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

15861

Vol. 62, No. 64

Thursday, April 3, 1997

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97–ANE–15]

RIN 2120–AA64

Airworthiness Directives; General

Electric Company CT58 Series

Turboshaft 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

General Electric Company (GE) CT58

series turboshaft engines. This proposal

would require removal from service of

compressor rear shafts, initial and

repetitive inspections of ten rotating

parts, and replacement if found cracked,

until those parts are removed from

service and replaced with improved

design parts. This proposal is prompted

by a stage 2 turbine wheel incident in

1993 which resulted in an increased

awareness of small features on critical

rotating parts which could affect part

life. The actions specified by the

proposed AD are intended to prevent

fatigue cracking on specific critical

rotating parts, which could result in

failure of the part, causing an

uncontained engine failure and damage

to the aircraft.

DATES: Comments must be received by

June 2, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), New England

Region, Office of the Assistant Chief

Counsel, Attention: Rules Docket No.

97-ANE–15, 12 New England Executive

Park, Burlington, MA 01803-5299.

Comments may also be sent via the

Internet using the following address: ‘‘9-

ad-engineprop@faa.dot.gov’’. Comments

sent via the Internet must contain the

docket number in the subject line.

Comments may be inspected at this

location between 8:00 a.m. and 4:30

p.m., Monday through Friday, except

Federal holidays.

The service information referenced in

the proposed rule may be obtained from

General Electric Aircraft Engines,

Technical Publications, 1000 Western

Avenue, Lynn, MA 01910; telephone

(617) 594–5102, fax (617) 594–2717.

This information may be examined at

the FAA, New England Region, Office of

the Assistant Chief Counsel, 12 New

England Executive Park, Burlington,

MA.

FOR FURTHER INFORMATION CONTACT:

Diane Cook, Aerospace Engineer, Engine

Certification Office, FAA, Engine and

Propeller Directorate, 12 New England

Executive Park, Burlington, MA 01803–

5299; telephone (617) 238–7134, fax

(617) 238–7199.

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

should 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–ANE–15.’’ 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, New England Region, Office of the

Assistant Chief Counsel, Attention:

Rules Docket No. 97–ANE–15, 12 New

England Executive Park, Burlington, MA

01803–5299.

Discussion

The Federal Aviation Administration

(FAA) received a report of a stage 2

uncontained turbine wheel failure on a

General Electric Company (GE) Model

CT58–140–1 turboshaft engine. The

investigation resulted in the issuance of

airworthiness directive (AD) 94–07–05

and an increased awareness of all small

features on CT58 critical rotating parts.

The manufacturer began a review of all

small features on critical rotating parts

on the CT58 engine that could affect the

life capability of that part. A small

feature is identified as a fillet radius,

breakage, or edge radius that is 0.20

inches or less. Subsequent to the

issuance of AD 94–07–05 the FAA has

determined that a small feature may be

the life limiting area of a critical rotating

part and may result in a lower crack

initiation part life than what is currently

published. Because of the small

feature’s size, any local departures from

the true contour (but still within the

tolerance requirements) could affect the

part fatigue life, and depending on the

nature and location of the local

departure(s), this small feature could

become the life limiting area and subject

to fatigue cracking prior to the

published life limit. This condition, if

not corrected, could result in fatigue

cracking on specific critical rotating

parts, which could result in failure of

the part, causing an uncontained engine

failure and damage to the aircraft.

The FAA has reviewed and approved

the technical contents of the following

GE Aircraft Engines Service Bulletins

(SB’s): No. (CT58) 72–181, CEB–284,

Revision 1, dated November 29, 1995,

that describes procedures for initial and

repetitive inspections of life limited

rotating parts; and No. (CT58) A72–163

(CEB–258), Revision 5, dated May 12,

1994, that describes procedures for an

improved methodology for determining

hours and cycles in service for aircraft

performing repetitive heavy lift (RHL)

operations.

