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 from
the 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: 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)