user’s guide stormscope · stormscope® wx-500 user’s guide 1-11-1 general description the...

Model WX-500

Series II Weather Mapping Sensor

®

User’s Guidefor the

StormscopeSeries II Weather Mapping Sensor


Model WX-500

Stormscope®

A Stormscope® WX-500 User’s GuideA

Stormscope® System Advantages

WelcomeL-3 Avionics Systems, one of the world’s most experiencedcompanies in airborne thunderstorm avoidance instruments,is pleased to welcome you to the family of tens of thousandsof pilots who are enjoying the benefits of safer flight with aStormscope® weather mapping system.

The OriginalDon’t be fooled by Stormscope system look-alikes. There isonly one Stormscope system, and only one company thatmakes the Stormscope line of weather mapping systems. TheStormscope system, the original, most accurate weathermapping system is manufactured by L-3 Avionics Systems.

Fly with Greater ConfidenceYou now own one of the leading instruments in the worldfor airborne detection and mapping of thunderstorms.Unlike any other product, your new Stormscope sensor willenable you to make better informed thunderstorm avoidancedecisions so you can fly more safely and with greater confi-dence than ever before.

Convenient FeaturesThe advanced, patented technology in your new Stormscopesensor was developed over many years and is so unique, sorevolutionary, it surpasses all others. Here are some of itsfeatures:

• Precisely maps electrical discharges up to 200 nmi away

• Provides for a 120° forward view and a 360° view of thesurrounding airspace

• Outputs both cell and strike data

© Copyright 1997, 2001, 2003L-3 Communications Avionics Systems, Inc.

Stormscope® is a registered trademark of L-3 Communications Avionics Systems, Inc.The white L3 in a circle design logo is a trademark of L-3 Communications Corporation.

Designed and manufactured in the United States of America by

Methods and apparatus disclosed and described herein have been developed solely on company fundsof 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 maybe subject to U.S. Patents existing or applied for. L-3 Communications Avionics Systems, Inc. reservesthe right to add, improve, modify, or withdraw functions, design modifications, or products at any timewithout notice.


Stormscope®

L-3 Communications Avionics Systems, Inc.5353 52nd Street, S.E.Grand Rapids, MI 49512 USA(800)253-9525 or (616)949-6600Fax (616)285-4224www.L-3com.com/as

Series II Weather Mapping Sensor

Model WX-500

Safety SummaryThese warnings and cautions appear later in this guide andare repeated here for emphasis:

Never use your Stormscope system to attempt to penetrate athunderstorm. 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 thunderstormidentified as severe or giving an intense radar echo.”

There are several atmospheric phenomena other than nearbythunderstorms which can cause isolated discharge points in thestrike display mode. Clusters of two or more discharge points inthe strike display mode however do indicate thunderstormactivity when they reappear after clearing the screen. Avoid theclusters and you’ll avoid the thunderstorms. In the cell displaymode, even a single discharge point may represent thunderstormactivity and should be avoided.

page 4-1

page 4-1

WARNING

CAUTION

A Stormscope® WX-500 User’s Guideii

Important NoticeAll Stormscope® WX-500 functions are controlled throughvarious Multi-Function Displays (MFDs). The many capabili-ties of the WX-500 allow MFD manufacturers to createscreens compatible with the various functions of theirdisplay. The display screens illustrated in this guide areintended to be characteristic of a group of MFDs that areconfigured to work with the WX-500. The examples areintended to assist the pilot in interpreting lightning dataoutput by the WX-500. Each MFD shows the informationconsistent with the capabilities of that particular display.

Revision HighlightsThis revision C of the user’s guide makes the following changes:

• Changes occurences of “Goodrich Avionics Systems” to“L-3 Communications Avionics Systems, Inc.” or just “L-3Avionics Systems” and makes related company contactinformation changes. (On March 28, 2003, GoodrichCorporation sold its Avionics Systems division to L-3Communications Corporation.)

• Eliminates the Warranty Information chapter. Warrantyinformation is now provided on a separate warranty card.

• Increases typeface size and adds more white space.

• Edits text for improved readability.

