21638 Federal Register / Vol. 65, No. 79 / Monday, April 24, 2000 / Rules and Regulations

(ICA), and for air carrier operations revise the

approved continuous airworthiness

maintenance program, by adding the

following:

‘‘MANDATORY INSPECTIONS

(1) Perform inspections of the following

parts at each piece-part opportunity in

accordance with the instructions provided in

the applicable manual provisions:

Part nomenclature Part No.

(P/N) Inspect per engine shop manual chapter

For CF6–6 Engines:

Disk, Fan Rotor Stage One .................................................. All ................. 72–21–03 Paragraph 2.F. or Paragraph 2.A.B. FluorescentPenetrant Inspect, and 72–21–03 Paragraph 3 or 3.A. Eddy

Current Inspection.

Disk, HPT Rotor Stage One ................................................. All ................. 72–53–03 Paragraph 1. Fluorescent-Penetrant Inspect, and

72–53–03 Paragraph 4. Eddy Current Inspection of the

HPTR Disk Rim Boltholes and 72–53–03 Paragraph 5. Disk

Bore Area Eddy Current Inspection.

Disk, HPT Rotor Stage Two ................................................. All ................. 72–53–04 Paragraph 1. Fluorescent-Penetrant Inspect, and

Paragraph 4. Eddy Current Inspection of the Stage 2 HPTR

Disk Rim Boltholes and 72–53–04 Paragraph 5. Eddy Current Inspection of the Stage 2 Disk Inner Boltholes and 72-

53–04 Paragraph 6. Disk Bore Area Eddy Current Inspection

For CF6–45, CF6–50 Engines:

Disk, Fan Rotor Stage One .................................................. All ................. Task 72–21–03–230–051 Fluorescent Penetrant Inspection,

and Task 72–21–03–250–002–052 Manual Eddy Current Inspection or 72–21–03–250–003–053 Automated Eddy Current Inspection.

Disk, HPT Rotor Stage One ................................................. All ................. Task 72–53–03–230–001–059 Fluorescent-Penetrant Inspect

Disk, and Task 72–53–03–250–052 Eddy Current Inspection

of the HPTR Stage 1 Rim Boltholes, and Task 72–53–03–

250–060, Disk Bore Area Eddy Current Inspection.

Disk, HPT Rotor Stage Two ................................................. All ................. Task 72–53–04–230–001–057 Fluorescent-Penetrant Inspect

Disk, and Task 72–53–04–250–053 Eddy Current Inspection

of the HPTR Stage 2 Rim and/or Inner Boltholes, and Task

72–53–04–250–060, Disk Bore Area Eddy Current Inspection.

(2) For the purposes of these mandatory

inspections, piece-part opportunity means:

(i) The part is considered completely

disassembled when accomplished in

accordance with the disassembly instructions

in the manufacturer’s engine manual; and

(ii) The part has accumulated more than

100 cycles in service since the last piece-part

opportunity inspection, provided that the

part was not damaged or related to the cause

for its removal from the engine.’’

(b) Except as provided in paragraph (c) of

this AD, and notwithstanding contrary

provisions in section 43.16 of the Federal

Aviation Regulations (14 CFR 43.16), these

mandatory inspections shall be performed

only in accordance with the Time Limits

Section of the manufacturer’s ICA.

Alternative Methods of Compliance

(c) 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 Engine Certification

Office (ECO). Operators shall submit their

requests through an appropriate FAA

Principal Maintenance Inspector, who may

add comments and then send it to the ECO.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this airworthiness directive,

if any, may be obtained from the ECO.

Ferry Flights

(d) Special flight permits may be issued in

accordance with sections 21.197 and 21.199

of the Federal Aviation Regulations (14 CFR

21.197 and 21.199) to operate the airplane to

a location where the requirements of this AD

can be accomplished.

