A well-planned flight is always your first-class ticket to the safest flight. Show Before even lifting off, you need to take the time to plan your journey. This includes the:
In the first episode of the Out-n-Back series, we take you through the fundamentals of flight planning. This includes pre-flight discipline, dress rehearsals and important resources to plan a safe and fun trip.
Taking the time to complete an accurate Weight and Balance sheet can mean the difference of a successful or failed flight. Never be shy to ask your passengers their weight. Explain to them the reasons why you need to know their accurate weight. Passengers will rarely lie once you explain the reasons. Remember to also explain maximum luggage of 7 kgs is the total. This means the total needs to include additional luggage such as coats, backpacks, and their kilo of snacks. Passenger expectations and itineraryAs pilot in command, you have an absolute right and legal responsibility to take necessary measures to ensure a safe flight. Talk to your passengers about the itinerary and set expectations with passengers early on. Explain to them that during the flight there may be changes to timings, routes, and whether it’s safe to take-off. This makes in-flight decisions easy, timely and rational. Dress rehearsalIt’s normal to feel a little apprehensive about that first day’s flying especially if you haven’t planned a long flight for some time. The best preparation can include a dress rehearsal while sitting at your desk. Gather the first couple of maps and go through the planned flight, step by step. During a dress rehearsal you can also:
Another good tip is to practice radio calls in the car on your way to the aerodrome. Planning for weatherThink about what you're going to do if the weather turns within the first half hour of take-off. What’s your Plan B? Fly over lower terrain or away from the bad weather? You should always consider delaying or cancelling the flight if you find yourself in these circumstances. Don't fall into the trap of 'get-there-itis'. Many pilots agree that you make fewer rational decisions concerning weather during the halfway point in the journey. The urge to reach your destination can sway you towards ill-fated decisions. Closer to departure, and with your personal checklist taken care of, it’s now time to cover all bases with a pre-flight briefing. CASA and Airservices Australia have resources that can guide you through preparing for your flight. En-route Supplement Australia (ERSA)In the weeks leading up to your safari, take some time to read through these useful sections in ERSA:
Airservices has a range of instructional videos to help pilots plan their flights via the NAIPS Internet Services (NIS). Take some time to watch these videos and refresh your memory on the correct methods.
 AIM 4/3/14 7−1−7 Meteorology NOTE − 1. For the purpose of this paragraph, SUA and relatedairspace includes the following types of airspace: alertarea, military operations area (MOA), warning area, andair traffic control assigned airspace (ATCAA). MTR dataincludes the following types of airspace: IFR trainingroutes (IR), VFR training routes (VR), and slow training routes (SR). 2. Pilots are encouraged to request updated information (b) A review of the Notices to Airmen Publication for pertinent NOTAMs and Special Notices. (c) Approximate density altitude data. (d) Information regarding such items as air traffic services and rules, customs/immigration procedures, ADIZ rules, search and rescue, etc. (e) GPS RAIM availability for 1 hour before to 1 hour after ETA or a time specified by the pilot. (f) Other assistance as required. c. Abbreviated Briefing. Request an Abbrevia- ted Briefing when you need information to supplement mass disseminated data, update a previous briefing, or when you need only one or two specific items. Provide the briefer with appropriate background information, the time you received the previous information, and/or the specific items needed. You should indicate the source of the information already received so that the briefer can limit the briefing to the information that you have not received, and/or appreciable changes in meteorologi- cal/aeronautical conditions since your previous briefing. To the extent possible, the briefer will provide the information in the sequence shown for a Standard Briefing. If you request only one or two specific items, the briefer will advise you if adverse conditions are present or forecast. (Adverse condi- tions contain both meteorological and/or aeronautical information.) Details on these conditions will be provided at your request. International data may be inaccurate or incomplete. If you are planning a flight outside of U.S. controlled airspace, the briefer will advise you to check data as soon as practical after entering foreign airspace, unless you advise that you have the international cautionary advisory. d. Outlook Briefing. You should request an Outlook Briefing whenever your proposed time of departure is six or more hours from the time of the briefing. The briefer will provide available forecast data applicable to the proposed flight. This type of briefing is provided for planning purposes only. You should obtain a Standard or Abbreviated Briefing prior to departure in order to obtain such items as adverse conditions, current conditions, updated forecasts, winds aloft and NOTAMs, etc. e. When filing a flight plan only, you will be asked if you require the latest information on adverse conditions pertinent to the route of flight. f. Inflight Briefing. You are encouraged to obtain your preflight briefing by telephone or in person before departure. In those cases where you need to obtain a preflight briefing or an update to a previous briefing by radio, you should contact the nearest FSS to obtain this information. After communications have been established, advise the specialist of the type briefing you require and provide appropriate background information. You will be provided information as specified in the above paragraphs, depending on the type of briefing requested. In addition, the specialist will recommend shifting to the Flight Watch frequency when conditions along the intended route indicate that it would be advantageous to do so. Remember that weather conditions can change rapidly and that a “go or no go” decision, as mentioned in paragraph 7−1−4b2, should be assessed at all phases of flight. g. Following any briefing, feel free to ask for any information that you or the briefer may have missed or are not understood. This way, the briefer is able to present the information in a logical sequence, and lessens the chance of important items being overlooked. 7 − 1 − 5. En Route Flight Advisory Service (EFAS) a. EFAS (radio call “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. In conjunction with this service, EFAS is also a central collection and distribution point for pilot reported weather information. EFAS is provided by specially trained FSS specialists controlling multiple Remote Communications Outlets covering a large geographical area and is normally available throughout the conterminous U.S. and Puerto Rico from 6 a.m. to 10 p.m. EFAS provides communica- Page 2
