Weather Tactics

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2ForewordThe following pages will take you on Operation Rain Check tours of Washington

Dulles International Airport (KIAD), the Washington Air Route Traffic Control Center

(ZDC), and the Leesburg (Virginia) Flight Service Station. These facilities provide

information that can help you make decisions critical to your success in avoiding

hazardous weather. Well focus on weather flying tacticsways to utilize the

weather resources available through air traffic control (ATC) and flight service while

flying through areas of actual or forecast adverse weather. Youll learn how to get

information on convective activity, as well as other atmospheric hazards such as

icing, turbulence, or encountering IFR conditions during a VFR flight. Dealing with

enroute weather involves tactical planning and response. Because conditions change

rapidly, pilots must be prepared for quick decision making and immediate action. In

these situations, ATC can provide invaluable assistance. To make optimal use of

ATCs assistance, pilots must be aware of the abilities and limitations of both air

traffic controllers and their equipment.

Washington Air Route Traffic Control Center

Dealing with Enroute WeatherTactics IFR or VFR?

Once the go decision has been made, its time toconsider the tactics youll use to complete the flightin safety and reasonable comfort. If the route takesyou through areas of possible adverse weather, thefirst major issue is whether to go IFR or VFR.

If youre a VFR pilot, the decision is already made.You must remain VFR. Air route traffic controlcenters (ARTCCs) will probably not have muchinformation on enroute ceiling and visibilities, butterminal approach controllers can often provideuseful information on conditions near the airport.Flight service and automated weather equipmentcan provide information for selected points.

If youre instrument rated, you have a choice, andthe conservative approach might suggest flyingIFR; after all, continued flight from VFR into IFRconditions remains one of the most often citedaccident factors in general aviation. But flying VFRcould be more prudent in some cases. Forexample, if afternoon thunderstorms are a

possibility, going VFR, and maintaining visualseparation from buildups, can be a better optionthan being stuck in the clouds on an IFR flightplan. Enroute altitude is another importantconsideration; 2,000 vertical feet can make all thedifference between being in the clouds and beingabove them. The part of the country over whichyoull be flying makes a difference, too. Kansasthunderstorms are often easy to spot and avoid;not so with embedded TRW along the East Coast.

Maintaining Flexibility and SafetyPilots often look at weather as either IFR or VFR.Standard protocol tells us to inform the brieferwhether we are going IFR or VFRbeforereceiving any weather information. This can be acart-before-the-horse kind of question, becausethe decision to file IFR is often based on theforecast. Also, despite advances in meteorologyand technology, conditions along a particular routemay be markedly different from the forecast.Being flexible means dealing with what is actuallyhappening and not fixating on what was supposedto happen.

If the route takes you through areas of possible adverseweather, the first major issue is whether to go IFR or VFR.

A highly visible thunderstorm

Operation Raincheck The FAA encourages pilots to visit air traffic control facilities towers, Tracons, centersand flight service stations. The agency hasestablished a program, Operation Raincheck,to facilitate tours of these facilities. The pro-gram is predicated on the belief that the morepilots know about the controllers and theirequipment, the safer they will be when flyingin weather. All pilotsIFR and VFRareencouraged to take advantage of this pro-gram. Call a nearby ATC facility to inquireabout Operation Raincheck tour schedules.

View from the tower

4Another way to be flexible is to realize there aremany gradations of IFR conditions. Pilots talk ofhard IFR and solid IFR, signifying conditionsof continual low visibility, possibly with ceilingslow enough to require instrument approachesdown to minimums.

IFR conditions along a route may be onlysporadic or only affect a narrow range ofaltitudes. IFR flights may be conducted in clearskies or in weather that only occasionally putsthe aircraft in instrument meteorologicalconditions (IMC). VFR conditions also come inmany shades, from ceiling and visibility unlimited(CAVU) to deteriorating visibility or low ceilings inwhich VFR flight, although legal, may not besafe. As stated above, actual and forecastconditions can differ markedly. In some cases, anIFR flight plan may not be needed; in others, onemay have to be filed at the last minute.