Stormscope® WX-500 User’s Guide iii

Table of ContentsSection Page

List of Illustrations ..............................vi

List of Tables ......................................vi

Chapter 1, System Description........... 1-1General Description ............................................................... 1-1Processor ................................................................................1-2Antenna ................................................................................. 1-2Functional Description ........................................................... 1-2Cell Data ............................................................................... 1-3Strike Data ............................................................................. 1-3Strike Rate ............................................................................. 1-3Features ................................................................................. 1-4

Chapter 2, Storm Mapping Principles .. 2-1Anatomy of a Thunderstorm ................................................... 2-1Stages of a Thunderstorm ........................................................2-3The WX-500 & Weather Radar .............................................. 2-4

Chapter 3, Operation........................ 3-1Introduction ..........................................................................3-1Power-Up............................................................................... 3-1Continuous & Operator-Initiated Self Test .............................. 3-1Clear All Discharge Points ....................................................... 3-2Heading Stabilization ............................................................. 3-2Error Messages ....................................................................... 3-2

Chapter 4, Weather Display Interpretation . 4-1Introduction ..........................................................................4-1Radial Spread ......................................................................... 4-2Typical Patterns ...................................................................... 4-3Mapping Headings Past Thunderstorms .................................. 4-6Special Patterns ..................................................................... 4-10

Chapter 5, Specifications .................. 5-1

Stormscope® WX-500 User’s Guide v

List of IllustrationsFigure Title Page

1-1 WX-500 Major Components ......................................................... 1-11-2 WX-500 Functional Diagram ........................................................1-2

2-1 Electrical Discharges in Thunderstorms .......................................... 2-12-2 Discharge Rate a Function of Wind Shear ....................................... 2-2

4-1 Airspace Diagram ..........................................................................4-14-2 Three Clusters Within 200 nmi ..................................................... 4-34-3 Range Changed to 100 nmi ........................................................... 4-44-4 Two Clusters Within 200 nmi ........................................................4-54-5 Range Set at 200 nmi ..................................................................... 4-64-6 Aircraft Progresses 100 nmi ............................................................ 4-74-7 Range Changes to 100 nmi ............................................................ 4-84-8 Aircraft Turns to Avoid Thunderstorms .......................................... 4-94-9 Randomly Scattered Discharge Points ...........................................4-104-10 Cluster & Splattering Within 25 nmi ...........................................4-114-11 Discharge Points Off the Aircraft’s Nose ........................................ 4-124-12 Line of Discharge Points While Taxiing .........................................4-134-13 Developing Cluster Within 25 nmi .............................................. 4-14

3-1 Error Messages .............................................................................. 3-3

5-1 WX-500 Specifications .................................................................. 5-1

Table Title PageList of Tables

A Stormscope® WX-500 User’s Guidevi

1-1Stormscope® WX-500 User’s Guide 1-1

General DescriptionThe Stormscope® Series II Weather Mapping Sensor, modelWX-500 (figure 1-1) detects electrical discharges fromthunderstorms within a 200 nmi radius of the aircraft. Thisinformation is then sent to an external Multi-FunctionDisplay (MFD) that plots the location of the thunderstorms.

The WX-500 is a passive sensor that listens for electromag-netic signals with a receiving antenna. There’s no transmitterand no harmful transmissions. The WX-500 works as well onthe ground as it does in the air, thereby giving the pilotimportant planning information before takeoff.

System DescriptionC h a p t e r 1

Figure 1-1. WX-500 Major Components

Processor Antenna

Stormscope® WX-500 User’s Guide1-2

Chapter 1 – System Description

Figure 1-2. WX-500 Functional Diagram

ProcessorThis compact, tray-mounted computer processor receiveselectrical discharge information from the antenna, processesit to determine range and azimuth, processes the headinginput, then forwards the information for presentation on theMFD. The processor may be installed almost anywhere inthe aircraft.

AntennaThis combined crossed-loop and sense antenna is sealed inan aerodynamic flat-pack and mounted on the outside of theaircraft where it detects electrical discharges associated withthunderstorms. Stormscope thunderstorm detection systemscan correlate the electric and magnetic signatures of light-ning strikes better than other systems due to their patentedsense channel technology. The antenna is designed to helpfilter out pulsed noise from sources other than atmosphericelectrical discharges.

Functional DescriptionFigure 1-2 and the following paragraphs describe how themajor components of the WX-500 connect to each other andto other aircraft systems.