AIM 4/3/14 7−1−8 Meteorology tions capabilities for aircraft flying at 5,000 feet above ground level to 17,500 feet MSL on a common frequency of 122.0 MHz. Discrete EFAS frequencies have been established to ensure communications coverage from 18,000 through 45,000 MSL serving in each specific ARTCC area. These discrete frequencies may be used below 18,000 feet when coverage permits reliable communication. NOTE − When an EFAS outlet is located in a time zone different fromthe zone in which the flight watch control station is located,the availability of service may be plus or minus one hour from the normal operating hours. b. In some regions of the contiguous U.S., especially those that are mountainous, it is necessary to be above 5000 feet AGL in order to be at an altitude where the EFAS frequency, 122.0 MHz, is available. Pilots should take this into account when flight planning. Other FSS communication frequencies may be available at lower altitudes. See FIG 7−1−2. c. Contact flight watch by using the name of the ARTCC facility identification serving the area of your location, followed by your aircraft identifica- tion, and the name of the nearest VOR to your position. The specialist needs to know this approximate location to select the most appropriate transmitter/receiver outlet for communications coverage. EXAMPLE − Cleveland Flight Watch, Cessna One Two Three Four Kilo, −O−R, over. d. Charts depicting the location of the flight watch control stations (parent facility) and the outlets they use are contained in the A/FD. If you do not know in which flight watch area you are flying, initiate contact by using the words “Flight Watch,” your aircraft identification, and the name of the nearest VOR. The facility will respond using the name of the flight watch facility. EXAMPLE − Flight Watch, Cessna One Two Three Four Kilo, −O−R, over. e. Radio outlets that provide En Route Flight Advisory Service are listed regionally in the A/FDs. f. EFAS is not intended to be used for filing or closing flight plans, position reporting, getting complete preflight briefings, or obtaining random weather reports and forecasts. En route flight advisories are tailored to the phase of flight that begins after climb-out and ends with descent to land. Immediate destination weather and terminal aero- drome forecasts will be provided on request. Pilots requesting information not within the scope of flight watch will be advised of the appropriate FSS frequency to obtain the information. Pilot participa- tion is essential to the success of EFAS by providing a continuous exchange of information on weather, winds, turbulence, flight visibility, icing, etc., between pilots and flight watch specialists. Pilots are encouraged to report good weather as well as bad, and to confirm expected conditions as well as unexpected to EFAS facilities. 7 − 1 − 6. Inflight Aviation Weather Advisories a. Background 1. Inflight Aviation Weather Advisories are forecasts to advise en route aircraft of development of potentially hazardous weather. All inflight aviation weather advisories in the conterminous U.S. are issued by the Aviation Weather Center (AWC) in Kansas City, Missouri. The Weather Forecast Office (WFO) in Honolulu issues advisories for the Hawaiian Islands. In Alaska, the Alaska Aviation Weather Unit (AAWU) issues inflight aviation weather advisories. All heights are referenced MSL, except in the case of ceilings (CIG) which indicate AGL. 2. There are three types of inflight aviation weather advisories: the SIGMET, the Convective SIGMET, and the AIRMET (text or graphical product). All of these advisories use the same location identifiers (either VORs, airports, or well−known geographic areas) to describe the hazardous weather areas. See FIG 7−1−3 and FIG 7−1−4. Graphics with improved clarity can be found in the latest version of Advisory Circular AC 00−45 series, Aviation Weath- er Services, which is available on the following Web site: http://www.faa.gov. 3. Two other weather products supplement these Inflight Aviation Weather Advisories: (a) The Severe Weather Watch Bulle- tins (WWs), (with associated Alert Messages) (AWW), and (b) The Center Weather Advisories (CWAs). b. SIGMET (WS)/AIRMET (WA or G −AIRMET) Page 3
AIM 4/3/14 7−1−9 Meteorology SIGMETs/AIRMET text (WA) products are issued corresponding to the Area Forecast (FA) areas described in FIG 7−1−5, FIG 7−1−6 and FIG 7−1−7. The maximum forecast period is 4 hours for SIGMETs and 6 hours for AIRMETs. The G−AIRMET is issued over the CONUS every 6 hours, valid at 3−hour increments through 12 hours with optional forecasts possible during the first 6 hours. The first 6 hours of the G−AIRMET correspond to the 6−hour period of the AIRMET. SIGMETs and AIRMETs are considered “wide- spread” because they must be either affecting or be forecasted to affect an area of at least 3,000 square miles at any one time. However, if the total area to be affected during the forecast period is very large, it could be that in actuality only a small portion of this total area would be affected at any one time. c. SIGMET (WS) 1. A SIGMET advises of non−convective weather that is potentially hazardous to all aircraft. SIGMETs are unscheduled products that are valid for 4 hours. However, conditions that are associated with hurricanes are valid for 6 hours. Unscheduled updates and corrections are issued as necessary. In the conterminous U.S., SIGMETs are issued when the following phenomena occur or are expected to occur: (a) Severe icing not associated with thunder- storms. (b) Severe or extreme turbulence or clear air turbulence (CAT) not associated with thunderstorms. (c) Widespread dust storms or sandstorms lowering surface visibilities to below 3 miles. (d) Volcanic ash. 2. In Alaska and Hawaii, SIGMETs are also issued for: (a) Tornadoes. (b) Lines of thunderstorms. (c) Embedded thunderstorms. (d) Hail greater than or equal to 3 / 4 inch in diameter. 3. SIGMETs are identified by an alphabetic designator from November through Yankee exclud- ing Sierra and Tango. (Sierra, Tango, and Zulu are reserved for AIRMET text [WA] products; G−AIRMETS do not use the Sierra, Tango, or Zulu designators.) The first issuance of a SIGMET will be labeled as UWS (Urgent Weather SIGMET). Subsequent issuances are at the forecaster’s discre- tion. Issuance for the same phenomenon will be sequentially numbered, using the original designator until the phenomenon ends. For example, the first issuance in the Chicago (CHI) FA area for phenomenon moving from the Salt Lake City (SLC) FA area will be SIGMET Papa 3, if the previous two issuances, Papa 1 and Papa 2, had been in the SLC FA area. Note that no two different phenomena across the country can have the same alphabetic designator at the same time. EXAMPLE − Example of a SIGMET: FLOW. CONDS CONTG BYD 1000Z. d. Convective SIGMET (WST) 1. Convective SIGMETs are issued in the conterminous U.S. for any of the following: (a) Severe thunderstorm due to: (1) Surface winds greater than or equal to 50 knots. (2) Hail at the surface greater than or equal to 3 / 4 inches in diameter. (3) Tornadoes. (b) Embedded thunderstorms. (c) A line of thunderstorms. (d) Thunderstorms producing precipitation greater than or equal to heavy precipitation affecting 40 percent or more of an area at least 3,000 square miles. 2. Any convective SIGMET implies severe or greater turbulence, severe icing, and low−level wind shear. A convective SIGMET may be issued for any convective situation that the forecaster feels is hazardous to all categories of aircraft. Page 4
AIM 4/3/14 7−1−10 Meteorology FIG 7 −1−2 EFAS Radio Coverage Areas NOTE − EFAS radio coverage at 5000 feet AGL. The shaded areas depict limited coverage areas in which altitudes above 5000 feet Page 5
AIM 4/3/14 7−1−11 Meteorology FIG 7 −1−3 Inflight Advisory Plotting Chart Page 6
AIM 4/3/14 7−1−12 Meteorology FIG 7 −1−4 Geographical Areas and Terrain Features Page 7
AIM 4/3/14 7−1−13 Meteorology FIG 7 −1−5 Aviation Area Forecasts FA Locations − Contiguous United States Page 8
AIM 4/3/14 7−1−14 Meteorology FIG 7 −1−6 Alaska Area Forecast Sectors FIG 7 −1−7 Hawaii Area Forecast Locations Page 9