Filing in the Air Sometimes the need for IFR flight only becomesapparent when airborne. In these cases, there areseveral ways of getting into the system.

If you know or strongly suspect youll need to goIFR at some point in your flight, you can file acomposite flight plan in which you designate thepoint where you wish to switch from VFR to IFR.At that point, you can contact flight service or, insome cases, ATC, to pick up your IFR clearance.Getting the clearance from ATC will be easier ifyoure already on flight following.

Its possible to request an IFR clearance fromATC without having a previously filed IFR flightplan. Controllers will often accommodate such

requests if theyre not too busy. Pilots mustrealize, however, that ATCs main responsibility isseparating trafficeverything else is secondary.

A surefire way to file in the air is to contactflight service. File an IFR flight plan to beactivated over a designated point. Obviously, youcant wait until youre in IMC to ask for aclearancethat requires exercising the leastattractive option.

Declaring an emergency is another way to getIFR service in flight. Both VFR and IFR pilotsshould never hesitate to use their PIC authority tocope with emergency situations. Its difficult tounderstand how a prudent aviator couldinadvertently stray very far from VMC into IMC,but it happens all too frequently with fatal results.

The Eyes Have It Pilots vision has always been the best system forhazardous weather avoidance. If you can see the

The eyes are the best means to avoid the weather.

The controlling ARTCC facility

The boundary between ARTCC facilities airspace

clouds, you can avoid them, so pilots should planall flights to give the best opportunity of seeingthe weather. That naturally means adjustingcruising altitude as required, but it may also meandelaying departure or leaving earlier.

Here are some tactics to improve the view:

Try to get on top of the weather.

Obviously you wont be able to top thunderstorms,but its often possible to top the veiling clouds thatobscure your view of the nasty stuff.

IFR pilots should request VFR-on-topclearances. They accord considerable latitude inweather avoidance.

ATC is less likely to approve VFR-on-top incrowded airspace. Here pilots should requestcruising altitudes that will allow them to seewhats ahead at least part of the time.

VFR-on-top is legal for VFR pilots too, butyouve obviously traded one problem for a biggerone if you have to declare an emergency todescend through the clouds.

During IFR flights in actual instrument conditions, ourability to monitor weather visually is significantlyrestricted. We cant see weather beyond the horizonthat may be affecting our destination or peer througha solid cloud deck to know if there is ice, turbulence,or heavy rain ahead. During trying times like these,ATC may be able to provide some answers.

ATC and AirspaceKnowledge of which ATC facility controls theairspace youre in, and the location of theboundaries between these facilities, is important inplanning and conducting an IFR flight. On IFRenroute low altitude charts, the controlling ARTCCfacility and frequencies for contacting them viaremoted sites are identified within small boxeswith blue serrated borders. The boundary betweencontiguous ARTCC facilities airspace is indicatedby the same serrated blue line.

Airspace under the jurisdiction of approach controlfacilities in Class B and Class C airspace is denoted bya solid, light blue area on IFR charts and by magentaor blue lines on VFR charts. Approach controltypically owns the airspace for 40 to 50 nauticalmiles from the airport at the center of the airspace.

Some approach control facilities are not graphicallydepicted on IFR enroute charts, but their

IFR enroute chart tabular communication dataApproach frequencies for Class B and C airspace are easy to seeon VFR terminal area charts as shown here. On sectionalcharts, Class C frequencies are shown the same way; however,you must refer to the tabulation printed on the side panel forClass B approach frequencies.

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VFR sectional chart tabular data

communication frequencies are found in thetabular data on VFR and IFR charts.

If youre on an IFR flight plan or have requestedVFR flight following, youre already talking withcontrollers who can either provide weatherupdates or refer you to a frequency where you canget them.

Knowing who controls the airspace and whereboundaries are can be helpful to VFR pilots, as well.For example: Youre flying VFR at 4,500 feet. Theforecast calls for a 40 percent probability ofthunderstorms for later in the afternoon, andtheres a buildup on the horizon. Has the convectiveactivity started ahead of schedule? If you knowwhose airspace youre in and the frequency to use,you can call Center or Approach and ask about thepresence of convective weather along your route.Knowing the airspace boundaries is important

because radar coverage tends to be at its weakestalong the border areas. If you need help from ATCto avoid the heavy weather, these areas of fringecoverage arent the best place to get it.