Major Components

DischargeSignals

Test StrikeControl

Heading Input

AntennaPower±12 V dc

ExternalClearInput

CommMic

Inhibit

Processor

WX-500

PowerInput

11–32 V dcHeading Valid Input

Electromagnetic Signals Radiating from AtmosphericElectrical Discharges Associated with Thunderstorms

Antenna

RS-232or

RS-422MFD


Chapter 1 – System Description Functional Description

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 theaircraft and sends the resulting “discharge signals” to theprocessor. The processor digitizes, analyzes, and converts thedischarge signals into range and bearing data then stores thedata in memory. The processor then sends this informationto the MFD as cells and strikes. The WX-500 updates theMFD every 2 seconds.

Cell DataThe WX-500 uses a clustering algorithm to locate storm cells.Cell data is most useful during periods of heavy electricaldischarge activity. Displaying cell data during these periodsallows the pilot to quickly see where the cells are without havingto sift through and analyze a screen full of discharge points.

Strike DataStrike data is most useful during periods of light electricalactivity because strike data may show the initial dischargesassociated with a building thunderstorm sooner than celldata would. The WX-500 plots strike discharge points inrelation to where the discharges are actually detected insteadof plotting them close to an associated group of dischargepoints as is done with cell data.

Strike RatePilots may use the strike rate (approximate number of strikesper minute) to determine if storm cells are building ordecaying. The MFD calculates the strike rate for the currentrange and view.


Chapter 1 – System Description

Features• Detects and plots intra-cloud, inter-cloud, and cloud-to-

ground electrical discharges

• Operates passively requiring no transmitter

• Allows total control through the MFD

• Detects discharges up to 200 nmi away

• Outputs cell and strike data to the MFD

• Repositions discharge points automatically on the displayrelative to the latest aircraft heading (heading stabilization)when connected to a compatible heading system

• Performs three types of self test: power-up, continuous,and operator-initiated

• Allows the pilot to clear discharge points using a remotely-mounted “clear screen” button (not supplied)

• Inhibits thunderstorm processing when the communica-tions transmitter is keyed to prevent the processing ofcorrupted data (some installations need to use this micinhibit feature, others don’t)

Features


Anatomy of a ThunderstormThe WX-500 is intended to help pilots avoid the dangersassociated with thunderstorms (convective wind shear,lightning, icing, tornadoes, etc.). The WX-500 locatesthunderstorms by detecting the electrical discharges thatthunderstorms always generate. Figure 2-1 shows howthunderstorms create electrical discharges and radiateelectromagnetic signals.

a. The convective flow of air currents (warm air going upand cold air going down) leads to friction between theopposing air currents and wind shear in the spacebetween the opposing air currents. The closer togetherthe opposing air currents are, the greater the shearingforce of the air currents.

War

m A

ir M

ass

Cold A

ir Mass

War

m A

ir M

ass

Cold A

ir Mass

100 nmi

200 nmi

a bb c d

Figure 2-1. Electrical Discharges in Thunderstorms

Storm MappingPrinciples

C h a p t e r 2


Chapter 2 – Storm Mapping Principles

b.The friction between the opposing air currents causeselectrical charges in the area to separate. As positive (+)and negative (–) electrical charges are separated, theyaccumulate in masses of similar charges (positivecharges near the top of the cloud and negative chargesnear the bottom).

c. Electrical discharges occur as the accumulated massesof separated positive and negative charges attempt torejoin. These discharges continue to occur repetitivelyas long as the convective wind shear persists. A few ofthe discharges are visible as lightning, but most electri-cal discharges occur within a cloud or between cloudsand are hidden by those clouds. Only a small percent-age of discharges occurs between the clouds and theground. Cloud to ground lightning occurs when thenegatively charged lower part of a cloud induces apositive charge on an object on the ground. Theimmense charge separation finally breaks down theinsulating air and a discharge occurs dumping negativecharge from the cloud onto the object and the sur-rounding ground.

d.All electrical discharges radiate electromagnetic signalsin all directions close to the speed of light. The electro-magnetic signals have unique characteristics andvarying 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 ModerateIncreasing Turbulence Due to Convective Wind Shear

Incr

easi

ng R

ate

ofE

lect

rica

l Dis

char

ges

Severe

Figure 2-2. Discharge Rate a Function of Wind Shear

Anatomy of a Thunderstorm



tive wind shear turbulence present. In fact, as convective windshear increases, the rate of electrical discharges increases at anincreasing rate. This relationship means that if you find theelectrical discharges, you’ve found the wind shear.