Continuous Airworthiness Maintenance

Program

(e) FAA-certificated air carriers that have

an approved continuous airworthiness

maintenance program in accordance with the

record keeping requirement of § 121.369 (c)

of the Federal Aviation Regulations (14 CFR

121.369 (c)) must maintain records of the

mandatory inspections that result from

revising the Time Limits Section of the ICA

and the air carrier’s continuous airworthiness

program. Alternately, certificated air carriers

may establish an approved system of record

retention that provides a method for

preservation and retrieval of the maintenance

records that include the inspections resulting

from this AD, and include the policy and

procedures for implementing this alternate

method in the air carrier’s maintenance

manual required by § 121.369 (c) of the

Federal Aviation Regulations (14 CFR

121.369 (c)); however, the alternate system

must be accepted by the appropriate PMI and

require the maintenance records be

maintained either indefinitely or until the

work is repeated. Records of the piece-part

inspections are not required under § 121.380

(a) (2) (vi) of the Federal Aviation

Regulations (14 CFR 121.380 (a) (2) (vi)). All

other Operators must maintain the records of

mandatory inspections required by the

applicable regulations governing their

operations.

Note 3: The requirements of this AD have

been met when the engine shop manual

changes are made and air carriers have

modified their continuous airworthiness

maintenance plans to reflect the

requirements in the engine shop manuals.

(f) This amendment becomes effective on

October 23, 2000.

Issued in Burlington, Massachusetts, on

April 14, 2000.

Jay J. Pardee,

Manager, Engine and Propeller Directorate,

Aircraft Certification Service.

[FR Doc. 00–10158 Filed 4–21–00; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98–ANE–49–AD; Amendment

39–11698; AD 2000–08–12]

RIN 2120–AA64

Airworthiness Directives; General

Electric Company CF6–80A, CF6-80C2,

and CF6–80E1 Series Turbofan

Engines

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment supersedes

an existing airworthiness directive (AD),

applicable to certain General Electric

Federal Register / Vol. 65, No. 79 / Monday, April 24, 2000 / Rules and Regulations 21639

Company CF6–80A, CF6–80C2, and

CF6–80E1 series turbofan engines, that

currently requires revisions to the

Airworthiness Limitations Section

(ALS) of the manufacturer’s Instructions

for Continued Airworthiness (ICA) to

include required enhanced inspection of

selected critical life-limited parts at

each piece-part exposure. This action

adds additional eddy current

inspections (ECI) for the high pressure

turbine rotor (HPTR) Stage 1 and 2 disks

for all affected engine models, and

would add fan forward shaft inspections

for the CF6–80C2 engine model only.

This amendment is prompted by

additional focused inspection

procedures for critical life-limited

rotating engine parts that have been

developed by the manufacturer. The

actions specified by this AD are

intended to prevent critical life-limited

rotating engine part failure, which could

result in an uncontained engine failure

and damage to the airplane.

DATES: Effective October 23, 2000.

ADDRESSES: The information referenced

in this AD may be examined at the

Federal Aviation Administration (FAA),

New England Region, Office of the

Regional Counsel, 12 New England

Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT:

Karen Curtis, Aerospace Engineer,

Engine Certification Office, FAA, Engine

and Propeller Directorate, 12 New

England Executive Park, Burlington, MA

01803–5299; telephone (781) 238–7192,

fax (781) 238–7199.

SUPPLEMENTARY INFORMATION: A

proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39)

by superseding (AD) 99–08–13,

Amendment 39–11119 (64 FR 1795,

April 13, 1999), that is applicable to

General Electric Company (GE) CF6–

80A, CF6–80C2, and CF6–80E1 series

turbofan engines, was published in the

Federal Register on October 7, 1999 (64

FR 54594). That action proposed to

require revisions to the Life Limits

Section of the manufacturer’s

Instructions for Continued

Airworthiness (ICA) for GE CF6–80A,

CF6–80C2, and CF6–80E1 series

turbofan engines to include required

enhanced inspection of selected critical

life-limited parts at each piece-part

exposure.

New Inspection Procedures

Since the issuance of that AD,

additional focused inspection

procedures for other critical life-limited

rotating engine parts have been

developed by GE. This AD will require

modification of the airworthiness

limitations section in the manufacturers

manual and an air carrier’s approved

continuous airworthiness maintenance

program to incorporate these inspection

procedures.