ATC RadarIFR flights in controlled airspace, or VFR flightunder flight following, are nearly always tracked byATC radar. This surveillance radar is designedprimarily to see airplanes, and there are two basictypes: airport surveillance radar (ASR) and air routesurveillance radar (ARSR). ASR is used in approachcontrol facilities in terminal areas; ARSR is used inARTCC facilities. Whats most important for pilotsto know about them is what each can and cant see.

Surveillance Radar and Weather The same radar that sees airplanes in the sky canalso see some adverse weather. Unlike its 20-20vision for spotting transponder-equipped aircraft,surveillance radars vision for weather is, well,clouded. Furthermore, ASR and ARSR are not equalwhen it comes to seeing weather. Knowledge ofhow radar sees weather is the first step to under-standing the basic weather information availablefrom ATC. Radar transmits a radio wave thatsweeps the sky as it revolves and listens for thereturn echo caused by the wave bouncing off anobject. The returning energy is displayed on ascreen as a primary return. Attached to the primaryradar antenna is a secondary antenna that trans-mits a query to aircraft transponders. Thetransponder reply is called a secondary return.

Air route surveillance radar (ARSR)

Precipitation as seen on Tracon radar

Many pilots fly with GPS or loran receivers thatfeature extensive airport, ATC, and navigationfacility databases. If you know where to look, itsa simple matter to find the appropriatecommunication frequency.

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Primary radar senses not only airplanes, but alsoterrain and weather. Radar energy is reflected bywater in the form of rain. The more water, thestronger the return. The faster the radar turns, thegreater the number of returns and the more com-prehensive the picture of the echoes it paints.However, as the speed of the sweeping radarincreases, its range decreases. Hail and snow arepoor reflectors of radar waves; thus, ATC radar ismore limited in its ability to see them.

All radar is prone to certain errors. Radar wavescan be bent and reflected by atmosphericphenomena besides rain. Temperature inversions,for example can create radar returns that looklike precipitation. Controllers learn how tointerpret most false returns, and they becomefamiliar with errors that are common in particularareas due to surrounding topography or recurringatmospheric conditions.

Levels of Storm Intensity

For aviation, precipitation is measured in levels ofintensity. Level one and level two may not makehearts flutter, but a level three activity aheadshould command our undivided attention. Theintensity levels are determined by the amount ofwater the radar detects, which is correlated toamounts of rainfall as follows:

Turbulence

How well does radar imagery of precipitationcorrelate with turbulence?

Doppler radarthe kind you see on televisionweather programscan show air movementthroughout and around thunderstorms. Providedthis imagery is interpreted correctly, it canaccurately show areas of turbulence.

Unfortunately doppler radar isnt found in manycockpits, nor is it available to individual controllersso, for the present, we can only see precipitation.

High altitude studies conducted by NOAA and the U.S. Air Force1 showed that significant turbulencedoes occur outside of the thunderstorm proper.How far the turbulence extends is hard to say, butpilots should avoid any convective activity by atleast 20 miles. Even at that range, theres noguarantee you will avoid all the turbulence.11973-1977 Rough Rider Turbulence-Radar Intensity Study. J.T. Lee, D.

Carpenter; National Severe Storms Laboratory, Environmental Research

Laboratories, National Oceanic and Atmospheric Administration.

Turbulence Tips How clouds look can tell you a lot about the rideyoull get as you fly through them.

Flat stratus clouds form in a stable atmosphereand will yield little or no turbulence.

Cumulus clouds form in unstable conditions andwill give you a rougher ride.

Look at the shape of cumulus clouds. If the contours are rounded and pillow-like, the turbulence will most likely be manageablehardangular contours indicate more turbulent conditions.

Shredded clouds, torn apart by wind, usuallypredict turbulence.

Lenticular clouds that form in mountain waveconditions have particularly well defined edges,and not surprisingly, they can be associated withextreme turbulence particularly below the cloud.