Since an unsafe condition has been

identified that is likely to exist or
15862 Federal Register / Vol. 62, No. 64 / Thursday, April 3, 1997 / Proposed Rules

develop on other products of this same

type design, the proposed AD would

require removal from service of

compressor rear shafts, initial and

repetitive inspections of ten rotating

parts, and replacement if found cracked,

until those parts are removed from

service and replaced with improved

design parts. The actions would be

required to be accomplished in

accordance with the SB’s described

previously.

There are approximately 5,550

engines of the affected design in the

worldwide fleet. The FAA estimates that

380 civil engines installed on aircraft of

U.S. registry and 2,600 U.S. military

engines would be affected by this

proposed AD. The FAA estimates that

for 95 engines the compressor will need

to be debladed to accomplish the

inspection, that it would take

approximately 40 work hours per engine

to accomplish the proposed actions, that

the average labor rate is $60 per work

hour, and that required parts would cost

approximately $100 per engine. For 285

engines, the inspection can be

accomplished during scheduled

maintenance, and the inspection would

take an estimated 8.33 work hours, with

no required parts cost. For 114 engines,

the compressor would be required to be

removed early, with a pro rated parts

cost of $1,300 per engine. Based on

these figures, the total cost impact of the

proposed AD on U.S. operators is

estimated to be $528,143.

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 USC 106(g), 40113, 44701.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

General Electric Company: Docket No. 97–

ANE–15.

Applicability: General Electric Company

(GE) Models CT58–100–2, –110–1/–2, –140–

1/–2, and T58–GE–3/–5/–10/–100 turboshaft

engines, installed on but not limited to

Boeing Vertol 107 series, and Sikorsky S61

and S62 series aircraft.

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 (f)

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 fatigue cracking on specific

critical rotating parts, which could result in

failure of the part, causing an uncontained

engine failure and damage to the aircraft,

accomplish the following:

(a) Determine hours time in service (TIS)

and cycles in service (CIS) in accordance

with the improved methodology described in

GE Aircraft Engines Service Bulletin (SB) No.

(CT58) A72–162 (CEB–258), Revision 5,

dated May 12, 1994.

(b) For engines that have engaged in

repeated heavy lift (RHL) operations, as

defined in paragraph (e) of this AD,

accomplish the following:

(1) For compressor rear shafts, Part

Numbers (P/N’s) 4000T29P01/P03,

5016T95P01/P04, and 5013T86P03,

accomplish the following:

(i) For compressor rear shafts, with either

2,975 or more hours TIS, or 9,550 or more

CIS, on the effective date of this AD, remove

compressor rear shafts and replace with a

serviceable compressor rear shaft at the next

light overhaul or next exposure of

compressor rear shafts after the effective date

of this AD, whichever occurs first.

(ii) For all other compressor rear shafts,

remove compressor rear shafts and replace

with a serviceable compressor rear shaft,

prior to accumulating 3,000 hours TIS, or

9,600 CIS, whichever occurs first.

(iii) For all compressor rear shafts, remove

from service and replace with a serviceable,

redesigned compressor rear shaft, P/N

5016T95P06, not later than December 31,

1997.

(2) Initially inspect the ten rotating parts

specified in paragraph (d) of this AD for

cracks at the times specified in subparagraphs (i) and (ii) of this paragraph, and,

thereafter, inspect at each light overhaul or

major overhaul until the parts are retired

from service. Perform the inspections in

accordance with the procedures described in

GE Aircraft Engines SB No. (CT58) 72–181,

CEB284, Revision 1, dated November 29,

1995. Prior to further flight, replace parts

found cracked during these inspections with

serviceable parts.

(i) For parts with greater than the baseline

time in service (TIS) on the effective date of

this AD, inspect at the earliest occurrence of

the following after the effective date of this

AD: the next light overhaul, the next major

overhaul, or the next exposure of the affected

parts.

(ii) For parts with less than or equal to the

baseline TIS on the effective date of this AD,

inspect within 1,000 hours TIS from the

listed baseline TIS.