AIM 4/3/14 7−1−15 Meteorology 3. Convective SIGMET bulletins are issued for the western (W), central (C), and eastern (E) United States. (Convective SIGMETs are not issued for Alaska or Hawaii.) The areas are separated at 87 and 107 degrees west longitude with sufficient overlap to cover most cases when the phenomenon crosses the boundaries. Bulletins are issued hourly at H+55. Special bulletins are issued at any time as required and updated at H+55. If no criteria meeting convective SIGMET requirements are observed or forecasted, the message “CONVECTIVE SIGMET... NONE” will be issued for each area at H+55. Individual convective SIGMETs for each area (W, C, E) are numbered sequentially from number one each day, beginning at 00Z. A convective SIGMET for a continuing phenomenon will be reissued every hour at H+55 with a new number. The text of the bulletin consists of either an observation and a forecast or just a forecast. The forecast is valid for up to 2 hours. EXAMPLE − CONVECTIVE SIGMET 44CVALID UNTIL 1455ZAR TX OKFROM 40NE ADM-40ESE MLC-10W TXK-50WNWLFK-40ENE SJT-40NE ADMAREA TS MOV FROM 26025KT. TOPS ABV FL450.OUTLOOK VALID 061455-061855FROM 60WSW OKC-MLC-40N TXK-40WSWIGB-VUZ-MGM-HRV-60S BTR-40NIAH-60SW SJT-40ENE LBB-60WSW OKCWST ISSUANCES EXPD. REFER TO MOST RECENTACUS01 KWNS FROM STORM PREDICTION CENTER FOR SYNOPSIS AND METEOROLOGICAL DETAILS e. International SIGMET 1. Some NWS offices have been designated by the ICAO as Meteorological Watch Offices (MWOs). These offices are responsible for issuing International SIGMETs for designated areas that include Alaska, Hawaii, portions of the Atlantic and Pacific Oceans, and the Gulf of Mexico. 2. The offices which issue international SIGMETs are: (a) The AWC in Kansas City, Missouri. (b) The AAWU in Anchorage, Alaska. (c) The WFO in Honolulu, Hawaii. 3. These SIGMETs are considered “wide- spread” because they must be either affecting or be forecasted to affect an area of at least 3,000 square miles at any one time. The International SIGMET is issued for 6 hours for volcanic ash events, 6 hours for hurricanes and tropical storms, and 4 hours for all other events. Like the domestic SIGMETs, interna- tional SIGMETs are also identified by an alphabetic designator from Alpha through Mike and are numbered sequentially until that weather phenome- non ends. The criteria for an international SIGMET are: (a) Thunderstorms occurring in lines, em- bedded in clouds, or in large areas producing tornadoes or large hail. (b) Tropical cyclones. (c) Severe icing. (d) Severe or extreme turbulence. (e) Dust storms and sandstorms lowering visibilities to less than 3 miles. (f) Volcanic ash. EXAMPLE − Example of an International SIGMET: 022015/030015 KKCI − MIAMI OCEANIC FIR NEW YORK OCEANIC FIR SAN JUAN FIR FRQ TS WI AREABOUNDED BY 2711N6807W 2156N6654W 2220N7040W2602N7208W 2711N6807W. TOPS TO FL470. MOV NE15KT. WKN. BASED ON SAT AND LTG OBS. MOSHER f. AIRMET 1. AIRMETs (WAs) are advisories of signifi- cant weather phenomena but describe conditions at intensities lower than those which require the issuance of SIGMETs. AIRMETs are intended for dissemination to all pilots in the preflight and en route phase of flight to enhance safety. AIRMET information is available in two formats: text bulletins (WA) and graphics (G−AIRMET). Both formats meet the criteria of paragraph 7−1−3i1 and are issued on a scheduled basis every 6 hours beginning at 0245 UTC. Unscheduled updates and corrections are issued as necessary. AIRMETs contain details about IFR, extensive mountain obscuration, turbulence, strong surface winds, icing, and freezing levels. 2. There are three AIRMETs: Sierra, Tango, and Zulu. After the first issuance each day, scheduled Page 10
AIM 4/3/14 7−1−16 Meteorology or unscheduled bulletins are numbered sequentially for easier identification. (a) AIRMET Sierra describes IFR conditions and/or extensive mountain obscurations. (b) AIRMET Tango describes moderate turbulence, sustained surface winds of 30 knots or greater, and/or nonconvective low−level wind shear. (c) AIRMET Zulu describes moderate icing and provides freezing level heights. EXAMPLE − Example of AIRMET Sierra issued for the Chicago FAarea:CHIS WA 131445AIRMET SIERRA UPDT 2 FOR IFR AND MTN OBSCNVALID UNTIL 132100.AIRMET IFR...KY FROM 20SSW HNN TO HMV TO 50ENE DYR TO20SSWHNN CIG BLW 010/VIS BLW 3SM PCPN/BR/FG. CONDSENDG BY 18Z. .AIRMET IFR....MN LSFROM INL TO 70W YQT TO 40ENE DLH TO 30WNW DLH TO 50SE GFK TO 20 ENE GFK TOINL CIG BLW 010/VIS BLW 3SM BR. CONDS ENDG 15 − 18Z. .AIRMET IFR....KSFROM 30N SLN TO 60E ICT TO 40S ICT TO 50WLBL TO 30SSW GLD TO 30N SLNCIG BLW 010/VIS BLW 3SM PCPN/BR/FG. CONDS ENDG 15 −18Z. .AIRMET MTN OBSCN...KY TNFROM HNN TO HMV TO GQO TO LOZ TO HNNMTN OBSC BY CLDS/PCPN/BR. CONDS CONTGBYD 21Z THRU 03Z. ..... EXAMPLE − Example of AIRMET Tango issued for the Salt Lake CityFA area:SLCT WA 131445AIRMET TANGO UPDT 2 FOR TURB VALID UNTIL132100.AIRMET TURB...MT FROM 40NW HVR TO 50SE BIL TO 60E DLN TO60SW YQL TO 40NW HVR MOD TURB BLW 150. CONDS DVLPG 18 −21Z. CONDS CONTG BYD 21Z THRU 03Z..AIRMET TURB....ID MT WY NV UT CO FROM 100SE MLS TO 50SSW BFF TO 20SW BTY TO 40SW BAM TO 100SE MLSMOD TURB BTN FL310 AND FL410. CONDS CONTG BYD 21Z ENDG 21 −00Z. .AIRMET TURB...NV AZ NM CA AND CSTL WTRSFROM 100WSW ENI TO 40W BTY TO 40S LAS TO30ESE TBE TO INK TO ELP TO 50S TUS TO BZATO 20S MZB TO 150SW PYE TO 100WSW ENIMOD TURB BTWN FL210 AND FL380. CONDSCONTG BYD 21Z THRU 03Z. .... EXAMPLE − Example of AIRMET Zulu issued for the San FranciscoFA area:SFOZ WA 131445AIRMET ZULU UPDT 2 FOR ICE AND FRZLVL VALIDUNTIL 132100.NO SGFNT ICE EXP OUTSIDE OF CNVTV ACT.. FRZLVL....RANGING FROM SFC −105 ACRS AREA MULT FRZLVL BLW 080 BOUNDED BY 40SE −60NNW GEG−60SW MLP−30WSW BKE− 20SW BAM −70W BAM−40SW YKM−40E HUH− 40SE YDC −30SSE HUH−60S SEA 50NW LKV −60WNWOAL−30SW OAL 040 ALG 40W HUH −30W HUH−30NNW SEA−40N PDX −20NNW DSD 080 ALG 160NW FOT −80SW ONP−50SSW EUG 40SSE OED −50SSE CZQ−60E EHF−40WSW LAS .... 3. Graphical AIRMETs (G −AIRMETs), found on the Aviation Weather Center webpage at http://aviationweather.gov, are graphical forecasts of en−route weather hazards valid at discrete times no more than 3 hours apart for a period of up to 12 hours into the future (for example, 00, 03, 06, 09, and 12 hours). Additional forecasts may be inserted during the first 6 hours (for example, 01, 02, 04, and 05). 00 hour represents the initial conditions, and the subsequent graphics depict the area affected by the particular hazard at that valid time. Forecasts valid at 00 through 06 hours correspond to the text AIRMET bulletin. Forecasts valid at 06 through 12 hours correspond to the text bulletin outlook. G−AIRMET depicts the following en route aviation weather hazards: (a) Instrument flight rule conditions (ceiling < 1000’ and/or surface visibility <3 miles) (b) Mountain obscuration (c) Icing (d) Freezing level Page 11
AIM 4/3/14 7−1−17 Meteorology (e) Turbulence (f) Low level wind shear (LLWS) (g) Strong surface winds G−AIRMETs are snap shots at discrete time intervals as defined above. The text AIRMET is the result of the production of the G−AIRMET but provided in a time smear for a 6hr valid period. G−AIRMETs provide a higher forecast resolution than text AIRMET products. Since G−AIRMETs and text AIRMETs are created from the same forecast “production” process, there exists perfect consist- ency between the two. Using the two together will provide clarity of the area impacted by the weather hazard and improve situational awareness and decision making. Interpolation of time periods between G−AIRMET valid times: Users must keep in mind when using the G−AIRMET that if a 00 hour forecast shows no significant weather and a 03 hour forecast shows hazardous weather, they must assume a change is occurring during the period between the two forecasts. It should be taken into consideration that the hazardous weather starts immediately after the 00 hour forecast unless there is a defined initiation or ending time for the hazardous weather. The same would apply after the 03 hour forecast. The user should assume the hazardous weather condition is occurring between the snap shots unless informed otherwise. For example, if a 00 hour forecast shows no hazard, a 03 hour forecast shows the presence of hazardous weather, and a 06 hour forecast shows no hazard, the user should assume the hazard exists from the 0001 hour to the 0559 hour time period. EXAMPLE − See FIG 7 −1−8 for an example of the G−AIRMET graphical product. g. Severe Weather Watch Bulletins (WWs) and Alert Messages (AWWs) 1. WWs define areas of possible severe thunderstorms or tornado activity. The bulletins are issued by the Storm Prediction Center (SPC) in Norman, OK. WWs are unscheduled and are issued as required. 2. A severe thunderstorm watch describes areas of expected severe thunderstorms. (Severe thunder- storm criteria are 3 / 4 −inch hail or larger and/or wind gusts of 50 knots [58 mph] or greater.) 3. A tornado watch describes areas where the threat of tornadoes exists. 