Slow down well before entering the cloud orsuspected turbulence area. This meansmaneuvering speed or less.

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Levels of Storm Intensity

Level Intensity Rainfall per Hour

1 Very light Trace to .02

2 Light to moderate Up to .09

3 Strong Up to .48

4 Very strong Up to 2.5

5 Intense Up to 5.7

6 Extreme Up to 13

Line of clouds seen from 68,000 feet

Remember that maneuvering speed (Va)decreases as the aircraft weight decreases; i.e., alightly loaded airplane with one pilot must be flownmore slowly than one with all the seats filled.

Dont chase the airspeed, but try to keep itwithin 10 knots of maneuvering speed.

Lowering the landing gear can help to stabilizethe aircraft, and the increased drag will help tokeep you from overspeeding in the case of amomentary upset.

Do not lower the flaps. The aircraft is strongestwith flaps up.

Fly attitude not altitude.

Concentrate on keeping the wings level. Turningimposes greater stress on the aircraft.

The shortest way through the turbulence isusually a straight line.

Its very difficult to maintain altitude inmoderate or greater turbulence, so request a blockaltitude from ATC.

Dont make radical pitch changes.

If youre using an autopilot, turn off altitude hold.

Hail is another hazard thats often present inthunderstorms.

Terminal Radar In airspace around major airports, ATC radarservice is provided by Traconterminal radarcontrol. The various forms of ASR found in thesefacilities are more accurate but have less rangecapability than the ARSR systems employed atcenter (ARTCC) facilities. Typically, ASRs have arange of 50 to 60 miles, but the practical limit isabout 40 miles from the site.

The radar, together with software and hardware suchas the controllers display screens, comprise anautomated radar terminal system (ARTS). The radarscreen controllers look at, called the plan view display,or PVD, can show returns from both primary andsecondary radar. Returns from the secondary radarthe transponder responsesare much stronger andeasier to see, and the Mode C returns report aircraftaltitude. Thats why aircraft without Mode Ctransponders are excluded from within 30 miles of theprimary airport in Class B airspace, the Mode-C veil.

Terminal radars rotate every four to five seconds,compared to the 12-second sweep of ARSRsystems. They are more accurate in showing

Slow down well before entering the cloudor suspected turbulence area.

These clouds must be avoided.

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Tracon radar display

9both aircraft and rain than ARSR systems, buttheir range is considerably shorter. This accuracydifferential means that aircraft under terminalradar control radar need only three miles ofseparation, while those under centers radarrequire a five-mile separation. Accuracydecreases as range increases, so aircraft morethan 40 miles from the terminal radar site mustalso be separated by five miles. At the limits ofits range, surveillance radar cant distinguishbetween an aircraft and other objects in theatmosphere such as a large balloon, a flock ofbirds, or atmospheric phenomena such as atemperature inversion.

Older models of terminal radar (ASRs-4, -7 and -8), though still in operation, are being replaced orhave been replaced at larger facilities by ASR-9and ASR-11 systems. These newer systems havededicated weather radar that works in conjunctionwith the surveillance radar. Computers process the

weather radar data to create digitized compositeweather images that are displayed on thecontrollers PVDs.

With their dedicated weather radar antennas, ASR-9 and -11 systems display weather in six levels,corresponding to the six levels of precipitationintensity. To reduce visual clutter, the computereliminates most indistinct returns from the screen.Controllers can select any two of the six levels fordisplay on their PVDs.

Each aircraft under their control is tagged with adata block containing the aircrafts N number, acomputer code number, altitude, and groundspeedbased on history. When flying through an approachfacilitys airspace, pilots in radar contact will bedirected to contact successive frequencies as theytransit from one controllers sector to the next.

Additional Tracon Weather Monitors Terminal facilities have additional weathermonitoring devices besides the standardmeteorological suite of barometer, anemometer,and thermometer.

A low-level wind shear alert system (LLWAS), ananomaly detector, compares winds from sensorsaround the perimeter and center of an airport inorder to spot indications of wind shear.

