This section of the FEDERAL REGISTER

contains notices to the public of the proposed

issuance of rules and regulations. The

purpose of these notices is to give interested

persons an opportunity to participate in the

rule making prior to the adoption of the final

rules.

Proposed Rules Federal Register

27685

Vol. 63, No. 97

Wednesday, May 20, 1998

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97–NM–89–AD]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 747–400 Series Airplanes

Powered by Pratt and Whitney PW4000

Engines

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 Boeing Model 747–400 series

airplanes. This proposal would require

repetitive inspections to detect

improper installation and fatigue

damage of the end cap of the forward

engine mount, and replacement of the

forward engine mount end cap assembly

with an improved end cap assembly.

Such replacement, when accomplished,

would terminate the repetitive

inspections. This proposal is prompted

by a report of fatigue cracking of end

cap bolts, caused by improper

installation. Subsequent investigation

revealed that properly installed end

caps also are subject to early fatigue

cracking. The actions specified by the

proposed AD are intended to prevent

failure of the end cap assembly, which

could lead to separation of the engine

from the airplane in the event of a

primary thrust linkage failure.

DATES: Comments must be received by

July 6, 1998.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 97–NM–

89–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:

Tamara L. Anderson, Aerospace

Engineer, Airframe Branch, ANM–120S,

FAA, Transport Airplane Directorate,

Seattle Aircraft Certification Office,

1601 Lind Avenue, SW., Renton,

Washington 98055–4056; telephone

(425) 227–2771; 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 97–NM–89–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–89–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The FAA has received a report of

broken end cap bolts of the forward

engine mount, which were found during

overhaul of a Pratt & Whitney PW4000

engine that had been installed on a

Boeing Model 747–400 series airplane.

Investigation revealed that the end cap

had been installed backwards. A

properly installed end cap does not

normally react any significant engine

thrust loads; it is intended to provide a

secondary load path if the primary

thrust linkage fails. An end cap installed

backwards will react the engine thrust

loads along with the primary thrust

linkage, which will result in premature

fatigue failure of the end cap or end cap

bolts. In addition, fatigue analysis and

testing have confirmed that a properly

installed end cap assembly would fail in

a low number of flight cycles after a

primary thrust linkage failure. Failure of

the end cap assembly, if not corrected,

could lead to separation of the engine

from the airplane in the event of

primary thrust linkage failure.

Other Relevant Rulemaking

There is a high degree of similarity

between the configurations of the engine

installations on the incident airplane

(Model 747–400) and certain Model 767

series airplanes. The FAA may consider

rulemaking to address this condition on

Model 767 series airplanes; therefore,

this proposed rule is applicable only to

Model 747–400 series airplanes.

Explanation of Relevant Service

Information

The FAA has reviewed and approved

Boeing Alert Service Bulletin 747–

71A2283, dated October 10, 1996,

which describes procedures for

repetitive detailed visual inspections to

detect improper installation and fatigue

damage of the end cap of the forward

engine mount, and replacement of the

end cap assembly of the forward engine

mount with an improved assembly.

Such replacement would eliminate the

need for the repetitive inspections.

Accomplishment of this replacement, as

described in the alert service bulletin, is

intended to adequately address the

identified unsafe condition.
27686 Federal Register / Vol. 63, No. 97 /Wednesday, May 20, 1998 / Proposed Rules

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 accomplishment of the actions

specified in the alert service bulletin

described previously, except as

discussed below.

Differences Between Proposed Rule and

Service Bulletin

Boeing Alert Service Bulletin 747–

71A2283 divides the affected airplanes

into two groups depending upon the

particular engine configuration of the

affected airplane, and provides different

procedures depending upon group

classification and engine on-wing flight

cycles. Operators should note that,

whereas the alert service bulletin

specifies that operators of Group 1

airplanes should contact the

manufacturer for disposition of the

terminating action, this proposed AD

would require that the end cap and bolts

be replaced in accordance with the

procedures specified in Chapter 71–00–

00 of the Boeing 747 Airplane

Maintenance Manual (AMM).

Additionally, the alert service bulletin

specifies that certain actions required by

this proposed AD may be accomplished

in accordance with ‘‘an operator’s

equivalent procedure.’’ However, this

proposed AD requires that those actions

be accomplished in accordance with the

procedures specified in Chapter 71–00–

00 of the AMM. An ‘‘operator’s

equivalent procedure’’ may be used only

if approved as an alternative method of

compliance in accordance with

paragraph (e) of this proposed AD.

Cost Impact

There are approximately 133

airplanes of the affected design in the

worldwide fleet. The FAA estimates that

36 airplanes of U.S. registry would be

affected by this proposed AD: 35 Group

1 airplanes, and 1 Group 2 airplane.

It would take approximately 36 work

hours per Group 1 airplane (9 work

hours per engine) 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 $75,600, or $2,160 per

airplane, per inspection cycle.

It would take approximately 272 work

hours per airplane (68 work hours per

engine) for both Group 1 and Group 2

airplanes to accomplish the proposed

replacement of the forward engine

mount end cap and/or end cap bolts, at

an average labor rate of $60 per work

hour. Required parts would cost

approximately $1,000 per airplane.

Based on these figures, the cost impact

of this proposed replacement on U.S.

operators is estimated to be $623,520, or

$17,320 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 97–NM–89–AD.

