NASA Technical Memorandum 101720

Overview of the NASA Ames-Dryden

Integrated Test Facility

Dale Mackall, David McBride, and Dorothea Cohen

May 1990

National Aeronautics and

Space Administration

https://ntrs.nasa.gov/search.jsp?R=19990110575 2018-05-11T19:24:15+00:00Z
NASA Technical Memorandum 101720

Overview of the NASA Ames-Dryden

Integrated Test Facility

Dale Mackall, David McBride, and Dorothea Cohen

Ames Research Center, Dryden Flight Research Facility, Edwards, California

199O

National Aeronautics and

Space Administration

Ames Research Center

Dryden Flight Research Facility

Edwards, California 93523-5000
OVERVIEW OF THE NASA AMES-DRYDEN INTEGRATED TEST FACILITY

Dale Mackall, David McBride, and Dorothea Cohen

NASA Ames Research Center

Dryden Flight Research Facility

Edwards, California

ABSTRACT

The Integrated Test Facility (ITF), being built at the NASA

Ames Research Center's Dryden Flight Research Facility

(ADFRF), will provide new real-time test capabilities for

emerging research aircraft. An overview of the ITF and the

real-time systems being developed to operate this unique facility are outlined in this paper. The ITF will reduce flighttest risk by minimizing the difference between the flightand ground-test environments. The ground-test environment is provided by combining real-time flight simulation

with the actual aircraft. The generic capabilities of the 1TF

real-time systems, the real-time data recording, and the remotely augmented vehicle (RAV) monitoring system will be

discussed. The benefits of applying simulation to aircraftin-the-loop testing and RAV monitoring system capabilities

to the X-29A flight research program will also be discussed.

INTRODUCTION

The Integrated Test Facility (ITF) will reduce flight-test

risk by minimizing the difference between the flight- and

ground-test environments for advanced research aircraft.

These aircraft rely on embedded digital control systems and

are characterized by the integration of flight control, propulsion, structures, and aerodynamics. Exhaustive ground testing of the embedded control systems is required to assure

aircraft safety and the efficient use of flight-test missions.

The ITF addresses the ground-test needs of aircraft with integrated systems through the application of advanced realtime capabilities. (1)

The Integrated Test Facility

A cutaway view of the ITF is shown in Figure 1. The facility contains test bay (hangar) space for six fighter-size or

fewer larger size aircraft, and is divided into three separate

areas. The engineering staff is located in the front section of

the building, and office space is provided for visiting contractors. The aircraft technicians and maintenance staff are

on the first floor of the central section. The flight simulation systems are located on the second floor of the center

section of the building, near all six test bays. The location

of the flight simulation systems to the test bays provides the

short connection distances needed for closed-loop simulation with the flight vehicle.

Aircraft services, such as electrical power, hydraulic supplies, and cooling air are provided to support aircraft-inthe-loop simulations. All the aircraft services can be monitored in real time when performing tests with the aircraft

(Figure 2).

The electrical power includes 277/480 volts (V) and

120/208 V, three phase, 60-Hz power; 120/208 V,

three phase, 400-Hz power, and 28 volts direct current

(Vdc) power.

The planned hydraulic systems for the six test bays will be

independent, allowing different pressures and fluids to be

used. The initial hydraulic system has three pumps providing 35 gallons per minute (gal/min) at 5000 pounds per

square inch 0b/in 2) pressure. The flow per pump can be

increased to 50 gal/min at a pressure of 3500 lb/in z .

The planned aircraft cooling system is designed to provide

each test bay with 4000 cubic feet per minute (ft3/min) of

air flow. Exit air temperature is 40 ° F, provided through two

14-in. supply ducts.

Generic Real-Time Capabilities of the ITF Test Systems

This section provides an overview of the ITF's real-time test

systems. The simulation system is at the core of the realtime systems. It provides high fidelity modeling of the atmosphere, aircraft rigid body dynamics, and the flight control

system (FCS). The section explains how simulation, realtime data recording, remotely augmented vehicle (RAV),

and remotely augmented vehicle expert system (RAVES)

are used to support testing aircraft with integrated systems.