4. In order to alert the WFOs, CWSUs, FSSs, and other users, a preliminary notification of a watch called the Alert Severe Weather Watch bulletin (AWW) is sent before the WW. (WFOs know this product as a SAW). EXAMPLE − Example of an AWW: −020000Z AXIS..80 STATUTE MILES EAST AND WEST OF A − 30 NW ARG/ WALNUT RIDGE AR/ ..AVIATION COORDS.. 70NM E/W /58W GGG − 25NW ARG/ 3 / 4 INCHES. WIND GUSTS..70 KNOTS. MAX TOPS TO 450. MEAN WIND 5. Soon after the AWW goes out, the actual watch bulletin itself is issued. A WW is in the following format: (a) Type of severe weather watch, watch area, valid time period, type of severe weather possible, watch axis, meaning of a watch, and a statement that persons should be on the lookout for severe weather. (b) Other watch information; i.e., references to previous watches. (c) Phenomena, intensities, hail size, wind speed (knots), maximum cumulonimbus (CB) tops, and estimated cell movement (mean wind vector). (d) Cause of severe weather. (e) Information on updating Convective Outlook (AC) products. EXAMPLE − Example of a WW: − IMMEDIATE BROADCAST REQUESTED TORNADO WATCH NUMBER 381STORM PREDICTION CENTER NORMAN OK556 PM CDT MON JUN 2 1997THE STORM PREDICTON CENTER HAS ISSUED ATORNADO WATCH FOR PORTIONS OF NORTHEASTNEW MEXICO TEXAS PANHANDLEEFFECTIVE THIS MONDAY NIGHT AND TUESDAYMORNING FROM 630 PM UNTIL MIDNIGHT CDT. TORNADOES...HAIL TO 2 3 / 4 INCHES IN DIAME- TER...THUNDERSTORM WIND GUSTS TO 80MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. Page 12
AIM 4/3/14 7−1−18 Meteorology THE TORNADO WATCH AREA IS ALONG AND 60STATUTE MILES NORTH AND SOUTH OF A LINEFROM 50 MILES SOUTHWEST OF RATON NEWMEXICO TO 50 MILES EAST OF AMARILLO TEXAS.REMEMBER...A TORNADO WATCH MEANS CON-DITIONS ARE FAVORABLE FOR TORNADOES ANDSEVERE THUNDERSTORMS IN AND CLOSE TO THEWATCH AREA. PERSONS IN THESE AREAS SHOULDBE ON THE LOOKOUT FOR THREATENING WEATH-ER CONDITIONS AND LISTEN FOR LATERSTATEMENTS AND POSSIBLE WARNINGS.OTHER WATCH INFORMATION...CONTINUE... WW 378...WW 379...WW 380 DISCUSSION...THUNDERSTORMS ARE INCREASINGOVER NE NM IN MOIST SOUTHEASTERLY UPSLOPEFLOW. OUTFLOW BOUNDARY EXTENDS EASTWARDINTO THE TEXAS PANHANDLE AND EXPECT STORMSTO MOVE ESE ALONG AND NORTH OF THEBOUNDARY ON THE N EDGE OF THE CAP. VEERINGWINDS WITH HEIGHT ALONG WITH INCREASGINGMID LVL FLOW INDICATE A THREAT FOR SUPER- CELLS. AVIATION...TORNADOES AND A FEW SEVERE THUN- 3 / 4 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBIWITH MAXIMUM TOPS TO 550. MEAN STORM MOTION VECTOR 28025. 6. Status reports are issued as needed to show progress of storms and to delineate areas no longer under the threat of severe storm activity. Cancellation bulletins are issued when it becomes evident that no severe weather will develop or that storms have subsided and are no longer severe. 7. When tornadoes or severe thunderstorms have developed, the local WFO office will issue the warnings covering those areas. h. Center Weather Advisories (CWAs) 1. CWAs are unscheduled inflight, flow control, air traffic, and air crew advisory. By nature of its short lead time, the CWA is not a flight planning product. It is generally a nowcast for conditions beginning within the next two hours. CWAs will be issued: (a) As a supplement to an existing SIGMET, Convective SIGMET or AIRMET. (b) When an Inflight Advisory has not been issued but observed or expected weather conditions meet SIGMET/AIRMET criteria based on current pilot reports and reinforced by other sources of information about existing meteorological conditions. (c) When observed or developing weather conditions do not meet SIGMET, Convective SIGMET, or AIRMET criteria; e.g., in terms of intensity or area coverage, but current pilot reports or other weather information sources indicate that existing or anticipated meteorological phenomena will adversely affect the safe flow of air traffic within the ARTCC area of responsibility. 2. The following example is a CWA issued from the Kansas City, Missouri, ARTCC. The “3” after ZKC in the first line denotes this CWA has been issued for the third weather phenomena to occur for the day. The “301” in the second line denotes the phenomena number again (3) and the issuance number (01) for this phenomena. The CWA was issued at 2140Z and is valid until 2340Z. EXAMPLE − ZKC3 CWA 032140ZKC CWA 301 VALID UNTIL 032340ISOLD SVR TSTM over KCOU MOVG SWWD 10 KTS ETC. 7 − 1 − 7. Categorical Outlooks a. Categorical outlook terms, describing general ceiling and visibility conditions for advanced planning purposes are used only in area forecasts and are defined as follows: 1. LIFR (Low IFR). Ceiling less than 500 feet and/or visibility less than 1 mile. 2. IFR. Ceiling 500 to less than 1,000 feet and/or visibility 1 to less than 3 miles. 3. MVFR (Marginal VFR). Ceiling 1,000 to 3,000 feet and/or visibility 3 to 5 miles inclusive. 4. VFR. Ceiling greater than 3,000 feet and visibility greater than 5 miles; includes sky clear. b. The cause of LIFR, IFR, or MVFR is indicated by either ceiling or visibility restrictions or both. The contraction “CIG” and/or weather and obstruction to vision symbols are used. If winds or gusts of 25 knots or greater are forecast for the outlook period, the word “WIND” is also included for all categories including VFR. EXAMPLE − 1. LIFR CIG −low IFR due to low ceiling. 2. IFR FG −IFR due to visibility restricted by fog. Page 13
AIM 4/3/14 7−1−19 Meteorology 3. MVFR CIG HZ FU −marginal VFR due to both ceiling and visibility restricted by haze and smoke. 4. IFR CIG RA WIND −IFR due to both low ceiling and visibility restricted by rain; wind expected to be 25 knots or 7 − 1 − 8. Telephone Information Briefing Service (TIBS) a. TIBS, provided by FSS, is a system of automated telephone recordings of meteorological and aeronautical information available throughout the United States. Based on the specific needs of each area, TIBS provides route and/or area briefings in addition to airspace procedures and special an- nouncements concerning aviation interests that may be available. Depending on user demand, other items may be provided; for example, surface weather observations, terminal forecasts, wind and temperat- ures aloft forecasts, etc. b. TIBS is not intended to be a substitute for specialist−provided preflight briefings from FSS. TIBS is recommended as a preliminary briefing and often will be valuable in helping you to make a “go” or “no go” decision. c. Pilots are encouraged to utilize TIBS, which can be accessed by dialing the FSS toll−free telephone number, 1−800−WX−BRIEF (992−7433) or specific published TIBS telephone numbers in certain areas. Consult the “FSS Telephone Numbers” section of the A/FD or the Alaska or Pacific Chart Supplement book. NOTE − A touch −tone telephone is necessary to fully utilize TIBS. 7 − 1 − 9. Transcribed Weather Broadcast (TWEB) (Alaska Only) Equipment is provided in Alaska by which meteorological and aeronautical data are recorded on tapes and broadcast continuously over selected L/MF and VOR facilities. Broadcasts are made from a series of individual tape recordings, and changes, as they occur, are transcribed onto the tapes. The information provided varies depending on the type equipment available. Generally, the broadcast contains a summary of adverse conditions, surface weather observations, pilot weather reports, and a density altitude statement (if applicable). At the discretion of the broadcast facility, recordings may also include a synopsis, winds aloft forecast, en route and terminal forecast data, and radar reports. At selected locations, telephone access to the TWEB has been provided (TEL−TWEB). Telephone numbers for this service are found in the Supplement Alaska A/FD. These broadcasts are made available primarily for preflight and inflight planning, and as such, should not be considered as a substitute for specialist−provided preflight briefings. 