Federal Register / Vol. 63, No. 142 / Friday, July 24, 1998 / Proposed Rules 39765

may be directed to the facilitator,

Francis X. Cameron.

The meetings will have a pre-defined

scope and agenda focused on the

Commission’s resolution of the major

issues addressed during the

development of the proposed rule and

MPS. However, the meeting format will

be sufficiently flexible to allow for the

introduction of additional related issues

that the participants may want to raise.

The meeting commentary will be

transcribed and made available to the

participants and the public.

Copies of the proposed revision of

Part 35 and the MPS will be provided

to the meeting participants. Also, copies

will be available for members of the

public in attendance at the meetings.

The availability of the proposed rule,

and associated documents, and the MPS

for individuals who are unable to attend

any of the public meetings will be noted

in the Federal Register notices for these

documents.

Public comments on the proposed

rule and MPS are solicited but, to be

most helpful, should be received by the

date that will be announced in the

Federal Register notices on the

proposed rule and MPS. Comments

received after this date will be

considered if it is practical to do so, but

the Commission only is able to ensure

consideration of comments received on

or before this date. Written input and

suggestions can be sent to Secretary,

Nuclear Regulatory Commission,

Washington, DC 20555–0001, Attention:

Rulemakings and Adjudications Staff.

Hand-deliver comments to 11555

Rockville Pike, Rockville, MD, between

7:30 a.m. and 4:15 p.m. on Federal

workdays.

Dated at Rockville, Maryland this 17th day

of July, 1998.

For the Nuclear Regulatory Commission.

Frederick C. Combs,

Acting Director, Division of Industrial and

Medical Nuclear Safety, Office of Nuclear

Material Safety and Safeguards.

[FR Doc. 98–19805 Filed 7–23–98; 8:45 am]

BILLING CODE 7590–01–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98–NM–163–AD]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 747 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 all

Boeing Model 747 series airplanes. This

proposal would require a one-time

inspection to detect discrepancies of the

center fuel tank, and corrective actions,

if necessary; replacement of all

components of the fuel quantity

indicating system (FQIS) of the center

tanks with new FQIS components; and

replacement of the FQIS wiring with

new wiring. For certain airplanes, this

proposal also would require a one-time

inspection to detect discrepancies of the

FQIS, and corrective actions, if

necessary; and installation of a flame

arrestor in the scavenge pumps of the

center fuel tank. This proposal is

prompted by design review and testing

results obtained in support of an

accident investigation. The actions

specified by the proposed AD are

intended to prevent ignition sources and

consequent fire/explosion in the center

fuel tank.

DATES: Comments must be received by

September 8, 1998.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 98–NM–

163–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:

Dionne Stanley, Aerospace Engineer,

Propulsion Branch, ANM–140S, FAA,

Transport Airplane Directorate, Seattle

Aircraft Certification Office, 1601 Lind

Avenue, SW., Renton, Washington

98055–4056; telephone (425) 227–2250;

fax (425) 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 98–NM–163–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.

98–NM–163–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

On July 17, 1996, a Boeing Model 747

series airplane was involved in an

accident shortly after takeoff from John

F. Kennedy International Airport in

Jamaica, New York. In support of the

subsequent accident investigation, the

FAA has participated in design review

and testing to determine possible

sources of ignition in the center fuel

tank. The cause of the accident has not

yet been determined.

This design review has identified the

need to detect any conditions of inservice deterioration of the wiring,

bonding, tubing installations, and other

component installations inside the

center fuel tank. If such conditions are

detected, repair of these discrepancies

would reduce the likelihood of these

components becoming in-tank ignition

sources due to lightning strikes, static

electricity, or electrical failures outside

of the fuel tank.