(c) For engines that have never engaged in

RHL operations, accomplish the following:

(1) For compressor rear shafts, P/N’s

4000T29P01/P03, 5016T95P01/P04, and

5013T86P03, remove compressor rear shafts

and replace with a serviceable compressor

rear shaft, prior to accumulating 9,600 CIS,

or 9,000 hours TIS, whichever occurs first.

Prior to December 31, 1999, replace

compressor rear shafts with a serviceable,

redesigned compressor rear shaft, P/N

5016T95P06.

(2) Initially inspect the ten rotating parts

specified in paragraph (d) of this AD for

cracks at the times specified in subparagraphs (i) and (ii) of this paragraph, and,

thereafter, at each light overhaul or major

overhaul until the parts are retired from

service. Perform the inspections in

accordance with the procedures described in

GE Aircraft Engines SB No. (CT58) 72–181,

CEB284, Revision 1, dated November 29,

1995. Prior to further flight, replace parts

found cracked during these inspections with

serviceable parts.

(i) For parts with greater than the baseline

TIS on the effective date of this AD, inspect

at the earliest occurrence of the following

after the effective date of this AD: the next

light overhaul, the next major overhaul, or

the next exposure.

(ii) For parts with less than or equal to the

baseline TIS on the effective date of this AD,

inspect within 2,000 hours TIS from the

listed baseline hours.

(d) For the purpose of performing the

inspections required by paragraphs (b)(2) and
Federal Register / Vol. 62, No. 64 / Thursday, April 3, 1997 / Proposed Rules 15863

(c)(2) of this AD, the following baseline TIS

are established:

(i) For compressor rotor spool assemblies,

P/N’s 6010T57G04 and 6010T57G08,

whether or not used in RHL operations,

baseline is 2,000 hours TIS.

(ii) For turbine front shafts, P/N’s

5003T35P01 and 573D358P002, whether or

not utilized in RHL operation, baseline is

1,000 hours TIS.

(iii) For turbine coupling shafts, P/N’s

4001T26P01 and 278D987P002, if utilized in

RHL operation, baseline is 1,000 hours TIS;

if never utilized in RHL operations, baseline

is 2,000 hours TIS.

(iv) For turbine rear shafts, P/N’s

4005T29P01 and 37D400244P101, whether or

not utilized in RHL operation, baseline is

2,000 hours TIS.

(v) For Stage 1 front cooling plates, P/N’s

37C300055P101, whether or not utilized in

RHL operation, baseline is 1,000 hours TIS.

(vi) For Stage 1 aft cooling plates, P/N’s

3002T25P01 and 645C334P002, whether or

not utilized in RHL operation, baseline is

1,000 hours TIS.

(vii) For Stage 2 front cooling plates, P/N’s

3000T88P02 and 645C332P002, whether or

not utilized in RHL operation, baseline is

1,000 hours TIS.

(viii) For Stage 2 aft cooling plates, P/N’s

3002T27P01 and 645C336P002, whether or

not utilized in RHL operation, baseline is

1,000 hours TIS.

(ix) For Stage 1 turbine wheels, P/N

4002T17P02 TF3, if utilized in RHL

operation, baseline is 1,000 hours TIS; if

never utilized in RHL operation, baseline is

2,000 hours TIS.

(x) For Stage 2 turbine wheels, P/N

4002T96P02 TF3, if utilized in RHL

operation, baseline is 1,000 hours TIS; if

never utilized in RHL operation, baseline is

2,000 hours TIS.

(e) For the purpose of this AD, the

following definitions apply:

(1) RHL operation is defined as performing

more than 10 lift-carry-drop cycles per hour

TIS without landing, or more than 10 takeoffs

and landings per hour TIS.

(2) Light overhaul is defined as scheduled

engine maintenance that allows the engine to

continue in service until scheduled major

overhaul time is reached.

(3) Major overhaul is defined as scheduled

engine maintenance including complete

engine inspections and tests with repair or

replacement of parts or components as

necessary.

(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, Engine

Certification Office. The request should be

forwarded through an appropriate FAA

Principal Maintenance Inspector, who may

add comments and then send it to the

Manager, Engine Certification Office.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this airworthiness directive,

if any, may be obtained from the Engine

Certification Office.

