Federal Register / Vol. 62, No. 152 / Thursday, August 7, 1997 / Proposed Rules 42433

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:

Construcciones Aeronauticas, S.A., CASA:

Docket 97–NM–162–AD.

Applicability: All Model CN–235 series

airplanes, certificated in any category.

Note 1: This AD applies to each airplane

identified in the preceding applicability

provision, regardless of whether it has been

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 (b) 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 failure of the fuse in battery

number 1 during battery starting of engines,

accomplish the following:

(a) Within 6 months after the effective date

of this AD, install a contactor in the battery

circuit and relocate the existing fuse in

accordance with CASA Service Bulletin SB–

235–24–07M, dated June 4, 1995; or Revision

1, dated January 25, 1996.

(b) 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.

(c) Special flight permits may be issued in

accordance with sections 21.197 and 21.199

of the Federal Aviation Regulations (14 CFR

21.197 and 21.199) to operate the airplane to

a location where the requirements of this AD

can be accomplished.

Issued in Renton, Washington, on July 31,

1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–20731 Filed 8–6–97; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96–NM–264–AD]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 737–100 and –200 Series

Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes the

supersedure of an existing airworthiness

directive (AD), applicable to certain

Boeing Model 737–100 and –200 series

airplanes, that currently requires that

the FAA-approved maintenance

inspection program be revised to

include inspections that will give no

less than the required damage tolerance

rating for each Structural Significant

Item, and repair of cracked structure.

That AD was prompted by a structural

re-evaluation by the manufacturer

which identified additional structural

elements where, if damage were to

occur, supplemental inspections may be

required for timely detection. This

action would require additional and

expanded inspections, and repair of

cracked structure. This action also

would expand the applicability of the

existing AD to include additional

airplanes. The actions specified by the

proposed AD are intended to ensure the

continued structural integrity of the

Boeing Model 737–100 and –200 fleet.

DATES: Comments must be received by

September 16, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 96–NM–

264–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: Greg

Schneider, Aerospace Engineer,

Airframe Branch, ANM–120S, FAA,

Seattle Aircraft Certification Office,

1601 Lind Avenue, SW., Washington;

telephone (425) 227–2028; 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,
42434 Federal Register / Vol. 62, No. 152 / Thursday, August 7, 1997 / Proposed Rules

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–264–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–264–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Determination To Develop the

Supplemental Structural Inspection

Program

As part of its continuing work to

maintain the structural integrity of older

transport category airplanes, in the early

1980’s, the FAA concluded that the

incidence of fatigue cracking may

increase as these airplanes reach or

exceed their design service objective

(DSO). A significant number of these

airplanes were approaching or had

exceeded the DSO on which the initial

type certification approval was

predicated. In light of this, and as a

result of increased utilization, longer

operational lives, and the high levels of

safety expected of the currently

operated transport category airplanes,

the FAA determined that a

supplemental structural inspection

program (SSIP) was necessary to ensure

a high level of structural integrity for all

airplanes in the transport fleet.

Issuance of Advisory Circular

As a follow-on from that

determination, the FAA issued Advisory

Circular (AC No. 91–56), ‘‘Supplemental

Structural Inspection Program for Large

Transport Category Airplanes,’’ dated

May 6, 1981. The AC provides guidance

material to manufacturers and operators

for use in developing a continuing

structural integrity program to ensure

safe operation of older airplanes

throughout their operational lives. This

guidance material applies to large

transport airplanes that were certified

under the fail-safe requirements of Civil

Air Regulations 4b or damage tolerance

structural requirements of 14 CFR part

25, and that have a maximum gross

weight greater than 75,000 pounds. The

procedures set forth in this AC are

applicable to the large transport

category airplanes operated under

subpart F of 14 CFR part 91 and parts

121, 123, 125, and 135. The objective of

the SSIP was to establish inspection

programs to ensure timely detection of

fatigue cracking.

Development of the Supplemental

Structural Inspection Program

In order to evaluate the effect of

increased fatigue cracking with respect

to maintaining fail-safe design and

damage tolerance of the structure of

Boeing Model 737–100 and –200 series

airplanes, Boeing conducted a structural

reassessment of those airplanes, using

modern damage tolerance evaluation

techniques. Boeing accomplished this

reassessment using the criteria

contained in AC No. 91–56, as well as

14 CFR 25.571; Amdt. 25–45. During the

reassessment, members of the airline

industry participated with Boeing in

working group sessions and developed

the SSIP for Model 737–100 and –200

series airplanes. Engineers and

maintenance specialists from the FAA

also attended these sessions to observe

these developments. Subsequently,

based on the working group’s

recommendations, Boeing developed

the Supplemental Structural Inspection

Document (SSID) for Model 737–100

and –200 series airplanes.