Stages of a ThunderstormAll thunderstorms begin as cumulus clouds, build to anintense mature stage, and finally dissipate. Each of thesestages in the life of a thunderstorm present a different set ofdangers to aircraft. The WX-500 maps all stages in the life ofa thunderstorm so that you won’t be caught unaware by athunderstorm that can build, mature, and dissipate in aslittle as 20 minutes.

Cumulus StageThe cumulus or beginning stage of a thunderstorm is usuallyprecipitation free. In this stage, the risks to an aircraft andits occupants include strong vertical winds, severe turbu-lence, icing, and convective wind shear.

Mature StageIn the mature and most intense stage of a thunderstorm, thewater droplets within the cloud collide and combine to formrain and hail and, at cooler temperatures, sleet and snow. Thisstage poses many hazards to aircraft including heavy precipita-tion, high winds, convective wind shear, severe turbulence,downbursts, hail, icing, tornadoes, and lightning.

Dissipating StageIn the dissipating stage, the updraft weakens and at the sametime, the convective wind shear and other hazardous condi-tions begin to subside. There may be high rainfall rates inthis stage, but the severe dangers are diminishing.

Stages of a Thunderstorm



The WX-500 & Weather RadarThe storm mapping technology used in the WX-500 isfundamentally different than the technology used in weatherradar. Weather radar operates by transmitting UHF radiowaves in the direction of interest and then receiving echoesfrom water droplets, whereas the WX-500 operates byreceiving signals already present in the atmosphere due toelectrical discharges. The WX-500 processor analyzes theunique characteristics of these signals, their signal strength,and their varying rates of recurrence to determine thelocation and intensity of the thunderstorms that generatedthe discharges. The WX-500 can receive radiated electromag-netic signals from electrical discharges up to 200 nmi away.

One disadvantage of weather radar is that the cumulus stageof a thunderstorm (usually precipitation free) is unlikely toappear on weather radar; however, it generally does containelectrical discharges which will be detected by the WX-500 asa 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 mayunderstate its intensity. The WX-500 is not subject toattenuation. With the WX-500, electrical discharges aremapped throughout the storm area. The size of the cluster ofdischarge points detected by your WX-500 indicates the sizeof the storm area. The speed with which the dischargepoints appear indicate the intensity of the storm regardlessof the size of the cluster. The more intense the storm, thefaster the discharge points reappear.

Storm Mapping Technology


IntroductionThe MFD controls the WX-500 functions. Refer to yourAircraft Flight Manual Supplement (AFMS) and the docu-mentation supplied with the MFD for detailed operatinginstructions. This chapter provides supplemental informa-tion. The user should already be familiar with their AFMSand MFD.

Power-UpAt power-up, the WX-500 performs a power-up self test. Theself test takes about 25 seconds to ensure that all major WX-500 functions, including antenna reception, memory, andmicroprocessor functions, are operating properly. An errormessage is displayed if a fault is detected. Refer to the ErrorMessages section later in this chapter for more information.

Continuous & Operator-Initiated Self TestThe WX-500 performs a continuous self test of antenna opera-tion, microprocessor functions, memory, and heading inputsamong others several times a minute. The WX-500 alsoprovides for an operator-initiated self test through the MFD.

OperationC h a p t e r 3


Chapter 3 – OperationClear All Discharge Points

Clear All Discharge PointsClearing the discharge points periodically while you’remonitoring thunderstorms is a good way to determine if thestorm is building or dissipating. Discharge points in abuilding storm will reappear faster and in larger numbers.Discharge points in a dissipating storm will appear slowerand in smaller numbers. The WX-500 allows for the clearingof discharge points through the MFD or an optional RemoteClear button.

If you have the standard heading stabilization featureconnected and turned on, you do not have to clear dischargepoints after every heading change to ensure that the dis-charge points are positioned correctly with respect to thecurrent heading.

Heading StabilizationThe heading stabilization feature automatically adjusts theposition of the discharge points on the display when youraircraft changes heading. Normally, if the WX-500 is in-stalled to use the heading stabilization feature, you shouldnever have to turn heading stabilization off; however, asituation may occur in which the heading input appears tobe invalid but no heading flag is displayed. In this case, youshould turn heading stabilization off until the heading inputis corrected. If you are flying with heading stabilizationturned off, or do not have a compatible heading system, youcan clear all discharge points after each heading change todisplay new discharge points in the proper location relativeto the nose of the aircraft.

