Airworthiness Directives; McDonnell Douglas Model DC-9, DC-9-80, and C-9 (Military) Series Airplanes, and Model MD-88 Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 94-NM-92-AD]

Airworthiness Directives; McDonnell Douglas Model DC-9, DC-9-80,

and C-9 (Military) Series Airplanes, and Model MD-88 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing

airworthiness directive (AD), applicable to McDonnell Douglas Model DC-

9, DC-9-80, and C-9 (military) series airplanes, and Model MD-88

airplanes, that currently requires certain inspections and structural

modifications. This action would require additional inspections and

structural modifications. This proposal is prompted by an evaluation

conducted by the Airworthiness Assurance Working Group (AAWG), Model

DC-9/MD-80 Task Group, which identified additional modifications for

mandatory action. The actions specified by the proposed AD are intended

to prevent degradation in the structural capabilities of the affected

airplanes. This action also reflects the FAA's decision that long term

continued operational safety should be assured by actual modification

of the airframe, where feasible, rather than only by repetitive

inspections for known service problems.

DATES: Comments must be received by December 23, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-103,

Attention: Rules Docket No. 94-NM-92-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, P.O. Box 1771, Long Beach,

California 90801-1771, Attention: Business Unit Manager, Technical

Administrative Support, Department L51, M.C. 2-98. This information may

be examined at the FAA, Transport Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington; or at the FAA, Transport Airplane

Directorate, Los Angeles Aircraft Certification Office, 3229 East

Spring Street, Long Beach, California.

FOR FURTHER INFORMATION CONTACT: David Y. J. Hsu, Aerospace Engineer,

Airframe Branch, ANM-122L, FAA, Transport Airplane Directorate, Los

Angeles Aircraft Certification Office, 3229 East Spring Street, Long

Beach, California 90806-2425; telephone (310) 988-5323; fax (310) 988-

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 94-NM-92-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. 94-NM-92-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

On August 6, 1990, the FAA issued AD 90-18-03, amendment 39-6701

(55 FR 34704, August 24, 1990), applicable to Model DC-9, DC-9-80, and

C-9 (military) series airplanes, and Model MD-88 airplanes, to require

certain inspections and structural modifications. That action was

prompted by reports of incidents involving fatigue cracking, corrosion,

and stress corrosion cracking in transport category airplanes that are

approaching or have exceeded their economic design goal. These

incidents have jeopardized the airworthiness of the affected airplanes.

The requirements of that AD are intended to prevent degradation in the

structural capabilities of the affected airplanes.

Since the issuance of that AD, the Airworthiness Assurance Working

Group (AAWG), Model DC-9/MD-80 Task Group, comprised of representatives

from operators of Model DC-9/MD-80 series airplanes, the manufacturer,

and the FAA, has completed its review of certain service bulletins that

are applicable to aging Model DC-9/MD-80 series airplanes. The Task

Group has recommended these service bulletins for mandatory inspection

and structural modification in order to reduce the potential for major

structural failure of those airplanes.

Consequently, McDonnell Douglas has issued Revision B to Report No.

MDC K1572, ``DC-9/MD80 Aging Aircraft Service Action Requirements

Document,'' dated January 15, 1993. The Task Group's most recent

recommendations for mandatory actions are contained in Tables 2.3, 2.4,

and 3.1 of that document. (The actions contained in Tables 2.1 and 2.2

were made mandatory by AD 90-18-03.) The FAA has reviewed and approved

that document. Tables 2.3 and 2.4 of the document reference the

following service bulletins:

1. One service bulletin that describes inspections and modification

of the slat drive mechanism;

2. Four service bulletins that describe inspections and

modifications of the doors;

3. Eleven service bulletins that describe inspections and

modifications of the fuselage;

4. Four service bulletins that describe inspections and

modifications of the horizontal stabilizers;

5. Two service bulletins that describe inspections and

modifications of the wings;

6. One service bulletin that describes inspections and modification

of the engine thrust reverser system;

7. One service bulletin that describes inspections and modification

of the nose gear steering;

8. Two service bulletins that describe inspections and

modifications of the engine pylon;

9. One service bulletin that describes inspections and modification

of the rudder; and

10. Two service bulletins that describe inspections and

modifications of the main landing gear structures.

