1866 Federal Register / Vol. 62, No. 9 / Tuesday, January 14, 1997 / Proposed Rules

Issued in Fort Worth, Texas, on January 7,

1997.

Eric Bries,

Acting Manager, Rotorcraft Directorate,

Aircraft Certification Service.

[FR Doc. 97–879 Filed 1–13–97; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 96–NM–185–AD]

RIN 2120–AA64

Airworthiness Directives; Fokker

Model F28 Mark 0100 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 Fokker Model F28 Mark 0100

series airplanes. This proposal would

require repetitive inspections of certain

flanges and finger strips at rib 5.0 of the

vertical stabilizer to detect fatigue

cracking, and repairs, if necessary. It

also would require modifications that

would strengthen the torsion box at rib

5.0 and prevent fatigue cracking; one of

these modifications would be

terminating action for the repetitive

inspections. This proposal is prompted

by reports indicating that, during fullscale fatigue testing, cracking has been

found on the vertical stabilizer of the

test article. The actions specified by the

proposed AD are intended to detect and

prevent fatigue cracking in the subject

area, which, if not corrected, could

reduce the structural integrity of the

vertical stabilizer.

DATES: Comments must be received by

February 24, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 96–NM–

185–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

Fokker Services B.V., Technical Support

Department, P.O. Box 75047, 1117 ZN

Schiphol Airport, The Netherlands. This

information may be examined at the

FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton,

Washington.

FOR FURTHER INFORMATION CONTACT: Tim

Dulin, Aerospace Engineer,

Standardization Branch, ANM–113,

FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton,

Washington 98055–4056; telephone

(206) 227–2141; fax (206) 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 96–NM–185–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–103, Attention: Rules Docket No.

96–NM–185–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The Rijksluchtvaartdienst (RLD),

which is the airworthiness authority for

the Netherlands, has notified the FAA

that an unsafe condition may exist on

certain Fokker Model F28 Mark 0100

series airplanes. The RLD advises that it

has received reports indicating that

cracks have been found on the vertical

stabilizer during the manufacturer’s fullscale fatigue tests on the Fokker Model

F28 Mark 0100 test article. These fatigue

cracks were detected at the bolt holes of

the right-hand flange of the torsion box,

and in the finger strip on the left-hand

flange at rib 5.0 of the vertical stabilizer.

The RLD also advises that it has

received reports indicating that

subsequent full-scale fatigue tests have

detected additional cracks in rib 5.0 of

the vertical stabilizer after a stiffener

had been added to the torsion box in

accordance with Fokker Service Bulletin

SBF100–55–018. Although this

modification was performed to

strengthen this area against fatigue

cracking, investigation has shown that

the stiffener produces a too-rapid

change in the structural strength of the

torsion box, which may lead to fatigue

cracking in an adjacent area.

Fatigue cracking in the subject area, if

not prevented, could reduce structural

integrity of the vertical stabilizer.

Explanation of Relevant Service

Information

Fokker has issued Service Bulletin

SBF100–55–019, Revision 1, dated May

19, 1993, which describes procedures

for conducting repetitive eddy current

inspections of the flanges and finger

strips at rib 5.0 of the vertical stabilizers

to detect fatigue cracking, and repair, if

necessary.

Fokker also has issued Service

Bulletin SBF100–55–018, Revision 1,

dated December 27, 1993, which

describes procedures for modifying the

torsion box at rib 5.0 of the vertical

stabilizer by installing stiffening to the

rib web and flanges for added strength.

This service bulletin also describes

procedures for a pre-modification eddy

current inspection of the vertical

stabilizer to detect cracking, and repair,

if necessary, in accordance with Fokker

Service Bulletin SBF100–55–019.

Accomplishment of this modification

eliminates the need for repetitive

inspections to detect fatigue cracking.

Additionally, Fokker has issued

Service Bulletin SBF100–55–023, dated

January 3, 1995, which describes

procedures for another modification to

strengthen rib 5.0 of the vertical

stabilizer. This modification, which

entails the cold expansion of holes in

the torsion box at rib 5.0, is intended to

prevent additional fatigue cracking that

could be caused by the earlier

installation of the torsion box stiffener.

The RLD classified these service

bulletins as mandatory and issued

Netherlands airworthiness directives

(BLA) 93–069 (A), dated June 1, 1993,

and BLA 1995–017 (A), dated February

28, 1995, in order to assure the

continued airworthiness of these

airplanes in the Netherlands.
Federal Register / Vol. 62, No. 9 / Tuesday, January 14, 1997 / Proposed Rules 1867

FAA’s Conclusions

This airplane model is manufactured

in the Netherlands and is type

certificated for operation in the United

States under the provisions of section

21.29 of the Federal Aviation

Regulations (14 CFR 21.29) and the

applicable bilateral airworthiness

agreement. Pursuant to this bilateral

airworthiness agreement, the RLD has

kept the FAA informed of the situation

described above. The FAA has

examined the findings of the RLD,

reviewed all available information, and

determined that AD action is necessary

for products of this type design that are

certificated for operation in the United

States.

