Airworthiness Directives; McDonnell Douglas Model MD-11 Series Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 93-NM-86-AD; Amendment 39-8844; AD 94-05-06]

Airworthiness Directives; McDonnell Douglas Model MD-11 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 certain McDonnell Douglas Model MD-11 series airplanes,

that requires modification or replacement of designated passenger cabin

floor panels. This amendment is prompted by a report that, during

manufacture, the inserts that attach the floor panels to the seat

tracks and floor beams were installed using sealant rather than

required adhesive. The actions specified by this AD are intended to

prevent loss of the passenger cabin floor capability to support the

airplane interior inertia loads under emergency landing conditions.

DATES: Effective April 4, 1994.

The incorporation by reference of certain publications listed in

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

of April 4, 1994.

ADDRESSES: The service information referenced in this AD may be

obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach,

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

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

examined at the Federal Aviation Administration (FAA), Transport

Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton,

Washington; or at the FAA, Los Angeles Aircraft Certification Office,

3229 East Spring Street, Long Beach, California; or at the Office of

the Federal Register, 800 North Capitol Street, NW., suite 700,

Washington, DC.

FOR FURTHER INFORMATION CONTACT: Wahib Mina, Aerospace Engineer,

Airframe Branch, ANM-121L, FAA, Transport Airplane Directorate, Los

Angeles Aircraft Certification Office, 3229 East Spring Street, Long

Beach, California 90806-2425; telephone (310) 988-5324; fax (310) 988-

5210.

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

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

applicable to certain McDonnell Douglas Model MD-11 series airplanes

was published in the Federal Register on August 19, 1993 (58 FR 44150).

That action proposed to require modification or replacement of

designated passenger cabin floor panels.

Interested persons have been afforded an opportunity to participate

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

the comments received.

Two commenters support the proposed rule.

The Air Transport Association (ATA) of America, on behalf of

several of its members, requests that the FAA withdraw the proposed

rule. The commenter states that all U.S. operators and all but one non-

U.S. operator have accomplished the modification or replacement

specified in McDonnell Douglas MD-11 Service Bulletin 53-31, which is

cited in the proposed rule, thereby ensuring that 9g crash

certification requirements are satisfied. The commenter adds that

McDonnell Douglas MD-11 Service Bulletins 53-32 and 53-33, which are

also cited in the proposal, were only included in the manufacturer's

service program to ensure commonality between operators, but were not

included in that program to return the aircraft to its original design

intent. The commenter concludes that, since all U.S. operators have

accomplished the actions described in McDonnell Douglas MD-11 Service

Bulletin 53-31, there is no need for an AD. Further, the commenter

believes that issuance of the AD would contradict the principles of

Presidential Executive Order 12866 (Regulatory Planning and Review),

and would cause an unjustifiable expense to operators.

The FAA does not concur with the commenter's request to withdraw

the proposed rule. As explained in the preamble to the proposal, the

FAA has determined that accomplishment of the modification or

replacement described in McDonnell Douglas MD-11 Service Bulletin 53-31

is necessary to correct an unsafe condition described as loss of the

passenger cabin floor capability to support the airplane interior

inertia loads under emergency landing conditions. Under existing

bilateral airworthiness agreements, the FAA is obligated, through the

AD process, to advise foreign airworthiness authorities of unsafe

conditions relating to products produced in the United States, and to

provide instructions determined necessary to correct the unsafe

condition addressed. The appropriate vehicle for mandating such action

to correct an unsafe condition is the airworthiness directive.