Issuance of AD 91–14–20, Amendment

39–7061

On August 9, 1991, the FAA issued

AD 91–14–20, amendment 39–7061 (56

FR 30680, July 5, 1991), which is

applicable to certain Boeing Model 737

series airplanes. That AD currently

requires that the FAA-approved

maintenance inspection program be

revised to include inspections that will

give no less than the required damage

tolerance rating (DTR) for each

Structural Significant Item (SSI), and

repair of cracked structure. The AD

references Boeing Document No. D6–

37089, ‘‘Supplemental Structural

Inspection Document’’ (SSID), Revision

B, dated February 18, 1987, and

Revision C, dated January 1990, as the

appropriate source of service

information. That action was prompted

by a structural re-evaluation that

identified additional structural

components where fatigue cracking is

likely to occur. The requirements of that

AD are intended to ensure the

continued structural integrity of the

entire Boeing Model 737 fleet.

Actions Since Issuance of Previous AD

Since issuance of AD 91–14–20, the

FAA has reconsidered the following

four aspects of the existing SSID:

1. Classification of Fuselage Skin as

‘‘Damage Obvious’’ or ‘‘Malfunction

Evident’’

AC No. 91–56, Change 2, dated April

15, 1983, recommends that the SSID

should contain inspections of all critical

parts or components for each airplane to

ensure the continued safe operation of

the existing fleet. The fuselage skin is an

example of a critical component.

Cracking in any critical part or

component, if not detected and

corrected in a timely manner, could

result in reduced structural integrity of

the airplane.

Revisions B and C of the SSID

excluded the fuselage skin from directed

inspections, since it was classified as

‘‘damage obvious’’ or ‘‘malfunction

evident.’’ At the time of this

classification, Revisions B and C of the

SSID relied on venting or flapping to

indicate cracks in the fuselage skin.

Venting is a gradual loss of cabin

pressure as a result of cracking in the

pressurized area of the fuselage skin.

Based on the design philosophy of

flapping, these cracks in the fuselage

skin would grow only to a specific

length and then turn direction because

of certain structural components.

Because venting and flapping were

considered to be readily apparent,

Boeing considered that it was

unnecessary to provide for additional

inspections of the fuselage skin.

Reliance also was placed on venting or

flapping to allow for the safe operation

of an airplane with such cracks. This

technique worked well in ground tests

and in some in-service incidents, but

proved to be unreliable in other cases.

In one such case, a large portion of

Section 43 of the fuselage structure

separated from a Boeing Model 737

series airplane. Results of a National

Transportation Safety Board (NTSB)

investigation revealed that this incident

occurred as a result of the catastrophic

failure of the fuselage skin at a lap joint.

The results also revealed that, contrary

to the design philosophy, controlled

decompression of the structure (i.e.,

flapping or venting) did not occur due

to the presence of widespread fatigue

damage. As a result of this failure, the

NTSB recommended that the SSID be

revised to discontinue classification of

the fuselage skin as ‘‘damage obvious’’

or ‘‘malfunction evident.’’

The FAA concurs with the NTSB’s

recommendation. Therefore, the FAA

has determined that additional

inspections are necessary to ensure

timely detection of cracks in the

fuselage skin structure.
Federal Register / Vol. 62, No. 152 / Thursday, August 7, 1997 / Proposed Rules 42435

2. Deletions of Modified, Altered, or

Repaired Structure from the SSIP

Paragraph 1.4 of Appendix 1,

‘‘Guidelines for Development of

Supplemental Inspection Document,’’ of

AC No. 91–56, Change 2, dated April 15,

1983, states, ‘‘the effect of repairs and

modifications approved by the

manufacturer should also be taken into

account. In addition, it may be

necessary to consider the effect of

repairs and operator-approved

modifications on individual airplanes.

The operator has the responsibility for

ensuring notification and consideration

of any such aspects.’’

In addition, the FAA’s current policy

is that operators of transport category

airplanes that are subject to AD’s that

mandate SSID programs should follow

the guidelines of AC No. 91–56 and

should continue to inspect any SSI that

is modified, altered, or repaired in any

way. Any modification that affects the

loading spectrum, stress levels, or

damage tolerance characteristics of the

structure must be reassessed to

determine its impact on the inspection

program. Such a reassessment may

require the development of additional

inspection requirements for that

modification.

The FAA’s policy also states that,

‘‘* * * the [SSID] programs are based

on type design crack growth data

generated from analysis or structural

tests using a realistic and conservative

loading spectrum, material properties,

part geometry, etc. For this reason,

structural modifications that may

increase stress levels in load carrying

structures, including maximum weight

limit increases, cargo door installations,

and repairs to load carrying structures,

must be reassessed for its impact on the

structural inspection program.’’

(Reference: Transport Airplane

Directorate’s Policy Letter, Information:

Policy Regarding Impact of

Modifications and Repairs on the

Damage Tolerance Characteristics of

Transport Category Airplanes, dated

October 27, 1989. This letter will be

retained in Rules Docket No. 96–NM–

264–AD.)