Interested persons have been afforded

an opportunity to participate in the

making of this amendment. Due

consideration has been given to the

thirteen comments received.

Addition to Required Inspections

One commenter recommends adding

the –80E1 Fan Forward Shaft (FFS) vent

holes to the list of required inspections

because it is similar to the –80C2 FFS,

which will require the mandatory

inspection. The FAA agrees and the

inspection will be added to the Final

Rule.

‘‘Unsafe Condition’’

One commenter objects to the

language in the preamble of the NPRM

supersedure for the second phase of

enhanced inspections which includes a

finding of an ‘‘unsafe condition.’’ The

commenter asks that the term ‘‘unsafe

condition’’ be deleted and replaced with

the justification language from the

original NPRM. The FAA does not

agree. This commenter does not disagree

with the proposed rule itself but rather

with the term ‘‘unsafe condition’’

contained in the preamble to the NPRM.

It is not the intent of the FAA to

completely change the enhanced disk

inspection program established by the

current AD, which evolved as a

cooperative effort between the FAA and

industry. This intervention strategy was

designed to reduce the number of

uncontained engine failures by

mandating enhanced nondestructive

inspections of critical components that

could most likely result in a hazard to

the airplane in the event of a disk

failure. Since the engine maintenance

manuals did not mandate these

enhanced inspections, the current AD

was necessary to establish the

inspection program as an airworthiness

limitation. Regardless of the fact that it

was not stated explicitly in the original

NPRM, the FAA determined that an

‘‘unsafe condition’’ existed because the

engine maintenance manuals did not

contain enhanced inspections as an

airworthiness limitation. There was no

intent to imply any defect in the actual

engine hardware, but simply to state

that the maintenance manuals, that form

part of the approved engine design,

must be revised to mandate the

enhanced inspections. The supersedure

repeats that finding with respect to the

additional parts being added to the

enhanced inspection program. Because

a finding of an ‘‘unsafe condition’’ is

required for the FAA to issue an AD,

future NPRM’s adding parts to the

program will also include that finding.

Request To Change All References

From ‘‘Time Limits Section’’ to

‘‘Airworthiness Limitations Section’’

One commenter recommends

replacing references to the ‘‘Life Limits’’

section with references to the

‘‘Airworthiness Limitations’’ section

because Chapter 5 now contains two

subsets, 05–11 for Life Limits, and 05–

21 for the mandatory inspection. The

FAA agrees in part. The manufacturer

recently revised their engine manual to

include the heading ‘‘Airworthiness

Limitations’’ for Chapter 05–00–00 for

the CF6–80C2/–80E1 models and,

therefore, they can be referenced as

such. Should the manufacturer revise

the section headings in the CF6–80A

manual, any future AD’s could then

reference the revised section headings.

Request for Clarification of When FAA

Approval or AMOC Is Required

One commenter requests clarification

be added to this AD on when equivalent

substitutes for tools, equipment, or

procedures used for performing the

mandatory enhanced inspections

require FAA approval or an approved

alternate method of compliance

(AMOC).

The FAA does not agree that further

clarification is necessary in the AD.

When allowed for in an AD, an AMOC

provides a method by which an operator

may secure FAA approval for complying

with the requirements of that AD in a

manner or at a time other than specified

by the AD. This AD, and other similar

AD’s issued as part of the so-called Disk

Inspection Initiative of the Safer Skies

Program, are intended to address the

need to include mandatory detail

inspections in the FAA approved

portion of the engine maintenance

manual. This portion of the engine

maintenance manual is sometimes

referred to as the Airworthiness

Limitations Sections (ALS) of the

Instructions for Continued

Airworthiness. The FAA does not

intend that this AD specify the exact

method or tools with which to conduct

the inspection. Rather, the AD requires

only that the ALS be revised to include

a mandatory opportunistic inspection.

