Airworthiness Directives; Boeing Model 707 Series Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 93-NM-82-AD; Amendment 39-8856; AD 94-06-08]

Airworthiness Directives; Boeing Model 707 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD),

applicable to Boeing Model 707 series airplanes, that requires the

incorporation of a certain structural modification of the wing front

spar lower chord. This amendment is prompted by an evaluation and

recommendation by the Airworthiness Assurance Task Force to mandate the

actions described in certain Boeing service bulletins as part of the

``Aging Airplane Structural Modification Program.'' The actions

specified by this AD are intended to prevent reduced structural

integrity of the wing. The actions also reflect the FAA's decision that

long term continued operational safety should be assured by actual

modification of the airframe rather than repetitive inspections.

DATES: Effective April 21, 1994.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of April 21, 1994.

ADDRESSES: The service information referenced in this AD may be

obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle,

Washington 98124-2207. This information may be examined at the Federal

Aviation Administration (FAA), Transport Airplane Directorate, Rules

Docket, 1601 Lind Avenue, SW., Renton, Washington; or at Boeing

Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-

2207; or at the Office of the Federal Register, 800 North Capitol

Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Phil Forde, Aerospace Engineer,

Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle

Aircraft Certification Office, 1601 Lind Avenue SW., Renton, Washington

98055-4056; telephone (206) 227-2771; fax (206) 227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal

Aviation Regulations to include an airworthiness directive (AD) that is

applicable to Boeing Model 707 series airplanes was published in the

Federal Register on September 7, 1993 (58 FR 47085). That action

proposed to require incorporation of a certain structural modification

of the wing front spar lower chord.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. Due consideration has been given to

the comments received.

-One commenter supports the proposal.

-Another commenter requests that the structural inspections and

modifications referenced in sections A.3 and A.4 of appendix A of

Boeing Document Number D6-54996, ``Aging Airplane Service Bulletin

Structural Modification and Inspection Program--Model 707/720,''

Revision D, dated January 23, 1992, be addressed in a single AD action,

rather than in two different actions, as presently proposed by the FAA.

This commenter points out that the FAA has issued a separate proposed

AD, Docket 93-NM-80-AD (58 FR 53678, October 18, 1993), which would

require the accomplishment of certain actions listed in section 4 and

appendix A.4 of the Boeing Document, while this proposal (93-NM-82-AD)

would require the accomplishment of actions referenced in appendix A,

section A.3. The commenter contends that by issuing a single AD to

cover both sections of the Boeing Document, the FAA will contribute to

reducing the cost and complexity of publishing and tracking multiple

AD's, while maintaining the same level of safety.

-The FAA does not concur with the commenter's request, specifically

because of the nature of the requirements of the currently proposed

rules. The actions proposed in Docket 93-NM-80-AD address structural

inspections of both the Model 707 and Model 720, which are listed in

section 4 and appendix A.4 of the Boeing Document. Those inspection

actions entail various compliance times for implementation and a

specified ``phase-in'' period for repetitive inspection intervals. On

the other hand, the action proposed by this AD addresses a single

modification of only Model 707 series airplanes, which is listed in

appendix A.3. of the Boeing Document. The modification action entails a

specific compliance time for implementation based on either a flight

cycle count or a calendar time limit. The FAA considers that to have

combined the requirements for these dissimilar actions into one complex

AD, would have created unnecessary confusion for affected operators.

Therefore, as issued, there will be one AD addressing ``inspections

only'' and another AD addressing the modification. This method of

issuance will also ensure easier tracking of and proper compliance with

the requirements of the AD's.

-After careful review of the available data, including the comments

noted above, the FAA has determined that air safety and the public

interest require the adoption of the rule as proposed.

-There are approximately 374 Model 707 series airplanes of the

affected design in the worldwide fleet. The FAA estimates that 70

airplanes of U.S. registry will be affected by this AD within the

initial threshold of 4 years. Approximately 194 work hours will be

required to accomplish the modification, at an average labor charge of

$55 per work hour. (This figure does not include downtime, planning,

set up, familiarization, or tool acquisition costs.) The cost of the

required modification kit is approximately $3,500 per airplane. Based

on these figures, the total cost impact of this AD on U.S. operators

within the initial threshold of 4 years is estimated to be $991,900, or

$14,170 per airplane.

-The total cost impact figure discussed above is based on

assumptions that no operator has yet accomplished any of the

requirements of this AD action, and that no operator would accomplish

those actions in the future if this AD were not adopted.

-The regulations adopted herein will 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 final

rule does not have sufficient federalism implications to warrant the

preparation of a Federalism Assessment.

-For the reasons discussed above, I certify that this action (1) is

not a ``significant regulatory action'' under Executive Order 12866;

(2) is not a ``significant rule'' under DOT Regulatory Policies and

Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action

and it is contained in the Rules Docket. A copy of it may be obtained

from the Rules Docket at the location provided under the caption

ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by

reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the

Administrator, the Federal Aviation Administration amends 14 CFR part

39 of the Federal Aviation Regulations 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 adding the following new

airworthiness directive:

94-06-08 Boeing: Amendment 39-8856. Docket 93-NM-82-AD.

-Applicability: Model 707-300, -300B, -300C, and -400 series

airplanes, certificated in any category. -

Compliance: Required as indicated, unless accomplished

previously. -

To prevent reduced structural integrity of the wing, accomplish

the following: -

(a) Prior to the accumulation of 20,000 total flight cycles or

within the next 4 years after the effective date of this AD,

whichever occurs later, accomplish the structural modification

specified in Appendix A., Section A.3., of Boeing Document Number

D6-54996, ``Aging Airplane Service Bulletin Structural Modification

and Inspection Program--Model 707/720,'' Revision D, dated January

23, 1992.

Note 1: Appendix A., Section A.3., of Boeing Document Number D6-

54996 references Boeing Service Bulletin 3475 for procedures to

modify the wing front spar lower chord at wing station 529.5.

-Note 2: The modification required by this paragraph does not

terminate the inspection requirements of any other AD unless that AD

specifies that any such modification constitutes terminating action

for the inspection requirements.

-(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, Seattle 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, Seattle ACO.

-Note 3: Information concerning the existence of approved

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

obtained from the Seattle ACO.

-(c) Special flight permits may be issued in accordance with

FAR 21.197 and 21.199 to operate the airplane to a location where

the requirements of this AD can be accomplished. -

(d) The modification shall be done in accordance with Boeing

Document Number D6-54996, ``Aging Airplane Service Bulletin

Structural Modification and Inspection Program--Model 707/720,''

Revision D, dated January 23, 1992, which contains the following

list of effective pages:

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Revision

Page No. symbol shown Date shown on page

on page

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List of active pages, pages D (These pages are not dated.)

c.1 and c.2.

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This incorporation by reference was approved by the Director of

the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR

Part 51. Copies may be obtained from Boeing Commercial Airplane

Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be

inspected at the FAA, Transport Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington; or at the Office of the Federal

Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

-

(e) This amendment becomes effective on April 21, 1994.

Issued in Renton, Washington, on March 7, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-5702 Filed 3-21-94; 8:45 am]

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