It is important to note that all the ITF real-time systems, except for RAVES, can be controlled by an automated test system. This allows the test engineer to automatically run test

cases from a high level mouse and menu interface.
Simulation

The NASA Ames-Dryden simulation facility will become

an integral part of the ITF. This relocation will bring to the

ITF 30 years of real-time simulation experience. Simulations are important engineering tools used through all phases

of flight research (2) and perform various tests which include time response, frequency response, redundancy management, failure modes and effects testing, and pilot evaluation. Simulations are used to test a proposed modification

in the ITF before it is installed on the aircraft.

To augment these diverse uses, the ITF will provide multiple simulation configurations for ggiven project with varying levels of aircraft hardware included. These simulations

include simple batch versions, which use only the computer

and a user terminal, as well as complex aircraft-in-the-loop

versions. This diversity allows the project team to easily select the level of hardware needed to support a session's activities. This flexibility permits quick comparisons between

software models and flight hardware.

High-fidelity modeling of the aircraft and its systems is of

key importance in the 1TF. This high-fidelity modeling provides aircraft hardware with a realistic flight environment

while in ground test. The success of this modeling becomes increasingly important as aircraft systems become

more interdependent.

The simulation interfaces give users fingertip control of the

simulation. The simulations can be controlled by buttons

and switches in the cockpit, or from a menu of display pages

on a cathode ray tube (CRT), or the entire control mechanism can be run from the automated test system workstations. The user generates simulation command files to automate the process of running tests. This approach eliminates the need to know the simulation commands which

would otherwise be entered through the simulation CRT

display page.

Real-Time Data Recording

The ability to record all the data needed to verify the correct

response to a test and to analyze anomalies is essential to

any environment used to test complex interdependent digital systems. Such recording is perhaps the most demanding

problem faced by the ITF. In the past, when a problem occurred the detailed data needed to resolve the problem were

often not recorded. The test would then be rerun with the

proper instrumentation, but the anomaly would not repeat.

By recording all possible aircraft and simulation data during

a run, the ability to resolve a problem without repeat runs is

greatly increased.

The ITF real-time data recording system will record data

from the simulation, the aircraft flight control analog interfaces and digital busses, the telemetry system, and the ITF

services (hydraulics and electrical power). The data from

these sources are supplied to the data recording system by

way of an interprocessor communication link. This link

connects the different computers at memory access speeds

over long distances. The estimate of the quantity of data to

be recorded is shown in Table 1. These data are time tagged

to provide exact correlation of events which occur at different data sources.

Remotely Augmented Vehicles

The ITF provides RAV capabilities for ADFRF's research

aircraft. The RAV laboratory provides ground-based computers interfaced to the aircraft in flight through telemetry

and uplink radio links. These components allow the groundbased computers to provide closed-loop control of vehicles

or to drive aircraft displays which aid the pilot. As with the

simulation systems, ADFRF has a great deal of experience

with RAV systems.

The ground-based computers are known as the control

law computer and the pulse code modulation (PCM) computer and are FORTRAN programmable. The control law

computer is used to augment the onboard control systems. The control law computer uses telemetry downlink data and software coded control laws to generate aircraft commands. The PCM computer shares memory with

the control law computer and is the interface between the

control law computer and the aircraft's telemetry stream.

The PCM computer converts scaled integers used in the

telemetry stream to engineering units used by the control

law computer.

Currently, hardware identical to the control law computer is

paired with each simulation computer for verification and

validation of the RAV ground-based software. The simulations are designed to interface to this computer in the

same manner as the PCM computer. Timing relationships

are preserved to model the flight system accurately. The relationship between the control law computer and the PCM

computer in the RAV laboratory and in the simulation lab is

shown in Figure 3.

The RAV activity is divided into three categories as described in the following and shown in Figure 4.

1o

.

Remotely augmented vehicles (RAV) use the ground

computer to augment the onboard control system. This

capability can be used to test alternate control laws, insert sophisticated autopilots to fly precise research maneuvers, or to generate pulses or frequency sweeps for

data analysis. The X-29A airplane is an example of a

current research aircraft using RAV operation.

Remotely computed displays help guide the pilot in flying precise maneuvers. The control law computer uses

downlinked data to calculate the fly-to signals sent to
.

the aircraft display. This capability is used extensively

by the flight research projects.