In addition, investigation has revealed

that the knurled terminal blocks on

‘‘series 3’’ (and earlier series) probes of

the fuel quantity indication system

(FQIS) on Model 747 series airplanes are

subject to chafing against their
39766 Federal Register / Vol. 63, No. 142 / Friday, July 24, 1998 / Proposed Rules

connecting wires; this chafing could

result in an ignition source in the center

fuel tank. ‘‘Series 4’’ (and subsequent

series) probes, in contrast, incorporate a

smooth-surface terminal block, nylon

wire clamps, and a protective shrinkwrapped coating on the wires.

Installation of ‘‘series 4’’ (or subsequent

series) probes would prevent a potential

in-tank ignition source due to incorrect

terminal block configuration and

resultant chafing damage to the wiring.

The FAA’s review of the design of the

scavenge pump assembly of the Model

747 center fuel tank has identified its

vulnerability to center fuel tank ignition

as a result of a potential mechanical

failure of the pump. This condition

could cause a spark or flame front to

emanate from the pump assembly,

propagate through the pump inlet line,

and ignite the fuel-air mixture inside the

center fuel tank.

Further, the FAA has become aware of

numerous FQIS probe failures and

system reliability problems in military

applications. Subsequent investigation

of Model 747 FQIS wiring has revealed

the presence of corrosion, in the form of

copper sulfur residue, on the affected

probes and silver-plated copper wiring.

This corrosion of the commonly used

silver-plated copper wire is attributed to

sulfur compounds inherently present in

aviation fuels, bacterial growth, and the

polysulfide sealant used in fuel tanks.

Testing has demonstrated the potential

for arcing and incandescing of copper

sulfur residues at a given voltage, which

could create a possible ignition source

in the center fuel tank. A hot short

failure in the FQIS outside of the fuel

tank, in conjunction with the latent

condition of excessive copper sulfur

residue on probes or wiring inside the

tank, could cause arcing or hightemperature leakage paths in fuel tanks.

By contrast, nickel-plated wires have

been shown to exhibit little or no

corrosion in this same environment.

The unsafe conditions associated with

damage to the center fuel tank wiring

and other components described above,

if not corrected, could result in ignition

sources and consequent fire/explosion

in the center fuel tank.

Wing Fuel Tanks vs. Center Fuel Tanks

The actions identified by the FAA

during the course of the ongoing

accident investigation are part of

continued activity to correct any designor maintenance-related deficiencies in

the Boeing 747 fuel tanks that may lead

to the existence of an ignition source.

This proposed AD focuses on the center

fuel tanks only.

Over the past 30 years, the service

history for turbine-powered transport

airplanes, excluding those used in

military combat, has shown that inflight explosions in wing fuel tanks

occurred mainly when wide-cut fuels or

a mixture of wide-cut fuel and kerosenetype fuels were used. The FAA has

considered several factors that may

contribute to the significantly improved

safety record of wing fuel tanks relative

to center fuel tanks:

1. On average, wing tank temperatures

are lower than those in the center tanks

because wing tanks have no significant

on-airplane heat sources located in or

near them, and the top and bottom

surfaces of the wing tanks cool quickly

as the airplane climbs into colder air.

2. Except for immediately after

landing, wing tanks usually contain a

relatively large amount of fuel to act as

a heat sink while the airplane is on the

ground being heated by sunlight and

ambient air, whereas center tanks are

often empty or near empty on airplanes

during operation; and

3. Wing tank fuel pumps are normally

operated with their pump inlets covered

with fuel, which ensures that the wing

tank pumps are always fuel-cooled

during operation and mechanical sparks

or high metal temperatures at the

impeller cannot ignite vapor in the fuel

tank.

In general, the flammability of a fuel

is dependent on the concentration of

fuel/air mixture and the fuel

temperature. As a function of

temperature, the fuel/air mixture can be

too lean for combustion (lower

flammability limit) or too rich for

combustion (upper flammability limit).

For kerosene-type fuels such as Jet A,

elevated fuel/air mixture temperatures

increase the likelihood of the mixture

being within the flammable range.