(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 aircraft to

a location where the inspection requirements

of this AD can be accomplished.

Issued in Burlington, Massachusetts, on

March 27, 1997.

James C. Jones,

Acting Manager, Engine and Propeller

Directorate, Aircraft Certification Service.

[FR Doc. 97–8475 Filed 4–2–97; 8:45 am]

BILLING CODE 4910–13–U 1

14 CFR Part 71

[Airspace Docket No. 97–AWP–14]

Proposed Revision of Class E

Airspace; Sacramento, CA

AGENCY: Federal Aviation

Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking.

SUMMARY: This notice proposes to revise

the Class E airspace area at Sacramento,

CA. This action removes from the

Sacramento E5 airspace area description

that portion of airspace defined as a

surface area for Sacramento Executive

Airport and corresponding references.

Deleting this portion of the description

which describes a surface area conforms

to the E5 airspace area standard. This

surface area is thoroughly and

appropriately described in the

Sacramento Executive Airport, CA,

Class E2 airspace area. A review of

airspace classification and air traffic

procedures has made this action

necessary. The intended effect of this

action is to remove overlapping

descriptions of controlled airspace.

DATES: Comments must be received on

or before April 15, 1997.

ADDRESSES: Send comments on the

proposal in triplicate to: Federal

Aviation Administration, Attn:

Manager, Operations Branch, AWP–530,

Docket No. 97–AWP–14, Air Traffic

Division, P.O. Box 92007, Worldway

Postal Center, Los Angeles, California

90009.

The official docket may be examined

in the Office of the Assistant Chief

Counsel, Western Pacific Region,

Federal Aviation Administration, Room

6007, 15000 Aviation Boulevard,

Lawndale, California 90261.

An informal docket may also be

examined during normal business at the

Office of the Manager, Operations

Branch, Air Traffic Division at the above

address.

FOR FURTHER INFORMATION CONTACT:

William Buck, Airspace Specialist,

Operations Branch, AWP–530, Air

Traffic Division, Western-Pacific

Region, Federal Aviation

Administration, 15000 Aviation

Boulevard, Lawndale, California 90261,

telephone (310) 725–6556.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested parties are invited to

participate in this proposed rulemaking

by submitting such written data, views,

or arguments as they may desire.

Comments that provide the factual basis

supporting the views and suggestions

presented are particularly helpful in

developing reasoned regulatory

decisions on the proposal. Comments

are specifically invited on the overall

regulatory, aeronautical, economic,

environmental, and energy-related

aspects of the proposal.

Communications should identify the

airspace docket number and be

submitted in triplicate to the address

listed above. Commenters wishing the

FAA to acknowledge receipt of their

comments on this notice must submit

with the comments a self-addressed,

stamped postcard on which the

following statement is made:

‘‘Comments to Airspace Docket No. 97–

AWP–14.’’ The postcard will be date/

time stamped and returned to the

commenter. All communications

received on or before the specified

closing date for comments will be

considered before taking action on the

proposed rule. The proposal contained

in this notice may be changed in light

of comments received. All comments

submitted will be available for

examination in the Operations Branch,

Air Traffic Division, at 15000 Aviation

Boulevard, Lawndale, California 90261,

both before and after the closing date for

comments. A report summarizing each

substantive public contact with FAA

personnel concerned with this

rulemaking will be filed in the docket.

Availability of NPRM

Any person may obtain a copy of this

Notice of Proposed Rulemaking (NPRM)

by submitting a request to the Federal

Aviation Administration, Operations

Branch, P.O. Box 92007, Worldway

Postal Center, Los Angeles, California

90009. Communications must identify

the notice number of this NPRM.

Persons interested in being placed on a

mailing list for future NPRM’s should

also request a copy of Advisory Circular

No. 11–2A, which describes the

application procedures.

The Proposal

The FAA is considering an

amendment to part 71 of the Federal

Aviation Regulations (14 CFR part 71) to

revise the class E airspace area at

Sacramento, CA. This action removes

from the Sacramento E5 airspace area