Remotely piloted research vehicles (RPRV) are flown

from a ground-based cockpit. The vehicle's control laws are coded in FORTRAN and executed in

the control law computer. The RPRV that have

been flown at the ADFRF range from the subscale

highly maneuverable aircraft technology (HiMAT)

vehicles to the joint Federal Aviation Administration/NASA controlled impact demonstration using a

Boeing 720. C3)

The Remotely Augmented Vehicle Expert System

The RAVES was designed to enhance real-time monitoring of critical flight parameters in the RAV laboratory. The earlier RAV displays were enhanced to use

color graphics and mouse capabilities. The color graphics

and mouse capabilities allow quicker comprehension of inflight problems.

The RAVES is based upon NASA Johnson Space Center's

(JSC) real-time display system used in support of the space

shuttle. C4)The benefits of using JSC's software are twofold.

First, development costs are reduced by using existing software. Secondly, NASA ADFRF and NASA JSC share in

any new developments to the software.

The RAVES workstation receives the data for display by

way of a 16-bit parallel interface and a Loral advanced decommutation system (ADS)-100A. The ADS-100A can receive data from the raw PCM telemetry stream and the MilStd-1553 bus connected to the RAV computers, Figure 5,

allowing the user to monitor the data from either or both

sources. There is an RS-232 serial port connection between the workstation and the Loral ADS-100A for setting

up the system.

A unique aspect of the RAVES is the implementation of

both Masscomp ® graphics primitives and Visual Intelligence Corporation's Data-Views ® (DV) graphics displays

running simultaneously under the same program. Incorporating two diverse graphics packages in the same program

allows the programmer to tailor the graphics to the application. For example, the project specific main displays are

developed with DV-Draw, an interactive drawing program

which is included in DV, while the fault window, a simple

text display requiring a fast update rate, is programmed in

Masscomp ® graphics primitives. Data-Views ® allows engineers to design their own displays quickly Cs)and does not

require programming. New displays can be designed, im-

®Masscomp is a registered trademark of Concurrent Corporation, Tmton

Falls, NJ.

®Data-Views is a registered trademark of Visual Intelligence Corporation, Amherst, MA.

plemented, and tested in as little as one hour. This is a vast

improvement over previous methods, which could take as

long as one week.

The four major windows in RAVES are status line, main display, fault message window, and expert system popup window. The status line shows which aircraft is being monitored and its flight number. The date is displayed with the

day of the week, month, day, year, and Julian date. The

current time is continuously updated. The main display is

either a generic RAVES or a project specific display. The

user chooses the main display from a menu of options. The

fault message window displays a message whenever a failure occurs, (63 even if the current main display is not processing that parameter. These messages are continuously

scrolled in the fault message window and are color-coded

according to urgency. Sound (the bell) may also be added to

a message.

The RAVES was designed to acclimate new engineers

quickly to the RAV system and its terminology. This is

done two ways (1) displays that have warnings written out

in English terms and (2) the expert system popup window.

The display which uses English terms has a corresponding

display which uses acronyms and variable names from the

source code. By using these two displays an engineer can

become familiar with the acronyms while monitoring the

RAV system. The expert system popup window can be chosen at start up and suggests what to do in a failure situation

by explaining the cause of the failure. Troubleshooting instructions are provided in an easy step-by-step format.

Although currently being used only in the RAV laboratory,

RAVES will soon be used as part of the ITF systems to monitor aircraft ground tests.

The Application of the ITF Real-Time Systems to

Flight Projects

The following sections show how the ITF real-time systems

have been applied to the X-29A program to meet the safety

and operational requirements of the project. The first section

discusses the X-29A ground testing performed by connecting the actual aircraft to the flight simulation. The second

section describes the application of the RAVES capability to

the monitoring of the X-29A RAV system.

X-29A ITF Requirements

Advanced flight research aircraft like the X-29A (7) require

extensive end-to-end testing of their complex interdependent systems prior to flight. Figure 6 is a photograph of the

X-29A test configuration. The purpose of the X-29A testing

was to safely evaluate the functions of the aircraft systems

in as near a flight configuration as possible.
Fivemajortestcapabilitieswere required of the ITF systems

by the X-29A program:

1.

2,

.

4,

,

A five degree of freedom (DOF) real-time simulation

which included as much of the aircraft systems as possible. (The sixth DOF (altitude) will be incorporated in

the final ITF configuration.)

Capabilities to use automated test techniques to perform and document tests.

A failure modes and effects testing capability which

used the actual flight vehicle systems.

