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Federal Aviation Administration General Aviation Pilot’s Guide to Preflight Weather Planning, Weather Self-Briefings, and Weather Decision Making General Aviation Pilot’s Guide Preflight Planning, Weather Self-Briefings, and Weather Decision Making Foreword…………………………………………………………… ii Introduction……………………………………………………… 1 I Preflight Weather Planning…………………………………… 2 Perceive – Understanding Weather Information…………………..... 2 Process – Analyzing Weather Information ………………..………... 7 Perform – Making A Weather Plan.…………………………………... 11 II In-flight Weather Decision-Making…………………………… 14 Perceive – In-flight Weather Information…………………….......... 14 Process – (Honestly) Evaluating In-flight Conditions…………….. 16 Perform – Putting It All Together…………………………………… 20 III Post-Flight Weather Review…………………………………... 22 IV Resources………………………………………………………… 23 Appendix 1 – Weather Products & Providers Chart……………... 24 Appendix 2 – Items for Standard Briefing…………………………. 25 Appendix 3 – Automated Weather Systems (definitions)………... 26 Appendix 4 – Developing Personal Weather Minimums. ……….. 27 Appendix 5 –Aviation Weather Analysis Worksheets…..…………. 31 Appendix 6 –Weather Analysis Checklists (VFR)…………………. 32 Appendix 7 – Weather Analysis Checklists (IFR)………………….. 34 Appendix 8 – Estimating In-flight Visibility & Cloud Clearance…….. 36 Preflight Guide v. 1.1 Preflight Weather Planning Perceive – Understanding Weather Information When you plan a trip in a general aviation (GA) airplane, you might find yourself telling friends and family that you are first going to “see” if weather conditions are suitable. In other words, your first major preflight task is to perceive the flight environment by collecting information about current and forecast conditions along the route you intend to take, and then using the information to develop a good mental picture of the situation you can expect to encounter during the flight. Because there are many sources of weather information today, the first challenge is simply knowing where and how to look for the weather information you need. For many GA pilots, the FAA Flight Service Station (FSS) remains the single most widely used source of comprehensive weather information. Like other weather providers, the FSS bundles, or “packages,” weather products derived from National Weather Service (NWS) data and other flight planning information into a convenient, user-friendly package that is intended to offer the pilot not only specific details, but also a big picture view of the flight environment. In this respect, you might think of the FSS as “one-stop shopping” for GA weather information. Flight Service offers four basic briefing packages: • Outlook (for flights more than six hours away), • Standard (for most flights), • Abbreviated (to update specific items after a standard briefing); and • TIBS (telephone information briefing service), which provides recorded weather information. The specific weather information packaged into a standard briefing includes a weather synopsis, sky conditions (clouds), and visibility and weather conditions 2 08/06 Preflight Guide v. 1.1 at the departure, en route, and destination points. Also included are adverse conditions, altimeter settings, cloud tops, dew point, icing conditions, surface winds, winds aloft, temperature, thunderstorm activity, precipitation, precipitation intensity, visibility obscuration, pilot reports (PIREPs), AIRMETs, SIGMETs, Convective SIGMETS, and Notices to Airmen (NOTAMs), including any temporary flight restrictions (TFRs). Although a Flight Service weather briefing is still the single most comprehensive source of weather data for GA flying, it can be difficult to absorb all the information conveyed in a telephone briefing. Pictures are priceless when it comes to displaying complex, dynamic information like cloud cover and precipitation. For this reason, you may find it helpful to begin the preflight planning process by looking at weather products from a range of providers. The goal of this self-briefing process is to develop an overall mental picture of current and forecast weather conditions, and to identify areas that require closer investigation with the help of an FSS briefer. Here is one approach to conducting your initial self-briefing. Keep in mind a simple rule-of-thumb as you work through the weather data collection process: the more doubtful the weather, the more information you need to obtain. Television/Internet Sources. For long-range weather planning, many pilots start with televised or online weather, such as The Weather Channel (TWC) on television or the Internet. TWC is not an FAA- approved source of weather information, but its television and Internet offerings provide both tactical and strategic summaries and forecasts (up to 10 per day). TWC provides compact, easy-to-use information that can be a useful supplement to approved sources. For example, one TWC Internet page includes a weather map with color-coding for Instrument Flight Rules (IFR) and Marginal Visual Flight Rules (MVFR) conditions at airports around the country (http://www.weather.com/maps/aviation.html). This and other TWC features can give you a very useful first snapshot of weather conditions you will need to evaluate more closely. The National Weather Service’s Aviation Weather Center (http://aviationweather.gov/) is another useful source of initial weather information. A look at the AIRMET and SIGMET watch boxes can quickly give you an idea of areas of marginal or instrument weather. Direct User Access Terminal System (DUATS). Next, get a printed version of the FSS briefing package by obtaining a standard briefing for your route on DUATS. Free and accessible to all pilots via the Internet at www.duat.com (DTC) or www.duats.com (CSC), this resource provides weather 3 08/06 Preflight Guide v. 1.1 information in an FAA-approved format and records the transaction as an official weather briefing. You might want to print out selected portions of the DUATS computer briefing for closer study and easy reference when you speak to a Flight Service briefer. Aviation Digital Data Service (ADDS): You should also take a look at the wealth of weather information and resources available online via the Aviation Digital Data Service (ADDS), a joint effort of NOAA Forecast Systems Laboratory, NCAR Research Applications Program (RAP), and the National Centers for Environmental Prediction (NCEP) Aviation Weather Center (AWC). Available at http://adds.aviationweather.noaa.gov, ADDS combines information from National Weather Service (NWS) aviation observations and forecasts and makes them available on the Internet along with visualization tools to help pilots use this information for practical flight planning. For example: • For METARs, TAFS, AIRMETS, and SIGMETS, the ADDS java tool can zoom in on specific parts of the country. • For pilot reports (PIREPs), the ADDS Java tool can zoom in on a specific part of the country and specify the type of hazard reported (icing, turbulence, sky and weather). The tool also allows you to limit data to specified altitudes and time periods. Map overlays including counties, highways, VORs, and Air Route Traffic Control Boundaries are available. • For the National Convective Weather Forecast (NCWF), the latest convection diagnostic is shown together with the one hour forecast. The java tool allows the user to select the height and speed of the forecasted thunderstorm, as well as the one-hour forecast from the previous hour to help the user understand how well the NCWF is performing. 4 08/06 Preflight Guide v. 1.1 Process – Analyzing Weather Information Obtaining weather information is only the first step. The critical next step is to study and evaluate the information to understand what it means for your circumstances. The knowledge tests for most pilot certificates include questions on weather theory and use of weather products in aviation. However, it takes continuous study and experience to develop your skill in evaluating and applying weather data to a specific flight in a GA airplane. You might find it helpful to approach the task of practical, real world weather analysis with several basic concepts in mind. What creates weather? Most pilots can recite the textbook answer -- “uneven heating of the earth’s surface” – but what does that mean when you are trying to evaluate weather conditions for your trip? Let’s take a look. The three basic elements of weather are: • Temperature (warm or cold); • Wind (a vector with speed and direction); and • Moisture (or humidity). Temperature differences (e.g., uneven heating) support the development of low pressure systems, which can affect wide areas. Surface low pressure systems usually have fronts associated with them, with a “front” being the zone between two air masses that contain different combinations of the three basic elements (temperature, wind, and moisture). The illustration shows the “classic” northern hemisphere low pressure system with the associated cold and warm fronts. Remembering that air circulates counterclockwise around a low pressure system in the Northern Hemisphere will help you visualize the overall temperature, wind, and moisture patterns in a given area. Because weather is associated with fronts, which are in turn associated with low pressure systems, you can get some idea of possible conditions just by looking to see where the low pressure systems are in relation to your route. What can weather do to you? Temperature, wind, and moisture combine to varying degrees to create conditions that affect pilots. The range of possible 7 08/06 Preflight Guide v. 1.1 combinations is nearly infinite, but weather really affects pilots in just three ways. Specifically, the three basic weather elements can: • Reduce visibility • Create turbulence • Reduce aircraft performance How do you evaluate weather data? One approach to practical weather analysis is to review weather data in terms of how current and forecast conditions will affect visibility, turbulence, and aircraft