procedures in the Airplane Maintenance

Manual (AMM) are inadequately

defined to allow for accomplishment of

the operational checks; therefore, the

procedures are included in an appendix

to this AD. Accordingly, this action

revises paragraphs (d) and (e) of that AD

to remove all references to the AMM for

accomplishment of the operational

checks, and replace those references

with references to Appendix 1

(including Figure 1) of this AD, which

describes the Gearbox Lock and Air

Motor Brake Test procedures required

for accomplishment of the operational

checks.

In addition, all references to the

procedures specified in the Master

Minimum Equipment List and the

Dispatch Deviation Guide in paragraphs

(b) and (e) of the existing AD have been

removed because the FAA is unable to

determine that an airplane is safe for

operation if the thrust reverser

functional tests are not successfully

passed, or if the tests are unable to be

performed. These procedures are

retracted by the FAA because failure of

the functional test might indicate that a

fault or faults are present, which could

lead to an uncommanded deployment of

a thrust reverser during flight.

Explanation of Requirements of Rule

Since an unsafe condition has been

identified that is likely to exist or

develop on other airplanes of this same

type design, this AD supersedes AD 99–

18–03 to continue to require repetitive

inspections and tests of the thrust

reverser control and indication system

on each engine, and corrective actions,

if necessary; installation of a

terminating modification; and repetitive

operational checks of that installation,

and repair, if necessary. The actions are

required to be accomplished in

1052 Federal Register / Vol. 65, No. 5 / Friday, January 7, 2000 / Rules and Regulations

accordance with the service bulletins

described previously, except as

discussed below.

Repetitive operational checks to

detect discrepancies of the gearbox

locks and the air motor brake are

required to be accomplished in

accordance with the procedure included

in Appendix 1 (including Figure 1) of

this AD. Correction of any discrepancy

detected is required to be accomplished

in accordance with the procedures

described in the Boeing 747 Airplane

Maintenance Manual.

Cost Impact

None of the Model 747 series

airplanes affected by this action are on

the U.S. Register. All airplanes included

in the applicability of this rule currently

are operated by non-U.S. operators

under foreign registry; therefore, they

are not directly affected by this AD

action. However, the FAA considers that

this rule is necessary to ensure that the

unsafe condition is addressed in the

event that any of these subject airplanes

are imported and placed on the U.S.

Register in the future.

Should an affected airplane be

imported and placed on the U.S.

Register in the future:

It would require approximately 24

work hours (6 work hours per engine) to

accomplish the required inspections

and tests, at an average labor rate of $60

per work hour. Based on these figures,

the cost impact of the inspections and

tests required by this AD would be

approximately $1,440 per airplane, per

inspection/test cycle.

It would require approximately 392

work hours to accomplish the required

installation of provisional wiring, at an

average labor rate of $60 per work hour.

Required parts would cost

approximately $22,298 per airplane.

Based on these figures, the cost impact

of this modification required by this AD

would be approximately $45,818 per

airplane.

It would require approximately 306

work hours to accomplish the required

installation of the locking gearbox, at an

average labor rate of $60 per work hour.

Required parts would be provided by

the manufacturer at no cost to the

operators. Based on these figures, the

cost impact of the installation required

by this AD would be approximately

$18,360 per airplane.

It would require approximately 2

work hours to accomplish the required

operational check, at an average labor

rate of $60 per work hour. Based on

these figures, the cost impact of the

operational check required by this AD

would be approximately $120 per

airplane, per check.

Determination of Rule’s Effective Date

Since this AD action does not affect

any airplane that is currently on the

U.S. register, it has no adverse economic

impact and imposes no additional

burden on any person. Therefore, prior

notice and public procedures hereon are

unnecessary and the amendment may be

made effective in less than 30 days after

publication in the Federal Register.

Comments Invited

Although this action is in the form of

a final rule and was not preceded by

notice and opportunity for public

comment, comments are invited on this

rule. Interested persons are invited to

comment on this 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 under the caption

ADDRESSES. All communications

received on or before the closing date

for comments will be considered, and

this rule may be amended in light of the

comments received. Factual information

that supports the commenter’s ideas and

suggestions is extremely helpful in

evaluating the effectiveness of the AD

action and determining whether

additional rulemaking action would be

needed.