Error MessagesThe WX-500 detects most common faults and sends errormessages to the MFD indicating the nature of the faults andwhich functions may be inoperative. These error messagesenable your authorized Stormscope dealer or L-3 AvionicsSystems factory service personnel to quickly diagnose andcorrect the fault. Table 3-1 lists all the possible error mes-sages, the probable causes, and the recommended actions.


Chapter 3 – Operation Error Messages

Table 3-1. Error Messages

*F=Fatal, NF=Nonfatal, R=Recoverable, NR=Nonrecoverable (Description follows table.)**Flying within 5 nmi of a certain Government antenna near Annapolis Maryland can also cause thiserror to appear. The recommended action in this case is to do nothing.

Error Fault Source Type* Recommended Action

Error 01Processor Fault

Main processor F Turn off the unit and see yourdealer for service.

Errors 05 thru 08Processor Fault

Main processormemory

F Turn off the unit and see yourdealer for service.

Errors 09 thru 12Processor Fault

DSP memory F Turn off the unit and see yourdealer for service.

Errors 14 and 15Processor Fault

DSP F Turn off the unit and see yourdealer for service.

Error 16Antenna Fault

Antenna is notable to receive orforward thenecessarythunderstormdata or it couldbe a faultyconnection

NF/R Continue without weathermapping functions. See yourdealer for service.


No test strikes** NF/R Continue without weathermapping functions. See yourdealer for service if this erroroccurs frequently.


Invalid test strikes NF/R Continue without weathermapping functions. See yourdealer for service if this erroroccurs frequently.


Main Processordata overload

NF/R Continue without weathermapping functions. See yourdealer for service if this erroroccurs frequently.

Error 20ConfigurationChanged

Antenna jumperconfigurationchanged sincelast time powerwas applied tothe system

NF/R Select antenna location viaMFD. If selection matchesprocessor configurationjumpers, normal operationreturns. If not correctable,continue without weathermapping functions and see yourdealer for service.



Error 22Invalid SynchroSignals

Invalid XYZ input(gyro may still bespinning up)

NF/R Continue without headingstabilization. See your dealer forservice.


Chapter 3 – OperationError Messages

*F=Fatal, NF=Nonfatal, R=Recoverable, NR=Nonrecoverable (Description follows table.)

Table 3-1. Error Messages (Continued)

Error Fault Source Type* Recommended Action

Error 23Invalid Synchro Ref

No 400 Hzreference

NF/R Continue without headingstabilization. See your dealer forservice.

Error 24Mic Key Stuck

Mic key (inhibitline) stuck. Themicrophone keyhas beendepressed formore than 1minute

NF/R Check your microphone key tocorrect the problem. If notcorrectable, continue withoutweather mapping functions andsee your dealer for service.

Errors 25 thru 34Software Error


Errors 35 and 36Processor Fault

DSP or mainprocessor

NF/R Continue without weathermapping functions. See yourdealer for service.


Main processor NF/R See your dealer for service ifthis error occurs frequently.


DSP or mainprocessor

F Turn off the unit and see yourdealer for service.



Error 43Invalid Request

MFD NF/R See your dealer for service ifthis error occurs frequently.

Error 44 thru 49SerialCommunications


Error 50Illegal HeadingValue


Error 51Invalid Message


Error 52Invalid AntennaChange Request


Error 53 thru 54CommunicationsBuffer Overload



Chapter 3 – Operation Error Messages

Nonfatal FaultsIf a nonfatal fault occurs, all functions not directly affectedby the fault continue to operate. See your authorizedStormscope dealer as soon as possible to correct the fault.

Recoverable FaultsA recoverable fault is one that allows the affected functions toautomatically resume proper operation after the fault goes away.

A messaging error (errors 43 through 51, 53 and 54) is anexample of a recoverable fault. Messaging errors are likelycaused by excessive noise on the communication lines, or anMFD communications problem. These messages automati-cally clear after the message is processed and therefore mayappear only briefly on the MFD.

Nonrecoverable FaultsA nonrecoverable fault allows continued operation, butwithout the function affected by the fault. The affectedfunction will not resume proper operation until the systemis turned off and repaired.

Fatal FaultsIf a fatal fault occurs, all functions will cease to operate. Inthis case, turn off the WX-500 and see your authorizedStormscope dealer for service.