performance for your specific flight. Here’s how it works. Suppose you want to make a flight from Cincinnati Municipal Airport (KLUK) to Ohio State University Airport in Columbus, Ohio (KCMH). You want to depart KLUK around 1830Z and fly VFR at 5,500 MSL. Your estimated time enroute (ETE) is approximately one hour. Your weather briefing includes the following information: METARs: KLUK 261410Z 07003KT 3SM -RA BR OVC015 21/20 A3001 KDAY 261423Z 14005KT 3SM HZ BKN050 22/19 A3003 KCMH 261351Z 19005KT 3SM HZ FEW080 BKN100 OVC130 22/17 A3002 TAFs KLUK 261405Z 261412 00000KT 3SM BR BKN015 TEMPO 1416 2SM -SHRA BR FM1600 14004KT 5SM BR OVC035 TEMPO 1618 2SM -SHRA BR BKN015 FM1800 16004KT P6SM BKN040 FM0200 00000KT 5SM BR BKN025 TEMPO 0912 2SM BR BKN018 KDAY 261303Z 261312 06003KT 5SM BR SCT050 OVC100 TEMPO 1315 2SM -RA BR BKN050 FM1500 15006KT P6SM BKN050 TEMPO 1519 4SM -SHRA BR BKN025 FM1900 16007KT P6SM BKN035 FM0200 14005KT 5SM BR BKN035 FM0600 14004KT 2SM BR BKN012 KCMH 261406Z 261412 19004KT 4SM HZ SCT050 BKN120 FM1800 17006KT P6SM BKN040 TEMPO 1922 4SM -SHRA BR FM0200 15005KT 5SM BR BKN035 FM0700 14004KT 2SM BR BKN012 WINDS ALOFT 3000 6000 9000 12000 15000 18000 21000 24000 27000 CMH 1910 2108+15 2807+10 2712+05 2922-07 2936-17 294532 294540 313851 CVG 2310 2607+16 2811+11 2716+06 3019-05 2929-16 293430 293240 293652 8 08/06 Preflight Guide v. 1.1 Remember that you have the option of getting this information in “plain English” format if you prefer not to decode. Whichever format you select, the first step is to look at your weather data in terms of three specific ways that weather can affect your flight: turbulence, visibility, and aircraft performance. Organize the information into tables such as the one below, (see Appendix 5 for blank forms). This kind of format allows you to see and make “apples-to-apples” comparisons more easily. The column headings in the top row – arranged to match the order in which the briefing information is presented – can help you quickly identify the specific weather hazard(s) you might face on this trip. You may also find it helpful to convert Zulu (UTC) times to local time, and to write note expected ETAs for each waypoint on your flight plan. Using the Cincinnati (KLUK) to Columbus (KCMH) trip as example: CURRENT CONDITIONS Turbulence Ceiling & Visibility Visibility & Performance Trends Place Time Wind Visibility Weather Ceiling Temp/Dewpt Altimeter KLUK 1410Z 07003KT 3SM RA, BR OVC015 21/20 A3001 KDAY 1432Z 14005KT 3SM HZ BKN050 22/19 A3003 KCMH 1351Z 19005KT 3SM HZ FEW080, OVC130 22/17 A3002 FORECAST CONDITIONS Turbulence Ceiling & Visibility Place Time Wind Visibility Weather Ceiling KLUK FM1800Z 16004KT P6 SM BKN040 TEMPO 1519Z -- 4SM -SHRA BKN025 KDAY FM1900Z 16007KT P6 SM -- BKN035 FM1800Z 17006KT P6 SM -- BKN040 KCMH TEMPO 1922Z -- 4SM -SHRA, BR -- WINDS ALOFT Turbulence Visibility & Performance Place Altitude Wind Temp CVG 6000 260/07 16 C CMH 6000 210/08 15 C 9 08/06 Preflight Guide v. 1.1 Know the minimum safe altitude for each segment of your flight. All VFR sectional charts include a maximum elevation figure (MEF) in each quadrangle. The MEF is determined by locating the highest obstacle (natural or man-made) in each quadrangle, and rounding up by 100 to 300 feet. Charts for IFR navigation include a Minimum Enroute Altitude (MEA) and a Minimum Obstruction Clearance Altitude (MOCA). Jeppesen charts depict a Minimum Off Route Altitude (MORA), while FAA/NACO charts show an Off Route Obstruction Clearance Altitude (OROCA) that guarantees a 1,000-foot obstacle clearance in non- mountainous terrain and a 2,000 foot obstacle clearance in mountainous terrain. In addition to these sources, many GPS navigators (both panel-mount and handheld) include a feature showing the Minimum Safe Altitude (MSA), Enroute Safe Altitude (ESA), or Minimum Enroute Altitude (MEA) relative to the aircraft’s position. If you have access to such equipment, be sure you understand how to access and interpret the information about safe altitudes. The Air Safety Foundation’s Terrain Avoidance Plan is another helpful resource. Passenger Plan: A number of GA weather accidents have been associated with external or social pressures, such as the pilot’s reluctance to appear “cowardly” or to disappoint passengers eager to make or continue a trip. There is almost always pressure to launch, and pressure to continue. Even the small investment in making the trip to the airport can create pressure to avoid “wasted” time. For this reason, your weather planning should include preflighting your passengers (and anyone waiting at your destination) as well as your aircraft. If you jointly plan for weather contingencies and brief your passengers before you board the aircraft, you as the pilot will be less vulnerable later on to the pressure to continue in deteriorating weather conditions. Suggestions: DO use the worksheet in Appendix 4 to develop personal minimums that will help you make the toughest go / no-go and continue / divert decisions well in advance of any specific flight. DO