L3 comminications Stormscope II Series Manual

Model WX-950
®
Series II Weather Mapping System
Pilot’s Guide
for the
Stormscope
Series II Weather Mapping System
Pilot’s Guide
for the
Model WX-950
Stormscope®
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WX-950 Pilot’s Guide
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Important Notices
• This data is provided at no charge, or at cost, to the
public and is considered publicly available, No License
Required (NLR) as defined in the Export Administration
Regulations (EAR) Part 734.7-11.
• This guide provides general information about the
operation of the WX-950. This guide does not cover all
possible interconnections with all possible types of aircraft
systems. Refer to your aircraft flight manual and flight
manual supplement for information specific to your
aircraft. If there is conflicting information between those
manuals and this pilot’s guide, your aircraft flight manual
and flight manual supplement take precedence over this
pilot’s guide.
Safety Summary
These warnings and cautions appear later in this guide and
are repeated here for emphasis:
Never use your Stormscope system to attempt to penetrate a
thunderstorm. The FAA Advisory Circular, Subject: Thunder-
storms, and the Airman’s Information Manual (AIM) recom-
mend that you “avoid by at least 20 miles any thunderstorm
identified as severe or giving an intense radar echo.”
There are several atmospheric phenomena other than nearby
thunderstorms which can cause isolated discharge points in the
strike display mode. Clusters of two or more discharge points in
the strike display mode however do indicate thunderstorm
activity when they reappear after clearing the screen. Avoid the
clusters and you’ll avoid the thunderstorms. In the cell display
mode, even a single discharge point may represent thunderstorm
activity and should be avoided.
page 4-1
page 4-1
WARNING
CAUTION

© Copyright 1996, 2004
L-3 Communications Avionics Systems, Inc.
Stormscope
®
is a registered trademark of L-3 C ommunications A vionics S ystems, Inc.
The white
L3 in a circle design logo is a trademark of L-3 C ommunications C orporation.
Designed and manufactured in the United States of America by
Methods and apparatus disclosed and described herein have been developed solely on company funds
of L-3 Communications Avionics Systems, Inc. No government or other contractual support or rela-
tionship whatsoever has existed which in any way affects or mitigates proprietary rights of L-3 Commu-
nications Avionics Systems, Inc. in these developments. Methods and apparatus disclosed herein may
be subject to U.S. Patents existing or applied for. L-3 Communications Avionics Systems, Inc. reserves
the right to add, improve, modify, or withdraw functions, design modifications, or products at any time
without notice.
Series II Weather Mapping System
Pilot’s Guide
for the
Model WX-950
Stormscope®
L-3 Communications Avionics Systems, Inc.
5353 52nd Street, S.E.
Grand Rapids, MI 49512 USA
[phone] or [phone]
Fax [phone]
www.L-3com.com/as
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Stormscope
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WX-950 Pilot’s Guide
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Stormscope® System Advantages
Welcome
L-3 Communications Avionics Systems, Inc. one of the
world’s most experienced companies in airborne thunder-
storm avoidance instruments, is pleased to welcome you to
the family of tens of thousands of pilots who are enjoying
the benefits of safer flight with a Stormscope®weather
mapping system.
The Original
Don’t be fooled by Stormscope system look-alikes. There is
only one Stormscope system, and only one company that
makes the Stormscope line of weather mapping systems. The
Stormscope system, the original, most accurate weather
mapping system is manufactured by L-3 Avionics Systems.
Fly with Greater Confidence
You now own one of the leading instruments in the world
for airborne detection and mapping of thunderstorms.
Unlike any other product, your new Stormscope system will
enable you to make better informed thunderstorm avoidance
decisions so you can fly more safely and with greater confi-
dence than ever before.
Convenient Features
The advanced, patented technology in your new Stormscope
system was developed over many years and is so unique, so
revolutionary, it surpasses all others. Here are some of its
features:
• Maps electrical discharges
• Operates in 25, 50, 100, and 200 nmi ranges
• Provides a 120° forward view and a 360° view of the
surrounding airspace
• Uses a high resolution 3-inch ATI CRT display/processor