Comments are specifically invited on

the overall regulatory, economic,

environmental, and energy aspects of

the rule that might suggest a need to

modify the 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 that

summarizes each FAA-public contact

concerned with the substance of this AD

will be filed in the Rules Docket.

Commenters wishing the FAA to

acknowledge receipt of their comments

submitted in response to this rule must

submit a self-addressed, stamped

postcard on which the following

statement is made: ‘‘Comments to

Docket Number 99–NM–361–AD.’’ The

postcard will be date stamped and

returned to the commenter.

Regulatory Impact

The regulations adopted herein will

not have a substantial direct effect 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, it is

determined that this final rule does not

have federalism implications under

Executive Order 13132.

For the reasons discussed above, I

certify that this action (1) Is not a

‘‘significant regulatory action’’ under

Executive Order 12866; (2) Is not a

‘‘significant rule’’ under DOT

Regulatory Policies and Procedures (44

FR 11034, February 26, 1979); and (3)

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 final evaluation has

been prepared for this action and it is

contained in the Rules Docket. A copy

of it may be obtained from the Rules

Docket at the location provided under

the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation

safety, Incorporation by reference,

Safety.

Adoption of the Amendment

Accordingly, pursuant to the

authority delegated to me by the

Administrator, the Federal Aviation

Administration amends 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

removing amendment 39–11269 (64 FR

47365, August 31, 1999), and by adding

a new airworthiness directive (AD),

amendment 39–11502, to read as

follows:

2000–01–05 Boeing: Amendment 39–11502.

Docket 99–NM–361–AD. Supersedes AD

99–18–03, Amendment 39–11269.

Applicability: Model 747–100B, –200,

–300, and SP series airplanes, equipped with

Rolls Royce RB211–524B2, C2, and D4

engines; certificated in any category, as listed

in the following service bulletins:

• Boeing Alert Service Bulletin 747–

78A2148, dated June 1, 1995;

• Boeing Service Bulletin 747–78A2148,

Revision 1, dated July 20, 1995;

• Boeing Service Bulletin 747–78–2136,

dated May 11, 1995; and

• Boeing Service Bulletin 747–78–2156,

dated October 31, 1996.

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 (f) of this AD. The

request should include an assessment of the

Federal Register / Vol. 65, No. 5 / Friday, January 7, 2000 / Rules and Regulations 1053

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 inadvertent deployment of a

thrust reverser during flight and consequent

reduced controllability of the airplane,

accomplish the following:

Restatement of Requirements of AD

99–18–03

Repetitive Inspections and Tests

(a) Within 90 days after September 15,

1999 (the effective date of AD 99–18–03,

amendment 39–11269): Perform the

applicable inspections and tests of the thrust

reverser control and indication system on

each engine, in accordance with Part III.A.

through III.G. of the Accomplishment

Instructions of Boeing Alert Service Bulletin

747–78A2148, dated June 1, 1995, or Boeing

Service Bulletin 747–78A2148, Revision 1,

dated July 20, 1995. Repeat the applicable

inspections and tests thereafter at intervals

not to exceed 18 months, until

accomplishment of paragraph (c) of this AD.

Corrective Actions

(b) If any inspection or test required by

paragraph (a) of this AD cannot be

successfully performed as specified in the

service bulletin, or if any discrepancy is

detected during any inspection or test, prior

to further flight, repair in accordance with

Boeing Alert Service Bulletin 747–78A2148,

dated June 1, 1995, or Boeing Service

Bulletin 747–78A2148, Revision 1, dated July

20, 1995. Additionally, prior to further flight,

any failed inspection or test required by

paragraph (a) of this AD must be repeated

and successfully accomplished.

Modification

(c) Within 36 months after September 15,

1999: Install an additional locking system on

the thrust reversers in accordance with the

Accomplishment Instructions of Boeing

Service Bulletin 747–78–2156, dated October

31, 1996. Prior to or concurrent with

accomplishment of Boeing Service Bulletin

747–78–2156, dated October 31, 1996:

Accomplish Boeing Service Bulletin 747–78–

2136, dated May 11, 1995; and Rolls-Royce

Service Bulletins RB.211–71–B545, Revision

2, dated August 8, 1997, RB.211–71–B551,

Revision 1, dated March 20, 1998, and

RB.211–78–B552, dated June 21, 1996.