Terminal Doppler weather radar (TDWR) willeventually replace LLWAS. TDWR looks at the

Tracon radar display

Aircraft data block

Radar in the tower

airspace along approach and departure paths andover the airport to detect microbursts, gust fronts,wind shifts, and precipitation intensities. Pilots getbetter information with TDWR than LLWAS, butits important to realize that this radar is designedto look only at the arrival and departure ends ofrunwaysnot all around the airport. TDWR willnot detect gusty or crosswind conditions, but windchecks from the tower accomplish this. Neitherwill it detect turbulence, although that may beinferred when the wind is strong enough.

Airport surface detection radar is used towatch traffic on taxiways and aprons. Though nottypically thought of as weather radar, in times oflow visibility due to fog or mist, it can help pilotssafely navigate on the ground around largeairports. Pilots unfamiliar with the field can askfor progressive taxi instructions, a wise requestwhen the alternatives include possible incursiononto an active runway.

Using Tracon Radar on the GroundPilots who launch into weather from airportsserved by Tracons have more resources to call onthan those flying out of remote or nontoweredairports with only a unicom and an ASOS forweather information.

Tower controllers often have access to the sameweather information available to controllers in theTracon. A monitor in the tower can display outputfrom the facilitys radar. While taxiing, pilots canrequest an update on area weather from groundcontrol or from the tower just before takeoff.Before engine start-up or while waiting to taxi,pilots at Tracon airports can monitor approachcontrol for wind shear reports or deviation requests.

Air Route Traffic Control CenterARTCCThe hand-off from approach to center puts pilotsin contact with controllers at one of the 21 ARTCCfacilities across the country. Their air routesurveillance radar (ARSR) -3 and -4 can pick upradar echoes from about 200 to 250 miles,respectively. The radar is usually located off-sitefrom the ARTCC, on strategically high groundminimizing terrain obstructions. The primary radarconsists of an array of several transmitters andreceivers for expanded width of the coverage area.Here again, aircraft being tracked are tagged withdata blocks, indicating the aircrafts N or flightnumber, assigned altitude, altitude climbing ordescending through, destination, andgroundspeed. The arrays relatively slow rotatingspeed of five times a minute enhances its range.The PVD image, like those at approach control, ishighly processed. Though the radar itself revolves,the traditional radar sweep is eliminated fromcenters PVDs; the data blocks and position oftargets on the screen move incrementally witheach sweep of the radar.

Seeing Weather On ARTCC PVDs, level 1, or light precipitation,shows up as long straight lines. Hs indicate level2 and higher rainfall rates. Cross-hatched areasshowing a cluster of Hs where the linesconverge indicate heavy weather. (The cross-hatching is a composite picture from two or moreradars simultaneously.) Hs at the end of longsingle lines often indicate false returns. Thesereturns are the controllers prime source ofweather information to pass along to pilots.Center controllers do, however, have access toadditional weather data.

Terminal Doppler weather radar (TDWR)

Hs indicate level 2 and higher rainfall rates.

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The CWSU Every ARTCC has a Center Weather Service Unit, orCWSU, staffed by a National Weather Servicemeteorologist. The meteorologist meets with thecenters supervisor twice a day to review theweather and possible problems it may cause. Theposition of the jet stream and areas of rain, snow,icing, turbulence and thunderstorms are discussed.If the weather is expected to interfere with normalflight operations, controllers are informed.

Cloud-to-Ground Lightning MonitorThe cloud-to-ground lightning monitor is agraphic representation of thunderstorm activityacross the United States. The color shows theactivitys history. Cyan represents the first 55seconds of lightning activity. After 55 seconds,the color goes to green, and to red after 5minutes, enabling the screen to display where thestorms are most violent.

The CWSU includes displays of weather sensorsthat may, in the not-too-distant future, be feddirectly into cockpits in real time, vastly enhancingthe safety of weather flying. For example, thenational Doppler radar weather summary showsthe echoes from Doppler radars all across thecountry, and the display (referred to as Nexrad)can be overlaid on airways to get a better glimpseof how and where the convective weather mightaffect flights. A nationwide network of cloud-to-ground lightning monitors likewise indicatesthunderstorms and convective activity across thecountry in real time.