Avoiding airplane operation with fuel

temperatures in the flammable range

reduces the fuel/air mixture’s exposure

to ignition in the presence of an ignition

source.

The unique environmental and

operational conditions and service

history information of fuel tanks show

that the risk of an in-flight explosion is

lower in wing fuel tanks than in center

fuel tanks. Therefore, the FAA is not

proposing to include the wing fuel tanks

in this rulemaking activity.

Explanation of Relevant Service

Information

The FAA has reviewed and approved

Boeing Service Bulletin 747–28–2205,

Revision 1, dated April 16, 1998. This

service bulletin describes procedures for

a visual inspection to detect

discrepancies (damage, disbonding, and

incorrect installation) of the center fuel

tank wiring and components; and

corrective actions, if necessary.

Corrective actions involve repair or

replacement of discrepant parts with

new or serviceable parts. In addition,

this service bulletin describes

procedures for an electrical bonding test

of the center fuel tank components, and

reworking of any component with

bonding outside specified maximum

resistance limits.

The FAA has reviewed and approved

Boeing Alert Service Bulletin 747–

28A2208, dated May 14, 1998. This alert

service bulletin describes procedures

for:

• insulation resistance testing of the

FQIS;

• visual inspection of the FQIS wiring

and components to detect discrepancies

(chafing damage to the wiring and

incorrect configuration of the terminal

blocks), and repair of discrepant

components or replacement with new or

serviceable components;

• replacement of ‘‘series 3’’ (or earlier

series) FQIS probes with new ‘‘series 4’’

(or subsequent series) probes;

• retermination of the wires to the

tank units and compensator, and

replacement of FQIS wire bundle

assemblies with new parts, if necessary;

• retesting (insulation resistance) of

all components; and

• performing a system adjustment

and a system operational test of the

FQIS.

The FAA also has reviewed and

approved Boeing Alert Service Bulletin

747–28A2210, dated May 14, 1998. This

alert service bulletin describes

procedures for installation of a flame

arrestor in the inlet line of the scavenge

pump of the center fuel tank.

FAA’s Determinations

The FAA has examined the

circumstances and reviewed all

available information related to the

accident and subsequent investigations.

The FAA finds that, in addition to the

actions specified in the service bulletins

described previously, replacement of

the Model 747 FQIS components (FQIS

probes, compensator, and terminal strip)

and wiring will reduce the risk of

ignition in the center fuel tank, for the

reasons described in the Discussion

section above.

The FAA has determined that

repeated entry into the fuel tank will

increase the risk of damage to in-tank

components and systems. Moreover,

extensive time and effort are required to

access, purge, and close the fuel tank to

accomplish each action proposed by

this AD. Therefore, the FAA proposes a

compliance time of 24 months to allow

operators to concurrently perform all of

the proposed actions in order to reduce
Federal Register / Vol. 63, No. 142 / Friday, July 24, 1998 / Proposed Rules 39767

the risk of damage to the airplane from

repeated entry. The proposed

compliance time for accomplishment of

the actions also would provide

operators time for planning and

scheduling, thus reducing the cost

impact on the operators.

The FAA is currently considering

separate rulemaking to address longterm maintenance issues.

Explanation of Requirements of

Proposed Rule

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

require:

1. Performing a one-time visual

inspection to detect damage,

disbonding, and incorrect installation of

the center fuel tank wiring and

components; and repair or replacement,

if necessary.

2. Performing an electrical bonding

test of the center fuel tank components;

and rework, if necessary.

3. For certain airplanes, performing an

insulation resistance test of the FQIS

and a one-time visual inspection to

detect discrepancies of the FQIS;

replacement of ‘‘series 3’’ (and earlier

series) FQIS probes with new ‘‘series 4’’

(and subsequent series) FQIS probes;

and corrective actions, if necessary.

4. Replacing all FQIS components

(FQIS probes, compensator, and

terminal strip) with new components.

5. Replacing silver-plated copper

FQIS wiring with new nickel-plated

copper FQIS wiring.