be aware that the presence of others can influence your decision-making and your willingness to take risks, and let your passengers know up front that 12 08/06 Preflight Guide v. 1.1 safety is your top priority. Share your personal minimums with your passengers and anyone who might be waiting for you at the destination. DO establish “weather check” checkpoints every 25-30 nm along the route, at which you will reevaluate conditions. If possible, have your passengers assist by tracking progress and conditions at each weather checkpoint. DO use your pre-established personal minimums to determine exactly what conditions will trigger a diversion at any given weather checkpoint. Let your passengers know what these conditions are. DO decide specifically what you will do if you have to divert at any particular point, and inform your passengers of these plans. Preflight is the time to make alternative arrangements (e.g., hotel and rental car reservations) in the event that weather conditions worsen. You can always put passengers (or yourself) on an airliner if you absolutely have to return on time. DO advise anyone meeting you at your destination that your plans are flexible and that you will call them when you arrive. Be sure that they too understand that safety is your top priority, and that you will delay or divert if weather becomes a problem. DO remember that one of the most effective safety tools at your disposal is waiting out bad weather. Bad weather (especially involving weather fronts) normally does not last long, and waiting just a day can often make the difference between a flight with high weather risk and a flight that you can make safely. 13 08/06 Preflight Guide v. 1.1 In-flight Decision-Making Perceive – Obtaining In-flight Weather Information Many times, weather is not forecast to be severe enough to cancel the trip, so pilots often choose to take off and evaluate the weather as they go. While it is not necessarily a bad idea to take off and take a look, staying safe requires staying alert to weather changes. GA pilots and their aircraft operate in (rather than above) most weather. At typical GA aircraft speeds, making a 200-mile trip can leave a two to three hour weather information gap between the preflight briefing and the actual flight. In-flight updates are vital! Let’s take a closer look at in-flight weather data sources. Visual Updates. One of the most important things you can do is to look outside. Use your eyes to survey the weather and literally see whether the conditions around you match the conditions that were reported or forecast. Sometimes there are local deviations in weather conditions (isolated cells, fog, etc.) that may not be immediately known to the FSS specialist or that may not appear on weather-product depictions, especially if there is no weather-reporting capability at your departure point. Even if you looked at radar during your preflight briefing process, remember that NEXRAD data is at least 8 minutes old by the time you see it on a display, and older still by the time you are ready to depart. Weather can change very rapidly. ATIS/ASOS/AWOS. One of the easiest ways to monitor conditions en route is to listen to ATIS and ASOS/AWOS broadcasts along your route. These broadcasts can help you update and validate preflight weather information about conditions along your route of flight. Enroute Flight Advisory Service (EFAS, or Flight Watch). Available on 122.0 in the continental United States from 5,000 AGL to 17,500 MSL, EFAS, addressed as Flight Watch, is a service specifically designed to provide en route aircraft with timely and meaningful weather advisories pertinent to the type of flight intended, route of flight, and altitude. If you are in contact with ATC, request permission to leave the frequency to contact EFAS. Provide your aircraft identification and the name of the VOR nearest to your position. 14 08/06 Preflight Guide v. 1.1 Awareness is important in overcoming these challenges, but you can also develop your visual interpretation skills. Appendix 8 provides tips and techniques you can use to estimate in-flight visibility and cloud clearance, thus enhancing your ability to evaluate in-flight weather conditions accurately. ATIS/ASOS/AWOS. In-flight weather information obtained from ATIS and ASOS/AWOS broadcasts can contribute useful pieces to the en route weather picture, but it is important to understand that this information is only a weather “snapshot” of a limited area. ATIS and ASOS/AWOS broadcasts are primarily intended to provide information on conditions in the airport vicinity. The information reported is derived from an array of sensors. While these systems are designed to be as accurate as possible and are increasingly sophisticated, the automated system is actually monitoring only a very small area on the airfield and that it reports only what it can "see." For example, sensors that measure visibility are actually measuring a section of air less than 24 inches wide. Even a dense fog on a portion of the airfield