In addition to the briefing material, eachsupervisors position has a dedicated weather

briefing terminal that can display the same dataavailable in the CWSU: radar maps, satellite data,text messages regarding significant weathertheworks. Yet most of this information is rarelyavailable to pilots via the controllers. Why? Thecontrollers primary responsibility is trafficseparation, and in times when this information ismost valuablethat is, in conditions ofdeteriorating weathercontroller work loads areat their peak. Aircraft may request deviations,aircraft that might otherwise be flying VFR insteadare IFR, and some traffic might require vectoringaround the weather. This doesnt leave time forturning away from the PVD to consult the weatherbriefing terminal. In addition to work loadconstraints, controllers are not trained asmeteorologists, and some are, naturally, reluctantto take on that role.

What Are Your Intentions?

Despite not being trained as meteorologists,controllers may advise pilots if they are on acollision course with hazardous weather.Controllers can make suggestions for stormavoidance, but they cant tell pilots what to do.They may simply advise of convective activityahead, or less often, they may suggest a headingfor a deviation. Why dont they tell pilots what todo about avoiding weather? First, they dont knowthe limitations or abilities of a given pilot or hisaircraft. One pilot may have no problem copingwith level 2 precipitation, whereas another willwant to stay well clear. As weve already shown,radarparticularly center radardoes not show allthe weather. Finally, there is a liability issue. If anaccident occurs following the issuance andacceptance of such instructions, the FAA could finditself in court.

Lighting Detection Network

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Nexrad overlaid on airways

Often getting the information you need is simply amatter of asking the right questions:

Are you showing any weather along my route?

Is it showing as light or heavy?

Has anyone flown through that area recently, ator near my altitude?

How was their ride?

If pilots are avoiding that area, in which directionare they deviating?

Can you give me a heading to follow thesuccessful deviators?

The same line of questioning can be usedregarding icing or turbulence, although these donot show on radar. The controller will be relying onpilot reports. ATC will supply you with weatherinformation and suggestions to the extentpossible, but the resulting decisions, and theconsequences, are all yours.

Sometimes it may take a few moments to digestthe information and decide what to do about it.Of course, controllers want to know your courseof action immediately; they have to separate youfrom airplanes. If you dont have a quick answer,the controller may ask, What are yourintentions? If youre not sure, you can ask formore help; for example, request vectors forgetting around a cell. You need to be aware of theoptions available to you. It could be a change ofaltitude to get over or under the weather or adeviation to the right or left. Its up to you as pilotin command to know the tactics at your disposaland make the right decision.

Deviations ATC will let aircraft deviate as long as they dontconstitute a collision hazard. Deviation is as muchart as it is science. Here are a few tactics:

Try to deviate north of convective activity; usuallythe south side contains the water thats fuelingthe storms.

Give a wide berth to the downwind sidethedirection the storm is movingas turbulence mayextend far into clear air. Because storms oftenmove from southwest to northeast, thissuggestion might seem to conflict with the oneabove. Tornadoes most often form on thesouthwest side of storms, though, so youreusually better off with northerly deviations.

Dont fly under anvils and overhangs. Thatswhere your chance of hail encounters is greatest.

Come no closer than 20 miles to the weatheryoure deviating around.

If a deviation is required, ask for it as soon aspossible. This will give the controllers time tocoordinate with other traffic.

Try to deviate 45 degrees or less from course.Controllers dont like to process requests for 90-degree deviations because they greatly

Once in the air, deal with what is actually happeningnot what was supposed to happen.

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Time OutLets take a moment to put things in perspective.This publication deals with tactics for flying in oraround weather, but pilots must realize that thereare some weather situations that no airplane/pilotcombination is capable of handling. In other words,all the technology in the world will not makeunflyable weather flyable.