6. For certain airplanes, installing a

flame arrestor into the inlet line of the

scavenge pumps of the center fuel tank.

The actions are required to be

accomplished in accordance with the

service bulletins (described previously),

the 747 Maintenance Manual, or a

method approved by the FAA.

The proposed AD also would require

that operators report inspection findings

to the manufacturer.

Other Relevant Rulemaking

Other fuel tank ignition scenarios

have been studied by the FAA and have

resulted in rulemaking action.

On December 9, 1997, the FAA issued

AD 97–26–07, amendment 39–10250 (62

FR 65352, December 12, 1997),

applicable to Boeing Model 747 series

airplanes, which superseded AD 96–26–

06, amendment 39–9870 (62 FR 304,

January 3, 1997). AD 97–26–07 requires

repetitive inspections of the Teflon

sleeves that protect wiring to the boost

pumps on the outboard main tanks on

all Boeing 747 series airplanes. The

Teflon sleeves are intended to protect

the main tank boost pump wiring from

chafing damage caused by the wires

rubbing against each other or against the

metal conduit that encases the wiring

routed through the fuel tank. Chafing of

these wires could lead to electrical

arcing, which could potentially cause

ignition of flammable vapors within the

outboard wing fuel tanks. Similar action

was taken on Model 737 series airplanes

by telegraphic AD 98–11–52, issued

May 14, 1998. The FAA is currently

reviewing other Boeing airplane models

to determine whether similar action is

warranted.

During the inspections required by

AD 97–26–07, one operator discovered

that the required Teflon sleeves were

missing on one airplane. In response, on

May 5, 1998, the FAA issued AD 98–10–

10, amendment 39–10522 (63 FR 26063,

May 12, 1998), to require all operators

of Boeing 747 series airplanes to verify

that the protective Teflon sleeves were

installed on the main tank boost pump

wiring. AD 98–10–10 requires any

operator discovering the absence of any

Teflon sleeve on an airplane to perform

corrective action prior to further flight.

On November 26, 1997, the FAA

issued a notice of proposed rulemaking

(NPRM) (Docket 97-NM–272-AD) (62 FR

63624, December 1, 1997), applicable to

all Boeing Model 747–100, –200, and

–300 series airplanes. This NPRM

proposed a modification of the FQIS to

incorporate separation, shielding, and/

or electrical transient suppression

features to prevent electrical signals

with excessive energy from entering the

fuel tanks. This action is intended to

preclude electrical energy needed to

produce ignition from entering the fuel

tanks and will preclude the

development of an ignition source

within the FQIS if damage to wiring,

corrosion, or other failures were to

occur. On April 14, 1998, the FAA

issued a similar NPRM (Docket 98–NM–

50–AD) (63 FR 19852, April 22, 1998),

for Boeing Model 737 series airplanes.

The FAA is currently reviewing other

Boeing airplane models to determine

whether similar action is warranted.

In addition, the FAA is addressing

airplane fuel tank flammability issues

with respect to the transport airplane

fleet. On January 23, 1998, the FAA

established an Aviation Rulemaking

Advisory Committee (ARAC) working

group on fuel tank flammability

reduction with the publication of a

Notice of New Task Assignment in the

Federal Register. This notice gives the

ARAC working group until July 23,

1998, to provide the FAA and Joint

Aviation Authority (JAA) with a report

outlining specific recommendations and

proposed regulatory text that will

eliminate or significantly reduce the

hazards associated with explosive

vapors in the fuel tanks of transport

category airplanes.

As mentioned previously, the FAA

also is considering rulemaking to

require that each type certificate holder

develop a fuel tank maintenance and

inspection program, and that each

operator have an FAA-approved fuel

system maintenance program. That

proposal also would require a review of

the original certification compliance

findings to revalidate that failures

within the fuel system will not result in

ignition sources.