will go undetected by the system unless the fog actually obscures the sensors. The system will not “see” an approaching thunderstorm until it is almost directly over the automated site’s ceiling instruments. EFAS. Assuming that you do find or suspect deteriorating conditions while en route, be sure to contact the En route Flight Advisory Service (EFAS – Flight Watch) for additional information. EFAS can be an immensely helpful resource, but interpreting and applying the information you receive while you are also flying the aircraft – especially if you are in adverse or deteriorating conditions with no autopilot – can be very challenging. The key is understanding where the weather is in relation to your position and flight path, where it is going, and how fast it is moving. A good practice is to have an aeronautical chart with your route clearly marked readily available before you call Flight Watch. The chart will help you visualize where the weather conditions are in relation to your current position and intended route of flight, and determine whether (and where) you need to deviate from the original plan. Another interpretation useful tool is the In-flight Advisory Plotting Chart (figure 7- 1-2 in Chapter 7 of the Aeronautical Information Manual (AIM)). This chart includes the location and identifier for VORs and other locations used to describe hazardous weather areas. Consider keeping copies of this chart in your flight bag for easy reference whenever you call EFAS. ATC. ATC radar can detect areas of precipitation, but does not detect clouds or turbulence. The existence of turbulence may be implied by the intensity of a precipitation return: the stronger the return, the more likely the presence of 17 08/06 Preflight Guide v. 1.1 turbulence. Similarly, icing may be inferred by the presence of moisture, clouds, and precipitation at temperatures at or below freezing. ARTCC facilities and many of the terminal approach control facilities now have digital radar display systems with processors that can better determine the intensity (dBZ) of radar weather echoes and display that information to the controller. Consequently, approach controllers, center controllers, and AFSS specialists have all begun using four terms to describe weather radar echoes to pilots: “light,” “moderate,” “heavy,” and “extreme.” Each term represents a precipitation intensity level paired with a decibel (dBZ) range to help pilots interpret the severity of the flight conditions present. (Note: A dBZ is a measure of radar reflectivity in the form of a logarithmic power ratio with respect to radar reflectivity factor “Z.”) Although the terms are consistent, there are still some equipment-related differences in what can be described. In Air Route Traffic Control Centers, NEXRAD data is fed through the Weather and Radar Processor (WARP), which organizes 16 NEXRAD levels into four reflectivity (dBZ) categories. Reflectivity returns of less than 30 dBZ are classified as “LIGHT” and are filtered out of the center controllers’ display, which means that center controllers cannot report areas of “light” weather radar echoes. A terminal radar approach control has neither NEXRAD nor WARP, so weather radar echoes are displayed by the Airport Surveillance Radar (ASR) systems using Common Automated Radar Terminal System (Common ARTS) or Standard Terminal Automation Replacement System (STARS) digital weather processors. Paired with a weather processor, digitized ASR 9 and 11 systems display the four weather radar echo intensity categories to the controller. Terminal radar approach control facilities can, and do, display “light” (less than 30 dBZ) areas of precipitation. Not all terminal facilities have digitized systems, however, and systems without digital processors cannot discern radar echo intensity. In these cases, ATC can describe the position of weather radar echoes, but will state “intensity unknown” instead of using the terms, “light,” “moderate,” “heavy,” or “extreme.” A critical element in interpreting weather information from ATC is a thorough understanding of pilot-controller communications. Be sure to review the AIM Pilot/Controller Glossary, and clarify points you do not understand. Datalink and Weather Avoidance Equipment. When analyzing this information, it is vital to remember that the quality of the information depends heavily upon 18 08/06 Preflight Guide v. 1.1 update rate, resolution, and coverage area. When flying an aircraft that has datalink equipment, safe and accurate interpretation of the information you receive depends on your understanding of each of these parameters. Datalink does not provide real-time information. Although weather and other navigation displays can give pilots an unprecedented quantity of high quality weather data, their use is safe and appropriate only for strategic decision making (attempting to avoid the hazard altogether). Datalink is not accurate enough or current enough to be safely used for tactical decision making (negotiating a path through a weather hazard