Table 3.1 of the document references the following service

bulletins for mandatory inspections:

1. One service bulletin that describes inspections of the doors;

2. One service bulletin that describes inspections of the engine

pylons; and

3. Two service bulletins that describe inspections of the wings.

(These two service bulletins were made mandatory by AD 90-18-03.) -

The Task Group has also recommended, for mandatory modification,

the actions contained in McDonnell Douglas DC-9 Service Bulletin 53-

230, Revision 1, dated January 12, 1993. The FAA has reviewed and

approved this service bulletin, which describes procedures for

installation of doublers and clips at the intersections of upper

longerons/intercostals and fuselage frames between longerons 10L and

10R at various overwing stations between Y=484.000 and Y=851.000, as

applicable, depending upon series of the airplane. Accomplishment of

these modifications would terminate the inspections required by AD 88-

24-08 R2, amendment 39-6469 (55 FR 1002, January 11, 1990), which

requires external eddy current inspection to detect cracking of the

fuselage skin and certain longerons, internal visual inspections of

certain longerons, and repair of any findings of cracking. -

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 90-18-03 to require additional

structural modifications and inspections. The actions would be required

to be accomplished in accordance with the document described

previously. -

There are approximately 892 Model DC-9 and C-9 (military) series

airplanes of the affected design in the worldwide fleet. -

The FAA estimates that 568 Model DC-9 and C-9 (military) series

airplanes of U.S. registry were originally affected by AD 90-18-03. The

requirements of that AD were estimated to take approximately 946 work

hours to accomplish, at a current average labor rate of $55 per work

hour. The cost for required modification kits was estimated to be

$15,140 per airplane. Based on these figures, the FAA estimated that

the total cost impact of AD 90-18-03 on U.S. operators of Model DC-9

and C-9 (military) series airplanes would be $38,152,560, or $67,170

per airplane, over the initial 4-year time period. (These figures do

not include the cost of downtime, planning, set-up, familiarization, or

tool acquisition.) -

The FAA estimates that a total of 511 Model DC-9 and C-9 (military)

series airplanes of U.S. registry would be affected by the new

requirements specified in this proposed AD. The new additional

requirements proposed by this AD action would take approximately 638

additional work hours per airplane to accomplish, at an average labor

rate of $55 per work hour. Required parts would cost an additional

$37,027 per airplane. Based on these figures, the total additional cost

impact of this proposed AD on U.S. operators is estimated to be

$36,851,787, or $72,117 per airplane, over a 4-year time period. (These

figures do not include the cost of downtime, planning, set-up,

familiarization, and tool acquisition.) -

There are approximately 1,090 Model DC-9-80 series airplanes and

Model MD-88 airplanes of the affected design in the worldwide fleet. -

The FAA estimates that 173 Model DC-9-80 series airplanes and Model

MD-88 airplanes of U.S. registry were originally affected by AD 90-18-

03. The requirements of that AD were estimated to take approximately 47

work hours to accomplish, at a current average labor rate of $55 per

work hour. The cost for required modification kits was estimated to be

$752 per airplane. Based on these figures, the FAA estimated that the

total cost impact of AD 90-18-03 on U.S. operators of Model DC-9-80

series airplanes and Model MD-88 airplanes would be $577,301, or $3,337

per airplane, over the initial 4-year time period. (These figures do

not include the cost of downtime, planning, set-up, familiarization, or

tool acquisition.) -

The FAA estimates that a total of 615 Model DC-9-80 series

airplanes and Model MD-88 airplanes of U.S. registry would be affected

by the new requirements specified in this proposed AD. This increase in

the number of affected airplanes is due to various reasons, including

transfer of ownership and the fact that additional airplanes have

accumulated time-in-service since the issuance of AD 90-18-03 and have

reached the threshold for modification/inspection. The new additional

requirements proposed by this AD action would take approximately 13

additional work hours per airplane to accomplish, at an average labor

rate of $55 per work hour. Required parts would cost an additional $943

per airplane. Based on these figures, the total additional cost impact

of this proposed AD on U.S. operators is estimated to be $1,019,670, or

$1,658 per airplane, over a 4-year time period. (These figures do not

include the cost of downtime, planning, set-up, familiarization, or

tool acquisition.) -

The total cost impact figure discussed above is based on

assumptions that no operator has yet accomplished the currently

required or the newly proposed requirements of this AD action; however,

it can reasonably be assumed that a majority of affected operators have

already initiated the inspections and structural modifications required

by AD 90-18-03 [retained in paragraphs (a) and (d) of this AD] and many

may have already initiated the additional inspections and structural

modifications proposed in this new AD action. -

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.

-

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. App. 1354(a), 1421 and 1423; 49 U.S.C.

106(g); and 14 CFR 11.89.