The pilot in command is responsible for knowingwhen to press on and when to call it a day. Wemust regularly evaluate the weather and ourairplanes capability and our own as each flightprogresses. If the weather is more than we canhandle, were responsible for the decision todivert, land, and wait for conditions to improve,or turn back and try it another day. The pressureof this decision is greater when we have aschedule to keep or passengers to impress, butthe decision must be made solely on the safetyof flight. Unless your passengers are alsoqualified crew members, its best to make thedecision without their input.

complicate the separation task and the need forcoordination with other control sectors is likely.

If you want to climb over some clouds but dontwant to request and remain at a designatedaltitude, ask for a block altitude. This request willmore likely be granted when traffic density is light.

When requesting a deviation, keep the routing assimple as possible. Remember, if the weather isaffecting you, its probably affecting lots of otherpilots too, and the simpler you can keep the request,the more likely you are to get what you ask for.

If your request is met with an unable at acritical juncture and youre worried about flyinginto dangerous weather, you can invoke your rightsas pilot in command to deviate in accordance withFARs 91.3 and 91.123. However, if youre payingattention and working with ATC properly, itshouldnt come to this.

Additional Enroute Weather SourcesGetting enroute updates can reduce the stress ofcross-country flying in challenging weather. Pilotson VFR cross-country flights should also use theseresources, due to the ever-present possibility ofdeteriorating conditions that lurks in even themost optimistic forecast.

Flight Service Stations (FSSs) Flight service stations remain a mainstay ofaviation weather resources. Enroute, theirprimary contact frequency is 122.2. The sameinformation is available in telephone briefings,and pilots are encouraged to use the phonewhenever possible to avoid frequency congestion.FSS communicates with pilots through remotetransmitters, so replies are only heard by radiosin the appropriate area. Thus, its important tostate the aircrafts position when contactingflight service. The name of the controlling facilityis helpful, too, but as long as you tell them yourposition and frequencyLeesburg Radio, this isDebonair One-Five-Eight-Eight Sierra, fifteensouth of the Philipsburg VOR, 122.2if theyhear you, they will respond.

Flight WatchFlight Watch, also known as the Enroute FlightAdvisory Service, or EFAS, is designed toprovide information on weather affecting yourroute of flight, as the name implies. Itsavailable on frequency 122.0 from 6 a.m. to 10p.m. daily, at altitudes from 5,000 to 17,500feet and on selected frequencies for high-altitude flights. Provided through selectedFSSs, its not meant to provide detailedbriefings like FSS or for filing flight plans.When you need quick, concise informationabout actual or suspected adverse enrouteconditions, this is the frequency to use.

Controllers can make suggestions for storm avoidance, but they cant tell pilots what to do.

Often getting the information you need is simply a matter of asking the right questions.

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Again, its imperative to state your position inyour initial report, so that briefers know whichremote transmitter to use.

Flight Watch briefers are specially trained toprovide the real-time weather information pilotsneed to make in-flight decisions. They have thelatest Nexrad Doppler radar image composites ona monitor at the briefing console. They also havepireps and surface observations. Flight Watchblurs the line between strategic and tacticalplanning. In one sense, if youre in the air, all yourdecisions are tactical, but pilots have to keep inmind the age of the information theyve received.Pireps can age quickly in fast-developing weathersituations, and even Nexrad images may be up to15 minutes old. Add to that the difficulty ofrelating your position to the weather describedby the briefer, and you can see that the earlieryou talk to Flight Watch, the more time youllhave to deviate well clear of the hazards.

The same questioning routine you use with ATCcontrollers will work with Flight Watch.

Where is the weather?

What are the pilots saying about it?

Whats the best way to turn?

Where are the successful deviators going?

You can also learn a lot about developing weatherby simply listening to Flight Watch. When thingsare popping, you can usually hear a lot ofweather information requests on 122.0.Monitoring the frequency for a few minutesbefore contacting the briefer can save time whenits your turn to ask the questions.

Automatic Terminal Information Service (ATIS) These hourly updates on airport weather,broadcast at many towered airports, are avaluable enroute tool. Monitor ATIS reports fromnearby airports. Though the weather may be upto an hour old, any significant changes will bemarked by a special observation, an easygiveaway about trends. You dont even have toleave the frequency to do it (assuming you havetwo radiosalways a good idea when flyingIFR). Just monitor the ATIS frequency on yoursecond radio.