Cost Impact

There are approximately 1,069

airplanes of the affected design in the

worldwide fleet. The FAA estimates that

251 airplanes of U.S. registry would be

affected by this proposed AD.

The FAA estimates that it would take

approximately 40 work hours per

airplane to purge, access, and close the

center fuel tank, at an average labor rate

of $60 per work hour. The cost impact

on U.S. operators to purge, access, and

close the fuel tank is estimated to be

$2,400 per airplane.

The FAA estimates that the proposed

inspection of the center fuel tank would

be required to be accomplished on 251

airplanes. It would take approximately

56 work hours per airplane to

accomplish the proposed inspection, at

an average labor rate of $60 per work

hour. Based on these figures, the cost

impact of this proposed inspection on

U.S. operators is estimated to be

$843,360, or $3,360 per airplane.

The FAA estimates that the proposed

FQIS inspection and system operational

test, probe replacement, and insulation

resistance test would be required to be

accomplished on 202 airplanes. It

would take approximately 60 work

hours (maximum) per airplane to

accomplish the proposed FQIS

inspection, at an average labor rate of

$60 per work hour. Required parts

would cost approximately $30,000 per

airplane (maximum). Based on these

figures, the cost impact of this proposed

inspection on U.S. operators is

estimated to be a maximum of

$6,787,200, or $33,600 per airplane.

The FAA estimates that the proposed

installation of a flame arrestor would be

required to be accomplished on 214

airplanes. It would take approximately 2

work hours per airplane to accomplish

the proposed installation, at an average

labor rate of $60 per work hour.

Required parts would cost

approximately $1,107 per airplane.

Based on these figures, the cost impact

of this proposed installation on U.S.
39768 Federal Register / Vol. 63, No. 142 / Friday, July 24, 1998 / Proposed Rules

operators is estimated to be $262,578, or

$1,227 per airplane.

The FAA estimates that the proposed

replacement of all FQIS components

would be required to be accomplished

on 251 airplanes. It would take

approximately 24 work hours per

airplane to accomplish the proposed

replacement, at an average labor rate of

$60 per work hour. Required parts

would cost approximately $10,000 per

airplane. Based on these figures, the cost

impact of this proposed replacement on

U.S. operators is estimated to be

$2,871,440, or $11,440 per airplane.

The FAA estimates that the proposed

replacement of the FQIS wiring would

be required to be accomplished on 251

airplanes. It would take approximately

24 work hours per airplane to

accomplish the proposed replacement,

at an average labor rate of $60 per work

hour. Required parts would cost

approximately $10,000 per airplane.

Based on these figures, the cost impact

of this proposed replacement on U.S.

operators is estimated to be $2,871,440,

or $11,440 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.

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:

Boeing: Docket 98-NM–163-AD.

Applicability: All Model 747 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 (g) 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 ignition sources and

consequent fire/explosion in the center fuel

tank, accomplish the following:

(a) Within 24 months after the effective

date of this AD, accomplish paragraphs (a)(1)

and (a)(2), in accordance with Boeing Service

Bulletin 747–28–2205, Revision 1, dated

April 16, 1998.

(1) Perform a visual inspection of the

center fuel tank wiring and components to

detect discrepancies (damage, disbonding,

and incorrect installation). If any discrepancy

is detected, prior to further flight, repair the

discrepant component, or replace it with a

new or serviceable component. And

(2) Perform an electrical bonding test of the

center fuel tank components. If any measured

resistance exceeds the limit specified by

Figure 1 of the service bulletin, prior to

further flight, rework the discrepant

component.

Note 2: Revision 1 of Boeing Service

Bulletin 747–28–2205 provides two

additional actions (inspection of the body

fuel tank components and measurement of

the ground resistance of the pressure switch

case on the auxiliary power unit pump) that

were not provided in the original version of

this service bulletin. Inspections and testing

accomplished prior to the effective date of

this AD in accordance with Boeing Service

Bulletin 747–28–2205, dated June 27, 1997,

are considered acceptable for compliance

with the applicable actions specified in this

AD.