7 − 1 − 10. Inflight Weather Broadcasts a. Weather Advisory Broadcasts. ARTCCs broadcast a Severe Weather Forecast Alert (AWW), Convective SIGMET, SIGMET, or CWA alert once on all frequencies, except emergency, when any part of the area described is within 150 miles of the airspace under their jurisdiction. These broadcasts contain SIGMET or CWA (identification) and a brief description of the weather activity and general area affected. EXAMPLE − 1. Attention all aircraft, SIGMET Delta Three, from Mytonto Tuba City to Milford, severe turbulence and severe clearicing below one zero thousand feet. Expected to continue beyond zero three zero zero zulu. 2. Attention all aircraft, convective SIGMET Two SevenEastern. From the vicinity of Elmira to Phillipsburg.Scattered embedded thunderstorms moving east at onezero knots. A few intense level five cells, maximum tops four five zero. 3. Attention all aircraft, Kansas City Center weatheradvisory one zero three. Numerous reports of moderate tosevere icing from eight to niner thousand feet in a three zeromile radius of St. Louis. Light or negative icing reportedfrom four thousand to one two thousand feet remainder of Kansas City Center area. NOTE − 1. Terminal control facilities have the option to limit theAWW, convective SIGMET, SIGMET, or CWA broadcast asfollows: local control and approach control positions mayopt to broadcast SIGMET or CWA alerts only when anypart of the area described is within 50 miles of the airspace under their jurisdiction. 2. In areas where HIWAS is available, ARTCC, TerminalATC, and FSS facilities no longer broadcast InflightWeather Advisories as described above in paragraph a. See paragraphs b1 and b2 below. b. Hazardous Inflight Weather Advisory Ser- vice (HIWAS). HIWAS is an automated, continuous broadcast of inflight weather advisories, provided by FSS over select VOR outlets, which include the Page 14
AIM 4/3/14 7−1−20 Meteorology following weather products: AWW, SIGMET, Convective SIGMET, CWA, AIRMET (text [WA] or graphical [G−AIRMET] products), and urgent PIREP. HIWAS is available throughout the conter- minous United States as an additional source of hazardous weather information. HIWAS does not replace preflight or inflight weather briefings from FSS or real−time weather updates from Enroute Flight Advisory Service (EFAS), radio call “Flight Watch.” Pilots should call FSS or Flight Watch if there are any questions about weather that is different than forecasted or if the HIWAS broadcast appears to be in error. 1. Where HIWAS is available, ARTCC and terminal ATC facilities will broadcast, upon receipt, a HIWAS alert once on all frequencies, except emergency frequencies. Included in the broadcast will be an alert announcement, frequency instruction, number, and type of advisory updated; for example, AWW, SIGMET, Convective SIGMET, or CWA. EXAMPLE − Attention all aircraft. Hazardous weather information (text [WA] or graphical [G −AIRMET] product) , Urgent Pilot Weather Report [UUA], or Center Weather Advisory[CWA], Number or Numbers) for (geographical area)available on HIWAS, Flight Watch, or Flight Service frequencies. 2. Upon notification of an update to HIWAS, FSS will broadcast a HIWAS update announcement once on all frequencies except emergency frequen- cies. Included in the broadcast will be the type of advisory updated; for example, AWW, SIGMET, Convective SIGMET, CWA, etc. EXAMPLE − Attention all aircraft. Hazardous weather information for(geographical area) available from Flight Watch or Flight Service. 3. HIWAS availability is notated with VOR listings in the Airport/Facility Directory (A/FD), and is shown by symbols on IFR Enroute Low Altitude Charts and VFR Sectional Charts. The symbol depiction is identified in the chart legend. Page 15
AIM 4/3/14 7−1−21 Meteorology FIG 7 −1−8 G −AIRMET Graphical Product Page 16
AIM 4/3/14 7−1−22 Meteorology 7 − 1 − 11. Flight Information Services (FIS) a. FIS . FIS is a method of disseminating meteorological (MET) and aeronautical information (AI) to displays in the cockpit in order to enhance pilot situational awareness, provide decision support tools, and improve safety. FIS augments traditional pilot voice communication with Flight Service Stations (FSSs), ATC facilities, or Airline Operations Control Centers (AOCCs). FIS is not intended to replace traditional pilot and controller/flight service specialist/aircraft dispatcher preflight briefings or inflight voice communications. FIS, however, can provide textual and graphical information that can help abbreviate and improve the usefulness of such communications. FIS enhances pilot situational awareness and improves safety. 1. Data link Service Providers (DLSP) - DLSP deploy and maintain airborne, ground-based, and, in some cases, space-based infrastructure that supports the transmission of AI/MET information over one or more physical links. DLSP may provide a free of charge or for-fee service that permits end users to uplink and downlink AI/MET and other information. The following are examples of DLSP: (a) FAA FIS-B. A ground-based broadcast service provided through the ADS-B Universal Access Transceiver (UAT) network. The service provides users with a 978 MHz data link capability when operating within range and line-of-sight of a transmitting ground station. FIS-B enables users of properly equipped aircraft to receive and display a suite of broadcast weather and aeronautical informa- tion products. (b) Non-FAA FIS Systems. Several commer- cial vendors provide customers with FIS data over both the aeronautical spectrum and on other frequencies using a variety of data link protocols. Services available from these providers vary greatly and may include tier based subscriptions. Advance- ments in bandwidth technology permits preflight as well as inflight access to the same MET and AI information available on the ground. Pilots and operators using non-FAA FIS for MET and AI information should be knowledgeable regarding the weather services being provided as some commercial vendors may be repackaging NWS sourced weather, while other commercial vendors may alter the weather information to produce vendor−tailored or vendor−specific weather reports and forecasts. 2. Three Data Link Modes. There are three data link modes that may be used for transmitting AI and MET information to aircraft. The intended use of the AI and/or MET information will determine the most appropriate data link service. (a) Broadcast Mode: A one-way interaction in which AI and/or MET updates or changes applicable to a designated geographic area are continuously transmitted (or transmitted at repeated periodic intervals) to all aircraft capable of receiving the broadcast within the service volume defined by the system network architecture. (b) Contract/Demand Mode: A two-way interaction in which AI and/or MET information is transmitted to an aircraft in response to a specific request. (c) Contract/Update Mode: A two-way inter- action that is an extension of the Demand Mode. Initial AI and/or MET report(s) are sent to an aircraft and subsequent updates or changes to the AI and/or MET information that meet the contract criteria are automatically or manually sent to an aircraft. 3. To ensure airman compliance with Federal Aviation Regulations, manufacturer’s operating manuals should remind airmen to contact ATC controllers, FSS specialists, operator dispatchers, or airline operations control centers for general and mission critical aviation weather information and/or NAS status conditions (such as NOTAMs, Special Use Airspace status, and other government flight information). If FIS products are systemically modified (for example, are displayed as abbreviated plain text and/or graphical depictions), the modifica- tion process and limitations of the resultant product should be clearly described in the vendor’s user guidance. 4. Operational Use of FIS. Regardless of the type of FIS system being used, several factors must be considered when using FIS: (a) Before using FIS for inflight operations, pilots and other flight crewmembers should become familiar with the operation of the FIS system to be used, the airborne equipment to be used, including its system architecture, airborne system components, coverage service volume and other limitations of the particular system, modes of operation and indications of various system failures. Users should also be familiar with the specific content and format of the services available from the FIS provider(s). Sources Page 17