Section 5.0 of Revisions B and C of

the SSID contains provisions that allow

for the deletion of modified, altered, or

repaired areas from the SSIP because

Boeing considers these areas not to be

‘‘representative of the fleet.’’ The FAA is

aware that there have been a significant

number of such deletions. As a result,

contrary to the FAA’s policy discussed

above, operators are not following the

guidelines of AC No. 91–56 and not

continuing to inspect any SSI that is

modified, altered, or repaired in any

way.

In addition, for Boeing Model 737–

100 and –200 series airplanes that have

been converted from a passenger

configuration to an all-cargo

configuration by the Supplemental Type

Certification (STC) process, the FAA

finds that Revisions B and C of the SSID

do not include procedures for

inspection of new SSI’s created by this

conversion, or unmodified SSI’s affected

by this conversion. (There are

approximately 100 of these airplanes in

the worldwide fleet of which several are

listed in the effectivity listing of

Revisions B and C of the SSID.) These

conversions have the effect of removing

SSI’s from the SSIP and creating a large

number of new SSI’s that have not been

assessed. Consequently, airplanes that

have been converted to an all-cargo

configuration do not have a SSID that

specifies an inspection method and

compliance time for each new SSI.

Additionally, an unmodified SSI also

could require a new inspection method

and compliance time because the

modification may increase the loads or

change the load distributions in that

SSI. These conditions would necessitate

that the inspection interval for that

affected, unmodified SSI be shorter than

required in the Boeing SSID. Hence, the

FAA finds that the objectives of the

SSIP are not being met for these

modified airplanes.

Likewise, a design change (such as an

increase in the maximum certified

weight or in the center of gravity limits)

also may cause an increase in the loads

or change the load distributions in the

affected, unmodified SSI’s. The effect of

this increase or change would be similar

to the effect that a cargo conversion

would have on an unmodified SSI. As

a result, the inspection interval for an

affected, unmodified SSI may need to be

lower than required in the Boeing SSID.

Thus, the DTR specified in the SSID for

any SSI affected by a design change may

no longer be applicable. Therefore, the

FAA finds that the objectives of the

SSIP are not being met for airplanes

with such design changes.

Furthermore, in consideration of AC

No. 91–56 and current FAA policy, the

FAA has determined that new

inspection methods and compliance

times are necessary for areas that have

been modified, altered, or repaired to

ensure timely detection of cracking in

those areas. The FAA also has

determined that new inspection

methods and compliance times are

necessary for those areas that were

deleted from the SSIP by previously

approved alternative methods of

compliance, which includes those areas

deleted in accordance with the

requirements of Section 5.0 of the SSID.

Furthermore, the new inspection

methods and compliance times should

meet the requirements of 14 CFR

25.1529, Amdt. 25–45; 14 CFR 25.571,

Amdt. 25–45; 14 CFR 25.571, Amdt. 25–

54; 14 CFR 25.571, Amdt. 25–72; or the

guidelines of AC 91–56.

3. Candidate Fleet vs. Inspection

Threshold Approach

Paragraph 4.4 of AC No. 91–56,

Change 2, dated April 15, 1983, states,

‘‘Inspection thresholds for supplemental

inspections should be established.

These inspections would be

supplemental to the normal inspection

including the detailed internal

inspections.’’ Moreover, paragraph 4.4.2

of AC No. 91–56 states, ‘‘* * * this

threshold should be such as to include

sufficient [high-cycle] airplanes in the

inspection to develop added confidence

in the integrity of the structure * * *.’’

A properly established inspection

threshold ensures that: (1) The SSI

inspections are accomplished; (2)

fatigue cracks in SSI’s are detected in a

timely manner; (3) airplanes are

automatically added to the SSIP; and (4)

the SSIP includes a statistically valid

number of airplanes.

Among other things, Revisions B and

C of the SSID define a candidate fleet

approach to ensure that fatigue cracks in

SSI’s are detected in a timely manner in

the entire fleet. The initial Boeing

Model 737 candidate fleet consisted of

a number of airplanes that had exceeded

37,500 flight cycles by April 30, 1983.

In other words, Boeing considered

37,500 flight cycles to be the threshold

for the airplanes in the candidate fleet.

These airplanes were the most likely in

the fleet to experience initial fatigue

damage since they had the highest

number of flight cycles. Boeing

produced this SSID with the assumption

that the airplanes in the candidate fleet

would continue to represent the entire

fleet and would have the highest

number of flight cycles in the fleet.

Under the existing SSIP, Boeing

intended to periodically review the

airplanes in the candidate fleet for

significant changes in fleet distribution,

composition, or utilization, and update

the candidate fleet, if any significant

change was detected. It was intended

that the FAA would then mandate any

change to the SSID through the

rulemaking process.