A ground resonance and limit cycle testing capability

to investigate structure/FCS interaction on the flight

vehicle. The capabilities include the summation of

pulses and sine sweeps with pitch, roll, and yaw rate

signals and the capability to introduce pulses and sine

sweeps of various amplitudes and time durations into

the stick and pedal command channels.

Rapid reduction of data into a format for comparison

with existing data and predicted results. Reduction of

data and analysis of results in near real time.

X-29A Flight Control System and Test Configuration

Under normal flight conditions the X-29A flight control

computers (FCC) output surface position commands to provide aerodynamic control and stability. Deflection of aircraft structure is a secondary effect of surface motion. The

motion of the aircraft and response of the surfaces are fed

back to the FCC and summed with pilot commands. The

results of this summation are used in further surface commands. The interactions of all these components are of primary interest during ITF aircraft-in-the-loop testing.

During testing, the simulation computer reads aircraft surface positions, calculates the rigid body aerodynamic response, and provides various signals required by the aircraft,

Figure 7. These signals are transmitted to the simulation

interface device (SID) where they are summed, converted,

scaled, and distributed to the X-29A aircraft. Vehicle surface positions are also routed through the SID, then back to

the simulation computer. Other simulation input signals are

routed by way of a Mil-Std- 1553 bus from the extended aircraft interrogation and display system (XAIDS) which was

used to monitor real-time system performance, es)

X-29A ITF Test

Three types of tests were performed using the ITF capabilities to verify the FCS characteristics of the X-29A aircraft:

1. Open loop: rigid body, open loop, frequency response

tests-aircraft sensors out of the loop.

2. Closed loop: rigid body, closed loop, frequency response test including limit cycle tests-aircraft sensors

out of the loop.

3. Ground resonance: flexible body, closed loop, active

flight control system tests-aircraft sensors in the loop.

This series of end-to-end ground tests was required to provide the program team with adequate confidence to proceed

with the first flight of X-29A ship 2.

Open-Loop Tests

These tests measured the open-loop frequency response

characteristics of the sensor to control surface paths (with

the simulation providing test stimulus by way of sensor inputs to the FCS) as shown in Figure 8.

For each test the aircraft was supported on jacks. The aircraft sensor inputs to the FCS were replaced by simulated

sensors interfaced through the SID. In each case the feedback path of interest was opened and the forcing function,

a sine sweep, was inserted in place of the feedback. The

results of each test were compared to predictions obtained

by running the same test on the X-29A hardware-in-theloop simulation.

Closed-Loop Tests

The closed-loop tests are intended to verify the FCS/rigidbody stability by deriving equivalent open-loop gain and

phase margins. The gain and phase margins are derived

from frequency response and limit cycle tests with the FCS

as shown in Figure 9. This configuration requires that the

simulation computer close the aerodynamic loop around

the aircraft.

For each test the aircraft was supported on jacks. The aircraft sensors were replaced by simulated sensors interfaced

through the SID. The forcing function was a doublet, a step,

or a sine sweep.

Limit cycle tests were performed by increasing/decreasing

feedback gains in the simulation computer and measuring

frequency response in three axes. For each test the aircraft

was supported on jacks. The aircraft sensor signals were replaced by simulated signals interfaced through the SID. The

forcing function was a sine sweep. The feedback gains corresponding to each of the simulated sensors were changed

and a frequency response was generated to compare results

before and after the change.

Ground Resonance Tests

These tests are closed-loop, surface stimulated resonance

tests. The tests are intended to verify that undesirable structure/FCS interactions do not exist. The set up is shown in

Figure I0. Ifa problem relative to structural/FCS interaction

were to occur in flight, the effect could be a possible desta-
bilizationof the control system caused by high rate demands

on the actuators.

For each test the aircraft was sitting on the landing gear and

all panels except the external hydraulics access panel were

installed. Future ITF capabilities will provide "soft support"

for these types of tests. A soft support will provide a free

floating platform for the aircraft to rest on during the test,

removing unwanted gear dynamics.

Results of Using X-29A ITF Test Capabilities

The X-29A program experienced considerable time savings by using the ITF test capabilities. Compared to previous testing with the X-29A using different test facilities

and tools, approximately two-thirds of the actual test time

(3 weeks of testing reduced to 1 week) and 50 percent of the

preparation time was saved. Total effort for the program was

reduced approximately eight man months. This testing allowed the X-29A program team to proceed to the flight stage

with confidence, knowing that the flight control system was

working as designed.