Revision Highlights
This revision Bof the pilot’s guide makes the following changes:
• Changes occurrences of “Goodrich Avionics Systems” to
“L-3 Communications Avionics Systems, Inc.” or just “L-3
Avionics Systems” and makes related company contact
information changes. (On March 28, 2003, Goodrich
Corporation sold its Avionics Systems division to L-3
Communications Corporation.)
• Eliminates the Warranty Information chapter. Warranty
information is now provided on a separate warranty card.
• Increases typeface size and adds more white space.
• Adds export statement to inside front cover.
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WX-950 Pilot’s Guide iii

Table of Contents
Section Page
List of Illustrations ............................. vii
List of Tables .................................... viii
Chapter 1, System Description ........... 1-1
General Description ...............................................................1-1
Display/Processor ...................................................................1-2
Antenna .................................................................................1-2
Functional Description ...........................................................1-2
Cell Display Mode.............................................................1-2
Strike Display Mode .......................................................... 1-4
Discharge Rate .................................................................. 1-4
Features ................................................................................. 1-4
Chapter 2, Storm Mapping Principles .. 2-1
Anatomy of a Thunderstorm ...................................................2-1
Stages of a Thunderstorm ........................................................2-3
Cumulus Stage ..................................................................2-3
Mature Stage ..................................................................... 2-3
Dissipating Stage ...............................................................2-3
Storm Mapping Technology ....................................................2-4
The WX-950 & Weather Radar ......................................... 2-4
Automatic Updating ..........................................................2-4
Chapter 3, Operation ........................ 3-1
Introduction ..........................................................................3-1
Controls & Screen Elements ................................................... 3-1
Turn On the WX-950 ............................................................3-4
Adjust the Screen Brightness ................................................... 3-5
Switch to the MENU Screen ...................................................3-6
Scroll Through the Menu Items ...............................................3-6
Switch to a Weather View .......................................................3-6
Method A ......................................................................... 3-7
Method B ......................................................................... 3-7
Switch Between Weather Views ............................................... 3-8
Select the Range .....................................................................3-8
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WX-950 Pilot’s Guide v

Section Page
Table of Contents (continued)
Clear All Discharge Points .......................................................3-9
Switch Between WX Display Modes ......................................3-10
Run the Operator-Initiated Self Test ......................................3-11
Toggle Heading Stabilization On and Off ..............................3-12
Turn Off the WX-950 ..........................................................3-13
Continuous Self Test .............................................................3-13
Error Messages .....................................................................3-13
Non-Fatal Faults ..............................................................3-13
Recoverable Faults ...........................................................3-16
Non-Recoverable Faults ...................................................3-17
Fatal Faults ......................................................................3-18
Chapter 4, Weather Display Interpretation . 4-1
Introduction ..........................................................................4-1
Radial Spread .........................................................................4-2
Typical Patterns ...................................................................... 4-3
Three Clusters within the 200 nmi Range Ring...................4-3
Two Clusters within the 200 nmi Range Ring ..................... 4-5
Mapping Headings Past Thunderstorms .................................. 4-6
Range Set at 200 nmi ........................................................4-6
Aircraft Progresses 100 nmi ................................................4-7
Range Changes to 100 nmi ................................................4-8
Aircraft Turns to Avoid Thunderstorms ..............................4-9
Special Patterns .....................................................................4-10
Randomly Scattered Discharge Points ..............................4-10
Cluster & Splattering Within 25 nmi ...............................4-10
Discharge Points Off Aircraft’s Nose ................................. 4-12
Line of Discharge Points While Taxiing ............................ 4-13
Developing Cluster Within the 25 nmi Range Ring ..........4-14
Chapter 5, Specifications .................. 5-1
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List of Illustrations
Figure Title Page
1-1 WX-950 Major Components .........................................................1-1
1-2 WX-950 Functional Diagram ........................................................1-3
1-3 WX-950 Weather Views ................................................................ 1-3
2-1 Electrical Discharges in Thunderstorms ..........................................2-1
2-2 Discharge Rate a Function of Wind Shear .......................................2-2
3-1 Controls & Screen Elements ..........................................................3-1
3-2 Self Test in Progress ........................................................................3-4
3-3 All Tests Passed ..............................................................................3-5
3-4 Weather View at 200 nmi Range ....................................................3-5
3-5 MENU Screen with Weather View Highlighted .............................. 3-6
3-6 Switching Between Weather Views .................................................3-8
3-7 MENU Screen with WX Display Highlighted ..............................3-10
3-8 MENU Screen with Self Test Highlighted .....................................3-11
3-9 MENU Screen with HDG Stabilize Highlighted ..........................3-12
3-10 MENU Screen with HDG Stabilize N/A ......................................3-12
3-11 Error Message for a Recoverable Weather Fault ..............................3-14
3-12 Weather Mapping Inhibited Screen ..............................................3-16
3-13 Error Message for a Heading-Related Fault ................................... 3-17
3-14 Weather View with a Heading Flag ...............................................3-17
3-15 Error Message for a Fatal Fault ......................................................3-18
4-1 Airspace Diagram ..........................................................................4-1
4-2 Three Clusters Within 200 nmi ..................................................... 4-3
4-3 Range Changed to 100 nmi ...........................................................4-4
4-4 Two Clusters Within 200 nmi ........................................................4-5
4-5 Range Set at 200 nmi ..................................................................... 4-6
4-6 Aircraft Progresses 100 nmi ............................................................4-7
4-7 Range Changes to 100 nmi ............................................................4-8
4-8 Aircraft Turns To Avoid Thunderstorms ..........................................4-9
4-9 Randomly Scattered Discharge Points ...........................................4-10
4-10 Cluster & Splattering Within 25 nmi ...........................................4-11
4-11 Discharge Points Off the Aircraft’s Nose........................................4-12
4-12 Line of Discharge Points While Taxiing.........................................4-13
4-13 Developing Cluster Within 25 nmi ..............................................4-14
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WX-950 Pilot’s Guide vii