The FAA finds that the candidate fleet

approach is deviating from Boeing’s

original philosophy in that the

candidate fleet has not been updated to

reflect changes (such as cargo

conversions) in the fleet. This situation
42436 Federal Register / Vol. 62, No. 152 / Thursday, August 7, 1997 / Proposed Rules

could result in a statistically invalid

number of airplanes in the SSIP and

undetected fatigue cracks in SSI’s. The

candidate fleet approach also does not

automatically account for non-candidate

airplanes that eventually accumulate

more flight cycles than that of certain

candidate airplanes. High-cycle

airplanes are more likely to experience

initial fatigue damage in the fleet. The

confidence in the structural integrity of

the fleet of airplanes could be reduced

if high-cycle airplanes are excluded

from the SSIP.

The FAA has reconsidered the

candidate fleet approach described in

Revisions B and C of the SSID, since it

does not meet the guidelines of AC No.

91–56. The FAA has determined that

the Boeing Model 737 SSIP must

contain inspection thresholds for all

Boeing Model 737–100 and –200 series

airplanes to ensure the timely detection

of fatigue cracks in the SSI’s. (The FAA

is currently considering a separate

rulemaking action to address the

problems associated with fatigue

cracking on all Boeing Model 737–300,

–400, and –500 series airplanes.)

The FAA has reviewed the thresholds

derived from Boeing’s reliability

analysis. The analysis is based on a

certain probability that cracks will be

detected in the inspected fleet before

they initiate on other airplanes that have

not been inspected. The FAA has

determined that the thresholds

recommended in the analysis of past

service experience of the Boeing Model

737 fleet are acceptable. Therefore, for

Model 737–200C series airplanes, the

FAA has determined that a threshold of

46,000 total flight cycles is necessary in

order to produce a statistically valid

assessment of the service history for

these airplanes. For other Model 737–

100 and –200 series airplanes, the FAA

has determined that a threshold of

66,000 total flight cycles is necessary to

produce a valid assessment. The

threshold for Model 737–200C series

airplanes is lower than that of other

Model 737 series airplanes since Model

737–200C series airplanes have a lower

utilization rate and fewer airplanes in

the fleet. Since the utilization rate is

lower for Model 737–200C series

airplanes, these airplanes have

accumulated fewer flight cycles and

have fewer airplanes with higher flight

cycles than that of the remaining fleet.

It should be noted that, although the

proposed AD requires a threshold, the

FAA may approve requests for

adjustments to the compliance time [i.e.,

under paragraph (h)(1) of this proposed

AD] provided that no cracking is

detected in the airplane’s SSI’s. The

request should include a new inspection

threshold and must include data to

substantiate that such an adjustment

would provide an acceptable level of

safety.

Operators should note that the

alternative inspection threshold may be

based solely on the analysis of the data

of the existing fleet. However, the FAA

has determined that the analysis that

derives the new inspection threshold

must include: (1) Data relevant to a

sufficient number of high-cycle

airplanes, and (2) data that shows

accomplishment of the inspections of

the SSI’s. An adequate statistical

sampling size will provide confidence

in the structural integrity of the fleet of

airplanes. Therefore, additional

airplanes may need to be added to the

inspected fleet until a sufficient number

of airplanes have been inspected with

no crack findings.

4. Transferability of Airplanes

Since issuance of the SSID and AD

91–14–20, the FAA has issued several

AD’s that implement Corrosion

Prevention and Control Programs

(CPCP) for aging airplanes. While

developing the AD’s that mandated the

CPCP, the FAA recognized that an

operator of an airplane that has been

transferred from another operator could

revise its maintenance program to

restart the compliance times for the

required corrosion tasks. This situation

could lead to corrosion not being

detected and corrected in a timely

manner, which could reduce the

structural integrity of the airplane.

As a result, the CPCP AD’s require

that operators establish a program for

accomplishment of the subject corrosion

tasks before any airplane can be added

to an air carrier’s operations

specification. Establishment of this

program will ensure that airplanes

transferred from operator to operator are

inspected and that corrosion is detected

in a timely manner.

The FAA’s intent in AD 91–14–20

was that operators of candidate fleet

airplanes that have been previously

operated under an FAA-approved

maintenance program accomplish the

SSID inspections within the compliance

time established by the previous

operator. The FAA assumed that, under

the existing SSID, these airplanes would

be inspected in a manner similar to

CPCP requirements. However, the SSID

and AD 91–14–20 do not address the

transfer of airplanes in the candidate

fleet from one operator to another.

AD 91–14–20 currently requires that

the revision to the maintenance program

be included and be implemented in

accordance with the procedures

specified in Sections 5.0 and 6.0 of the

SSID. However, the FAA finds that

these sections do not provide explicit

instructions to repetitively inspect

airplanes that have been transferred

from one operator to another. It also

does not specify that new operators

must continue the SSID inspections at

the same frequency established by the

previous operator.

In addition, as AD 91–14–20 is

currently worded, the FAA finds that

operators that acquire candidate fleet

airplanes that have been previously

operated under a maintenance

inspection program could revise their

programs to restart the compliance

times. This situation is contrary to

standard AD requirements. An AD

typically mandates an initial

compliance time and a repetitive

interval that remains unchanged for all

operators of the affected airplanes.