Accomplishment of these actions

constitutes terminating action for the

repetitive inspections and tests required by

paragraph (a) of this AD.

Operational Checks

(d) Within 3,000 flight hours after

accomplishing the modification required by

paragraph (c) of this AD, or within 1,000

flight hours after September 15, 1999,

whichever occurs later: Perform operational

checks of the number 2 and number 3

gearbox locks and of the air motor brake, in

accordance with the procedures described in

Appendix 1 (including Figure 1) of this AD.

Repeat the operational checks thereafter at

intervals not to exceed 3,000 flight hours.

Corrective Actions

(e) If any operational check required by

paragraph (d) of this AD cannot be

successfully performed as specified in the

procedures described in Appendix 1

(including Figure 1) of this AD, or, if any

discrepancy is detected during any

operational check, prior to further flight,

repair in accordance with the procedures

specified in the Boeing 747 Airplane

Maintenance Manual. Additionally, prior to

further flight, any failed operational check

required by paragraph (d) of this AD must be

repeated and successfully accomplished.

Continue to repeat the operational checks

thereafter at intervals not to exceed 3,000

flight hours.

Alternative Methods of Compliance

(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 2: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Seattle ACO.

Special Flight Permits

(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.

Incorporation by Reference

(h) Except as provided by paragraphs (d)

and (e) of this AD, the actions shall be done

in accordance with the applicable service

bulletins:

• Boeing Service Bulletin 747–78–2136,

dated May 11, 1995;

• Boeing Alert Service Bulletin 747–

78A2148, dated June 1, 1995;

• Boeing Service Bulletin 747–78A2148,

Revision 1, dated July 20, 1995;

• Boeing Service Bulletin 747–78–2156,

dated October 31, 1996;

• Rolls-Royce Service Bulletin RB.211–78–

B552, dated June 21, 1996;

• Rolls-Royce Service Bulletin RB.211–71–

B545, Revision 2, dated August 8, 1997; or

• Rolls-Royce Service Bulletin RB.211–71–

B551, Revision 1, dated March 20, 1998.

This incorporation by reference was

approved previously by the Director of the

Federal Register as of September 15, 1999 (64

FR 47365, August 31, 1999). Copies may be

obtained from Boeing Commercial Airplane

Group, P.O. Box 3707, Seattle, Washington

98124–2207. Copies may be inspected at the

FAA, Transport Airplane Directorate, 1601

Lind Avenue, SW, Renton, Washington; or at

the Office of the Federal Register, 800 North

Capitol Street, NW, suite 700, Washington,

DC.

(i) This amendment becomes effective on

January 24, 2000.

Appendix 1—

Gearbox Lock and Air Motor Brake Test

A. General

To do the test of the gearbox locks and air

motor brake, you must do the steps that

follow:

(a) Do the deactivation procedure of the

thrust reverser system.

(b) Do the test of the air motor brake.

(c) Do the test of the gearbox locks.

(d) Do the activation procedure of the

thrust reverser system.

B. Equipment

(1) CP30784—INA Access Platform, RollsRoyce

(2) CP30769—Protection Pads, Rolls-Royce

(3) CP30785—Access Stools, Rolls-Royce

(4) UT1293/1—Load Tool, Rolls-Royce (2

required)

C. Procedure (Fig. 1)

Warning: Do the Deactivation Procedure of

the Thrust Reverser System, Which Must

Include the Installation of Lock Bars (or

Blockers), to Prevent the Accidental

operation of the Thrust Reverser. The

Accidental Operation of the Thrust Reverser

Could Cause Injury to Persons and Damage

to Equipment.

(1) Do the deactivation procedure of the

thrust reverser in the forward thrust position

for ground maintenance.

(2) Use a 0.25-inch (6.4-mm) square drive

to turn the manual lock release screw to

release the No. 2 and No. 3 gearbox locks.