3-1 Error Messages ............................................................................ 3-14
5-1 WX-950 System Specifications .......................................................5-1
Table Title Page
List of Tables
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WX-950 Pilot’s Guideviii

1-1
Stormscope
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WX-950 Pilot’s Guide 1-1
General Description
The Stormscope®Series II Weather Mapping System, model
WX-950 (figure 1-1) detects electrical discharges from
thunderstorms up to 200 nautical miles away and displays
the thunderstorm locations relative to your aircraft.
The WX-950 is a passive system so there is no transmitter
and no harmful transmissions. The system operates as well
on the ground as in the air, thereby giving the pilot impor-
tant planning information before takeoff.
Figure 1-1. WX-950 Major Components
System Description
Chapter 1
Antenna
Display/Processor

Stormscope
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WX-950 Pilot’s Guide1-2
Chapter 1 – System Description
Display/Processor
The display/processor mounts into any standard 3-inch ATI
cutout in the aircraft instrument panel. The display/proces-
sor houses two main functional components: a high resolu-
tion, raster scan CRT display with a dedicated graphics control-
ler, and two powerful processors on which the Stormscope
software runs. The processors are reprogrammable to allow
for future enhancements to the lightning detection software.
Antenna
This combined crossed-loop and sense antenna is sealed in
an aerodynamic flat-pack and mounted on the outside of the
aircraft where it detects electrical discharges associated with
thunderstorms. The WX-950 uses its patented sense channel
technology to correlate the electric and magnetic signatures
of lightning strikes. The antenna is also designed to help
filter out pulsed noise from sources other than atmospheric
electrical discharges.
Functional Description
Figure 1-2 and the following paragraphs describe how the
major components of the WX-950 connect to each other and
to other aircraft systems.
The antenna detects the electric and magnetic fields gener-
ated by intra-cloud, inter-cloud, or cloud-to-ground electri-
cal discharges that occur within a 200 nmi radius of the
aircraft and sends the resulting “discharge signals” to the
display/processor. The display/processor digitizes, analyzes,
and converts the discharge signals into range and bearing
data then stores the data in memory. The WX-950 then
displays discharges as storm cells or strikes depending on the
display mode selected (figure 1-3).
Cell Display Mode
In the cell display mode, the WX-950 plots a “+” symbol
(discharge point) on the display when it detects associated
discharges within the selected range and view. The processor
plots another “+” close to the first for each additional
Major Components