AIM 4/3/14 7−1−23 Meteorology of information that may provide this specific guidance include manufacturer’s manuals, training programs, and reference guides. (b) FIS should not serve as the sole source of aviation weather and other operational information. ATC, FSSs, and, if applicable, AOCC VHF/HF voice remain as a redundant method of communicating aviation weather, NOTAMs, and other operational information to aircraft in flight. FIS augments these traditional ATC/FSS/AOCC services and, for some products, offers the advantage of being displayed as graphical information. By using FIS for orientation, the usefulness of information received from conventional means may be enhanced. For example, FIS may alert the pilot to specific areas of concern that will more accurately focus requests made to FSS or AOCC for inflight updates or similar queries made to ATC. (c) The airspace and aeronautical environ- ment is constantly changing. These changes occur quickly and without warning. Critical operational decisions should be based on use of the most current and appropriate data available. When differences exist between FIS and information obtained by voice communication with ATC, FSS, and/or AOCC (if applicable), pilots are cautioned to use the most recent data from the most authoritative source. (d) FIS aviation weather products (for example, graphical ground−based radar precipitation depictions) are not appropriate for tactical (typical timeframe of less than 3 minutes) avoidance of severe weather such as negotiating a path through a weather hazard area. FIS supports strategic (typical timeframe of 20 minutes or more) weather decisionmaking such as route selection to avoid a weather hazard area in its entirety. The misuse of information beyond its applicability may place the pilot and aircraft in jeopardy. In addition, FIS should never be used in lieu of an individual preflight weather and flight planning briefing. (e) DLSP offer numerous MET and AI products with information that can be layered on top of each other. Pilots need to be aware that too much information can have a negative effect on their cognitive work load. Pilots need to manage the amount of information to a level that offers the most pertinent information to that specific flight without creating a cockpit distraction. Pilots may need to adjust the amount of information based on numerous factors including, but not limited to, the phase of flight, single pilot operation, autopilot availability, class of airspace, and the weather conditions encountered. (f) FIS NOTAM products, including Tempor- ary Flight Restriction (TFR) information, are advisory−use information and are intended for situational awareness purposes only. Cockpit dis- plays of this information are not appropriate for tactical navigation − pilots should stay clear of any geographic area displayed as a TFR NOTAM. Pilots should contact FSSs and/or ATC while en route to obtain updated information and to verify the cockpit display of NOTAM information. (g) FIS supports better pilot decisionmaking by increasing situational awareness. Better decision− making is based on using information from a variety of sources. In addition to FIS, pilots should take advantage of other weather/NAS status sources, including, briefings from Flight Service Stations, FAA’s en route “Flight Watch” service, data from other air traffic control facilities, airline operation control centers, pilot reports, as well as their own observations. (h) FAA’s Flight Information Service− Broadcast (FIS−B). (1) FIS−B is a ground−based broadcast service provided through the FAA’s Automatic Dependent Surveillance–Broadcast (ADS−B) Ser- vices Universal Access Transceiver (UAT) network. The service provides users with a 978 MHz data link capability when operating within range and line−of− sight of a transmitting ground station. FIS−B enables users of properly−equipped aircraft to receive and display a suite of broadcast weather and aeronautical information products. (2) The following list represents the initial suite of text and graphical products available through FIS−B and provided free−of−charge. Detailed information concerning FIS−B meteorological products can be found in Advisory Circular 00−45, Aviation Weather Services, and AC 00-63, Use of Cockpit Displays of Digital Weather and Aeronautic- al Information. Information on Special Use Airspace (SUA), Temporary Flight Restriction (TFR), and Notice to Airmen (NOTAM) products can be found in Chapters 3, 4 and 5 of this manual. Page 18
AIM 4/3/14 7−1−24 Meteorology [a] Text: Aviation Routine Weather Report (METAR) and Special Aviation Report (SPECI); [b] Text: Pilot Weather Report (PIREP); [c] Text: Winds and Temperatures Aloft; [d] Text: Terminal Aerodrome Forecast (TAF) and amendments; [e] Text: Notice to Airmen (NOTAM) Distant and Flight Data Center; [f] Text/Graphic: Airmen’s Meteorolo- gical Conditions (AIRMET); [g] Text/Graphic: Significant Meteoro- logical Conditions (SIGMET); [h] Text/Graphic: Convective SIG- MET; [i] Text/Graphic: Special Use Airspace (SUA); [j] Text/Graphic: Temporary Flight Restriction (TFR) NOTAM; and [k] Graphic: NEXRAD Composite Re- flectivity Products (Regional and National). (3) Users of FIS−B should familiarize themselves with the operational characteristics and limitations of the system, including: system architec- ture; service environment; product lifecycles; modes of operation; and indications of system failure. (4) FIS−B products are updated and transmitted at specific intervals based primarily on product issuance criteria. Update intervals are defined as the rate at which the product data is available from the source for transmission. Transmis- sion intervals are defined as the amount of time within which a new or updated product transmission must be completed and/or the rate or repetition interval at which the product is rebroadcast. Update and transmission intervals for each product are provided in TBL 7−1−1. (5) Where applicable, FIS−B products include a look−ahead range expressed in nautical miles (NM) for three service domains: Airport Surface; Terminal Airspace; and Enroute/Gulf−of− Mexico (GOMEX). TBL 7−1−2 provides service domain availability and look−ahead ranging for each FIS−B product. (6) Prior to using this capability, users should familiarize themselves with the operation of FIS−B avionics by referencing the applicable User’s Guides. Guidance concerning the interpretation of information displayed should be obtained from the appropriate avionics manufacturer. (7) FIS−B malfunctions not attributed to aircraft system failures or covered by active NOTAM should be reported by radio or telephone to the nearest FSS facility. Malfunctions may also be reported by submitting FAA Form 8740−5, Safety Improvement Report via mail, fax, or email to your local Flight District Standards Office, Safety Program Manager. b. Non −FAA FIS Systems. Several commercial vendors also provide customers with FIS data over both the aeronautical spectrum and on other frequencies using a variety of data link protocols. In some cases, the vendors provide only the commu- nications system that carries customer messages, such as the Aircraft Communications Addressing and Reporting System (ACARS) used by many air carrier and other operators. 1. Operators using non−FAA FIS data for inflight weather and other operational information should ensure that the products used conform to FAA/NWS standards. Specifically, aviation weather and NAS status information should meet the following criteria: (a) The products should be either FAA/NWS “accepted” aviation weather reports or products, or based on FAA/NWS accepted aviation weather reports or products. If products are used which do not meet this criteria, they should be so identified. The operator must determine the applicability of such products to their particular flight operations. (b) In the case of a weather product which is the result of the application of a process which alters the form, function or content of the base FAA/NWS accepted weather product(s), that process, and any limitations to the application of the resultant product, should be described in the vendor’s user guidance material. 2. An example would be a NEXRAD radar composite/mosaic map, which has been modified by changing the scaling resolution. The methodology of assigning reflectivity values to the resultant image components should be described in the vendor’s Page 19
