[Federal Register Volume 59, Number 87 (Friday, May 6, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-10776]


[[Page Unknown]]

[Federal Register: May 6, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-57-AD; Amendment 39-8910; AD 94-10-03]

 

Airworthiness Directives; McDonnell Douglas Model MD-11 and MD-
11F Series Airplanes Equipped With Honeywell Flight Management 
Computers

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 and MD-11F 
series airplanes. This action requires deactivation of the Visual 
Omnidirectional Receiver/Localizer (VOR/LOC) option by revising the 
program pin wiring for the Flight Management Computer/Flight Control 
Computer (FMC/FCC). This amendment is prompted by reports of 
uncommanded roll mode changes on these airplanes during takeoff and 
landing due to incorrect initialization of VOR/LOC logic within the 
FMC. The actions specified in this AD are intended to prevent the 
airplane from deviating from its intended flight path due to an 
uncommanded change in the course of direction.

DATES: Effective on May 23, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 23, 1994.
    Comments for inclusion in the Rules Docket must be received on or 
before July 5, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-57-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, Los Angeles Aircraft Certification Office, 
Transport Airplane Directorate, 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: Natalie Phan-Tran, Aerospace Engineer, 
Systems & Equipment Branch, ANM-130L, Los Angeles Aircraft 
Certification Office, FAA, Transport Airplane Directorate, 3229 East 
Spring Street, Long Beach, California 90806-2425; telephone (310) 988-
5343; fax (310) 988-5210.

SUPPLEMENTARY INFORMATION: The FAA has received reports of uncommanded 
roll mode changes that have occurred on McDonnell Douglas Model MD-11 
series airplanes during takeoff and landing. The airplanes involved in 
these incidents have been equipped with Honeywell Flight Management 
Computers (FMC) having part numbers 4059050-907 and 4059050-908. The 
incidents occurred when these FMC's were operating with the Visual 
Omnidirectional Receiver/Localizer (VOR/LOC) option selected.
    Investigation revealed that these incidents of uncommanded roll 
mode changes were caused by one of the two FMC's not automatically 
resetting or clearing all VOR mode logic upon landing. If the VOR mode 
was selected on the previous inbound flight, and if this VOR mode is 
not automatically cleared after the airplane lands, the VOR logic may 
remain valid (in operation) in one of the two FMC's onboard the 
airplane. If, during a subsequent flight, the autoflight system is 
engaged to the FMC that still has the valid VOR logic [either by 
disconnecting the autopilot (AP) or by swapping autopilots (AP1 to AP2, 
or vice versa) with the ``AUTOFLIGHT'' switch], that FMC will 
automatically command the airplane into a VOR roll mode. The airplane 
will then follow this VOR mode logic guidance and fly in a direction 
not planned by the flight crew. Such an uncommanded change in course 
direction, if not corrected, could result in the airplane deviating 
from its intended flight path.
    The FAA has reviewed and approved McDonnell Douglas MD-11 Alert 
Service Bulletin A34-55, dated April 22, 1994, that describes 
procedures for deactivating the VOR/LOC option on the subject Honeywell 
FMC's by removing the VOR/LOC pin from the Flight Management Computer/
Flight Control Computer (FMC/FCC) configuration plug on the main 
avionics rack. This procedure will minimize the possibility of 
uncommanded roll mode changes.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other Model MD-11 and MD-11F series airplanes of 
the same type design, this AD is being issued to prevent the airplane 
from deviating from its intended flight path due to an uncommanded 
change in the course of direction. This AD requires deactivating the 
VOR/LOC option on certain Honeywell FMC's by removing the VOR/LOC pin 
from the FMC/FCC configuration plug on the main avionics rack. The 
actions are required to be accomplished in accordance with the service 
bulletin described previously.
    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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 94-NM-57-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:

94-10-03 McDonnell Douglas: Amendment 39-8910. Docket 94-NM-57-AD.

    Applicability: Model MD-11 and MD-11F series airplanes; equipped 
with Honeywell Flight Management Computers having part numbers 
4059050-907 or 4059050-908; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent the airplane from deviating from its intended flight 
path due to an uncommanded change in the course of direction, 
accomplish the following:
    (a) Within 30 days after the effective date of this AD, 
deactivate the Visual Omnidirectional Receiver/Localizer (VOR/LOC) 
option by removing the VOR/LOC pin from the Flight Management 
Computer/Flight Control Computer (FMC/FCC) configuration plug on the 
main avionics rack, in accordance with McDonnell Douglas MD-11 Alert 
Service Bulletin A34-55, dated April 22, 1994.
    (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). Operators shall submit their requests through an 
appropriate FAA Principal Avionics 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 
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) The deactivation procedure shall be done in accordance with 
McDonnell Douglas MD-11 Alert Service Bulletin A34-55, dated April 
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, Los Angeles Aircraft Certification Office, Transport 
Airplane Directorate, 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 May 23, 1994.

    Issued in Renton, Washington, on April 29, 1994.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-10776 Filed 5-5-94; 8:45 am]
BILLING CODE 4910-13-U