The FAA also does not intend that this

AD change the manner in which

operators seek approval to use tools or

methods of inspections other than those

provided for in the engine

manufacturer’s manual. Operators,

particularly air carriers, should follow

the procedures already in place to

secure FAA review and approval to use

such substitutes, if needed, and to

21640 Federal Register / Vol. 65, No. 79 / Monday, April 24, 2000 / Rules and Regulations

document that approval if necessary.

Therefore, the AMOC paragraph in the

AD will remain as proposed.

Request To Extend the Comment Period

One commenter requests that the

NPRM comment period be extended

until after the proposed inspections are

published to allow time for the

operators to review the specific

inspections that will be required. The

FAA does not agree. The FAA believes

that the nature and scope of the added

inspections will not be significantly

different from existing inspections. In

addition, the effective date of this AD

has been extended to 180 days after

publication to allow time for the

specific procedures to be published.

Operators may submit comments on the

specific procedures once they are

published and the FAA will consider

extending the effective date further or

additional rulemaking, as necessary.

The FAA does not believe, however,

that this final rule need be delayed

pending the publication of the

inspection procedures.

Effective Date of Final Rule

Six commenters requested that the AD

effectivity date be set to allow sufficient

time for publication of the procedures,

procurement of the equipment, and

training. The FAA agrees. The effective

date for the Final rule has been

extended to 180 days after publication

to allow sufficient time for the

publication of the inspection procedures

and for operators to prepare.

Support

Two commenters expressed support

for the enhanced inspections at piece

part exposure.

Removal of ‘‘of This Chapter’’ From

Paragraph (e) of the Compliance

Section

The statement ‘‘of this chapter’’ has

been removed from the first sentence of

paragraph (e) to improve the clarity of

the paragraph.

Economic Analysis

No comments were received on the

economic analysis contained in the

proposed rules. The FAA has

determined that the annual cost of

complying with this AD does not create

a significant economic impact on small

entities.

Adoption of the Proposed Rule

After careful review of the available

data, including the comments noted

above, the FAA has determined that air

safety and the public interest require the

adoption of the rule with the changes

described previously. The FAA has

determined that these changes will

neither increase the economic burden

on any operator nor increase the scope

of the AD.

Regulatory Impact

This final rule does not have

federalism implications, as defined in

Executive Order 13132, because it does

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. Accordingly, the

FAA has not consulted with state

authorities prior to publication of this

final rule.

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, 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 39–11119 (64 FR

17951, April 13, 1999), and by adding

a new airworthiness directive,

Amendment 39–11698, to read as

follows:

AD 2000–08–12 General Electric Company:

Amendment 39–11698. Docket No. 98–

ANE–49–AD. Supersedes AD 99–08–13,

Amendment 39–11119.

Applicability: General Electric Company

(GE) CF6–80A, CF6–80C2, and CF6–80E1

series turbofan engines, installed on but not

limited to Airbus Industrie A300, A310, and

A330 series, Boeing 747 and 767 series, and

McDonnell Douglas MD–11 series airplanes.

Note 1: This airworthiness directive (AD)

applies to each engine 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 engines 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 (c)

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 critical life-limited rotating

engine part failure, which could result in an

uncontained engine failure and damage to

the airplane, accomplish the following:

Inspections

(a) Within the next 30 days after the

effective date of this AD, revise the

manufacturer’s Life Limits Section of the

Instructions for Continued Airworthiness

(ICA) for the CF6–80A model and the

Airworthiness Limitations Section of the ICA

for CF6–80C2/–80E1 models. For air carrier

operations, revise the approved continuous

airworthiness maintenance program, by

adding the following:

‘‘MANDATORY INSPECTIONS

(1) Perform inspections of the following

parts at each piece-part opportunity in

accordance with the instructions provided in

the applicable manual provisions:

Part nomenclature Part No.

(P/N) Inspect per engine manual chapter

For CF6–80A Engines:

Disk, Fan Rotor .................................................................... All ................. 72–21–03 Paragraph 3. Fluorescent-Stage 1 Penetrant Inspect, and 72–21–03 Paragraph 4. Eddy Current Inspect.