Monitoring of the X-29A Remotely Augmented

Vehicle System

The RAV system, when engaged, has direct control of the

X-29A aircraft control surfaces. Monitoring of RAV operations is essential to ensure both flight safety and mission

success. The RAVES capability meets this need with a variety of graphic displays.

The RAVES is a visually oriented monitoring system which

allows users to respond quickly to failures. The RAVES

generic capabilities are used for self-diagnosis, parameter

monitoring, and for event logging. Logging is the ability

to time tag significant events for easy post-flight processing. Six X-29A project specific displays are available in the

main display window, they are:

1. Status--a color coded alphanumeric display of con-

_ol law and PCM parameters using project specific acronyms.

, Alternate status--an alphanumeric display that provides all the information of the status display in more

common engineering terms. For example, ARMODE

on the status display is written out as analog reversion

on this display. See Figure 11.

. Dataflow---a high-level graphic block diagram display

of the RAV system components and data paths. See

Figure 12.

4. Aircraft fault detection--a graphic representation of

the onboard RAV mode disengagement logic.

5. Fall an alphanumeric display of ground and aircraft

failure parameters.

6. Expert--a popup window that gives information on

what caused a failure or situation and advice on how

to resolve it.

There are three major areas in which RAVES is beneficial to

the X-29A program: ease of new display implementation,

quick user response to failures, and rapid understanding of

RAV terminology by engineers.

Initial use of the RAVES during X-29A flight tests has

demonstrated a real-time monitoring system which will

have applications to other flight test programs and be a viable tool in the ITF.

ITF PROJECT STATUS

Test Systems Status

The development of the ITF computerized test systems discussed in this paper is nearly complete. The simulation

capability has long been a part of ADFRF's engineering

tools and has been interfaced to the X-29A and other aircraft. Our ability to monitor RAV performance has been

greatly enhanced with the RAVES. The final testing has begun on the real-time data recording capability and the interprocessor communication devices which link the ITF computers and their data at memory access speeds.

Building Status

The ITF building at the time of this writing is 60 percent

complete. The construction should be complete and the test

systems moved to the building by mid-1991. At that time

the full capabilities and benefits of the ITF developments

can be applied to all our flight research aircraft.

CONCLUDING REMARKS

The Integrated Test Facility, with its new capabilities, will

provide a ground-test facility crucial to the next generation

of flight research aircraft. Routinely interfacing the aircraft

with the ITF systems will reduce the risk of flight test by

creating the flight environment on the ground. Real-time

data recording and monitoring with the RAVES will greatly

enhance ground- and flight-test efficiency.

The ITF capabilities allowed the second X-29A aircraft

to enter its initial flight test phase safely and significantly

reduced the time required for the aircraft to achieve its

first flight

The ITF brings to the flight test community the capabilities

needed to maintain our leading role in aeronautics and provide safe, efficient flight testing.
REFERENCES

(1)Mackall, Dale A., Qualification Needs for Advanced

Integrated Aircraft, NASA TM-86731, Edwards, CA,

Aug. 1985.

(2) Evans, Martha B., and Schilling, Lawrence J., The Role of

Simulation in the Development and Flight Test of the HiMAT

Vehicle, NASA TM-84912, Edwards, CA, April 1984.

(3) Kempel, Robert W., and Horton, Timothy W., Flight Test

Experience and Controlled Impact of a Large, Four-Engine,

Remotely Piloted Airplane, NASA TM-86738, Edwards,

CA, Aug. 1985.

(4)Muratore, John F., "Trends in Space Shuttle Telemetry Applications," In Proceedings of the 1987 International

Telemetering Conference, pp. 283-290, International Foundation for Telemetering, San Diego, CA, Oct. 1987.

(5) Granaas, Michael M., and Rhea, Donald C., Techniques

for Optimizing Human-Machine Information Transfer Related to Real-Time Interactive Display Systems, NASA

TM-100450, Edwards, CA, Jan. 1989.

(6)Kao, Simon A., Laffey, Thomas J., Schmidt, James L.,

Read, Jackson Y., and Dunham, Larry L., "Real-Time Analysis of Telemetry Data," In Proceedings of the 1987 Expert

Systems in Government Conference, pp. 476-493, IEEE

Computer Society, Washington DC, Oct. 1987.