As a result of these omissions, the

SSID inspections of a candidate fleet

airplane could be deferred until it is

required by the maintenance inspection

program of the new operator. For

airplanes that are transferred frequently,

this situation could continue for the life

of the airplane. As a result, fewer Boeing

Model 737 candidate fleet airplanes are

being inspected; thus, the size of the

candidate fleet is in effect reduced. Even

if airplanes are ultimately inspected

under these circumstances, inspections

would not be performed frequently

enough to maintain the applicable DTR.

The FAA has determined that such a

reduction does not ensure the continued

structural integrity of the entire Boeing

Model 737 fleet.

Implementation of procedures in the

SSID that are similar to the CPCP will

ensure that: (1) Airplanes transferred

from operator to operator are inspected;

(2) the SSIP includes a statistically valid

number of airplanes; and (3) fatigue

cracks are detected in a timely manner.

Therefore, the FAA finds that, to

ensure the continued structural integrity

of the entire Model 737 fleet, the AD

91–14–20 must be revised to include

provisions that address the transfer of

airplanes. The FAA also finds that a

program must be established to

accomplish the inspections before any

airplane that is subject to this proposal

can be added to an air carrier’s

operations specifications.

FAA’s Conclusions

In light of all the factors discussed

above, the FAA has determined that AD

91–14–20 does not adequately ensure

timely detection of fatigue cracking in

SSI’s. Fatigue cracking in those items, if

not detected and corrected in a timely

manner, could result in reduced

structural integrity of the airplane.
Federal Register / Vol. 62, No. 152 / Thursday, August 7, 1997 / Proposed Rules 42437

Explanation of New Relevant Service

Information

The FAA has reviewed and approved

Boeing Document No. D6–37089,

‘‘Supplemental Structural Inspection

Document’’ (SSID), Revision D, dated

June 1995, which describes procedures

for revising the FAA-approved

maintenance inspection program for all

Boeing Model 737–100 and –200 series

airplanes. This revision of the Model

737 SSID incorporates additional and

expanded inspections from those that

were contained in the previous version

and mandated by AD 91–14–20. The

fuselage skin structure that was the

subject of an NTSB recommendation is

included in these inspections. The FAA

finds that accomplishment of these

inspections will ensure the continuing

structural integrity of the Boeing Model

737–100 and –200 fleet.

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

supersede AD 91–14–20.

Paragraph (a) of the proposed AD

restates the requirements of AD 91–14–

20.

Paragraph (b) of the proposed AD

would require incorporation of a

revision into the FAA-approved

maintenance inspection program that

provides no less than the required DTR

for each SSI listed in Revision D of the

SSID.

Paragraph (c) of the proposed AD

would establish specific compliance

times for performing the initial

inspection of the structure identified in

Revision D of the SSID. Once the initial

inspection has been performed,

operators would be required to perform

repetitive inspections at the intervals

specified in the Document in order to

remain in compliance with their

maintenance inspection programs,

which would have been revised in

accordance with paragraph (b) of this

proposed AD.

Paragraph (d) of the proposed AD

would require, for airplanes on which

any design change or repair has been

accomplished prior to the effective date

of this proposed AD, a revision to the

FAA-approved maintenance inspection

program to include an inspection

method for any new or affected SSI, and

to include the compliance times for this

inspection. This paragraph also would

require that any new inspection method

and the compliance times be approved

by the FAA.

Paragraph (e) of the proposed AD

would require that the repair of any

cracked structure is to be accomplished

in accordance with an FAA-approved

method.

Paragraph (f) of the proposed AD

would require, for airplanes on which

any design change or repair has been

accomplished after the effective date of

this proposed AD, a revision to the

FAA-approved maintenance inspection

program to include a new inspection

method for any new or affected SSI, and

to include the compliance times for this

inspection. This paragraph also would

require that any new inspection method

and the compliance times be approved

by the FAA.

Before any airplane that is subject to

this proposed AD can be added to an air

carrier’s operations specifications, a

program for the accomplishment of the

inspections required by this proposed

AD must be established. Paragraph (g) of

the proposed AD would require

accomplishment of the following:

1. For airplanes that have been

inspected in accordance with this

proposed AD, the inspection of each SSI

must be accomplished by the new

operator in accordance with the

previous operator’s schedule and

inspection method, or the new

operator’s schedule and inspection

method, whichever would result in the

earlier accomplishment date for that SSI

inspection. The compliance time for

accomplishment of this inspection must

be measured from the last inspection

accomplished by the previous operator.

After each inspection has been

performed once, each subsequent

inspection must be performed in

accordance with the new operator’s

schedule and inspection method.

2. For airplanes that have not been

inspected in accordance with this

proposed AD, the inspection of each SSI

must be accomplished either prior to

adding the airplane to the air carrier’s

operations specification, or in

accordance with a schedule and an

inspection method approved by the

FAA. After each inspection has been

performed once, each subsequent

inspection must be performed in

accordance with the new operator’s

schedule.