Note: It is not always easy to turn the

manual lock release screws. This is because

of a preload in the systems. To release the

preload, lightly turn the manual cycle and

lockout shafts in the stow direction.

(a) Make sure the lock indicators are

extended at gearboxes No. 2 and No. 3.

(3) Do a test of the air motor brake:

(a) If You Use the Load Tools;

Try to move the translating cowl in the

extend direction as follows:

(1) Remove the lock bars that you installed

in the deactivation procedure.

(2) Install the load tools through the

cutouts and into the No. 2 and No. 3

gearboxes.

(3) Attach the torque wrenches to the load

tools.

(4) Try to move the translating cowl in the

extend direction.

(b) If You Do Not Use the Load Tools;

Try to move the translating cowl in the

extend direction as follows:

(1) Remove the lock bars that you installed

in the deactivation procedure.

(2) Put the 0.25-inch (6.4-mm) square drive

extensions into the manual cycle and lockout

shaft at the No. 2 and No. 3 gearboxes.

(a) Attach the standard drive tools.

(3) Try to move the translating cowl in the

extend direction.

(c) If the translating cowl moves, replace

the air motor and shutoff valve.

(4) Do a test of the gear box locks:

Note: The steps that follow are for the No.

3 gearbox. Then, do these steps again for the

No. 2 gearbox.

1054 Federal Register / Vol. 65, No. 5 / Friday, January 7, 2000 / Rules and Regulations

(a) Install the lock bars in the manual cycle

and lockout shafts at the No. 2 and No. 3

gearboxes.

(b) Install the INA access platform in the

exhaust mixer duct.

(c) Install the protection pads and the

access stools.

(d) Release the air motor brake:

(1) Open the air motor access and pressure

relief panel.

(2) Pull the air motor brake release handle

forward and turn it counterclockwise to lock

the handle in its position.

(e) Turn the manual lock release screw

clockwise to engage the No. 3 gearbox lock.

(1) Make sure that the lock indicator is

retracted (under the surface) at gearbox No.

3.

(f) Make sure No. 2 gearbox lock is

released.

(1) Make sure the lock indicator is

extended at gearbox No. 2.

(g) If You Use the Load Tools;

Do a check of the lock dogs as follows:

(1) Remove the lock bars from the No. 2

and No. 3 gearboxes.

(2) Install the load tool through the cutout

and into the No. 3 gearbox.

(3) Attach the torque wrench to the load

tool.

Caution: Do Not Apply a Torque Load of

More Than 30 Pound-Inches (3.4 NewtonMeters) to the Manual Cycle and Lock Out

Shaft. A Larger Torque Load Can Cause

Damage to the Mechanism.

(4) Apply a torque counterclockwise

through the manual wind position of the No.

3 gearbox.

(a) If the translating cowl does not move,

the lock bar touched one of the two lock

dogs.

(b) If the translating cowl moved, lock the

thrust reverser until the No. 3 gearbox is

replaced.

(5) Turn the manual lock release screw

counterclockwise to release the gearbox lock.

(a) Make sure that the indication rod comes

out of the No. 3 gearbox.

(6) Turn the manual cycle and lockout

shaft counterclockwise 1⁄4 turn.

(7) Turn the manual lock release screw

clockwise to engage the No. 3 gearbox lock.

(a) Make sure that the indication rod is

fully retracted (under the surface).

Caution: Do Not Apply a Torque Load of

More Than 30 Pound-Inches (3.4 NewtonMeters) to the Manual Cycle and Lockout

Shaft. A Greater Torque Load Can Cause

Damage to the Mechanism.

(8) Apply a torque counterclockwise

through the manual wind position of the No.

3 gearbox.

(a) If the manual cycle and lockout shaft

can not be turned more than approximately

1⁄4 turn, the second lock dog is serviceable.

(b) If the manual cycle and lockout shaft

can be turned more than approximately 1⁄4

turn, the second lock dog is unserviceable.

Lock the thrust reverser until the No. 3

gearbox is replaced.

Note: The two lock dogs are found 1⁄2 turn

apart when you use the manual cycle and

lockout shaft. If necessary, do the check again

to make sure that the lock dogs are

serviceable.

(9) Do the procedure given above for the

No. 2 gearbox lock.