(b) Within 24 months after the effective

date of this AD, perform an insulation

resistance test of the fuel quantity indication

system (FQIS), visual inspection of the FQIS

wiring and components to detect

discrepancies (chafing damage to the wiring

and incorrect configuration of the terminal

blocks), replacement of ‘‘series 3’’ (or earlier

series) FQIS probes with new ‘‘series 4’’ (or

subsequent series) FQIS probes, and system

adjustment and system operational test; as

specified by paragraph (b)(1) or (b)(2) of this

AD, as applicable; in accordance with Boeing

Alert Service Bulletin 747–28A2208, dated

May 14, 1998. If any discrepancy is detected,

prior to further flight, perform corrective

actions in accordance with the alert service

bulletin.

(1) For Groups 1 and 2 airplanes, as listed

in the alert service bulletin: Accomplish the

inspection, testing, and corrective actions, as

applicable, in accordance with Figure 2 of

the alert service bulletin.

(2) For Groups 3 and 4 airplanes, as listed

in the alert service bulletin: Accomplish the

inspection, testing, and corrective actions, as

applicable, in accordance with Figure 3 of

the alert service bulletin.

(c) At the applicable time specified in

paragraph (c)(1) or (c)(2) of this AD, submit

a report of the results of the inspections

required by paragraphs (a) and (b) of this AD,

as applicable, to the Manager, Airline

Support, Boeing Commercial Airplane

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

98124–2207. The report must include the

information specified in Boeing Service

Bulletin 747–28–2205, Revision 1, dated

April 16, 1998 [for paragraph (a) of this AD];

and Boeing Alert Service Bulletin 747–

28A2208, dated May 14, 1998 [for paragraph

(b) of this AD]. Information collection

requirements contained in this regulation

have been approved by the Office of

Management and Budget (OMB) under the

provisions of the Paperwork Reduction Act of

1980 (44 U.S.C. 3501 et seq.) and have been

assigned OMB Control Number 2120–0056.

(1) For airplanes on which the inspections

required by paragraphs (a) and (b) of this AD,

as applicable, are accomplished after the

effective date of this AD: Submit the report

within 10 days after performing the

applicable inspection.

(2) For airplanes on which the inspections

required by paragraphs (a) and (b) of this AD,

as applicable, have been accomplished prior

to the effective date of this AD: Submit the

report within 10 days after the effective date

of this AD.

(d) Within 20 years since date of

manufacture, or within 24 months after the

effective date of this AD, whichever occurs

later: Replace all center fuel tank FQIS

components (FQIS probes, compensator, and

terminal strip) with new FQIS components,

in accordance with the 747 Maintenance

Manual, chapters 28–11–00, 28–41–00, 28–

41–01, 28–41–02, and 28–41–09.
Federal Register / Vol. 63, No. 142 / Friday, July 24, 1998 / Proposed Rules 39769

(e) Within 20 years since date of

manufacture, or within 24 months after the

effective date of this AD, whichever occurs

later: Replace the silver-plated copper FQIS

wiring of the center fuel tank with new

nickel-plated copper FQIS wiring, in

accordance with 747 Maintenance Manual,

chapters 28–11–00, 28–41–00, 28–41–01, 28–

41–02, and 28–41–09.

(f) For airplanes having line positions 1

through 971 inclusive: Within 24 months

after the effective date of this AD, install a

flame arrestor in the inlet line of the

electrical motor-operated scavenge pump of

the center fuel tank, in accordance with

Boeing Alert Service Bulletin 747–28A2210,

dated May 14, 1998.

(g) 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.

(h) Special flight permits may be issued in

accordance with sections 21.197 and 21.199

of the Federal Aviation Regulations (14 CFR

21.197 and 21.199) to operate the airplane to

a location where the requirements of this AD

can be accomplished.