Accomplishment of these inspections

will ensure that: (1) Operators’ newly

acquired airplanes comply with its SSIP

before being operated; and (2) frequently

transferred aircraft are not permitted to

operate without accomplishment of the

inspections defined in the SSID.

Differences Between SSID and

Proposed AD

Operators should note the following

differences between the procedures

specified in Revision D of the SSID and

the proposed requirements of this AD:

1. Paragraphs 5.1.17 and 5.1.18 of the

General Instructions of Revision D of the

SSID permit deletions of modified,

altered, or repaired structure from the

SSIP. As described previously in Item 2

of the ‘‘Actions Since Issuance of

Previous AD’’ section of this preamble,

the FAA has determined that such

deletions are unacceptable. Therefore,

for airplanes on which the areas

specified in the SSID have been

modified, altered, or repaired, the

proposed AD would require a revision

to the operator’s existing SSIP to

include procedures for accomplishing a

new FAA-approved inspection method

that provides a new DTR for that SSI.

2. Revision D of the SSID bases the

supplemental inspections on specific

high-cycle airplanes (i.e., candidate fleet

airplanes) and does not include an

inspection threshold for those airplanes.

It also does not automatically add

airplanes to the candidate fleet. Based

on the discussion described previously

in Item 3 of the ‘‘Actions Since Issuance

of Previous AD’’ section of this

preamble, the FAA has determined that

the proposed AD would expand the

applicability of this AD action to

include all Model 737–100 and –200

series airplanes. In addition, for Model

737–200C series airplanes, the proposed

inspection of all SSI’s would be

required to be accomplished prior to the

accumulation of 46,000 total flight

cycles, or within 18 months, whichever

occurs later. For other Model 737–100

and –200 series airplanes, the proposed

inspection of all SSI’s would be

required to be accomplished prior to the

accumulation of 66,000 total flight

cycles, or within 18 months, whichever

occurs later.

Cost Impact

There are approximately 1,021 Boeing

Model 737–100 and –200 series

airplanes of the affected design in the

worldwide fleet. The FAA estimates that

404 airplanes of U.S. registry would be

affected by this proposed AD.

The actions that are proposed in this

AD action would take approximately

1,200 work hours per airplane to

accomplish, at an average labor rate of

$60 per work hour. Based on these

figures, the cost impact of the proposed

requirements of this AD on U.S.

operators is estimated to be $29,088,000,

or $72,000 per airplane, per inspection

cycle.

The cost impact figure discussed

above is based on assumptions that no

operator has yet accomplished any of

the current or proposed requirements of

this AD action, and that no operator
42438 Federal Register / Vol. 62, No. 152 / Thursday, August 7, 1997 / Proposed Rules

would accomplish those actions in the

future if this AD were not adopted.

The number of required work hours,

as indicated above, is presented as if the

accomplishment of the actions proposed

in this AD were to be conducted as

‘‘stand alone’’ actions. However, in

actual practice, these actions for the

most part would be accomplished

coincidentally or in combination with

normally scheduled airplane

inspections and other maintenance

program tasks. Therefore, the actual

number of necessary additional work

hours would be minimal in many

instances. Additionally, any costs

associated with special airplane

scheduling would be minimal.

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

removing amendment 39–7061 (56 FR

30680, July 5, 1991), and by adding a

new airworthiness directive (AD), to

read as follows:

Boeing: Docket 96–NM–264–AD.

Supersedes AD 91–14–20, Amendment

39–7061.

Applicability: All Model 737–100 and –200

series airplanes, certificated in any category.

Compliance: Required as indicated, unless

accomplished previously.

To ensure the continued structural

integrity of the Boeing Model 737–100 and

–200 fleet, accomplish the following:

Note 1: Where there are differences

between the AD and the Supplemental

Structural Inspection Document, the AD

prevails.

(a) For airplanes listed in Section 3.0

of Boeing Document No. D6–37089,

‘‘Supplemental Structural Inspection

Document’’ (SSID), Revision B, dated

February 18, 1987, and Revision C,

dated January 1990: Within 12 months

after August 9, 1991 (the effective date

of AD 91–14–20, amendment 39–7061),

incorporate a revision into the FAAapproved maintenance inspection

program which provides no less than

the required damage tolerance rating

(DTR) for each Structural Significant

Item (SSI) listed in that document. (The

required DTR value for each SSI is listed

in the document.) The revision to the

maintenance program shall include and

shall be implemented in accordance

with the procedures in Sections 5.0 and

6.0 of the SSID. This revision shall be

deleted following accomplishment of

the requirements of paragraph (b) of this

AD.

Note 2: For the purposes of this AD, an SSI

is defined as a principal structural element

that could fail and consequently reduce the

structural integrity of the airplane.

