10490 Federal Register / Vol. 62, No. 45 / Friday, March 7, 1997 / Proposed Rules

flight, replace any loose pin, in

accordance with the service bulletin and

accomplish the following, as applicable:

(1) For any piston on which three

threaded screw pins are installed: No

further action is required by this AD for

this piston.

(2) For any piston on which one pin

is installed and two holes are sealed

with epoxy: Remove the epoxy, and

install two additional threaded screw

pins, in accordance with the service

bulletin. Thereafter, no further action is

required by this AD for this piston.

(3) For any piston on which one pin

is installed and no other holes exist:

(i) Repeat the inspection required by

paragraph (a) of this AD at intervals not

to exceed 600 hours time-in-service

until the modification required by

paragraph (a)(3)(ii) of this AD is

accomplished.

(ii) Prior to the accumulation of 1,800

hours time-in-service after the effective

date of this AD, or within 3 years after

the effective date of this AD, whichever

occurs later, modify this piston in

accordance with the service bulletin.

Accomplishment of this modification

constitutes terminating action for the

repetitive inspection requirements of

paragraph (a)(3)(i) of this AD.

Thereafter, no further action is required

by this AD with regard to that piston.

(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,

FAA, Transport Airplane Directorate.

Operators shall submit their requests

through an appropriate FAA Principal

Maintenance Inspector, who may add

comments and then send it to the

Manager, 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.

(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 February

28, 1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–5574 Filed 3–6– 97; 8:45 am]

BILLING CODE 4910–13–U

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96–NM–201–AD]

RIN 2120–AA64

Airworthiness Directives; McDonnell

Douglas Model MD–90–30 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 all

McDonnell Douglas Model MD–90–30

airplanes. This proposal would require

revising the Airworthiness Limitations

Section of the Instructions for

Continued Airworthiness [MD–90–30

Airworthiness Limitations Instructions

(ALI)]. The revision would incorporate

certain compliance times for inspections

to detect fatigue cracking of principal

structural elements (PSE) and to add

PSE’s to the ALI. This proposal is

prompted by analysis of data that

identified reduced initial inspection

thresholds, reduced repetitive

inspection intervals for PSE’s, and other

PSE’s to be added to the ALI. The

actions specified by the proposed AD

are intended to ensure that fatigue

cracking of various PSE’s are detected

and corrected; such fatigue cracking

could adversely affect the structural

integrity of these airplanes.

DATES: Comments must be received by

April 16, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 96–NM–

201–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

McDonnell Douglas Corporation, 3855

Lakewood Boulevard, Long Beach,

California 90846, Attention: Technical

Publications Business Administration,

Department C1–L51 (2–60). This

information may be examined at the

FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton,

Washington.

FOR FURTHER INFORMATION CONTACT:

Brent Bandley, Aerospace Engineer,

Airframe Branch, ANM–120L, FAA, Los

Angeles Aircraft Certification Office,

3960 Paramount Boulevard, Lakewood,

California 90712; telephone (310) 627–

5237; fax (310) 627–5210.

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–201–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–201–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

In accordance with airworthiness

standards requiring ‘‘damage tolerance

assessments’’ [reference current section

1529 of parts 23, 25, 27, and 29 of the

Federal Aviation Regulations (FAR);

section 4 of parts 33 and 35 of the FAR;

section 82 of part 31 of the FAR; and the

Appendices referenced in those

sections], all products certificated to

comply with those sections must have

Instructions for Continued

Airworthiness (or, for some products,

maintenance manuals), that include an

Airworthiness Limitations Section. That

section must set forth:

• mandatory replacement times for

structural components,

• structural inspection intervals, and
Federal Register / Vol. 62, No. 45 / Friday, March 7, 1997 / Proposed Rules 10491

• related approved structural

inspection procedures necessary to

show compliance with the damagetolerance requirements.

Compliance with the terms specified

in the Airworthiness Limitations

Sections is required by FAR sections

43.16 (for persons maintaining

products) and 91.403 (for operators).

As airplanes gain service experience,

or as the result of post-certification

testing and evaluation, it may become

necessary to add additional life limits or

structural inspections in order to ensure

the continued structural integrity of the

airplane. The manufacturer may revise

the Airworthiness Limitations Section

to include new or more restrictive life

limits and inspections. However, in

order to require compliance with those

revised life limits and/or inspection

intervals, the FAA must engage in

rulemaking.