(h) If You Do Not Use the Load Tools;

Do a check of the lock dogs as follows:

(1) Remove the lock bars from the No. 2

and No. 3 gearboxes.

(2) Put the 0.25-inch (6.4-mm) square drive

extensions into the manual cycle and lockout

shaft at the No. 2 and No. 3 gearboxes.

(a) Attach the standard drive tools.

Caution: Do Not Apply a Torque Load of

More Than 30 Pound-Inches (3.4 NewtonMeters) to the Manual Cycle and Lockout

Shaft. A Larger Torque Load Can Cause

Damage to the Mechanism.

(3) Apply a torque counterclockwise

through the manual wind position of the No.

3 gearbox.

(a) If the translating cowl does not move,

the lock bar touched one of the two lock

dogs.

(b) If the translating cowl moved, lock the

thrust reverser until the No. 3 gearbox is

replaced.

(4) Turn the manual lock release screw

counterclockwise to release the gearbox lock.

(a) Make sure that the indication rod comes

out of the No. 3 gearbox.

(5) Turn the manual cycle and lockout

shaft counterclockwise 1⁄4 turn.

(6) Turn the manual lock release screw

clockwise to engage the No. 3 gearbox lock.

(a) Make sure that the indication rod is

fully retracted (under the surface).

Caution: Do Not Apply a Torque Load of

More Than 30 Pound-Inches (3.4 NewtonMeters) to the Manual Cycle and Lockout

Shaft. A Greater Torque Load Can Cause

Damage to the Mechanism.

(7) Apply a torque counterclockwise

through the manual wind position of the No.

3 gearbox.

(a) If the manual cycle and lockout shaft

can not be turned more than approximately

1⁄4 turn, the second lock dog is serviceable.

(b) If the manual cycle and lockout shaft

can be turned more than approximately 1⁄4

turn, the second lock dog is unserviceable.

Lock the thrust reverser until the No. 3

gearbox is replaced.

Note: The two lock dogs are found 1⁄2 turn

apart when you use the manual cycle and

lockout shaft. If necessary, do the check again

to make sure that the lock dogs are

serviceable.

(8) Do the procedure given above for the

No. 2 gearbox lock.

(5) Install the lock bars in the manual cycle

and lockout shafts at the No. 2 and No. 3

gearboxes.

(6) Apply the air motor manual brake:

(a) Turn the air motor brake release handle

clockwise and then release.

(b) Close the air motor access and pressure

relief panel.

(7) Make sure the No. 2 and No. 3 gearbox

locks are released.

(a) Make sure the lock indicator rods are

extended at the No. 2 and No. 3 gearboxes.

(8) If You Use the Load Tools;

Try to move the translating cowl in the

extend direction as follows:

(a) Remove the lock bars from the No. 2

and No. 3 gearboxes.

(b) Install the load tools through the

cutouts and into the No. 2 and No. 3

gearboxes.

(c) Attach the torque wrenches to the load

tools.

(d) Try to move the translating cowl in the

extend direction.

(9) If You Do Not Use the Load Tools;

Try to move the translating cowl in the

extend direction as follows:

(a) Remove the lock bars from the No. 2

and No. 3 gearboxes.

(b) Put the 0.25-inch (6.4-mm) square drive

extensions into the manual cycle and lockout

shaft at the No. 2 and No. 3 gearboxes.

(1) Attach the standard drive tools.

(c) Try to move the translating cowl in the

extend direction.

(10) If the translating cowl moves, do the

full test again.

(a) If the translating sleeve moves again,

lock the thrust reverser until you can replace

the two locking gearboxes and the air motor

and shutoff valve.

(11) Remove the access stools and

protection pads.

(12) Remove the INA access platform from

the exhaust mixer duct.

(13) Do the activation procedure of the

thrust reverser system.

(14) Do the functional test of the thrust

reverser system.

BILLING CODE 4910–13–U

Federal Register / Vol. 65, No. 5 / Friday, January 7, 2000 / Rules and Regulations 1055

Issued in Renton, Washington, on January

3, 2000.

Vi L. Lipski,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 00–374 Filed 1–6–00; 8:45 am]

BILLING CODE 4910–13–C