(b) Within 12 months after the

effective date of this AD, incorporate a

revision into the FAA-approved

maintenance inspection program that

provides no less than the required DTR

for each SSI listed in Boeing Document

No. D6–37089, ‘‘Supplemental

Structural Inspection Document’’

(SSID), Revision D, dated June 1995

(hereinafter referred to as ‘‘Revision D’’).

(The required DTR value for each SSI is

listed in the document.) The revision to

the maintenance program shall include

and shall be implemented in accordance

with the procedures in Section 5.0,

‘‘Damage Tolerance Rating (DTR)

System Application’’ and Section 6.0,

‘‘SSI Discrepancy Reporting’’ of

Revision H. Upon incorporation of the

revision required by this paragraph, the

revision required by paragraph (a) of

this AD may be deleted.

(c) Except as provided in paragraph

(d) or (f) of this AD, as applicable,

perform an inspection to detect cracks

in all structure identified in Revision D

at the time specified in paragraph (c)(1)

or (c)(2) of this AD, as applicable.

(1) For Model 737–200C series airplanes:

Inspect prior to the accumulation of 46,000

total flight cycles, or within 18 months after

the effective date of this AD, whichever

occurs later.

(2) For Model 737–100 and –200 series

airplanes, except for those airplanes

identified in paragraph (c)(1) of this AD:

Inspect prior to the accumulation of 66,000

total flight cycles, or within 18 months after

the effective date of this AD, whichever

occurs later.

Note 3: Once the initial inspection has

been performed, operators are required to

perform repetitive inspections at the intervals

specified in Revision D in order to remain in

compliance with their maintenance

inspection programs, as revised in

accordance with paragraph (b) of this AD.

(d) For airplanes on which the structure

identified in Revision D is affected by any

design change or repair that was

accomplished prior to the effective date of

this AD: Within 18 months after the effective

date of this AD, revise the FAA-approved

maintenance inspection program to include

an inspection method for any new or affected

SSI, and to include the compliance times for

initial and repetitive accomplishment of this

inspection. For purposes of this section, an

SSI is ‘‘affected’’ if it has been altered or

repaired, or if the loads acting on the SSI

have been increased or redistributed.

Following accomplishment of the revision

and within the compliance times established,

perform an inspection to detect cracks in the

structure affected by any design change or

repair, in accordance with the new

inspection method. The new inspection

method and the compliance times shall be

approved by the Manager, Seattle Aircraft

Certification Office (ACO), FAA, Transport

Airplane Directorate, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056, fax

(425) 227–1181.

Note 4: Notwithstanding the provisions of

paragraphs 5.1.17 and 5.1.18 of the General

Instructions of Revision D, which would

permit deletions of modified, altered, or

repaired structure from the Supplemental

Structural Inspection Program (SSIP), the

inspection of SSI’s that are modified, altered,

or repaired shall be done in accordance with

a method approved by the Manager, Seattle

ACO.

Note 5: For the purposes of this AD, a

design change is defined as any modification,

alteration, or change to operating limitations.

(e) Cracked structure found during any

inspection required by this AD shall be

repaired, prior to further flight, in accordance

with an FAA-approved method.

(f) For airplanes on which the structure

identified in Revision D is affected by any

design change or repair that is accomplished

after the effective date of this AD: Within 12

months after that modification, alteration, or

repair for any new or affected SSI, revise the

FAA-approved maintenance inspection
Federal Register / Vol. 62, No. 152 / Thursday, August 7, 1997 / Proposed Rules 42439

program to include an inspection method for

any new or affected SSI, and to include the

compliance times for initial and repetitive

accomplishment of this inspection. For

purposes of this section, an SSI is ‘‘affected’’

if it has been altered or repaired, or if the

loads acting on the SSI have been increased

or redistributed. Following accomplishment

of the revision and within the compliance

times established, perform an inspection to

detect cracks in the structure affected by any

design change or repair, in accordance with

the new inspection method. The new

inspection method and the compliance times

shall be approved by the Manager, Seattle

ACO.

Note 6: Notwithstanding the provisions of

paragraphs 5.1.17 and 5.1.18 of the General

Instructions of Revision D, which would

permit deletions of modified, altered, or

repaired structure from the SIP, the

inspection of SSI’s that are modified, altered,

or repaired shall be done in accordance with

a method approved by the Manager, Seattle

ACO.

(g) Before any airplane that is subject to

this AD and that has exceeded the applicable

compliance times specified in paragraph (c)

of this AD can be added to an air carrier’s

operations specifications, a program for the

accomplishment of the inspections required

by this AD must be established in accordance

with paragraph (g)(1) or (g)(2) of this AD, as

applicable.

(1) For airplanes that have been inspected

in accordance with this AD, the inspection of

each SSI must be accomplished by the new

operator in accordance with the previous

operator’s schedule and inspection method,

or the new operator’s schedule and

inspection method, whichever would result

in the earlier accomplishment date for that

SSI inspection. The compliance time for

accomplishment of this inspection must be

measured from the last inspection

accomplished by the previous operator. After

each inspection has been performed once,

each subsequent inspection must be

performed in accordance with the new

operator’s schedule and inspection method.