Federal Register / Vol. 65, No. 79 / Monday, April 24, 2000 / Rules and Regulations 21641

Part nomenclature Part No.

(P/N) Inspect per engine manual chapter

Disk, HPT Rotor Stage One ................................................. All ................. 72–53–02 Paragraph 3. Fluorescent-Penetrant-Inspect Disk/

Shaft per 70–32–02, and 72–53–02 Paragraph 6. Eddy Current Inspection, and 72–53–02 Paragraph 6.D. Disk Bore

Area Eddy Current Inspection.

Disk, HPT Rotor Stage Two ................................................. All ................. 72–53–06 Paragraph 3. Fluorescent-Penetrant Inspection, and

72–53–06 Paragraph 6. Eddy Current Inspection of Rim

Boltholes for Cracks, and 72–53–06 Paragraph 7. Disk Bore

Area Eddy Current Inspection.

For CF6–80C2 Engines:

Disk, Fan Rotor Stage 1 ...................................................... All ................. Task 72–21–03–200–000–004 Fluorescent-Penetrant Inspection, and Task 72–21–03–200–000–008 Eddy Current Inspect Fan Rotor Disk Stage 1 Bore, Forward and Aft Hub

Faces, and Bore Radii.

Shaft, Fan Forward .............................................................. All ................. Task 72–21–05–200–000–001 Fluorescent Penetrant Inspection, and Task 72– 21–05–200–000–005 Vent Hole Eddy

Current Inspection.

Disk, HPT Rotor Stage One ................................................. All ................. Task 72–53–02–200–000–001 Fluorescent-Penetrant Inspect

the HPT Rotor Stage 1 Disk/Shaft, and Task 72–53–02–

200–000–005 Eddy Current Inspection, and Task 72–53–

02–200–000–006 Disk Bore Area Eddy Current Inspection.

Disk, HPT Rotor Stage Two ................................................. All ................. Task 72–53–06–200–000–002 Fluorescent-Penetrant Inspect

the Stage 2 Disk, and Task 72–53–06–200–000–006 Eddy

Current Inspection of the HPTR Stage 2 Rim Boltholes, and

Task 72–53–06–200–000–007 Disk Bore Area Eddy Current

Inspection.

For CF6–80E1 Engines:

Disk, Fan Rotor Stage One .................................................. All ................. Task 72– 21–03–230–051 Fluorescent-Penetrant Inspection,

and Task 72–21–03–250–051 or 72–21–03–250–052 Eddy

Current Inspection.

Shaft, Fan Forward .............................................................. All ................. Task 72–21–05–230–051 Fluorescent Penetrant Inspection,

and Task 72–21–05–250–051 Vent Hole Eddy Current Inspection

HPT Disk, Stage One ........................................................... All ................. Task 72–53–02–230–51 Fluorescent-Penetrant Inspection, and

Task 72–53–02–200–001–005 Eddy Current Inspection ,

and Task 72–53–02–250–054 Disk Bore Area Eddy Current

Inspection.

HPT Disk, Stage Two ........................................................... All ................. Task 72–53–06–230–051 Fluorescent-Penetrant Inspection,

and Task 72–53–06–200–001–006 Eddy Current Inspection

of the HPTR Stage 2 Rim Boltholes, and Task 72–53–06–

250–054 Disk Bore Area Eddy Current Inspection.

(2) For the purposes of these mandatory

inspections, piece-part opportunity means:

(i) The part is considered completely

disassembled when accomplished in

accordance with the disassembly instructions

in the manufacturer’s engine manual; and

(ii) The part has accumulated more than

100 cycles in service since the last piece-part

opportunity inspection, provided that the

part was not damaged or related to the cause

for its removal from the engine.’’

(b) Except as provided in paragraph (c) of

this AD, and notwithstanding contrary

provisions in section 43.16 of the Federal

Aviation Regulations (14 CFR 43.16), these

mandatory inspections shall be performed

only in accordance with the Life Limits

Section of the Instructions for Continued

Airworthiness (ICA) for the CF6–80A model

and the Airworthiness Limitations Section of

the ICA for CF6–80C2/–80E1 models.