Explanation of Requirements of

Proposed Rule

Since an unsafe condition has been

identified that is likely to exist or

develop on other airplanes of the same

type design registered in the United

States, the proposed AD would require

repetitive eddy current inspections to

detect fatigue cracking of the left-hand

and right-hand flanges and finger strips

at rib 5.0 of the vertical stabilizer, and

repair, if necessary.

The proposed AD also would require

modification of rib 5.0 by the

installation of a stiffener to the torsion

box; this modification would be

preceded by an eddy current inspection

to detect fatigue cracking, and repair, if

necessary. Accomplishment of this

modification would terminate the

requirement for repetitive eddy current

inspections.

In addition, the proposed AD would

require another modification of rib 5.0

by cold-expanding certain bolt holes on

the torsion box.

These actions would be required to be

accomplished in accordance with the

applicable service bulletins described

previously.

Differences Between the Proposed Rule

and the Service Bulletins

If any cracking is detected during an

eddy current inspection of the left-hand

and right-hand flanges and finger strips

at rib 5.0 of the vertical stabilizer, the

proposed rule would require that the

Manager, Standardization Branch,

ANM–113, FAA, Transport Airplane

Directorate approve the method of

repair. The applicable Fokker service

bulletins do not provide instructions for

repair, but recommend that Fokker be

contacted prior to repairing fatigue

cracks at rib 5.0.

Other Related Rulemaking Actions

The FAA has issued AD 91–18–15,

amendment 39–8018 (56 FR 43548,

September 3, 1991), which requires

reinforcement of the left-hand and righthand flanges of rib 5.0 of the vertical

stabilizer by the installation of

reinforcing finger clips, in accordance

with Fokker Service Bulletin F100–55–

014, dated November 29, 1990. That AD

was prompted by reports of cracking in

the flange of the torsion box at the

junction of rib 5.0 and intermediate spar

I; it is applicable to Fokker Model F28

Mark 0100 series airplanes having serial

numbers 11244 through 11335.

The reinforcement required by AD

91–18–15 is to be installed prior to the

accumulation of 6,000 total landings on

the airplane, or within 100 days after

October 8, 1991 (the effective date of

that AD), whichever is later. Under the

proposed AD, however, this

modification would not have to be

installed if the addition of steel

reinforcement to the torsion box [as

specified in proposed paragraph (b)(2)]

is accomplished before an airplane has

accumulated 6,000 total landings.

Cost Impact

The FAA estimates that 122 Fokker

Model F28 Mark 0100 series airplanes of

U.S. registry would be affected by this

proposed AD.

Approximately 77 airplanes would be

required to conduct repetitive

inspections of the left-hand and righthand flanges and finger strips at rib 5.0

of the vertical stabilizer. It would take

approximately 10 work hours per

airplane to accomplish each proposed

inspection. The average labor rate is $60

per work hour. Based on these figures,

the cost impact of the proposed

inspection requirement on U.S.

operators of these airplanes is estimated

to be $46,200, or $600 per airplane, per

inspection.

Approximately 77 airplanes also

would be required to accomplish the

proposed installation of steel

reinforcement in the torsion box at rib

5.0 of the vertical stabilizer. It would

take approximately 170 work hours per

airplane to accomplish this modification

(including a pre-modification

inspection). The average labor rate is

$60 per work hour. Required parts

would cost approximately $27,000.

Based on these figures, the cost impact

of this proposed action on U.S.

operators of these airplanes is estimated

to be $2,864,400, or $37,200 per

airplane.

Approximately 122 airplanes would

be required to accomplish the proposed

cold expansion of holes in the torsion

box at rib 5.0 of the vertical stabilizer.

It would take approximately 17 work

hours per airplane to accomplish this

modification, or approximately 8 work

hours per airplane if this proposed

action is done at the same time as the

proposed installation of steel

reinforcement. The average labor rate is

$60 per work hour. Required parts

would cost approximately $206. Based

on these figures, the cost impact of this

proposed action on U.S. operators of

these airplanes is estimated to be

between $83,692 and $149,572, or

between $686 and $1,226 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.
1868 Federal Register / Vol. 62, No. 9 / Tuesday, January 14, 1997 / Proposed Rules

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

Fokker: Docket 96–NM–185–AD.

Applicability: Model F28 Mark 0100 series

airplanes having the serial numbers specified

in Table 1 of this AD; certificated in any

category.

TABLE 1.—SERIAL NUMBERS OF

AIRPLANES SUBJECT TO THIS AD

11244 through 11460, inclusive

11463 through 11469, inclusive

11471

11474 through 11483, inclusive

11489 through 11491, inclusive

11497 through 11499, inclusive

11501

11502

11504

11506

11507

11512 through 11515, inclusive

11517

11520

Note 1: This AD applies to each airplane

identified in the preceding applicability

provision, regardless of whether it has been

otherwise 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 detect and prevent fatigue cracking in

the vertical stabilizer, which consequently

could reduce its structural integrity,

accomplish the following:

(a) For airplanes having serial numbers

11244 through 11419, inclusive, and 11421:

Except as provided by paragraph (c) of this

AD, prior to the accumulation of 8,500 total

landings or within 30 days after the effective

date of this AD, whichever occurs later,

perform an eddy current inspection to detect

fatigue cracking in the left-hand and righthand flanges and finger strips at rib 5.0 of the

vertical stabilizer, in accordance with Fokker

Service Bulletin SBF100–55–019, Revision 1,

dated May 19, 1993.