Tower This is another ATC facility few pilots contactunless departing, landing, or when requesting atransition through Class D airspace. Whatsgoing on under a cloud deck? Center may notbe able to see on their radar, but the controllerin the tower at a nearby airport can tell you.You can request a frequency change to check inwith an enroute tower.

ASOSAutomated Surface Observation SystemASOS is a valuable tool, bringing weatherinformation to hundreds of airports where noneexisted before. It is also envisioned as areplacement for observers at many airports nowstaffed by human weather watchers. Due tolimitations in equipment or in siting, ASOS cangive false reports on ceilings and visibilities, andits most prone to error in rapidly changingweather conditions. Therefore, a single ASOSreport cannot be relied on as accurate duringchanging conditions. ASOS stations should bemonitored for at least a 10-minute period ifpossible, with attention paid to trends.

Pilot Reports Controllers get pilot reports all the time, buttheyre not always passed along. Ask if thecontroller has any pireps relevant to your routeof flight. You can also solicit pilot reportsthrough a controller. For example, ask if thereare any reports of turbulence, icing, orprecipitation up ahead. Controllers will oftenquery other pilots on the frequency who areflying through the area youre asking about. Beech 88 Sierra, hows the ride? they may ask,or Beech 88 Sierra, what are your current flight

Call an enroute tower to ask about current weather conditions.

conditions? Thats some of the best weatherreporting you can get. Its just as important togive pireps as it is to receive them. Other pilotsare vitally interested in your experience, andtheyll appreciate information on good weatheras well as bad. Are conditions better, the same,or worse than forecast? Make it a habit toforward several pireps each flight. Any contactwith Flight Watch should include a pirep.

Approaches in Adverse Weather Every safe pilot knows the dangers of get-home-itis or get-there-itis. We must beespecially careful to maintain our objectivitywhen deciding whether to continue to adestination airport or continue an approachwhen hazardous weather is in the vicinity If

convective activity is in the area, look for tipoffsregarding its severity. In the summer, dew pointsabove 50 degrees, for example, may indicate thepresence of the enough moisture to set off athunderstorm. And a temperature/dew pointspread of 35 to 40 degrees or more is a signthat if a rainshower starts, it will rapidly build inintensity. A rule of thumb some seasoned pilotsrecommend is never conducting an approachwhen thunderstorms are within five miles of theapproach corridor. Pilots should also be awarethat severe-storm gust fronts can reach muchfarther than five miles. Approach controllers cantell you if airplanes ahead of you are completingthe approach or waiting for the weather topass. Tower controllers can provide especiallyuseful information when youre close to thefield. They can give you real-time information onweather at the airport. If you have two radios,you can monitor tower during the initial stagesof the approach.

Ultimately, radar cannot be relied oncompletely. Convective activity can boil up in amatter of minutes. You may descend into adeck of clouds on approach with no weathervisible on radar and find yourself in heavyprecipitation on final. Thats why its importantto remember the limitations, as well as theabilities of ATC services. Practice using them intimes of good weather, and youll make muchbetter use of them in the bad. Combine ATCsresources with your own tactical abilities, andyour flying will be not only safer, but moreenjoyable as well.

New Private or Instrument Certificate?While we have given you some guidance in thetactics of weather flying, there is no substitutefor actual experience. The AOPA Air SafetyFoundation encourages all new pilots, both VFRand instrument, to team up with a seasonedinstructor or mentor. The private pilotcertificate or instrument rating is only thebeginning of learning tactical weather flying.Most pilots get very limited experience duringbasic training, and the weather is frequently toogood. Take the time to explore carefullyyourskill and confidence will improve tremendously.

ASOS brings weather information to hundreds of airports where none existed before.

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Copyright 2003, AOPA Air Safety Foundation421 Aviation Way, Frederick, MD, 21701

Phone: (800) 638-3101Internet: www.asf.orgE-mail: asf@aopa.org

Publisher: Bruce LandsbergWriter: James Wynbrandt

Editors: John Steuernagle, Kathy Dondzila

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