Assessment of the AH-64D Longbow Apacheâ•Žs Handling Qualities for Instrument Meteorological

96 Pages·2017·9.61 MB·English

by  Michael J. Meely

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Michael J. Meely
University of Tennessee - Knoxville
Follow this and additional works at: https://trace.tennessee.edu/utk_gradthes
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Meely, Michael J., "Assessment of the AH-64D Longbow Apache’s Handling Qualities for Instrument
Meteorological Conditions/Instrument Flight Rules Flight. " Master's Thesis, University of Tennessee,
2004.
https://trace.tennessee.edu/utk_gradthes/2369
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To the Graduate Council:
I am submitting herewith a thesis written by Michael J. Meely entitled "Assessment of the
AH-64D Longbow Apache’s Handling Qualities for Instrument Meteorological Conditions/
Instrument Flight Rules Flight." I have examined the final electronic copy of this thesis for form
and content and recommend that it be accepted in partial fulfillment of the requirements for the
degree of Master of Science, with a major in Aviation Systems.
Ralph Kimberlin, Major Professor
We have read this thesis and recommend its acceptance:
Frank G. Collins, Richard Ranaudo
Accepted for the Council:
Carolyn R. Hodges
Vice Provost and Dean of the Graduate School
(Original signatures are on file with official student records.)
To the Graduate Council:

I am submitting herewith a thesis written by Michael J. Meely entitled “Assessment of the AH-64D
Longbow Apache’s Handling Qualities for Instrument Meteorological Conditions/Instrument Flight Rules
Flight.” I have examined the final electronic copy of this thesis for form and content and recommend that it
be accepted in partial fulfillment of the requirements for the degree of Master of Science with a major in
Aviation Systems.

Ralph Kimberlin
Major Professor

We have read this thesis and
recommend its acceptance:

Frank G. Collins

Richard J. Ranaudo

Acceptance for the Council:

Anne Mayhew
Vice Chancellor and Dean of Graduate Studies

(Original signatures are on file with official study records.)
Assessment of the AH-64D Longbow Apache’s Handling Qualities for Instrument Meteorological
Conditions/Instrument Flight Rules Flight

A Thesis
Presented for the
Master of Science Degree
The University of Tennessee, Knoxville

Michael Jesse Meely
May 2004
DEDICATION

This thesis is dedicated to my wife, DeAnn and my daughter Julianna, who endured my many hours of
study and supported me in every way and gave me that little extra push that enabled me to complete this
thesis. Also to my Mother who is not here today but through her I have been inspired to achieve my goals.
She gave me the drive and determination to work hard and do things to the best of my ability and that has
proved to be the major tools of my success.

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ACKNOWLEDGMENTS

I wish to thank all those who helped me complete my Masters of Science degree in Aviation Systems. I
would like to especially thank Dr. Kimberlin and Dr. Lewis for their effort in familiarizing me with flight
test techniques.

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ABSTRACT

An assessment of the handling of the AH-64D for flight in IMC and under IFR was conducted. Testing
was performed in the configurations listed in table 1 and under the conditions presented in tables 3 and 4.
All test objectives were met. IMC mission maneuvers with all systems working resulted in satisfactory
handling qualities with no excessive compensation required from the pilot (altitude and attitude holds ON).
However, as the aircraft systems were progressively degraded the workload for the evaluating pilot
increased significantly. The high workload coupled with the absence of a vertical speed indicator (VSI)
and torque indication during an AC failure and the observed errors in the standby altimeter and airspeed
indicators would most likely prevent flying a successful unusual attitude recovery, an airport surveillance
radar (ASR) approach, or a precision approach radar (PAR) approach. The inadequacy of the standby
instruments is a deficiency. The aircraft’s longitudinal gust response with FMC OFF required extensive
pilot compensation to maintain altitude and airspeed within adequate parameters, further increasing the
overall pilot workload, and is a deficiency. Additionally, the aircraft’s battery life does not meet the 30-
min requirement for IMC/IFR flight that would be required in the unlikely event of an aircraft AC power
failure and results in a deficiency. Engineering maneuvers conducted to quantify the handling qualities of
the AH-64D with FMC OFF confirmed the high pilot workload and extensive compensation required.
These maneuvers revealed an oscillatory divergent long-term mode, an oscillatory divergent
lateral-directional oscillation (LDO), negative spiral stability when banked to the right, and significant
coupling between pitch and roll. While conducting these maneuvers, excessive instrumentation lag was
observed in the standby altimeter during climbs and descents. This resulted in errors of up to 300 ft
between boom data and the standby altimeter. The excessive observed instrument lag and inaccuracy of the
standby altimeter is a shortcoming. Other findings included the absence of any information on IMC/IFR
procedures in the operator’s manual was also found to be a shortcoming. Consequently a clearance for
aircraft operation in IMC is not recommended. Plots of representative engineering data collected in the
heavy weapons (configuration 3) and two-tank configurations (configuration 5) are in Appendix D.
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TABLE OF CONTENTS