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WX-950 Pilot’s Guide 1-3
Chapter 1 – System Description
Figure 1-2. WX-950 Functional Diagram
Functional Description
Discharge
Signals
Test Strike
Control
Heading
Input
Antenna
Power
±12 V dc
External
Clear
Input
Comm
Mic
Inhibit*
Display/
Processor
WX-950
Power
Input
11–32 V dc
Heading
Valid
Input
Antenna
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Electromagnetic Signals Radiating from Atmospheric
Electrical Discharges Associated with Thunderstorms
*Not Required
discharge determined to be associated with the group. The
processor does not plot a “+” for any discharge not associ-
ated with a group unless it’s detected within a 25 nmi radius
of the aircraft. The effect of this clustering algorithm is to
display the location of storm cells instead of individual
discharges. The cell display mode is most useful during
periods of heavy electrical discharge activity. Using the cell
360° View, CELL Display Mode 120° View, STRIKE Display Mode
Figure 1-3. WX-950 Weather Views
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WX-950 Pilot’s Guide1-4
Chapter 1 – System Description
display mode during these periods allows the pilot to quickly
see where the cells are without having to sift through and
analyze a screen full of discharge points.
Strike Display Mode
In the strike display mode, the WX-950 immediately plots an
“x” symbol (discharge point) on the display for each indi-
vidual discharge it detects within the selected range and
view. The strike display mode plots discharge points on the
display in relation to where the discharges are actually
detected instead of plotting them close to an associated
group of discharge points as is done in the cell display mode.
The strike display mode is most useful during periods of
light electrical activity because it may plot discharges
associated with a building thunderstorm sooner than the cell
display mode would.
Discharge Rate
Pilots may use the discharge rate (approximate number of
electrical discharges per minute in the current range and
view) to determine if storm cells are building or decaying.
Features
• Four operator-selectable weather ranges:
–25 nmi
–50 nmi
–100 nmi
–200 nmi
• Two operator-selectable weather views (figure 1-3):
–360° view of surrounding airspace
–120° forward view
• Three types of self test:
–Power-up self test
–Continuous self test
–Operator initiated self test
Functional Description

1-5
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WX-950 Pilot’s Guide 1-5
Chapter 1 – System Description Features
• Heading stabilization – automatically repositions discharge
points on the display relative to the latest aircraft heading
when connected to a compatible heading system
• Local and remote clear – allows operator to clear displayed
discharge points using a button on the front of the WX-950
or from a remotely-mounted “clear screen” button (not
supplied)
• Discharge rate indicator – displays estimated average
discharge rate per minute for current range and view
• Mic inhibit – inhibits thunderstorm processing when the
communications transmitter is keyed to prevent the
processing of corrupted data (some aircraft need to use this
feature, others don’t)
• Integrity monitor – animated indicator on the display
confirms that the WX-950 is working. This feature is most
useful during periods of no electrical activity.
• Power/brightness control – allows operator to adjust the
CRT brightness and to turn the WX-950 on and off
• Four buttons – these function keys perform various
functions depending on what mode the WX-950 is in and
what screen is being displayed. This variability allows for
flexibility and future expansion.
• Cell and strike display modes – allows you to view all indi-
vidual discharges (strikes) or groups of discharges (cells)

1-1
Stormscope
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WX-950 Pilot’s Guide 2-1
Anatomy of a Thunderstorm
The WX-950 is intended to help pilots avoid the dangers
associated with thunderstorms (convective wind shear,
lightning, icing, tornadoes, etc.). The WX-950 locates
thunderstorms by detecting the electrical discharges that
thunderstorms always generate. Figure 2-1 shows how
thunderstorms create electrical discharges and radiate
electromagnetic signals.
a. The convective flow of air currents (warm air going up
and cold air going down) leads to friction between the
opposing air currents and wind shear in the space
between the opposing air currents. The closer together
the opposing air currents are, the greater the shearing
force of the air currents.
Warm Air Mass
Cold Air Mass
Warm Air Mass
Cold Air Mass
1
0
0
n
m
i
20
0
n
mi
abbc d
Figure 2-1. Electrical Discharges in Thunderstorms
Storm Mapping
Principles
Chapter 2