However, upon consideration of data submitted by the manufacturer

since issuance of the proposal, the FAA has determined that

accomplishment of the modification or replacement specified in

McDonnell Douglas MD-11 Service Bulletin 53-31 adequately addresses the

unsafe condition, and that the actions described in McDonnell Douglas

MD-11 Service Bulletins 53-32 and 53-33 are not necessary to address

that unsafe condition. The FAA's original concern was that

interchanging the floor panels could result in an unsafe condition

under emergency landing conditions. However, based on the data received

from the manufacturer, the FAA finds that its concern regarding floor

panel interchangeability is addressed by part number controls; original

panels are not interchangeable with reworked panels or new panels. In

light of this, the FAA has removed paragraphs (b) and (c) from the

final rule. In addition, references to McDonnell Douglas MD-11 Service

Bulletins 53-32 and 53-33 have been removed from the applicability of

the AD. The FAA also has revised the economic impact paragraph, below,

to reflect the fact that all U.S. airplanes have accomplished the

requirements of this AD.

One commenter requests that paragraph (a) of the proposed rule be

revised to clarify that each individual panel may be reworked in

accordance with Option I of McDonnell Douglas MD-11 Service Bulletin

53-31, or replaced in accordance with Option II of that service

bulletin, rather than implying that all panels must be either reworked

or replaced. The commenter also requests that the proposal be revised

to indicate that installation of operator-manufactured panels with

properly installed inserts are acceptable in lieu of production panels.

The FAA concurs. Paragraph (a) of this AD has been revised to

indicate that the requirements of that paragraph may be accomplished by

either reworking an individual panel in accordance with Option I of the

service bulletin, or replacing an individual panel in accordance with

Option II of the service bulletin. Paragraph (a) of the final rule also

has been revised to specify that new panels that meet the original type

design or FAA-approved equivalent panels are considered acceptable

replacement panels.

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 with the changes previously

described. The FAA has determined that these changes will neither

increase the economic burden on any operator nor increase the scope of

the AD.

There are approximately 32 Model MD-11 series airplanes of the

affected design in the worldwide fleet. The FAA estimates that 20

airplanes of U.S. registry will be affected by this AD. The FAA has

been advised that the requirements of this AD have been accomplished on

all 20 airplanes of U.S. registry.

However, should an affected airplane be imported and placed on the

U.S. Register in the future, the FAA has been advised that the

manufacturer plans to provide required parts and to accomplish the

required modification at no expense to operators. Therefore, there is

no future economic cost impact of this rule on U.S. operators.

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:

94-05-06 McDonnell Douglas: Amendment 39-8844. Docket 93-NM-68-AD.

Applicability: Model MD-11 series airplanes, as listed in

McDonnell Douglas MD-11 Service Bulletin 53-31, dated January 29,

1993; certificated in any category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent loss of the passenger cabin floor capability to

support the airplane interior inertia loads under emergency landing

conditions, accomplish the following:

(a) Within one year after the effective date of this AD, modify

or replace the passenger cabin floor panels designated in McDonnell

Douglas MD-11 Service Bulletin 53-31, dated January 29, 1993, in

accordance with that service bulletin. The requirements of this

paragraph may be accomplished by either reworking an individual

panel in accordance with Option I of the service bulletin, or

replacing an individual panel in accordance with Option II of the

service bulletin. New panels that meet the original type design or

FAA-approved equivalent panels are considered to be acceptable

replacement panels.

(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, 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: Information concerning the existence of approved

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

obtained from the Los Angeles ACO.

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

Federal Aviation Regulations (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 or replacement shall be done in accordance

with McDonnell Douglas MD-11 Service Bulletin 53-31, dated January

29, 1993. 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 McDonnell Douglas

Corporation, P.O. Box 1771, Long Beach, California 90801-1771,

Attention: Business Unit Manager, Technical Administrative Support,

Dept. L51, M.C. 2-98. Copies may be inspected at the FAA, Transport

Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or

at the FAA, Los Angeles Aircraft Certification Office, 3229 East

Spring Street, Long Beach, California; or at the Office of the

Federal Register, 800 North Capitol Street, NW., suite 700,

Washington, DC.

(e) This amendment becomes effective on April 4, 1994.

Issued in Renton, Washington, on February 22, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-4447 Filed 3-3-94; 8:45 am]

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