Applicability: Model 747–400 series

airplanes powered by Pratt & Whitney

PW4000 engines, as listed in Boeing Alert

Service Bulletin 747–71A2283, dated October

10, 1996; 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 (e) 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 possible separation of the

engine from the airplane in the event of a

primary thrust linkage failure, accomplish

the following:

(a) For Group 1 airplanes, as identified in

Boeing Alert Service Bulletin 747–71A2283,

dated October 10, 1996: Except as provided

by paragraph (c) of this AD, accomplish

paragraphs (a)(1) and (a)(2), of this AD, as

applicable, in accordance with the alert

service bulletin.

(1) Within 500 hours time-in-service after

the effective date of this AD, perform a

detailed visual inspection (Work Package 1)

to detect improper installation of the end cap

of the forward engine mount, in accordance

with the alert service bulletin.

(i) If no attachment hardware is found

loose or missing, and if no part shows signs

of damage, repeat the inspection thereafter at

intervals not to exceed 5,000 hours time-inservice or 15 months, whichever occurs first,

until the requirements of paragraph (a)(2) of

this AD have been accomplished.

(ii) If any attachment hardware is found

loose or missing, or if any part shows signs

of damage, prior to further flight, replace the

end cap and bolts with an improved end cap

and bolts (Work Package 2), in accordance

with the alert service bulletin.

Accomplishment of the replacement

constitutes terminating action for the

requirements of this AD for Group 1

airplanes.

(2) Replace the existing end cap and end

cap bolts of the forward engine mount with

an improved end cap and end cap bolts

(Work Package 2), at the earlier of the times

specified in paragraphs (a)(2)(i) and (a)(2)(ii)

of this AD. Accomplishment of the

replacement constitutes terminating action

for the requirements of this AD for Group 1

airplanes.

(i) Prior to the accumulation of 16,000 total

flight cycles on any engine, or within 500
Federal Register / Vol. 63, No. 97 /Wednesday, May 20, 1998 / Proposed Rules 27687

hours time-in-service after the effective date

of this AD, whichever occurs later; or

(ii) Within 3 years after the effective date

of this AD.

(b) For Group 2 airplanes, as identified in

Boeing Alert Service Bulletin 747–71A2283,

dated October 10, 1996: Except as provided

by paragraph (c) of this AD, within 3 years

after the effective date of this AD, replace the

existing end cap bolts of the forward engine

mount with improved end cap bolts (Work

Package 3), in accordance with the alert

service bulletin.

(c) Where Boeing Alert Service Bulletin

747–71A2283, dated October 10, 1996,

specifies that the actions required by this AD

may be accomplished in accordance with an

‘‘operator’s equivalent procedure,’’ the

actions must be accomplished in accordance

with Chapter 71–00–00 of the Boeing 747

Airplane Maintenance Manual (AMM), as

specified in the alert service bulletin.

(d) As of the effective date of this AD, no

person shall install on any airplane a forward

engine mount end cap having part number

310T3026–1.

(e) 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.

(f) 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 May 14,

1998.

John J. Hickey,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 98–13405 Filed 5–19–98; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98–NM–105–AD]

RIN 2120–AA64

Airworthiness Directives; Airbus Model

A320 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 Airbus Model A320 series

airplanes. This proposal would require

an electrical continuity test of the

discharge circuit for the cargo

compartment fire extinguisher bottle to

detect any cross-connection of the

electrical wires in the cargo

compartment discharge circuit, and

corrective actions, if necessary. This

proposal is prompted by issuance of

mandatory continuing airworthiness

information by a foreign civil

airworthiness authority. The actions

specified by the proposed AD are

intended to prevent incorrect

distribution of fire extinguishing

chemicals in the event of an unconfined

fire in the cargo compartment.

DATES: Comments must be received by

June 19, 1998.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 98–NM–

105–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

Airbus Industrie, 1 Rond Point Maurice

Bellonte, 31707 Blagnac Cedex, France.

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 98–NM–105–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–105–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The Direction Ge ́ne ́rale de l’Aviation

Civile (DGAC), which is the

airworthiness authority for France,

notified the FAA that an unsafe

condition may exist on certain Airbus

Model A320 series airplanes. The DGAC

advises that an operator found, on two

airplanes, cross-connections in the cargo

compartment discharge circuit for the

fire extinguisher bottle. The aft cargo

compartment electrical connector had

been fitted on the bottle discharge

circuit dedicated to the forward cargo

compartment fire extinguisher. The

forward cargo compartment electrical

connector was fitted on the aft

compartment electrical connector.

These cross-connections were attributed

to the wire loom (bundle) being

incorrectly identified, which the

manufacturer has since corrected. This

condition, if not corrected, could result

in the incorrect distribution of fire

extinguishing chemicals in the event of

an unconfined fire in the cargo

compartment.

Explanation of Relevant Service

Information

Airbus has issued All Operator Telex

(AOT) 26–10, dated April 5, 1993,

which describes procedures for an

electrical continuity test of the

discharge circuit for the cargo

compartment fire extinguisher bottle to

detect any cross-connection of the

electrical wires in the cargo

compartment discharge circuit, and

corrective actions, if necessary. The

corrective actions include reidentification of the wiring loom and

connection of electrical connectors to