area, such as a broken line of thunderstorms). Be aware that onboard weather equipment can inappropriately influence your decision to continue a flight. No matter how “thin” a line of storms appears to be, or how many “holes” you think you see on the display, it is not safe to fly through them. 19 08/06 Preflight Guide v. 1.1 Post-Flight Weather Review When you land after a challenging flight in the weather, you may want nothing more than to go home and unwind. The immediate post flight period, however, is one of the best opportunities to increase your weather knowledge and understanding. Studies show that pilots sometimes fly into bad weather simply because they lack relevant experience, and thus did not recognize that certain weather “cues” might create a safety hazard to the flight. Make it a point to learn something from every weather encounter. At the end of a flight involving weather, take a few minutes to mentally review the flight you just completed and reflect on what you learned from this experience. To guide your post flight weather review: What weather conditions/hazards existed, and how did they impact this flight? Turbulence / Winds __________________________________________ Ceilings / Visibility __________________________________________ Aircraft Performance _________________________________________ How did the conditions encountered during this flight compare with the information obtained in the preflight briefing? Which source(s) of preflight weather information provided the best (or most useful, most accurate, most relevant) data for this flight? Which source(s) of en route weather information provided the best (or most useful, most accurate, most relevant) data for this flight? Another way to develop your weather experience and judgment is simply to observe and analyze the weather every day. When you look out the window or go outside, observe the clouds. What are they doing? Why are they shaped as they are? Why is their altitude changing? This simple habit will help you develop the ability to “read” clouds, and understand how shape, color, thickness, and altitude can be valuable weather indicators. As your cloud-reading skill develops, start trying to correlate the temperature, dew point, humidity, and time of day to the types of clouds that have formed. Take note of the wind and try to visualize how it wraps around the tree or whips around the corner of a building. This exercise will help you become more aware of wind at critical points in your flight. Weather is a fact of life for pilots. Developing your weather knowledge and expertise is well worth the time and effort you put into it, because weather wisdom will help keep you – and your passengers – safe in the skies. 22 08/06 Preflight Guide v. 1.1 Resources Appendix 1 Weather Products and Weather Providers Chart Appendix 2 Items for Standard Briefing Appendix 3 Automated Weather Observing Systems Appendix 4 Developing Personal Weather Minimums Appendix 5 Aviation Weather Analysis Worksheets Appendix 6 Weather Analysis Checklist - VFR Appendix 7 Weather Analysis Checklist - IFR Appendix 8 Estimating In-flight Visibility and Cloud Clearance 23 08/06 Preflight Guide v. 1.1 Appendix 1 Weather Products and Weather Providers The table below lists some of the most common weather products and providers: So ur ce AC (S ev er e W x O ut lo ok ) AI R M ET / SI G M ET ch ar ts , C on ve ct iv e ou tlo ok ch ar ts , Pr og . ch ar ts , R ad ar (N EX R AD ) ch ar ts , R ad ar s um m ar y ch ar ts , S ur fa ce a na ly si s C en te r W ea th er A dv is or y (A TC ) ch ar ts , W ea th er d ep ic tio n FA (1 8- hr a re a fo re ca st ) FD (w in ds /te m ps a lo ft fo re ca st ) FD (w in ds /te m ps a lo ft fo re ca st ) M ET AR PI R EP Sa te llit e SD (h ou rly ra da r) TA Fs TW EB Format: T = text; G = Graphic. Text may be written or spoken. Preflight T T G G G G G T G T T G T T G T T T Commercial vendor Search Internet for "commercial weather products." Public NWS or NOAA site X X X X X X X X X X X X X ADDS (aviation digital data) X X X X X X X X X X X X X X X X X DUATS X X X X X X X X X X X FSS (automated TIBS) Short automated briefing, origin & radius, advisories & summary, ceil, vis, w. easy link to FS Specialist FSS (standard) FSS (abbreviated) FSS (outlook) The Weather Channel X X X En route cockpit avionics products vary EFAS HIWAS X X X TWEB Short automated synopsis, origin & radius, wx advisories, ceil, vis, winds, radar, PIREPS, alerts Both ASOS ATIS AWOS CWA Verbal synopsis of all available information Short, verbal synopsis, based on all available information Short, verbal forecast based on all available information Short, verbal synopsis, based on all available information Verbal synopsis, based on all available information ASOS, ATIS, AWOS are similar to METAR, incl. Place, Time, Wind direction/speed, Visibility, Ceiling, Temp/Dewpoint, Altimeter (NOTE: Products directly accessible to the user are marked with an “X.”) ADDS Aviation Digital Data Service (ADDS) (http://adds.aviationweather.noaa.gov/) ASOS