Never use your Stormscope system to attempt to penetrate athunderstorm. 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 thunderstormidentified as severe or giving an intense radar echo.”

There are several atmospheric phenomena other than nearbythunderstorms which can cause isolated discharge points in thestrike display mode. Clusters of two or more discharge points inthe strike display mode however do indicate thunderstormactivity when they reappear after clearing the screen. Avoid theclusters and you’ll avoid the thunderstorms. In the cell displaymode, even a single discharge point may represent thunderstormactivity and should be avoided.

IntroductionThe examples in this chapter are designed to help you relatethe cell or strike patterns shown on your MFD to the size andlocation of thunder-storms that may benear your aircraft.

A blue and whitegrid in the examplesrepresents theairspace aroundyour aircraft. (Seefigure 4-1.) Each

CAUTION

WARNING

Weather DisplayInterpretation

C h a p t e r 4

100 nmi

HeavyElectrical Activity

LightElectrical Activity

ModerateElectrical Activity

CurrentRangeStormscope

100 n

mi

Figure 4-1. Airspace Diagram


Chapter 4 – Weather Display Interpretation

square in the grid represents a 100 by 100 nmi area. A circlerepresents the area monitored by your WX-500. Areas of grayor black indicate thunderstorms. The darker the area, thegreater the rate of electrical discharge activity.

The WX-500 detects electrical discharges and sends theprocessed information to the MFD which may display thedischarges as cells or independent strikes. The examples inthis chapter include screen patterns to represent both celland strike displays.

Radial SpreadIn the strike display mode, it is common for a triangular-shaped stream of discharge points to appear between theaircraft symbol and a cluster of discharge points within therange of the WX-500. A similar stream of discharge pointsmay appear radiating away from the aircraft symbol in thedirection of possible thunderstorm activity beyond the rangeof the WX-500. These phenomena are examples of radial spread.Discharge points in radial spread do not necessarily indicate theexact location of atmospheric electrical discharges. To counter-act radial spread, L-3 Avionics Systems applied its extensiveresearch in lightning detection to develop enhanced lightningpositioning algorithms. These algorithms (used only in the celldisplay mode) greatly reduce radial spread and improve thedepiction of thunderstorms on the display.

Radial Spread



Figure 4-2. Three Clusters Within 200 nmi

Typical Patterns

1

2 3

Rate 62

200nm

STRIKE

:Rate 60

200nm

CELL

:

Typical PatternsThree Clusters within 200 nmi

Figure 4-2 shows the 360° weather view at the 200 nmi range.Using this knowledge, the three clusters of discharge pointson the left-hand screen (cell display mode) can be inter-preted as representing three thunderstorm cells at thefollowing azimuth and range:

Cluster Azimuth (clock position) Range1 11:00 180 nmi2 4:00 75 nmi3 4:00 180 nmi

Analysis of the right-hand screen (strike display mode) yieldsa similar, but less certain interpretation due to radial spread.The screen can also tell us about the relative amount ofelectrical discharge activity in thunderstorm cells. Clusters 2and 3 have more discharge points than cluster 1 indicatinggreater electrical discharge activity. All three clusters how-ever must be avoided because you can’t necessarily deter-



mine the severity of thunderstorms based strictly on thenumber of discharge points. For example, in the westernUnited States, a severe thunderstorm may only have a fewelectrical discharges.

When the range is changed to 100 nmi (figure 4-3), onlycluster 2 remains visible. Clusters 1 and 3 are beyond the 100nmi range and therefore no longer appear on the screen.(Clusters 1 and 3 would again be visible if the range werereturned to 200 nmi.) Cluster 2 is now more defined and thedischarge points are larger. The interpretation of cluster 2remains the same: a moderately active thunderstorm atazimuth 4:00, range 75 nmi. Notice on the right-hand screen(strike display mode) that there is less radial spread than onthe 200 nmi range. In general, radial spread is reduced onthe shorter ranges.

Typical Patterns

Figure 4-3. Range Changed to 100 nmi

Rate 28

100nm

STRIKE

:Rate 25

100nm

CELL

:


Chapter 4 – Weather Display Interpretation Typical Patterns

Two Clusters within 200 nmiFigure 4-4 illustrates the 360° weather view at the 200 nmirange. Using this knowledge, the two clusters of dischargepoints on the screen can be interpreted as one thunderstormcell at 5:30, about 150 nmi from the aircraft, and another cellat 1:00, about 100 nmi from the aircraft. The cluster at 1:00has less radial spread (in the strike display mode) and fewerdischarge points than the cluster at 5:30, indicating a lowerrate of electrical activity. Both clusters must be avoided.

