A well-planned flight is always your first-class ticket to the safest flight.
Before even lifting off, you need to take the time to plan your journey. This includes the:
- type of aircraft
- routes
- accommodation
- fuel stops
- passengers.
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 itinerary
As 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.
Preflight ERSA
Dress rehearsal
It’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:
- review your start-up and taxi procedures, run-up considerations and departure from the circuit
- think about any exchanges with ATC you'll need
- rehearse out aloud every radio call you think you’ll need (if you get it wrong, say it again until you get it right).
Another good tip is to practice radio calls in the car on your way to the aerodrome.
Planning for weather
Think 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.
Pre-flight planning
En-route Supplement Australia (ERSA)
In the weeks leading up to your safari, take some time to read through these useful sections in ERSA:
- ERSA INTRO (section 4 – aerodrome information) Includes advice on the NOTAM service.
- ERSA GEN-PF (entire chapter) goes into detail on contact numbers, NAIPS access, and Specific Pre-flight Information Briefing (SPFIB) AVFAX. It also includes Airspace Group codes and the Automated Meteorological Telephone Briefing Service (METBRIEF).
- ERSA GEN – FIS (flight Information services) provides info on AERIS frequencies, ATS In-flight information service. It also includes cancellation of SARWATCH and SARTIME, HF frequencies, designated remote areas and UAV testing.
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.
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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
from ATC facilities while in flight.
(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-
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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,
Mansfield V
−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,
Mansfield V
−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: //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)
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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:
BOSR WS 050600SIGMET ROMEO 2 VALID UNTIL 051000ME NH VTFROM CAR TO YSJ TO CON TO MPV TO CAROCNL SEV TURB BLW 080 EXP DUE TO STG NWLY
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.
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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
AGL would be required to contact EFAS.
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FIG 7
−1−3
Inflight Advisory Plotting Chart
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FIG 7
−1−4
Geographical Areas and Terrain Features
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FIG 7
−1−5
Aviation Area Forecasts
FA Locations
− Contiguous United States
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FIG 7
−1−6
Alaska Area Forecast Sectors
FIG 7
−1−7
Hawaii Area Forecast Locations
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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:
WSNT06 KKCI 022014SIGA0FKZMA KZNY TJZS SIGMET FOXTROT 3 VALID
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
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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
YDC
−60NNW GEG−60SW MLP−30WSW BKE−
20SW BAM
−70W BAM−40SW YKM−40E HUH−
40SE YDC
SFC ALG 20NNW HUH
−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
//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
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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:
MKC AWW 011734
WW 75 TORNADO TX OK AR 011800Z
−020000Z
AXIS..80 STATUTE MILES EAST AND WEST OF A
LINE..60ESE DAL/DALLAS TX/
− 30 NW ARG/ WALNUT
RIDGE AR/
..AVIATION COORDS.. 70NM E/W /58W GGG
− 25NW
ARG/
HAIL SURFACE AND ALOFT..1
3
/
4
INCHES. WIND
GUSTS..70 KNOTS. MAX TOPS TO 450. MEAN WIND
VECTOR 24045.
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:
BULLETIN
− 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.
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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-
DERSTORMS WITH HAIL SURFACE AND ALOFT TO 2
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.
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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
greater.
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
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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
(SIGMET, Convective SIGMET, AIRMET
(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.
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FIG 7
−1−8
G
−AIRMET Graphical Product
Page 16
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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
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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.
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[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
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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.
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Meteorology
TBL 7
−1−2
Product Parameters for Low/Medium/High Altitude Tier Radios
Product
Surface Radios
Low Altitude Tier
Medium Altitude
Tier
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.,
see Paragraph 7
−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,
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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.
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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-
tion test, one four five six zulu.”
(d)
The phrase “TEMPORARILY INOP-
ERATIVE” is added when the system is inoperative.
EXAMPLE
−
“Bremerton National Airport automated weather observ-
ing system temporarily inoperative.”
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-
tion, one four five six zulu. Ceiling two thousand overcast;”
“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.”
“Clear 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:
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(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
(AWSS).
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.
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(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
to magnetic north.
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,
Paragraph 7
−1−30, Key to Aerodrome Forecast (TAF) and Aviation
Routine Weather Report (METAR).
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FIG 7
−1−9
Key to Decode an ASOS
/AWSS
(METAR) Observation (Front)
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FIG 7
−1−10
Key to Decode an ASOS
/AWSS
(METAR) Observation (Back)