[Federal Register Volume 63, Number 137 (Friday, July 17, 1998)]
[Rules and Regulations]
[Pages 38464-38466]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-19044]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-209-AD; Amendment 39-10665; AD 98-15-14]
RIN 2120-AA64


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 supersedes an existing airworthiness directive 
(AD), applicable to certain McDonnell Douglas Model MD-11 series 
airplanes, that currently requires a revision of the Airplane Flight 
Manual (AFM) to alert the flightcrew that both flight management 
computers (FMC's) must be installed and operational. That AD also 
requires an inspection to determine the serial number of the FMC's; and

[[Page 38465]]

follow-on corrective actions, if necessary, which terminate the AFM 
revision. That amendment was prompted by a report indicating that, due 
to incorrect multiplexers that were installed in the FMC's during 
production, certain data busses failed simultaneously during a ground 
test. This amendment removes the terminating action from the existing 
AD. The actions specified in this AD are intended to prevent loss of 
airspeed and altitude indications on both primary flight displays in 
the cockpit, and/or loss or degradation of the autopilot functionality 
due to installation of incorrect multiplexers, and consequent failure 
of the data busses.

DATES: Effective August 3, 1998.
    Comments for inclusion in the Rules Docket must be received on or 
before September 15, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-209-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    Information pertaining to this rulemaking action 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, 3960 Paramount Boulevard, Lakewood, 
California.

FOR FURTHER INFORMATION CONTACT: Brett Portwood, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130L, FAA, Transport Airplane 
Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount 
Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5350; 
fax (562) 627-5210.

SUPPLEMENTARY INFORMATION: On April 28, 1998, the FAA issued AD 98-10-
01, amendment 39-10512 (63 FR 24742, May 5, 1998), applicable to 
certain McDonnell Douglas Model MD-11 series airplanes. That AD 
requires a revision of the Airplane Flight Manual (AFM) to alert the 
flightcrew that both flight management computers (FMC's) must be 
installed and operational. That AD also requires an inspection to 
determine the serial number of the FMC's, and follow-on corrective 
actions, if necessary; which terminate the AFM revision. That action 
was prompted by a report indicating that, due to incorrect multiplexers 
that were installed in the FMC's during production, certain data busses 
failed simultaneously during a ground test. The actions required by 
that AD are intended to prevent loss of airspeed and altitude 
indications on both primary flight displays in the cockpit, and/or loss 
or degradation of the autopilot functionality due to installation of 
incorrect multiplexers, and consequent failure of the data busses.

Actions Since Issuance of Previous Rule

    The existing AD requires terminating action for only a small 
subgroup of affected airplanes (those with FMC multiplexers having 
certain part numbers). However, since the issuance of that AD, 
additional defective multiplexers (not previously identified) have been 
found.
    Airplanes having affected FMC's that have been purged of suspected 
defective multiplexers, in compliance with AD 98-10-01, would be 
considered airworthy. However, FMC's or mutliplexes may have been 
exchanged or replaced during routine maintenance subsequent to 
compliance with AD 98-10-01, and it would be impossible to determine 
whether units inspected in accordance with that AD may now contain 
suspected defective multiplexers. Therefore, the AFM revision will 
continue to be required until the entire fleet can be systematically 
inspected for suspected defective multiplexers. The AFM revision 
requirement will ensure the continued safe operation of the entire 
fleet during this interim period.
    The AFM revision currently required by the existing AD, and 
retained in this new action, requires that both FMC's be installed and 
operational. The identified unsafe condition could not occur unless 
both FMC's fail. Therefore, the FAA finds that the AFM limitation 
adequately addresses the identified unsafe condition.

Interim Action

    This is considered to be interim action. The FAA may consider 
further rulemaking to require inspection of all MD-11 FMC's to detect 
defective multiplexers. However, the compliance time under 
consideration for these actions is sufficiently long so that notice and 
opportunity for prior public comment will be practicable.

Explanation of Requirements of Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of this same type design, this AD 
supersedes AD 98-10-01 to continue to require an AFM revision to alert 
the flightcrew that both FMC's must be installed and operational. In 
addition, this AD removes the terminating action required by AD 98-10-
01.

Determination of Rule's Effective Date

    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.

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 rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 98-NM-209-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    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.

[[Page 38466]]

    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it 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, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-10512 (63 FR 
24742, May 5, 1998), and by adding a new airworthiness directive (AD), 
amendment 39-10665, to read as follows:

98-15-14  McDonnell Douglas: Amendment 39-10665. Docket 98-NM-209-
AD. Supersedes AD 98-10-01, amendment 39-10512.

    Applicability: Model MD-11 series airplanes, manufacturer's 
fuselage numbers 0447 through 0552 inclusive, and 0554 through 0621 
inclusive; 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 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 (b) 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 prevent loss of airspeed and altitude indications on both 
primary flight displays in the cockpit, and/or loss or degradation 
of the autopilot functionality due to installation of incorrect 
multiplexers, and consequent failure of the data busses, accomplish 
the following:
    (a) Within 5 days after May 20, 1998 (the effective date of AD 
98-10-01, amendment 39-10512), revise Section 1, page 5-1, of the 
Limitations Section of the FAA-approved Airplane Flight Manual (AFM) 
to include the following statement. This may be accomplished by 
inserting a copy of this AD into the AFM.
    ``Prior to dispatch of the airplane, both Flight Management 
Computer 1 (FMC-1) and FMC-2 must be installed and operational.''
    (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 
Operations 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.

    (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.
    (d) This amendment becomes effective on August 3, 1998.

    Issued in Renton, Washington, on July 10, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-19044 Filed 7-16-98; 8:45 am]
BILLING CODE 4910-13-U