Figure 4-4. Two Clusters Within 200 nmi

Rate 45

200nm

STRIKE

:Rate 40

200nm

CELL

:



Mapping Headings Past ThunderstormsFigures 4-5 through 4-8 and the following paragraphs showthe progression of an aircraft past several thunderstorms.

Range Set at 200 nmiFigure 4-5 shows the 360° weather view at the 200 nmi range.Two thunderstorms appear almost as one cluster of dis-charge points off the nose of the aircraft, centered 180 nmiaway. A second cluster at 9:30 indicates a storm systemcontaining three thunderstorms.

Mapping Past Storms

Figure 4-5. Range Set at 200 nmi

Rate 125

200nm

STRIKE

:Rate 117

200nm

CELL

:



Aircraft Progresses 100 nmiFigure 4-6 shows that the aircraft has maintained its headingand progressed 100 nmi. The two thunderstorms off thenose of the aircraft appear to have expanded horizontally onthe screen. This effect is normal anytime you get close to astorm. The line of thunderstorms previously at 9:30 nowappears at 8:30.

Mapping Past Storms

Figure 4-6. Aircraft Progresses 100 nmi

Rate 127

200nm

STRIKE

:Rate 118

200nm

CELL

:



Range Changes to 100 nmiFigure 4-7 shows the screen a short time later in the 120°weather view at the 100 nmi range. The thunderstorms at8:30 are not visible in this view but the thunderstorms offthe nose of the aircraft appear in greater detail as twoseparate thunderstorms (at 11:30 and 12:15 centered 90 nmifrom the aircraft).

Mapping Past Storms

Figure 4-7. Range Changes to 100 nmi

Rate 75

CELL

:

100nm

Rate 75

STRIKE

:

100nm



Aircraft Turns to Avoid ThunderstormsFigure 4-8 shows the screen a short time later after theaircraft has turned to the right to avoid the thunderstorms.When connected to a compatible heading system, the WX-500 automatically rotates new discharge points to theircorrect position relative to the new heading.

Figure 4-8. Aircraft Turns to Avoid Thunderstorms

Rate 45

CELL

:

100nm

Rate 45

STRIKE

:

100nm

Mapping Past Storms



Special PatternsRandomly Scattered Discharge Points

Atmospheric instability associated with cumulus clouds, ordeveloping or dissipating thunderstorms could causerandomly scattered discharge points as shown in figure 4-9.Random discharge points are more likely to appear in thestrike display mode than in the cell display mode due to thecell display mode’s clustering algorithm. If you observerandom discharge points, continue to monitor the screen fordeveloping clusters which indicate thunderstorm activity.

Figure 4-9. Randomly Scattered Discharge Points

Rate 5

200nm

STRIKE

:Rate 3

200nm

CELL

:

Special Patterns

Cluster & Splattering Within 25 nmiFigure 4-10 shows the 360° weather view at the 25 nmi range.One moderately active thunderstorm appears as a cluster ofdischarge points at 8:30 centered 14 nmi away with a splat-tering of discharge points throughout the 25 nmi range.Such splattering is due to electrical discharges within 3 to 5nmi of the aircraft and indicates that the aircraft is too closeto the thunderstorm.



Continue to head away from the main cluster. While themain cluster should be your primary concern, you shouldalso avoid any groups of discharge points within the 25 nmirange. Switch to the other ranges to ensure that there is nothunderstorm activity along your intended path.

You’ll notice in figure 4-10 that the location of random,individual discharge points is about the same on both thecell and strike display modes. This is true because in the celldisplay mode, the WX-500 plots every electrical dischargedetected within the 25 nmi range at the exact location detectedunless the discharge is associated with a cluster of discharges, inwhich case the discharge point is clustered with the associateddischarge points. You’ll also notice that there are morepoints in the cluster of points at 8:30 in the cell displaymode than there are in the strike display mode. This is dueto the cell display mode’s clustering algorithm “pulling in”individual discharge points associated with the cluster.

