Airworthiness Directives; McDonnell Douglas Model MD-11 Series Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 94-NM-45-AD; Amendment 39-8889; AD 94-09-01]

Airworthiness Directives; McDonnell Douglas Model MD-11 Series

Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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

is applicable to certain McDonnell Douglas Model MD-11 series

airplanes. This action requires an eddy current inspection to detect

defects in the upper and lower lock links on the nose landing gear

(NLG), and rework or replacement of any defective link found. This

amendment is prompted by reports of cracking and subsequent failure of

certain lock links on these airplanes, which have been attributed to

forging defects in the lock links. The actions specified in this AD are

intended to prevent collapse of the NLG.

DATES: Effective May 5, 1994.

The incorporation by reference of certain publications listed in

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

of May 5, 1994.

Comments for inclusion in the Rules Docket must be received on or

before June 20, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No. 94-NM-45-AD, 1601 Lind Avenue, SW., Renton,

Washington 98055-4056.

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

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; 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: The FAA has received a report of cracking

and subsequent failure of an upper lock link on the center landing gear

(CLG) of a McDonnell Douglas Model MD-11 series airplane. Results of a

subsequent analysis attributed the failure to forging defects in the

lock link. An investigation conducted by the manufacturer revealed two

additional upper links on the CLG with similar forging defects. The

lower lock link on the CLG and the upper and lower lock links on the

nose landing gear (NLG) are similar in design and are manufactured by

the same supplier as the upper lock link on the CLG; therefore,

defective lock links could be installed at any of these locations.

Failure of the lock links on the CLG would result in collapse of the

CLG; collapse of the CLG would not present an unsafe condition.

However, cracking and subsequent failure of the lock links on the NLG,

if not corrected, could result in collapse of the NLG. This situation

could result in reduced controllability of the airplane during takeoff

or landing.

The FAA has reviewed and approved McDonnell Douglas MD-11 Alert

Service Bulletin A32-44, dated March 22, 1994, that describes

procedures for an eddy current inspection to detect defects in the lock

links of the NLG and CLG on certain airplanes, and rework or

replacement of any defective lock link found. Reworking or replacing

the lock links will minimize the possibility of failure of the lock

links on NLG and CLG and subsequent collapse of a landing gear.

Since an unsafe condition has been identified that is likely to

exist or develop on other Model MD-11 series airplanes of the same type

design, this AD is being issued to prevent collapse of the NLG. This AD

requires an eddy current inspection to detect defects in the upper and

lower lock links on the NLG, and rework or replacement of any defective

link found. The actions are required to be accomplished in accordance

with the alert service bulletin described previously. This AD also

requires that operators submit a report of inspection findings to the

FAA.

Since a situation exists that requires the immediate adoption of

this regulation, it is found that notice and opportunity for prior

public comment hereon are impracticable, and that good cause exists for

making this amendment effective in less than 30 days.

The required compliance time of 120 days is usually sufficient to

allow for a brief comment period before adoption of a final rule. In

this AD, however, that compliance time was selected because of a short-

term problem with availability of sufficient replacement parts if

defects are found; a shorter compliance time might have resulted in the

unnecessary removal of airplanes from service pending delivery of

replacement parts. Nevertheless, the FAA has determined that immediate

adoption is necessary in this case because of the importance of

initiating the required inspections as soon as possible.

Comments Invited

Although this action is in the form of a final rule that involves

requirements affecting flight safety and, thus, was not preceded by

notice and an opportunity for public comment, comments are invited on

this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All

communications received on or before the closing date for comments will

be considered, and this rule may be amended in light of the comments

received. Factual information that supports the commenter's ideas and

suggestions is extremely helpful in evaluating the effectiveness of the

AD action and determining whether additional rulemaking action would be

needed.

Comments are specifically invited on the overall regulatory,

economic, environmental, and energy aspects of the rule that might

suggest a need to modify the 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 that

summarizes each FAA-public contact concerned with the substance of this

AD 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-45-AD.'' The postcard will be date stamped and

returned to the commenter.

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.

The FAA has determined that this regulation is an emergency

regulation that must be issued immediately to correct an unsafe

condition in aircraft, and is not a ``significant regulatory action''

under Executive Order 12866. It has been determined further that this

action involves an emergency regulation under DOT Regulatory Policies

and Procedures (44 FR 11034, February 26, 1979). If it is determined

that this emergency regulation otherwise would be significant under DOT

Regulatory Policies and Procedures, a final regulatory evaluation will

be prepared and placed in the Rules Docket. A copy of it, if filed, 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:

94-09-01 McDonnell Douglas: Amendment 39-8889. Docket 94-NM-45-AD.

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

McDonnell Douglas MD-11 Alert Service Bulletin A32-44, dated March

22, 1994; certificated in any category.

Compliance: Required as indicated, unless accomplished

previously. To prevent collapse of the nose landing gear (NLG),

accomplish the following: (a) Within 120 days after the effective

date of this AD, perform an eddy current inspection to detect

defects in the upper lock links, part number ACG7396-1, and lower

lock links, part number ACG7237-1, on the NLG; in accordance with

McDonnell Douglas MD-11 Alert Service Bulletin A32-44, dated March

22, 1994.

(b) If no defect is found, prior to further flight, identify the

inspected lock link in accordance with McDonnell Douglas MD-11 Alert

Service Bulletin A32-44, dated March 22, 1994.

(c) If any defect is found, prior to further flight, accomplish

either paragraph (c)(1) or (c)(2) of this AD in accordance with

McDonnell Douglas MD-11 Alert Service Bulletin A32-44, dated March

22, 1994.

(1) Rework and identify the lock link. Or

(2) Replace the defective lock link with a serviceable lock link

that has been inspected and identified in accordance with paragraphs

(a) and (b) of this AD.

(d) Within 10 days after accomplishing the inspection required

by paragraph (a) of this AD, submit a report of inspection findings

to the Manager, Los Angeles Aircraft Certification Office (ACO),

3229 East Spring Street, Long Beach California 90806-2425; fax (310)

988-5210. The report must include the inspection results, a

description of any discrepancy found, the part numbers of all links

inspected, the airplane serial number, and the number of landings

and flight hours on the airplane. Information collection

requirements contained in this regulation have been approved by the

Office of Management and Budget (OMB) under the provisions of the

Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have

been assigned OMB Control Number 2120-0056.

(e) As of the effective date of this AD, no person shall install

an upper lock link, part number ACG7396-1, or a lower lock link,

part number ACG7237-1, on the NLG of any airplane unless that lock

link has been inspected and identified in accordance with paragraphs

(a) and (b) of this AD.

(f) 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.

(g) 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.

(h) The actions shall be done in accordance with McDonnell

Douglas MD-11 Alert Service Bulletin A32-44, dated March 22, 1994.

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, Transport Airplane Directorate, 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.

(i) This amendment becomes effective on May 5, 1994.

Issued in Renton, Washington, on April 14, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-9471 Filed 4-19-94; 8:45 am]

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