1. INTRODUCTION___________________________________________________________________1
BACKGROUND____________________________________________________________________1
TEST OBJECTIVES _________________________________________________________________1
DESCRIPTION _____________________________________________________________________2
TEST SCOPE_______________________________________________________________________7
TEST METHODOLOGY _____________________________________________________________8
2. RESULTS AND DISCUSSION_______________________________________________________15
STANDBY INSTRUMENT COMPARISON_____________________________________________15
Standby Airspeed Indicator (ASI) ____________________________________________________15
Minimum Speed On Standby Instruments______________________________________________15
Standby Altimeter_________________________________________________________________16
ENGINEERING MANEUVERS_______________________________________________________17
Flight Control Mechanical Characteristics______________________________________________17
Trimmed Flight Control Positions ____________________________________________________17
Longitudinal Static Stability_________________________________________________________17
Longitudinal Dynamic Stability______________________________________________________18
Lateral Directional Dynamic Stability_________________________________________________18
Spiral Stability _________________________________________________________________18
Sideforce Cues_________________________________________________________________19
Maneuvering Stability _____________________________________________________________19
MISSION MANEUVERS____________________________________________________________20
Instrument Takeoff________________________________________________________________20
Radio Navigation FMC On _________________________________________________________21
Radio Navigation With FMC Off_____________________________________________________22
NDB Approach___________________________________________________________________23
Global Positioning System (GPS) Approach____________________________________________25
Unusual Attitude Recovery Using Standby Instruments Only_______________________________26
Airport Surveillance Radar (ASR) Approach Using Standby Instruments Only_________________27
Precision Approach Radar (PAR) Using Standby Instruments Only__________________________28
OTHER FINDINGS_________________________________________________________________29
Battery Life _____________________________________________________________________29
GPS Database____________________________________________________________________29
Training ________________________________________________________________________30
Operator’s Manual________________________________________________________________30
3. CONCLUSIONS___________________________________________________________________31
GENERAL________________________________________________________________________31
DEFICIENCIES____________________________________________________________________32
SHORTCOMINGS _________________________________________________________________32
4. RECOMMENDATIONS ____________________________________________________________33
SPECIFIC_________________________________________________________________________33
REFERENCES_______________________________________________________________________34
APPENDIXES_______________________________________________________________________36
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APPENDIX A. FLIGHT CONTROL DESCRIPTION_________________________________________37
APPENDIX B. INSTRUMENTATION ____________________________________________________53
APPENDIX C. TEST DATA ___________________________________________________________57
VITA_______________________________________________________________________________82

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LIST OF TABLES

Table Page

1. Aircraft Test Configurations_____________________________________________________________7
2. Pilot Fight Experience _________________________________________________________________9
3. Test and Test Conditions for IMC/IFR____________________________________________________10
4. Mission Maneuvers Tests and Test Conditions for IMC/IFR___________________________________14
A-1. ARRD Normal Breakout Loads _______________________________________________________44

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