Because loss of structural integrity

would result in an unsafe condition, it

is appropriate to impose these

requirements through the AD process.

Actions Taken by the Manufacturer

McDonnell Douglas recently has

completed extensive analyses and

testing of fatigue cracking of Principal

Structural Elements (PSE) on Model

MD–90–30 airplanes, which included:

• crack growth analysis,

• service experience analysis,

• crack growth testing,

• fatigue testing, and

• analysis of the effectiveness of

applicable non-destructive inspection

techniques to detect cracking and other

anomalies.

The analyses and testing were similar

to methods used to develop the initial

MD–90 Airworthiness Limitations

Instructions (ALI), Document No. MDC–

94K9000, dated November 1994.

The results of the testing and analyses

demonstrated the need to revise certain

inspections contained in the current

ALI.

New Revisions of Airworthiness

Limitations Instructions (ALI)

The FAA has reviewed and approved

MD–90 ALI, Revision 1, dated January

1995, and Revision 2, dated July 1996.

These revisions describe specific

reduced initial inspection thresholds

and reduced repetitive inspection

intervals for certain PSE’s. They also

include additional PSE’s to be

inspected.

Explanation of Requirements of

Proposed Rule

Since an unsafe condition has been

identified that is likely to exist or

develop on other products of this same

type design, the proposed AD would

require operators to revise the MD–90

ALI to incorporate Revision 1, dated

January 1995, and Revision 2, dated July

1996.

Explanation of Action Taken by the

FAA

As stated previously, in order to

require compliance with these

inspection intervals and life limits, the

FAA must engage in rulemaking,

namely the issuance of an AD. For

products certificated to comply with the

referenced part 25 requirements, it is

within the authority of the FAA to issue

an AD requiring a revision to the

Airworthiness Limitations Section that

includes reduced life limits, or new or

different structural inspection

requirements. These revisions then are

mandatory for operators under section

91.403(c) of the FAR, which prohibits

operation of an airplane for which

Airworthiness Limitations have been

issued unless the inspection intervals

specified in those limitations have been

complied with.

Once that document is revised, as

required, and the AD has been fully

complied with, the life limit or

structural inspection change remains

enforceable as a part of the

Airworthiness Limitations. (This is

analogous to AD’s that require changes

to the Limitations Section of the

Airplane Flight Manual.)

Requiring a revision of the

Airworthiness Limitations, rather than

requiring individual inspections, is

advantageous for operators because it

allows them to record AD compliance

status only once—at the time they make

the revision—rather than after every

inspection. It also has the advantage of

keeping all Airworthiness Limitations,

whether imposed by original

certification or by AD, in one place

within the operator’s maintenance

program, thereby reducing the risk of

non-compliance because of oversight or

confusion.

Cost Impact

There are approximately 15 Model

MD–90 series airplanes of the affected

design in the worldwide fleet. The FAA

estimates that 11 airplanes of U.S.

registry would be affected by this

proposed AD, that it would take

approximately 1 work hour per airplane

to accomplish the proposed actions, and

that the average labor rate is $60 per

work hour. Based on these figures, the

cost impact of the proposed AD on U.S.

operators is estimated to be $660, or $60

per airplane.

The cost impact figure discussed

above is based on assumptions that no

operator has yet accomplished any of

the proposed requirements of this AD

action, and that no operator would

accomplish those actions in the future if

this AD were not adopted.

Regulatory Impact

The regulations proposed herein

would not have substantial direct effects

on the States, on the relationship

between the national government and

the States, or on the distribution of

power and responsibilities among the

various levels of government. Therefore,

in accordance with Executive Order

12612, it is determined that this

proposal would not have sufficient

federalism implications to warrant the

preparation of a Federalism Assessment.

For the reasons discussed above, I

certify that this proposed regulation (1)

is not a ‘‘significant regulatory action’’

under Executive Order 12866; (2) is not

a ‘‘significant rule’’ under the DOT

Regulatory Policies and Procedures (44

FR 11034, February 26, 1979); and (3) if

promulgated, will not have a significant

economic impact, positive or negative,

on a substantial number of small entities

under the criteria of the Regulatory

Flexibility Act. A copy of the draft

regulatory evaluation prepared for this

action is contained in the Rules Docket.

A copy of it may be obtained by

contacting the Rules Docket at the

location provided under the caption

ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation

safety, Safety.