(2) For airplanes that have not been

inspected in accordance with this AD, the

inspection of each SSI required by this AD

must be accomplished either prior to adding

the airplane to the air carrier’s operations

specification, or in accordance with a

schedule and an inspection method approved

by the Manager, Seattle ACO. After each

inspection has been performed once, each

subsequent inspection must be performed in

accordance with the new operator’s schedule.

(h)(1) 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

ACO. 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 7: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Seattle ACO.

(2) Alternative methods of compliance,

approved previously in accordance with AD

91–14–20, amendment 39–7061, are not

considered to be approved as alternative

methods of compliance with this AD.

(i) Special flight permits may be issued in

accordance with sections 21.197 and 21.199

of the Federal Aviation Regulations (14 CFR

21.197 and 21.199) to operate the airplane to

a location where the requirements of this AD

can be accomplished.

Issued in Renton, Washington, on July 31,

1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–20732 Filed 8–6–97; 8:45 am]

BILLING CODE 4910–13–O

SOCIAL SECURITY ADMINISTRATION

20 CFR Parts 404 and 422

RIN 0960–AE09

Federal Old-Age, Survivors, and

Disability Insurance; Disclosure of

Information to Consumer Reporting

Agencies and Overpayment Recovery

Through Administrative Offset Against

Federal Payments

AGENCY: Social Security Administration.

ACTION: Proposed rules.

SUMMARY: We propose to make several

revisions to our regulations dealing with

debt collection. First, we propose to

modify the regulations dealing with the

recovery of benefit overpayments under

title II of the Social Security Act (the

Act) to reflect statutory authority for the

Social Security Administration (SSA) to

selectively refer information to

consumer reporting agencies and to

recover title II overpayments through

administrative offset by the Department

of the Treasury against other Federal

payments to which the overpaid

individual may be entitled. These

collection practices would be limited to

overpayments made to a person after he

or she attained age 18 that are

determined to be otherwise

unrecoverable under section 204 of the

Act after the individual ceases to be a

beneficiary under title II of the Act.

Second, as an independent agency in

the executive branch of the U.S.

Government, we propose to establish a

new subpart D in part 422 of title 20 of

the Code of Federal Regulations which

will explain our rules on debt collection

procedures for both administrative debts

and for title II program overpayments

determined to be otherwise

unrecoverable under section 204 of the

Act. These proposed rules for the new

subpart D would address the reporting

of delinquent debts to consumer and

other credit reporting agencies and the

use of administrative offset through the

Department of the Treasury. Third, we

propose to revise our rules on the

recovery of title II program

overpayments through the use of the

Federal income tax refund offset (TRO)

provisions to reflect that, beginning

January 1, 1998, the Department of the

Treasury, rather than the Internal

Revenue Service (IRS), will administer

the TRO program, and to reflect other

changes in policies and procedures

applied by the IRS and the Department

of the Treasury in the TRO program.

DATES: To be sure your comments are

considered, we must receive them no

later than October 6, 1997.

ADDRESSES: Comments should be

submitted in writing to the

Commissioner of Social Security, P.O.

Box 1585, Baltimore, Maryland 21235,

sent by telefax to (410) 966–2830, sent

by e-mail to ‘‘regulations@ssa.gov,’’ or

delivered to the Division of Regulations

and Rulings, Social Security

Administration, 3–B–1 Operations

Building, 6401 Security Boulevard,

Baltimore, MD 21235, between 8:00 a.m.

and 4:30 p.m. on regular business days.

Comments may be inspected during

these same hours by making

arrangements with the contact person

shown below.

FOR FURTHER INFORMATION CONTACT:

Robert J. Augustine, Legal Assistant,

Division of Regulations and Rulings,

Social Security Administration, 6401

Security Boulevard, Baltimore, MD

21235, (410) 966–5121. For information

on eligibility or claiming benefits, call

our national toll-free number, 1–800–

772–1213.

SUPPLEMENTARY INFORMATION: Section

204 of the Act prescribes the methods

SSA may use to recover Social Security

benefits erroneously paid under title II

of the Act (title II program

overpayments), as distinguished from

the methods SSA may use to collect

other debts owed the agency

(administrative debts) that are

recoverable under other statutory

authority. Until recently, SSA was

authorized to recover title II program

overpayments only through adjustment

of future benefits payable to the

overpaid individual or to others on the

earnings record on which the

overpayment was made, by direct

recovery from the overpaid person (or

the overpaid person’s estate, if

deceased), or by offset against Federal

income tax refunds due from the

Department of the Treasury.

Amendments to section 204 of the Act

by section 5 of Pub. L. 103–387 (1994)

and section 31001(z)(2) of Pub. L. 104–

134 (1996) permit SSA to use several

debt collection procedures that have