Automated Surface Observing System ATIS Automated Terminal Information Service AWOS Automated Weather Observing System CWA Center Weather Advisory DUATS Direct User Access Terminal System EFAS En route Flight Advisory System FSS Flight Service Station HIWAS Hazardous In-flight Weather Advisory System LLWAS Low Level Wind Shear Alert System NOAA National Oceanic and Atmospheric Association NWS National Weather Service TIBS Telephone Information Broadcast Service TWEB Transcribed Weather Broadcast 24 08/06 If you are facing: Adjust baseline personal minimums to: Pilot Illness, medication, stress, or fatigue; lack of currency (e.g., haven’t flown for several weeks) A d d At least 500 feet to ceiling At least ½ mile to visibility Aircraft An unfamiliar airplane, or an aircraft with unfamiliar avionics/ equipment: At least 500 ft to runway length enVironment Airports and airspace with different terrain or unfamiliar characteristics S u b t r a c t At least 5 knots from winds External Pressures “Must meet” deadlines, passenger pressures; etc. Baseline Personal Minimums Weather Condition VFR MVFR IFR LIFR Ceiling Day Night Visibility Day Night Turbulence SE ME Make/Model Surface Wind Speed Surface Wind Gust Crosswind Component Performance SE ME Make/Model Shortest runway Highest terrain Highest density altitude 30 Weather Decision-Making Guide v. 1.1 Aug06 Federal Aviation Administration Getting the Maximum from Personal Minimums Step 1 – Review Weather Minimums Step 2 – Assess Your Experience and Personal Comfort Level Step 3 – Consider Other Conditions Step 4 – Assemble and Evaluate Step 5 – Adjust for Specific Conditions Step 6 – Stick to the Plan! Category Ceiling Visibility VFR greater than 3,000 feet AGL and greater than 5 miles Marginal VFR 1,000 to 3,000 feet AGL and/or 3 to 5 miles IFR 500 to below 1,000 feet AGL and/or 1 mile to less than 3 miles LIFR below 500 feet AGL and/or less than 1 mile 27 Weather Decision-Making Guide v. 1.1 Aug06 Think of personal minimums as the human factors equivalent of reserve fuel. Personal minimums should be set so as to provide a solid safety buffer between the skills required for the specific flight you want to make, and the skills available to you through training, experience, currency, and proficiency. CERTIFICATION LEVEL Certificate level (e.g., private, commercial, ATP) Ratings (e.g., instrument, multiengine) Endorsements (e.g., complex, high performance, high altitude) TRAINING SUMMARY Flight review (e.g., certificate, rating, Wings) Instrument Proficiency Check Time since checkout in airplane 1 Time since checkout in airplane 2 Time since checkout in airplane 3 Variation in equipment (e.g., GPS navigators, autopilot) EXPERIENCE Total flying time Years of flying experience RECENT EXPERIENCE (last 12 months) Hours Hours in this airplane (or identical model) Landings Night hours Night landings Hours flown in high density altitude Hours flown in mountainous terrain Crosswind landings IFR hours IMC hours (actual conditions) Approaches (actual or simulated) Review and record your certification, training, and recent experience history on the chart below. 28 Weather Decision-Making Guide v. 1.1 Aug06 Experience & “Comfort Level” Assessment Combined VFR & IFR Weather Condition VFR MVFR IFR LIFR Ceiling Day Night Visibility Day Night Summarize values for weather experience and “comfort level” in the chart below, and enter values for turbulence & performance. Experience & “Comfort Level” Assessment Wind & Turbulence SE ME Make/ Model Turbulence Surface wind speed Surface wind gusts Crosswind component Experience & “Comfort Level” Assessment Performance Factors SE ME Make/ Model Performance Shortest runway Highest terrain Highest density altitude 29 Weather Decision-Making Guide v. 1.1 Aug06 Preflight Guide v. 1.1 Appendix 5 Aviation Weather Analysis Forms CURRENT CONDITIONS (from METARs) Turbulence Ceiling & Visibility Visibility & Performance Trends Place Time Wind Visibility Weather Ceiling Temp/Dewpt Altimeter FORECAST CONDITIONS (from TAFs) Turbulence Ceiling & Visibility Place Time Wind Visibility Weather Ceiling WINDS ALOFT Turbulence Visibility & Performance Place Altitude Wind Temp 31 08/06 Preflight Guide v. 1.1 Appendix 7 Weather Analysis Checklist – IFR Flight Ceiling and Visibility Is the forecast ceiling for my estimated time of arrival high enough to make the approach? What visibility can I expect for each phase of flight (departure, enroute, destination)? --Will I have enough visibility to legally make an instrument approach at the destination? --Do current or forecast ceiling and visibility conditions require me to select and file an alternate? (1-2-3 rule.) --Where is the nearest GOOD weather alternative? How do reported and forecast conditions for ceiling and visibility compare with my personal minimums for IFR? Aircraft Performance Given temperature, altitude, density altitude, and aircraft loading, what is the expected aircraft performance? o Takeoff distance o Time & distance to climb o Cruise performance o Landing