Sec. 39.13 [Amended] -

2. Section 39.13 is amended by removing amendment 39-6701 (55 FR

34704, August 24, 1990), and by adding a new airworthiness directive

(AD), to read as follows:

McDonnell Douglas: Docket 94-NM-92-AD. Supersedes AD 90-18-03,

Amendment 39-6701.

Applicability: Model DC-9-10, -20, -30, -40, -50 series

airplanes; Model DC-9-81 (MD-81), -82 (MD-82), -83 (MD-83), and -87

(MD-87) series airplanes; Model MD-88 airplanes; and C-9 (military)

series airplanes; certificated in any category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent structural failure, accomplish the following:

(a) Within the threshold for inspections specified in the

service bulletins listed in either Table 2.1 [for Model DC-9-10, -

20, -30, -40, -50, and C-9 (military) series airplanes], or Table

2.2 [for Model DC-9-81, -82, -83, -87 (MD-81, -82, -83, -87), and

Model MD-88 airplanes], as applicable, of McDonnell Douglas Report

No. MDC K1572, ``DC-9/MD-80 Aging Aircraft Service Action

Requirements Document,'' Revision A, dated June 1, 1990 (hereinafter

referred to as ``SARD, Revision A''), or within one repetitive

inspection period specified in those service bulletins after

September 24, 1990 (the effective date of AD 90-18-03, Amendment 39-

6701), whichever occurs later: Inspect to detect cracks in

accordance with those service bulletins. Repeat these inspections

thereafter at the intervals specified in the service bulletins

listed in either Table 2.1 [for Model DC-9-10, -20, -30, -40, -50,

and C-9 (military) series airplanes], or Table 2.2 [for Model DC-9-

81, -82, -83, -87 (MD-81, -82, -83, -87), and Model MD-88

airplanes], as applicable, of SARD, Revision A, until the applicable

terminating modification required by paragraph (d) of this AD is

accomplished.

-Note 1: Paragraph (a) of this AD restates the requirements for

an initial inspection and the repetitive inspections contained in

paragraph A. of AD 90-18-03. Therefore, for operators who have

previously accomplished at least the initial inspection in

accordance with AD 90-18-03, paragraph (a) of this AD requires that

the next scheduled inspection be performed within the specified

repetitive inspection interval after the last inspection performed

in accordance with paragraph A. of AD 90-18-03.

-(b) Within the threshold for inspections specified in the

service bulletins listed in Tables 2.3 and 3.1 [for Model DC-9-10, -

20, -30, -40, -50, and C-9 (military) series airplanes], or Table

2.4 [for Model DC-9-81, -82, -83, -87 (MD-81, -82, -83, -87), and

Model MD-88 airplanes], as applicable, of McDonnell Douglas Report

No. MDC K1572, ``DC-9/MD-80 Aging Aircraft Service Action

Requirements Document,'' Revision B, dated January 15, 1993

(hereinafter referred to as ``SARD, Revision B''), or within one

repetitive inspection period specified in those service bulletins

after the effective date of this AD, whichever occurs later: Inspect

to detect cracks in accordance with those service bulletins. Repeat

these inspections thereafter at the intervals specified in the

service bulletins listed in either paragraph (b)(1) or (b)(2) of

this AD, as applicable, until the applicable terminating

modification required by paragraph (e) of this AD is accomplished. -

(1) For Model DC-9-10, -20, -30, -40, -50, and C-9 (military)

series airplanes: The service bulletins listed in Tables 2.3 and 3.1

of SARD, Revision B. Or -

(2) For Model DC-9-81, -82, -83, -87 (MD-81, -82, -83, -87), and

Model MD-88 airplanes: The service bulletins listed in Table 2.4 of

SARD, Revision B. -

(c) If any crack is found during any inspection required by this

AD, prior to further flight, either accomplish the applicable

terminating modification in accordance with paragraph (d) or (e) of

this AD, or repair in accordance with a method approved by the

Manager, Los Angeles Aircraft Certification Office (ACO), FAA,

Transport Airplane Directorate.

-Note 2: Detection of any discrepancy, other than cracking,

necessitates appropriate corrective action in accordance with the

provisions of part 43 of the Federal Aviation Regulations (14 CFR

part 43).

