[Federal Register Volume 59, Number 71 (Wednesday, April 13, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-8686]


[[Page Unknown]]

[Federal Register: April 13, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-29-AD; Amendment 39-8879; AD 94-08-07]

 

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 revising the FAA-approved 
Airplane Flight Manual (AFM) to ensure that the flight crews verify the 
accuracy of data provided by the Flight Management Computer (FMC) under 
certain conditions. This amendment is prompted by a report that certain 
FMC's may provide erroneous V speed data under certain conditions. The 
actions specified in this AD are intended to prevent the airplane from 
failing to achieve sufficient climb gradient, which may result in the 
airplane failing to achieve obstacle clearance.

DATES: Effective April 28, 1994.
    Comments for inclusion in the Rules Docket must be received on or 
before June 13, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-29-AD, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056.
    Information concerning this amendment may be obtained from or 
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.

FOR FURTHER INFORMATION CONTACT: Thomas A. Enyart, Aerospace Engineer, 
Flight Test Branch, ANM-162L, FAA, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3229 East Spring Street, Long 
Beach, California 90806-2425; telephone (310) 988-5372; fax (310) 988-
5210.

SUPPLEMENTARY INFORMATION: Recently, an operator of McDonnell Douglas 
Model MD-11 series airplanes reported that certain Honeywell Flight 
Management Computers (FMC) provided erroneous V speed data when the 
anti-ice system was turned ON during flex (assumed) temperature 
takeoffs. Investigation into this problem revealed that the takeoff 
decision speed (V1) could be as low as 12 knots below the V1 
speed data published in the FAA-approved Airplane Flight Manual (AFM), 
and the rotation speed (VR) could be as low as 4 knots below the 
VR speed data published in the FAA-approved AFM. An airplane 
rotating at low VR speeds could reach 35 feet at a speed less than 
the published minimum safety speed (V2). This condition, if not 
corrected, could result in these airplanes failing to achieve 
sufficient climb gradient, which may lead to these airplanes failing to 
achieve obstacle clearance.
    The FMC's installed on Model MD-11 series airplanes are identical 
to those installed Model MD-11F series airplanes.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other McDonnell Douglas Model MD-11 and MD-11F 
series airplanes of the same type design equipped with certain 
Honeywell FMC's, this AD is being issued to prevent these airplanes 
from failing to achieve sufficient climb gradient, which may result in 
these airplanes failing to achieve obstacle clearance. This AD requires 
revising the FAA-approved AFM to ensure that the flight crews verify 
the accuracy of data provided by the FMC when the anti-ice system is 
turned ON during flex temperature takeoffs.
    This is considered to be interim action. The manufacturer of these 
airplanes is currently developing new software, in concert with the 
manufacturer of the FMC, that will address the unsafe condition 
addressed by this AD. Once this software is developed, approved, and 
available, the FAA may consider additional rulemaking.
    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-29-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, 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:

94-08-07 McDonnell Douglas: Amendment 39-8879. Docket 94-NM-29-AD.

    Applicability: Model MD-11 and MD-11F series airplanes equipped 
with Honeywell Flight Management Computers having part numbers 
4059050-906, -907, and -908; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent the airplane from failing to achieve sufficient climb 
gradient, which may result in the airplane failing to achieve 
obstacle clearance, accomplish the following:
    (a) Within 20 days after the effective date of this AD, revise 
the Limitations Section (Section 1) of the FAA-approved Airplane 
Flight Manual (AFM), page 5-1, FLIGHT GUIDANCE, Flight Management 
System (FMS) Section, to include the following information. This may 
be accomplished by inserting a copy of this AD or an FAA-approved 
McDonnell Douglas AFM revision in the AFM.
    For any approved thrust level, the FMS computed V1, 
VR, and V2 must be verified with AFM derived data, unless 
all of the following conditions are met:
     Dry Runway.
     Balanced Field Length.
     Ice Protection OFF.
    (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: 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) This amendment becomes effective on April 28, 1994.

    Issued in Renton, Washington, on April 6, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-8686 Filed 4-12-94; 8:45 am]
BILLING CODE 4910-13-U