Alternative Methods of Compliance

(c) 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 Engine Certification

Office (ECO). Operators shall submit their

requests through an appropriate FAA

Principal Maintenance Inspector (PMI), who

may add comments and then send it to the

ECO.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this airworthiness directive,

if any, may be obtained from the ECO.

Ferry Flights

(d) Special flight permits may be issued in

accordance with sections 21.197 and 21.199

of the Federal Aviation Regulations (14 CFR

21.197 and 21.199) to operate the airplane to

a location where the requirements of this AD

can be accomplished.

Continuous Airworthiness Maintenance

Program

(e) FAA-certificated air carriers that have

an approved continuous airworthiness

maintenance program in accordance with the

record keeping requirement of § 121.369(c) of

the Federal Aviation Regulations [14 CFR

121.369(c)] must maintain records of the

mandatory inspections that result from

revising the Life Limits Section of the

Instructions for Continued Airworthiness

(ICA) for the CF6–80A model and the

Airworthiness Limitations Section of the ICA

for CF6–80C2/–80E1 models and the air

carrier’s continuous airworthiness program.

Alternately, certificated air carriers may

establish an approved system of record

retention that provides a method for

preservation and retrieval of the maintenance

records that include the inspections resulting

from this AD, and include the policy and

procedures for implementing this alternate

method in the air carrier’s maintenance

manual required by § 121.369(c) of the

Federal Aviation Regulations (14 CFR

121.369(c)); however, the alternate system

must be accepted by the appropriate PMI and

require the maintenance records be

maintained either indefinitely or until the

work is repeated. Records of the piece-part

inspections are not required under § 121.380

(a)(2)(vi) of the Federal Aviation Regulations

(14 CFR 121.380(a)(2)(vi)). All other

Operators must maintain the records of

mandatory inspections required by the

applicable regulations governing their

operations.

Note 3: The requirements of this AD have

been met when the engine manual changes

21642 Federal Register / Vol. 65, No. 79 / Monday, April 24, 2000 / Rules and Regulations

are made and air carriers have modified their

continuous airworthiness maintenance plans

to reflect the requirements in the engine

manuals.

(f) This amendment becomes effective on

October 23, 2000.

Issued in Burlington, Massachusetts, on

April 14, 2000.

Jay J. Pardee,

Manager, Engine and Propeller Directorate,

Aircraft Certification Service.

[FR Doc. 00–10159 Filed 4–21–00; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98–ANE–39–AD; Amendment

39–11696; AD 2000–08–10]

RIN 2120–AA64

Airworthiness Directives; General

Electric Company GE90 Series

Turbofan Engines

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment supersedes

an existing airworthiness directive (AD),

applicable to certain General Electric

Company GE90 series turbofan engines,

that currently requires revisions to the

Airworthiness Limitations Section

(ALS) of the manufacturer’s Instructions

for Continued Airworthiness (ICA) to

include required enhanced inspection of

selected critical life-limited parts at

each piece-part exposure. This action

adds additional critical life-limited parts

for enhanced inspection. This

amendment is prompted by additional

focused inspection procedures for other

critical life-limited rotating engine parts

that have been developed by the

manufacturer. The actions specified by

this AD are intended to prevent critical

life-limited rotating engine part failure,

which could result in an uncontained

engine failure and damage to the

airplane.

DATES: Effective October 23, 2000.

ADDRESSES: The information referenced

in this AD may be examined at the

Federal Aviation Administration (FAA),

New England Region, Office of the

Regional Counsel, 12 New England

Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT:

Karen Curtis, Aerospace Engineer,

Engine Certification Office, FAA, Engine

and Propeller Directorate, 12 New

England Executive Park, Burlington, MA

01803–5299; telephone (781) 238–7134,

fax (781) 238–7199.