(1) If no cracking is detected, repeat this

inspection thereafter at intervals not to

exceed 2,000 landings until the requirements

of paragraph (b) of this AD are accomplished.

(2) If any cracking is detected, prior to

further flight, repair in accordance with a

method approved by the Manager,

Standardization Branch, ANM–113, FAA,

Transport Airplane Directorate.

(b) For airplanes with serial numbers

11244 through 11419, inclusive, and 11421,

accomplish the requirements of both

paragraphs (b)(1) and (b)(2) of this AD:

(1) Except as provided by paragraph (c) of

this AD, prior to the accumulation of 13,500

total landings, or within 6 months after the

effective date of this AD, whichever occurs

later, perform an eddy current inspection to

detect fatigue cracking in the left-hand and

right-hand flanges and finger strips at rib 5.0

of the vertical stabilizer, in accordance with

Part 1 of the Accomplishment Instructions of

Fokker Service Bulletin SBF100–55–018,

Revision 1, dated December 27, 1993.

(i) If no cracking is detected, prior to

further flight, accomplish the requirements of

paragraph (b)(2) of this AD.

(ii) If any cracking is detected, prior to

further flight, repair in accordance with a

method approved by the Manager,

Standardization Branch, ANM–113, and

accomplish the requirements of paragraph

(b)(2) of this AD.

(2) After accomplishing the requirements

of paragraph (b)(1) of this AD, modify rib 5.0

of the vertical stabilizer by installing new

stiffening, in accordance with Part 2 of the

Accomplishment Instructions of Fokker

Service Bulletin SBF100–55–018, Revision 1,

dated December 27, 1993. Accomplishment

of this modification constitutes terminating

action for the repetitive inspections required

by paragraph (a) of this AD.

(c) The following exceptions apply with

regard to the requirements of paragraphs (a)

and (b) of this AD:

(1) Accomplishment of the inspection

specified in paragraph (a) and (b)(1) of this

AD is not required if the modification

specified in paragraph (b)(2) is accomplished

prior to the accumulation of 7,300 total

landings on the airplane.

(2) Compliance with AD 91–18–15,

amendment 39–8018, is not required if the

requirements of paragraph (b)(2) of this AD

are accomplished prior to the accumulation

of 6,000 total landings on the airplane.

(d) For all airplanes: At the applicable

times specified in paragraph (d)(1) or (d)(2),

modify the Hi-lok bolt holes at rib 5.0 of the

vertical stabilizer by cold expansion, in

accordance with Fokker Service Bulletin

SBF100–55–023, dated January 3, 1995.

(1) For airplanes that have been modified

in accordance with the requirements of

paragraph (b) of this AD prior to the effective

date of this AD: Modify prior to the

accumulation of either 10,000 landings after

in-service modification, or 10,000 landings

after delivery with factory modification, as

applicable; or within 30 days after the

effective date of this AD, whichever occurs

later.

(2) For all other airplanes: Modify

concurrent with accomplishing the

requirements of paragraph (b) of this AD.

(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,

Standardization Branch, ANM–113.

Operators shall submit their requests through

an appropriate FAA Principal Maintenance

Inspector, who may add comments and then

send it to the Manager, Standardization

Branch, ANM–113.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Standardization Branch,

ANM–113.

(f) Special flight permits may be issued in

accordance with §§ 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 January

8, 1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–883 Filed 1–13–97; 8:45 am]

BILLING CODE 4910–13–U

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Part 60

[FRL–5676–3]

New Source Performance Standards

and Emissions Guidelines: Sewage

Sludge Incinerators

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Notice of Additional

Information (NAI).

SUMMARY: This action announces the

EPA’s intention to issue regulations and

guidelines under Section 129 of the

Clean Air Act for Sewage Sludge

Incinerators (SSI) that combust sludge

from Publicly Owned Treatment Works

and to remove Sewage Sludge

Incinerators from the list of Major

Source Categories previously scheduled

for rule development under Section 112

of the Clean Air Act.

DATES: Comments must be received on

or before March 17, 1997.

ADDRESSES: Comments. Comments on

this notice should be submitted in

duplicate, if possible, to: The Air and

Radiation Docket and Information

Center (6102), ATTN: Docket No. A–96–

42, U.S. Environmental Protection

Agency, 401 M Street, S.W.,

Washington, D.C. 20460.

Docket. Dockets are available for

public inspections and copying between

8:00 a.m and 5:30 p.m., Monday through

Friday, at the Air and Radiation Docket

and Information Center, U.S. EPA, 401

M Street, S.W., Room M1500,

Washington, D.C. 20460. The center’s

telephone number is (202) 260–7548

and the fax number is (202) 260–4400.

A reasonable fee may be charged for

copying docket materials.

FOR FURTHER INFORMATION CONTACT: Mr.

Eugene Crumpler at (919) 541–0881,

Emissions Standards Division (MD–13),