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WX-950 Pilot’s Guide2-2
Chapter 2 – Storm Mapping Principles
b.The friction between the opposing air currents causes
electrical charges in the area to separate. As positive (+)
and negative (–) electrical charges are separated, they
accumulate in masses of similar charges (positive
charges near the top of the cloud and negative charges
near the bottom).
c. Electrical discharges occur as the accumulated masses
of separated positive and negative charges attempt to
rejoin. These discharges continue to occur repetitively
as long as the convective wind shear persists. A few of
the discharges are visible as lightning, but most electri-
cal discharges occur within a cloud or between clouds
and are hidden by those clouds. Only a small percent-
age of discharges occurs between the clouds and the
ground. Cloud to ground lightning occurs when the
negatively charged lower part of a cloud induces a
positive charge on an object on the ground. The
immense charge separation finally breaks down the
insulating air and a discharge occurs dumping negative
charge from the cloud onto the object and the sur-
rounding ground.
d.All electrical discharges radiate electromagnetic signals
in all directions close to the speed of light. The electro-
magnetic signals have unique characteristics and
varying rates of recurrence and signal strength.
Figure 2-2 shows that the rate of electrical discharges de-
tected in an area is directly related to the amount of convec-
Light Moderate
Increasing Turbulence Due to Convective Wind Shear
Increasing Rate of
Electrical Discharges
Severe
Figure 2-2. Discharge Rate a Function of Wind Shear
Anatomy of a Thunderstorm

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WX-950 Pilot’s Guide 2-3
Chapter 2 – Storm Mapping Principles
tive wind shear turbulence present. In fact, as convective wind
shear increases, the rate of electrical discharges increases at an
increasing rate. This relationship means that if you find the
electrical discharges, you’ve found the wind shear.
Stages of a Thunderstorm
All thunderstorms begin as cumulus clouds, build to an
intense mature stage, and finally dissipate. Each of these
stages in the life of a thunderstorm present a different set of
dangers to aircraft. The WX-950 maps all stages in the life of
a thunderstorm so that you won’t be caught unaware by a
thunderstorm that can build, mature, and dissipate in as
little as 20 minutes.
Cumulus Stage
The cumulus or beginning stage of a thunderstorm is usually
precipitation free. In this stage, the risks to an aircraft and
its occupants include strong vertical winds, severe turbu-
lence, icing, and convective wind shear.
Mature Stage
In the mature and most intense stage of a thunderstorm, the
water droplets within the cloud collide and combine to form
rain and hail and, at cooler temperatures, sleet and snow. This
stage poses many hazards to aircraft including heavy precipita-
tion, high winds, convective wind shear, severe turbulence,
downbursts, hail, icing, tornadoes, and lightning.
Dissipating Stage
In the dissipating stage, the updraft weakens and at the same
time, the convective wind shear and other hazardous condi-
tions begin to subside. There may be high rainfall rates in
this stage, but the severe dangers are diminishing.
Stages of a Thunderstorm

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WX-950 Pilot’s Guide2-4
Chapter 2 – Storm Mapping Principles
Storm Mapping Technology
The WX-950 & Weather Radar
The storm mapping technology used in the WX-950 is
fundamentally different than the technology used in weather
radar. Weather radar operates by transmitting UHF radio
waves in the direction of interest and then receiving echoes
from water droplets, whereas the WX-950 operates by
receiving signals already present in the atmosphere due to
electrical discharges. The WX-950 analyzes the unique
characteristics of these signals, their signal strength, and
their varying rates of recurrence to determine the location
and intensity of the thunderstorms that generated the
discharges. The WX-950 can receive radiated electromagnetic
signals from electrical discharges up to 200 nmi away.
One disadvantage of weather radar is that the cumulus stage
of a thunderstorm (usually precipitation free) is unlikely to
appear on weather radar; however, it generally does contain
electrical discharges which will appear on your WX-950
display as a light but increasing cluster of discharge points.
Another disadvantage of weather radar is that due to attenu-
ation, it may not see the “storm behind the storm” or may
understate its intensity. Your WX-950 is not subject to
attenuation. With the WX-950, electrical discharges are
mapped throughout the storm area. The size of the cluster of
discharge points on your WX-950 indicates the size of the
storm area. The speed with which the discharge points
appear indicates the intensity of the storm regardless of the
size of the cluster. The more intense the storm, the faster the
discharge points reappear.
Automatic Updating
The WX-950 receives and processes electrical discharge
information continuously and updates the screen as needed,
which may be many times every second. Even though the
electromagnetic signals from electrical discharges are of very
short duration, the WX-950 stores the resulting discharge points
in memory and displays each point for a maximum of 3
minutes before it is erased from the screen and from memory.
Storm Mapping Technology