-(d) Prior to reaching the incorporation thresholds listed in

either Table 2.1 [for Model DC-9-10, -20, -30, -40, -50, and C-9

(military) series airplanes], or Table 2.2 [for Model DC-9-81, -82,

-83, -87 (MD-81, -82, -83, -87), and Model MD-88 airplanes], as

applicable, of SARD, Revision A or Revision B, or within 4 years

after September 24, 1990 (the effective date of AD 90-18-03),

whichever occurs later: Accomplish the structural modifications

specified in the service bulletins listed in either Table 2.1 [for

Model DC-9-10, -20, -30, -40, -50, and C-9 (military) series

airplanes], or Table 2.2 [for Model DC-9-81, -82, -83, -87 (MD-81, -

82, -83, -87), and Model MD-88 airplanes], as applicable, of SARD,

Revision A or Revision B. Accomplishment of these modifications

constitutes terminating action for the applicable inspections

required by paragraph (a) of this AD.

-Note 3: Paragraph (d) of this AD restates the modification

requirements of paragraph B. of AD 90-18-03. As allowed by the

phrase, ``unless accomplished previously,'' if the requirements of

paragraph B. of AD 90-18-03 have been accomplished previously,

paragraph (d) of this AD does not require that they be repeated. -

Note 4: The service bulletin revision levels listed under

``Recommended Modification'' in either Table 2.1 [for Model DC-9-10,

-20, -30, -40, -50, and C-9 (military) series airplanes], or Table

2.2 [for Model DC-9-81, -82, -83, -87 (MD-81, -82, -83, -87), and

Model MD-88 airplanes], as applicable, of SARD, Revision B, are

acceptable revisions for modifications accomplished prior to

September 24, 1994.

-(e) Prior to reaching the incorporation thresholds listed in

either Table 2.3 [for Model DC-9-10, -20, -30, -40, -50, and C-9

(military) series airplanes], or Table 2.4 [for Model DC-9-81, -82,

-83, -87 (MD-81, -82, -83, -87), and Model MD-88 airplanes], as

applicable, of SARD, Revision B, or within 4 years after the

effective date of this AD, whichever occurs later: Accomplish the

structural modifications specified in the service bulletins listed

in either Table 2.3 [for Model DC-9-10, -20, -30, -40, -50, and C-9

(military) series airplanes], or Table 2.4 [for Model DC-9-81, -82,

-83, -87 (MD-81, -82, -83, -87), and Model MD-88 airplanes], as

applicable, of SARD, Revision B.

Accomplishment of this modification constitutes terminating

action for the applicable inspections required by paragraph (b) of

this AD.

-Note 5: The service bulletin revision levels listed under

``Recommended Modification'' in either Table 2.3 [for Model DC-9-10,

-20, -30, -40, -50, and C-9 (military) series airplanes], or Table

2.4 [for Model DC-9-81, -82, -83, -87 (MD-81, -82, -83, -87), and

Model MD-88 airplanes] of SARD, Revision B, are acceptable revisions

for modifications accomplished prior to the effective date of this

AD. -

Note 6: The modifications required by paragraphs (d) and (e) of

this AD do not terminate the inspection requirements of any other AD

unless that AD specifies that any such modification constitutes

terminating action for those specified inspection requirements.

(f) For Model DC-9-10, -20, -30, -40, -50, and C-9 (military)

series airplanes: Prior to the accumulation of 100,000 total

landings, accomplish the modifications specified in McDonnell

Douglas DC-9 Service Bulletin 53-230, Revision 1, dated January 12,

1993. Accomplishment of these modifications constitute terminating

action for the inspections required by AD 88-24-08 R2, amendment 39-

6469. -

(g) Accomplishment of the modifications in accordance with the

service bulletins listed in Tables 2.1 and 2.3 [for Model DC-9-10, -

20, -30, -40, -50, and C-9 (military) series airplanes], or Tables

2.2 and 2.4 [for Model DC-9-81, -82, -83, -87 (MD-81, -82, -83, -

87), and Model MD-88 airplanes] of SARD, Revision A or B, terminates

the individual inspection requirements of the applicable service

bulletin. -

(h) The requirements of this AD exclude the actions specified in

the following McDonnell Douglas service bulletins that are

referenced in the following tables of SARD, Revision A or B:

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Table(s)- Service Bulletin

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2.1 and 2.2-..... MD-80 Service Bulletin 53-186.

2.2-............. MD-80 Service Bulletin 53-216

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-(i) 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 7: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Los Angeles ACO.

(j) Alternative methods of compliance previously granted for

amendment AD 90-18-03, 39-6701 continue to be considered as

acceptable alternative methods of compliance with this amendment.

(k) 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 November 4, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-27853 Filed 11-9-94; 8:45 am]

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