SUPPLEMENTARY INFORMATION: A

proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39)

by superseding (AD) 990817,

Amendment 3911123 (64 FR 17961),

that is applicable to General Electric

Company GE90 series turbofan engine

was published in the Federal Register

on October 7, 1999 (64 FR 54591). That

action proposed to require revisions to

the Airworthiness Limitations Section

of the manufacturer’s Instructions for

Continued Airworthiness (ICA) for

General Electric Company (GE) GE90

series turbofan engines to include

required enhanced inspection of

selected critical life-limited parts at

each piece-part exposure.

New Inspection Procedures

Since the issuance of that AD,

additional focused inspection

procedures for other critical life-limited

rotating engine parts have been

developed by GE. This AD will require

modification of the airworthiness

limitations section in the manufacturers

manual and an air carrier’s approved

continuous airworthiness maintenance

program to incorporate these inspection

procedures.

Interested persons have been afforded

an opportunity to participate in the

making of this amendment. Due

consideration has been given to the five

comments received.

‘‘Unsafe Condition’’

One commenter objects to the

language in the preamble of the NPRM

supersedure for the second phase of

enhanced inspections which includes a

finding of an ‘‘unsafe condition.’’ The

commenter asks that the term ‘‘unsafe

condition’’ be deleted and replaced with

the justification language from the

original NPRM. The FAA does not

agree. The commenter does not disagree

with the proposed rule itself but rather

with the term ‘‘unsafe condition’’ that is

contained in the preamble to the NPRM.

It is not the intent of the FAA to

completely change the enhanced disk

inspection program established by the

current AD, which evolved as a

cooperative effort between the FAA and

industry. This intervention strategy was

designed to reduce the number of

uncontained engine failures by

mandating enhanced nondestructive

inspections of critical rotating

components that could most likely

result in a hazard to the airplane in the

event of a failure. Since the engine

maintenance manuals did not mandate

these enhanced inspections, the current

AD was necessary to establish the

inspection program as an airworthiness

limitation. Regardless of the fact that it

was not stated explicitly in the original

NPRM, the FAA determined that an

‘‘unsafe condition’’ existed because the

engine maintenance manuals did not

contain enhanced inspections as an

airworthiness limitation. There was no

intent to imply any defect in the actual

engine hardware, but simply to state

that the maintenance manuals, that form

part of the approved engine design,

must be revised to mandate the

enhanced inspections. The supersedure

repeats that finding with respect to the

additional parts being added to the

enhanced inspection program. Because

a finding of an ‘‘unsafe condition’’ is

required for the FAA to issue an AD,

future NPRM’s adding parts to the

program will also include that finding.

‘‘Life Limits’’ vs. ‘‘Airworthiness

Limitations’’ Sections

One commenter recommends

replacing references to the ‘‘Life Limits’’

section with references to the

‘‘Airworthiness Limitations’’ section

because Chapter 5 now contains two

subsets, 05–11 for Life Limits, and 05–

21 for the mandatory inspection. The

FAA agrees. The Final Rule references

the ‘‘Airworthiness Limitations’’ section

instead of the ‘‘Life Limits’’ section.

Task Numbers and Inspection

Descriptions

One commenter recommends that 2nd

level task numbers and inspection

descriptions be used instead of the

subtask numbers to ensure that all

appropriate preparatory steps (e.g.

cleaning) are included in the mandatory

inspection. The FAA agrees. The Final

Rule has been revised accordingly to

ensure that all appropriate preparatory

steps (e.g. cleaning) are included in the

mandatory inspection.

Effectivity Date

Two commenters request that the

AD’s effectivity date be set to allow

sufficient time for publication of the

procedures, equipment procurement

and training necessary to perform the

mandatory inspection. The FAA agrees.

The effectivity date for the Final rule

has been extended to 180 days after

publication to allow sufficient time for

the publication of the inspection

procedures and for operators to prepare.

Removal of ‘‘of This Chapter’’ From

Paragraph (e) of the Compliance

Section

The statement ‘‘of this chapter’’ has

been removed from the first sentence of

paragraph (e) to improve the clarity of

the paragraph.