Figure 4-10. Cluster & Splattering Within 25 nmi

Rate 50

25nm

CELL

:

STRIKE

Rate 47

25nm

:

Special Patterns



Discharge Points Off Aircraft’s NoseFigure 4-11 shows the 360° weather view at the 200 nmirange. The discharge points ahead of the aircraft could becaused by a strong thunderstorm just beyond the 200 nmirange. Another cause might be electrical discharge signalsarriving via atmospheric skip from a distant thunderstormwell beyond the WX-500 range. In either case, no immediateaction is required.

Figure 4-11. Discharge Points Off the Aircraft’s Nose

Rate 24

200nm

STRIKE

:Rate 16

200nm

CELL

:

Special Patterns



Line of Discharge Points While TaxiingPassing over a cable beneath the taxiway can cause a line ofdischarge points across the screen as shown in figure 4-12.Similar concentrations of discharge points across the screenmay appear while taxiing due to electrical signals from nearbyequipment such as arc welders or subway rails. After passing thesource of the interference, clear the screen.

Figure 4-12. Line of Discharge Points While Taxiing

Rate 45

200nm

STRIKE

:Rate 40

200nm

CELL

:

Special Patterns



Developing Cluster Within 25 nmiFigure 4-13 shows a developing thunderstorm 12 nmi fromthe aircraft. If you see a screen such as this with a developingcluster within 25 nmi, you should change course to avoid thestorm and continue to monitor the Stormscope sensorinformation displayed on the MFD.

Figure 4-13. Developing Cluster Within 25 nmi

Rate 14

50nm

STRIKE

:Rate 14

50nm

CELL

:

Special Patterns


Table 5-1. WX-500 Specifications*

Part Number Definition:805-11500-001 – WX-500 processor805-10930-001 – NY-163 antenna, white805-10930-002 – NY-163 antenna, black

Features:Cell or Strike mode200 nmi rangeBuilt-in self testsAutomatic heading stabilizationMicrophone inhibit lineIntegrity indicator

Size:Processor (includes mounting tray and pull handle):

5.6 in (14.22 cm) high2.2 in (5.59 cm) wide12.0 in (20.48 cm) deep

Antenna:1.00 in (2.54 cm) high3.45 in (8.76 cm) wide6.85 in (17.40 cm) long

Weight:Processor:

2.5 lb (1.13 kg)Antenna:

0.84 lb (0.38 kg) without doubler plate

Operating Altitude:55,000 ft max

SpecificationsC h a p t e r 5

*Specifications subject to change without notice.(Continues on next page)


Chapter 5 – SpecificationsWX-500 Specifications

Table 5-1. WX-500 Specifications* (Continued)

*Specifications subject to change without notice.

Electrical Characteristics:Input voltage:

11 to 32 V dcCurrent:

0.82 A max @ 12 V dc0.38 A max @ 28 V dc

RTCA Compliance:Processor Environmental:

DO-160C: F2-BA(NBM)XXXXXXZ(AB)ABZTZAZEZXXProcessor Software:

DO-178B Level DAntenna:

DO-160C: F2-AC(YCLM)XSFXXXXXXXZXZXXE3XX

TSO Compliance:Processor:

TSO-C110aAntenna:

TSO-C110a & JTSO-C110a

Record of Important Information

Dealer InformationName _________________________________________

Address ________________________________________

City, State, Zip __________________________________

Telephone ______________________________________

Equipment InformationDate of Purchase _________________________________

Installation Date _________________________________

Processor:Model Number_______________________________

Part Number ________________________________

Serial Number _______________________________

Mod Letter __________________________________

Firmware Version _____________________________

Antenna:Model Number_______________________________

Part Number ________________________________

Serial Number _______________________________

Mod Letter __________________________________

To ensure that a new or repaired WX-500 meets the TSO, meetsforeign government certification requirements, and meets L-3Avionics Systems performance standards, your WX-500 must beinstalled and tested by an L-3 Avionics Systems-authorizedStormscope dealer.

NOTE

009-11501-001 (Rev. C, 12/05/03)

L-3 Communications Avionics Systems, Inc.5353 52nd Street, S.E.Grand Rapids, MI 49512 USA(800)253-9525www.L-3com.com/as

Stormscope® WX-500

This data is provided at no charge, or at cost, tothe public and is considered publicly available, NoLicense Required (NLR) as defined in the ExportAdministration Regulations (EAR) Part 734.7-11.

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