distance Are these performance values sufficient for the runways to be used and the terrain to be crossed on this flight? (Remember that it is always good practice to add a 50% to 100% safety margin to the “book numbers” you derive from the charts in the aircraft’s approved flight manual (AFM)). Will weight restrictions allow me to carry more than the normal fuel reserve? (More fuel means that you have more options to escape weather.) Icing. What is the forecast freezing level for this flight? o Are there any pilot reports (PIREPS) for my route, or points on the route that support or rebut the icing forecast? o Where are the cloud bases and cloud tops? Turbulence Are the wind conditions at the departure and destination airports within the gust and crosswind capabilities of both the pilot and aircraft? What is the maneuvering speed (VA) for this aircraft at the expected weight? (Remember that VA is lower if you are flying at less than maximum gross weight.) Thunderstorms. Does the forecast include convective activity at any point along my proposed route? 34 08/06 Turbulence Ceiling & Visibility Visibility & Performance Trends Place Time Wind Visibility Weather Ceiling Temp/Dewpt Altimeter ___________ ground clearance- Lowest en route ceiling = ______ Planned altitude = _____________ - Highest en route obstacle =_____ Planned altitude = _____________ ___________ clearance - Highest en route terrain =______ Planned altitude = _____________ ___________ clearance Over mountainous terrain ? Yes No Over large bodies of water ? Yes No Ceiling and Visibility Analysis Departure visibility = ________________ Lowest en route visibility = ___________ Destination visibility = _______________ Personal IFR Approach Minimums: Ceiling = __________ Visibility = _________ Turbulence Analysis IFR Analysis Worksheet Performance Analysis Density altitude = _____________ Freezing level = ______________ Takeoff distance = ____________ Runway length = _____________ Landing distance = ____________ Runway length = _____________ Cruise performance = _________ Fuel available = ____gal____hrs Fuel required = ____gal____hrs Fuel reserve = ____gal____hrs Note: It is good practice to add a 50% to 100% safety margin to the “book numbers” you derive from charts in the approved flight manual (AFM). Personal Minimums: Wind speed = ______ Gust factor = _______ Crosswind = _______ Departure wind = ______@_______ Destination wind = _____@_______ En route wind = _______@_______ Maneuvering speed = ___________* * VA decreases as weight decreases T-storms forecast? Yes No Cloud bases = _______ Cloud tops = ________ Alternate required ? Yes No Convective SIGMETS? Yes No Nearest VFR Weather Direction: N S E W Distance: ____ nm Flying time to nearest good VFR:_______ 35 Preflight Guide v. 1.1 Appendix 8 Estimating In-flight Visibility & Cloud Clearance There are a number of ways to develop your skill in estimating your in-flight visibility and cloud clearance. These techniques will help you establish a continuous weather assessment habit. It will also help you calibrate your perceptions and learn when to trust what you see. Listen to the ATIS or ASOS/AWOS as you pass near an airport. First try to evaluate the basic weather conditions based on what you see. Then listen to the ATIS or ASOS/AWOS and compare the official report to your own evaluation of conditions, as well as with any previous reports you have seen from this location. Use the length of a runway you pass in flight to estimate distances. o A runway that is 5,300 feet long is about a mile. Look to see how far ahead you can see, and estimate the number of runways that it would take to cover that distance. o A 2,600 foot runway would be about a half mile, and so on. In this case, visibility is less than 3 miles if you cannot see 6 runway lengths ahead. If you know your aircraft’s groundspeed, you can estimate distance. Look to the most distant point you can see ahead and then time how long it takes to reach it. o If, for example, your ground speed is 105 knots, that’s about 120 mph and you’ll cover about 2 miles per minute. If you reach the point in less than 90 seconds, the in-flight visibility is less than 3 miles! o A simple variation on this technique it to use GPS or DME while flying directly to or from a waypoint or VOR. Just look at the beginning and ending mileage on the GPS or DME to see how far you’ve flown to reach the farthest point you can see. If you need to know the lateral distance to a cloud, start timing when the cloud is ahead of you and at about a 45° angle (halfway between your 10 and 11 o’clock or between your 1 and 2 o’clock positions). Stop timing when the cloud is off your wingtip. The distance you’ve traveled forward will now be equal to the distance between you and the cloud. If you were traveling at 120 mph, it will take you about 11 seconds to travel 2000 feet. If the cloud took less than 11 seconds to arrive off your wingtip, you are now less than 2000 feet horizontally from that cloud. (courtesy of Max Trescott, SJ Flight) 36 08/06