AIM 4/3/14 7−1−25 Meteorology guidance material to ensure that the user can accurately interpret the displayed data. TBL 7 −1−1 FIS −B Over UAT Product Update and Transmission Intervals Product FIS-B Over UAT Service Update Intervals 1 FIS-B Service Transmission Intervals 2 AIRMET As Available 5 minutes Convective SIGMET As Available 5 minutes METARs/SPECIs 1 minute/As Available 5 minutes NEXRAD Composite Reflectivity (CONUS) 15 minutes 15 minutes NEXRAD Composite Reflectivity (Regional) 5 minutes 2.5 minutes NOTAMs-D/FDC/TFR As Available 10 minutes PIREP As Available 10 minutes SIGMET As Available 5 minutes SUA Status As Available 10 minutes TAF/AMEND 8 Hours/As Available 10 minutes Temperatures Aloft 12 Hours 10 minutes Winds Aloft 12 Hours 10 minutes 1 The Update Interval is the rate at which the product data is available from the source. 2 The Transmission Interval is the amount of time within which a new or updated product transmission must be completed and the rate or repetition interval at which the product is rebroadcast. Page 20
AIM 4/3/14 7−1−26 Meteorology TBL 7 −1−2 Product Parameters for Low/Medium/High Altitude Tier Radios Product Surface Radios Low Altitude Tier Medium Altitude High Altitude Tier CONUS NEXRAD N/A CONUS NEXRAD not provided CONUS NEXRAD imagery CONUS NEXRAD imagery Winds & Temps Aloft 500 NM look−ahead range 500 NM look−ahead range 750 NM look−ahead range 1,000 NM look− ahead range METAR 100 NM look−ahead range 250 NM look−ahead range 375 NM look−ahead range CONUS: CONUS Class B & C airport METARs and 500 NM look−ahead range Outside of CONUS: 500 NM look-ahead range TAF 100 NM look−ahead range 250 NM look−ahead range 375 NM look−ahead range CONUS: CONUS Class B & C airport TAFs and 500 NM look−ahead range Outside of CONUS: 500 NM look-ahead range AIRMET, SIGMET, PIREP, and SUA/ SAA 100 NM look−ahead range. PIREP/SUA/ SAA is N/A. 250 NM look−ahead range 375 NM look−ahead range 500 NM look−ahead range Regional NEXRAD 150 NM look−ahead range 150 NM look−ahead range 200 NM look−ahead range 250 NM look−ahead range NOTAMs D, FDC, and TFR 100 NM look−ahead range 100 NM look−ahead range 100 NM look−ahead range 100 NM look−ahead range 7 − 1 − 12. Weather Observing Programs a. Manual Observations. With only a few exceptions, these reports are from airport locations staffed by FAA or NWS personnel who manually observe, perform calculations, and enter these observations into the (WMSCR) communication system. The format and coding of these observations are contained in Paragraph 7−1−30 , Key to Aviation Routine Weather Report (METAR) and Aerodrome Forecasts (TAF). b. Automated Weather Observing System (AWOS). 1. Automated weather reporting systems are increasingly being installed at airports. These systems consist of various sensors, a processor, a computer-generated voice subsystem, and a transmit- ter to broadcast local, minute-by-minute weather data directly to the pilot. NOTE − When the barometric pressure exceeds 31.00 inches Hg., −2−2, Procedures, for the altimeter setting procedures. 2. The AWOS observations will include the prefix “AUTO” to indicate that the data are derived from an automated system. Some AWOS locations will be augmented by certified observers who will provide weather and obstruction to vision informa- tion in the remarks of the report when the reported visibility is less than 7 miles. These sites, along with the hours of augmentation, are to be published in the A/FD. Augmentation is identified in the observation as “OBSERVER WEATHER.” The AWOS wind speed, direction and gusts, temperature, dew point, Page 21
AIM 4/3/14 7−1−27 Meteorology and altimeter setting are exactly the same as for manual observations. The AWOS will also report density altitude when it exceeds the field elevation by more than 1,000 feet. The reported visibility is derived from a sensor near the touchdown of the primary instrument runway. The visibility sensor output is converted to a visibility value using a 10−minute harmonic average. The reported sky condition/ceiling is derived from the ceilometer located next to the visibility sensor. The AWOS algorithm integrates the last 30 minutes of ceilometer data to derive cloud layers and heights. This output may also differ from the observer sky condition in that the AWOS is totally dependent upon the cloud advection over the sensor site. 3. These real-time systems are operationally classified into nine basic levels: (a) AWOS −A only reports altimeter setting; NOTE − Any other information is advisory only. (b) AWOS −AV reports altimeter and visibility; NOTE − Any other information is advisory only. (c) AWOS −l usually reports altimeter setting, wind data, temperature, dew point, and density altitude; (d) AWOS −2 provides the information pro- vided by AWOS−l plus visibility; and (e) AWOS −3 provides the information pro- vided by AWOS−2 plus cloud/ceiling data. (f) AWOS − 3P provides reports the same as the AWOS 3 system, plus a precipitation identifica- tion sensor. (g) AWOS − 3PT reports the same as the AWOS 3P System, plus thunderstorm/lightning reporting capability. (h) AWOS − 3T reports the same as AWOS 3 system and includes a thunderstorm/lightning reporting capability. (i) AWOS − 4 reports the same as the AWOS 3 system, plus precipitation occurrence, type and accumulation, freezing rain, thunderstorm, and runway surface sensors. 4. The information is transmitted over a discrete VHF radio frequency or the voice portion of a local NAVAID. AWOS transmissions on a discrete VHF radio frequency are engineered to be receivable to a maximum of 25 NM from the AWOS site and a maximum altitude of 10,000 feet AGL. At many locations, AWOS signals may be received on the surface of the airport, but local conditions may limit the maximum AWOS reception distance and/or altitude. The system transmits a 20 to 30 second weather message updated each minute. Pilots should monitor the designated frequency for the automated weather broadcast. A description of the broadcast is contained in subparagraph c. There is no two-way communication capability. Most AWOS sites also have a dial-up capability so that the minute-by-min- ute weather messages can be accessed via telephone. 5. AWOS information (system level, frequency, phone number, etc.) concerning specific locations is published, as the systems become operational, in the A/FD, and where applicable, on published Instru- ment Approach Procedures. Selected individual systems may be incorporated into nationwide data collection and dissemination networks in the future. c. AWOS Broadcasts. Computer-generated voice is used in AWOS to automate the broadcast of the minute-by-minute weather observations. In addition, some systems are configured to permit the addition of an operator-generated voice message; e.g., weather remarks following the automated parameters. The phraseology used generally follows that used for other weather broadcasts. Following are explanations and examples of the exceptions. 1. Location and Time. The location/name and the phrase “AUTOMATED WEATHER OBSERVA- TION,” followed by the time are announced. (a) If the airport’s specific location is included in the airport’s name, the airport’s name is announced. EXAMPLE − “Bremerton National Airport automated weather observa-tion, one four five six zulu;”“Ravenswood Jackson County Airport automated weather observation, one four five six zulu.” (b) If the airport’s specific location is not included in the airport’s name, the location is announced followed by the airport’s name. Page 22