(7) Chacon, Vince, and McBride, David, Operational Viewpoint of the X-29A Digital Flight Control System, NASA

TM-100434, May 1988.

(_) Glover, Richard D., Design and Initial Application of Extended Aircraft Interrogation and Display System: Multiprocessing Ground Support Equipment for Digital Flight

Systems, NASA TM-86740, Jan. 1987.

NOMENCLATURE

ADFRF

ADS

CRT

DOF

Ames-Dryden Flight Research Facility

advanced decommutation system

cathode ray tube

degrees of freedom

DV

F

FCC

FCS

gal/min

HiMAT

Hz

ITF

JSC

lb/in 2

Mil-Std

NASA

PCM

RAV

RAVES

RPRV

SID

Vdc

XAIDS

Data-Views ® product of Visual

Intelligence Corp.

degrees Fahrenheit

flight control computers

flight control system

gallons per minute

highly maneuverable aircraft technology

hertz

Integrated Test Facility

Johnson Space Center

pounds per square inch

Military Standard

National Aeronautics and Space Administration

pulse code modulation

remotely augmented vehicle

remotely augmented vehicle expert system

remotely piloted research vehicle

simulation interface device

volts direct current

extended aircraft interrogation and

display system

TABLE 1- DATA SOURCE AND ESTIMATED

QUANTITY FOR RECORDING

Number of Rate, Total

Source parameters Hz samples/sec

Simulation 50 100 5,000

Aircraft

flight conta'ol 300 100 30,000

digital busses 1500 100 150,000

Telemetry 100 100 10,000

ITF services 20 10 200

Total 195,200
Space for

large aircratt

135 x 225

Computer

General

simulation

area --_

Collocated systems,

controls, avionics,

research and test

staff

68 x 160ft

Test bay

control room

(typical, 1 o! 6)

Figure 1. Overview of the integrated test facility.

for small to

medium aircraft

100 x 100 ft

ice for two small

or one fairly large air.

craft 100 x 125 ft

y augmented

vehicles lab

10178
Control center

Simulation

system

Real.time

data

recording

Workstation provides

• Auto test

• Central

monitoring

Test bay

Aircraft interface

• Simulation

interface

device

PCM

Aircraft services

° Hydraulics,

electrical,

cooling air

Figure 2. Overview of ITF test systems.

10179

Remotely augmented

vehicle laboratory

[ Aircralt I

Uplink! _

downlink--_

Control law _ PCM decom I

system system

Shared memory

interface

Simulation laboratory

Simulation system models

the aircraft and PCM system

I Control law _ Simulation I

system system

Shared memory

interface

Development configuration

10180

Flight test configuration

Figure 3. Control law system configuration for flight and development.
(a) Remotely augmented vehicles.

Seosors] ___,,___

Uplin____._wnlink

o,s0,a,_,_,0eco------_l.__ _

systemI--I _'stemI L_/ 'l _ _o,,

(b) Remotely computed displays.

cockpit

L_enso,s _____ I

Downlink_ Uplink.

Controllaw _1 PCMdecom I-_---_

system J I system I j_./ I I \

8O45

(c) Remotely piloted vehicles.

Figure 4. The three remotely augmented vehicle configurations.

9
Switch

_,_=__ MiI-Std-1553

Uplink i,(._d._a ta bus

T

I Playback tape ]

I

('

Control

law

Shared

memory

PCM

v

PCM stream

Figure 5. The RAVES hardware configuration.

Graphics

display

Workstation

16-bit

parallel

interface

Loral

decomm

RS-232

10181

10
Figure 6. X-29A ITF test configuration.

11
Simulation

computer

Patch

panel

SID

MII-Std-1553

Terminal

i

Control

box

XAIDS

i< I Air

data

cart

10182

Figure 7. The ITF X-29A aircraft-in-the-loop simulation block diagram.

12
SIm FCS

i

E

E

E

L_ l--------- Sensors_--.-_

Figure 8. Open-loop test configuration.

10183

Sim

t

FCS _ Surfaces _'-

I '!

I

_,__oosors __ Structure_

Figure 9. Closed-loop test configuration.

10184

Sim

L

FCS _ Surfaces

Sensors I_ I Structure

Figure 10. Ground resonance test configuration.

10185

13
m__mmmmmz_m

Figure 11. Example of alternate status display.
L_h

Figure 12. Example of dataflow display.