Issued in Renton, Washington, on July 15,

1998.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 98–19460 Filed 7–23–98; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97–NM–106–AD]

RIN 2120–AA64

Airworthiness Directives; Short

Brothers Model SD3–60 and SD3–60

SHERPA Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Supplemental notice of

proposed rulemaking; reopening of

comment period.

SUMMARY: This document revises an

earlier proposed airworthiness directive

(AD), applicable to all Short Brothers

Model SD3–60 series airplanes, that

would have required repetitive

inspections to detect corrosion and/or

wear of the top and bottom shear decks

of the left and right stub wings in the

area of the forward pintle pin of the

main landing gear (MLG), and repair, if

necessary. That proposal was prompted

by issuance of mandatory continuing

airworthiness information by a foreign

civil airworthiness authority. This new

action revises the proposed rule by

expanding the applicability to include

an additional airplane model. The

actions specified by this new proposed

AD are intended to detect and correct

corrosion and/or wear of the top and

bottom shear decks of the left and right

stub wings in the area of the forward

pintle pin of the MLG, which could

result in failure of the MLG to extend or

retract.

DATES: Comments must be received by

August 18, 1998.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 97–NM–

106–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

Short Brothers, Airworthiness &

Engineering Quality, P. O. Box 241,

Airport Road, Belfast BT3 9DZ,

Northern Ireland. This information may

be examined at the FAA, Transport

Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Norman B. Martenson, Manager,

International Branch, ANM–116, FAA,

Transport Airplane Directorate, 1601

Lind Avenue, SW., Renton, Washington

98055–4056; telephone (425) 227–2110;

fax (425) 227–1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to

participate in the making of the

proposed rule by submitting such

written data, views, or arguments as

they may desire. Communications shall

identify the Rules Docket number and

be submitted in triplicate to the address

specified above. All communications

received on or before the closing date

for comments, specified above, will be

considered before taking action on the

proposed rule. The proposals contained

in this notice may be changed in light

of the comments received.

Comments are specifically invited on

the overall regulatory, economic,

environmental, and energy aspects of

the proposed rule. All comments

submitted will be available, both before

and after the closing date for comments,

in the Rules Docket for examination by

interested persons. A report

summarizing each FAA-public contact

concerned with the substance of this

proposal will be filed in the Rules

Docket.

Commenters wishing the FAA to

acknowledge receipt of their comments

submitted in response to this notice

must submit a self-addressed, stamped

postcard on which the following

statement is made: ‘‘Comments to

Docket Number 97-NM–106-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–106–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

A proposal to amend part 39 of the

Federal Aviation Regulations (14 CFR

part 39) to add an airworthiness

directive (AD), applicable to all Short

Brothers Model SD3–60 series airplanes,

was published as a notice of proposed

rulemaking (NPRM) in the Federal

Register on October 6, 1997 (62 FR

52053). That NPRM would have

required repetitive inspections to detect

corrosion and/or wear of the top and

bottom shear decks of the left and right

stub wings in the area of the forward

pintle pin of the main landing gear

(MLG), and repair, if necessary. That

NPRM was prompted by reports of

corrosion and/or wear of the top and

bottom shear decks of the left and right

stub wings in the area of the forward

pintle pin of the MLG. Such corrosion

or wear of the top and bottom shear

decks of the left and right stub wings in

the area of the forward pintle pin of the

MLG, if not corrected, could result in

failure of the MLG to extend or retract.

Actions Since Issuance of Previous

Proposal

Since the issuance of that NPRM, the

Civil Aviation Authority (CAA), which

is the airworthiness authority for the

United Kingdom, notified the FAA that

the unsafe condition described in the

original NPRM also may exist on all

Short Brothers Model SD3–60 SHERPA

series airplanes. The shear decks of the

stub wings on Model SD3–60 SHERPA

series airplanes are similar in design to

those on Model SD3–60 series airplanes;

therefore, both models are subject to the

same unsafe condition. The FAA has

revised the applicability of this