AIM 4/3/14 7−1−28 Meteorology EXAMPLE − “Sault Ste. Marie, Chippewa County International Airportautomated weather observation;”“Sandusky, Cowley Field automated weather observation.” (c) The word “TEST” is added following “OBSERVATION” when the system is not in commissioned status. EXAMPLE − “Bremerton National Airport automated weather observa- (d) The phrase “TEMPORARILY INOP- ERATIVE” is added when the system is inoperative. EXAMPLE − “Bremerton National Airport automated weather observ- 2. Visibility. (a) The lowest reportable visibility value in AWOS is “less than 1 / 4 .” It is announced as “VISIBILITY LESS THAN ONE QUARTER.” (b) A sensor for determining visibility is not included in some AWOS. In these systems, visibility is not announced. “VISIBILITY MISSING” is announced only if the system is configured with a visibility sensor and visibility information is not available. 3. Weather. In the future, some AWOSs are to be configured to determine the occurrence of precipitation. However, the type and intensity may not always be determined. In these systems, the word “PRECIPITATION” will be announced if precipita- tion is occurring, but the type and intensity are not determined. 4. Ceiling and Sky Cover. (a) Ceiling is announced as either “CEIL- ING” or “INDEFINITE CEILING.” With the exception of indefinite ceilings, all automated ceiling heights are measured. EXAMPLE − “Bremerton National Airport automated weather observa- “Bremerton National Airport automated weather observa-tion, one four five six zulu. Indefinite ceiling two hundred, sky obscured.” (b) The word “Clear” is not used in AWOS due to limitations in the height ranges of the sensors. No clouds detected is announced as “NO CLOUDS BELOW XXX” or, in newer systems as “CLEAR BELOW XXX” (where XXX is the range limit of the sensor). EXAMPLE − “No clouds below one two thousand.” (c) A sensor for determining ceiling and sky cover is not included in some AWOS. In these systems, ceiling and sky cover are not announced. “SKY CONDITION MISSING” is announced only if the system is configured with a ceilometer and the ceiling and sky cover information is not available. 5. Remarks. If remarks are included in the observation, the word “REMARKS” is announced following the altimeter setting. (a) Automated “Remarks.” (1) Density Altitude. (2) Variable Visibility. (3) Variable Wind Direction. (b) Manual Input Remarks. Manual input remarks are prefaced with the phrase “OBSERVER WEATHER.” As a general rule the manual remarks are limited to: (1) Type and intensity of precipitation. (2) Thunderstorms and direction; and (3) Obstructions to vision when the visibili- ty is 3 miles or less. EXAMPLE − “Remarks ... density altitude, two thousand five hundred ...visibility variable between one and two ... wind directionvariable between two four zero and three one zero...observed weather ... thunderstorm moderate rain showers and fog ... thunderstorm overhead.” (c) If an automated parameter is “missing” and no manual input for that parameter is available, the parameter is announced as “MISSING.” For example, a report with the dew point “missing” and no manual input available, would be announced as follows: EXAMPLE − “Ceiling one thousand overcast ... visibility three ...precipitation ... temperature three zero, dew point missing ... wind calm ... altimeter three zero zero one.” (d) “REMARKS” are announced in the following order of priority: Page 23
AIM 4/3/14 7−1−29 Meteorology (1) Automated “REMARKS.” [a] Density Altitude. [b] Variable Visibility. [c] Variable Wind Direction. (2) Manual Input “REMARKS.” [a] Sky Condition. [b] Visibility. [c] Weather and Obstructions to Vision. [d] Temperature. [e] Dew Point. [f] Wind; and [g] Altimeter Setting. EXAMPLE − “Remarks ... density altitude, two thousand five hundred ...visibility variable between one and two ... wind directionvariable between two four zero and three one zero ...observer ceiling estimated two thousand broken ... observer temperature two, dew point minus five.” d. Automated Surface Observing System (ASOS)/Automated Weather Sensor System The ASOS/AWSS is the primary surface weather observing system of the U.S. (See Key to Decode an ASOS/AWSS (METAR) Observation, FIG 7−1−9 and FIG 7−1−10.) The program to install and operate these systems throughout the U.S. is a joint effort of the NWS, the FAA and the Department of Defense. AWSS is a follow−on program that provides identical data as ASOS. ASOS/AWSS is designed to support aviation operations and weather forecast activities. The ASOS/AWSS will provide continuous minute-by-minute observations and perform the basic observing functions necessary to generate an aviation routine weather report (ME- TAR) and other aviation weather information. The information may be transmitted over a discrete VHF radio frequency or the voice portion of a local NAVAID. ASOS/AWSS transmissions on a discrete VHF radio frequency are engineered to be receivable to a maximum of 25 NM from the ASOS/AWSS site and a maximum altitude of 10,000 feet AGL. At many locations, ASOS/AWSS signals may be received on the surface of the airport, but local conditions may limit the maximum reception distance and/or altitude. While the automated system and the human may differ in their methods of data collection and interpretation, both produce an observation quite similar in form and content. For the “objective” elements such as pressure, ambient temperature, dew point temperature, wind, and precipitation accumula- tion, both the automated system and the observer use a fixed location and time-averaging technique. The quantitative differences between the observer and the automated observation of these elements are negligible. For the “subjective” elements, however, observers use a fixed time, spatial averaging technique to describe the visual elements (sky condition, visibility and present weather), while the automated systems use a fixed location, time averaging technique. Although this is a fundamental change, the manual and automated techniques yield remarkably similar results within the limits of their respective capabilities. 1. System Description. (a) The ASOS/AWSS at each airport location consists of four main components: (1) Individual weather sensors. (2) Data collection and processing units. (3) Peripherals and displays. (b) The ASOS/AWSS sensors perform the basic function of data acquisition. They continuously sample and measure the ambient environment, derive raw sensor data and make them available to the collection and processing units. 2. Every ASOS/AWSS will contain the following basic set of sensors: (a) Cloud height indicator (one or possibly three). (b) Visibility sensor (one or possibly three). (c) Precipitation identification sensor. (d) Freezing rain sensor (at select sites). (e) Pressure sensors (two sensors at small airports; three sensors at large airports). (f) Ambient temperature/Dew point tempera- ture sensor. (g) Anemometer (wind direction and speed sensor). (h) Rainfall accumulation sensor. 3. The ASOS/AWSS data outlets include: (a) Those necessary for on-site airport users. Page 24
AIM 4/3/14 7−1−30 Meteorology (b) National communications networks. (c) Computer-generated voice (available through FAA radio broadcast to pilots, and dial-in telephone line). NOTE − Wind direction broadcast over FAA radios is in reference 4. An ASOS/AWOS/AWSS report without human intervention will contain only that weather data capable of being reported automatically. The modifier for this METAR report is “AUTO.” When an observer augments or backs−up an ASOS/AWOS/ AWSS site, the “AUTO” modifier disappears. 5. There are two types of automated stations, AO1 for automated weather reporting stations without a precipitation discriminator, and AO2 for automated stations with a precipitation discriminator. As appropriate, “AO1” and “AO2” must appear in remarks. (A precipitation discriminator can deter- mine the difference between liquid and frozen/freezing precipitation). NOTE − To decode an ASOS /AWSS report, refer to FIG 7 −1−9 and FIG 7 −1−10. REFERENCE − A complete explanation of METAR terminology is located in AIM, −1−30, Key to Aerodrome Forecast (TAF) and Aviation Routine Weather Report (METAR). Page 25
AIM 4/3/14 7−1−31 Meteorology FIG 7 −1−9 Key to Decode an ASOS /AWSS (METAR) Observation (Front) Page 26
AIM 4/3/14 7−1−32 Meteorology FIG 7 −1−10 Key to Decode an ASOS /AWSS (METAR) Observation (Back) |
What type of weather briefing should be requested in those cases where a preflight briefing or an update to a previous briefing needs to be obtained over an aircrafts radio?
Pos Terkait
Copyright © 2024 membukakan Inc.