The Proposed Amendment

Accordingly, pursuant to the

authority delegated to me by the

Administrator, the Federal Aviation

Administration proposes to amend part

39 of the Federal Aviation Regulations

(14 CFR part 39) as follows:

PART 39—AIRWORTHINESS

DIRECTIVES

1. The authority citation for part 39

continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

McDonnell Douglas: Docket 96–NM–201–

AD.

Applicability: All Model MD–90–30 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

modified, altered, or repaired in the area
10492 Federal Register / Vol. 62, No. 45 / Friday, March 7, 1997 / Proposed Rules

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 (d) 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 ensure continued structural integrity of

these airplanes, accomplish the following:

(a) Within 180 days after the effective date

of this AD, revise the Airworthiness

Limitations Section of the Instructions for

Continued Airworthiness [Airworthiness

Limitations Instructions (ALI), McDonnell

Douglas Report No. MDC–94K9000, dated

November 1994] to incorporate the Item,

Location, and Inspection Interval of the

following principal structural elements: This

may be accomplished by inserting a copy of

Revision 1 of the ALI, dated January 1995, or

a copy of this AD into the ALI.

Item Location

Inspection interval (in

landings)

Initial Repeat

Item 53.30.02.3 ..... Skin Panels, STA 237 to 1395 Fuselage Skin in Constant Section from Longeron 3 Left to

Longeron 3 Right.

60,000 11,000

Item 53.30.02.4 ..... Skin Panels, STA 237 to 1395 Fuselage Hoop Skin Splice in Constant Section from Longeron 5 Left to Longeron 5 Right.60,000 30,000

Item 54.10.04.1 ..... Thrust Bulkhead, Pylon—STA Yn 170.5—Rear Spar and Engine Thrust Support Fitting

(Upper and Lower).

15,000 4,500

(b) Within 180 days after the effective date of this AD, revise the Airworthiness Limitations Section of the Instructions

for Continued Airworthiness [Airworthiness Limitations Instructions (ALI), McDonnell Douglas Report No. MDC–94K9000,

dated November 1994] to incorporate the Item, Location, and Inspection Interval of the following principal structural

elements: This may be accomplished by inserting a copy of Revision 2 to the ALI, dated July 1996, or a copy of

this AD into the ALI.

Item Location

Inspection interval (in

landings)

Initial Repeat

Item 55.13.01.1 ..... Plates/Skin—Upper STA Xh 27.2 Left to Xh 27.2 Right—Upper Aft Skin Plank with Integral

Stringers from Xh 7.234 to Xh 26.859.

60,000 8,100

(c) Except as provided in paragraph

(d) of this AD: After the actions

specified in paragraphs (a) and (b) of

this AD have been accomplished, no

alternative inspections or inspection

intervals may be approved for the parts

specified in paragraphs (a) and (b) of

this AD.

(d) 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, Los

Angeles Aircraft Certification Office

(ACO), FAA, Transport Airplane

Directorate. Operators shall submit their

requests through an appropriate FAA

Principal Maintenance Inspector, who

may add comments and then send it to

the Manager, Los Angeles ACO.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Los Angeles ACO.

(e) 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 February

28, 1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–5573 Filed 3–6–97; 8:45 am]

BILLING CODE 4910–13–U

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96–NM–203–AD]

RIN 2120–AA64

Airworthiness Directives; McDonnell

Douglas Model DC–9 and DC–9–80

Series Airplanes, Model MD–88

Airplanes, and C–9 (Military) 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

McDonnell Douglas Model DC–9 and

DC–9–80 series airplanes, Model MD–88

airplanes, and C–9 (military) series

airplanes. This proposal would require

repetitive high frequency eddy current

inspections of the external areas of the

fuselage to detect cracks of the skin and/

or longeron, and various follow-on

actions. The proposal also would

require the installation of a preventative

modification, which would terminate

the repetitive inspections. This proposal

is prompted by reports indicating that,

due to material fatigue caused by

installation preload and cabin

pressurization cycles, fatigue cracks

were found in the skin and longerons of

the fuselage. The actions specified by

the proposed AD are intended to

prevent such fatigue cracks, which

could result in loss of the structural

integrity of the fuselage and,

consequently, lead to rapid

depressurization of the airplane.

DATES: Comments must be received by

April 16, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No.96–NM–

203–AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055–4056.

Comments may be inspected at this