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AIM

4/20/23

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Meteorology

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 conduct a self

briefing using online resources or obtain your

preflight briefing by telephone or in person (Alaska only) 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. En Route advisories tailored to the phase of
flight that begins after climb

out and ends with descent to land are provided upon pilot request. Besides Flight

Service, there are other resources available to the pilot in flight, including:

Automatic Dependent Surveillance

Broadcast (ADS

B)

. Free traffic, weather, and flight information are

available on ADS

B In receivers that can receive data over 978 MHz (UAT) broadcasts. These services are

available across the nation to aircraft owners who equip with ADS

B In, with further advances coming from

airborne and runway traffic awareness. Even search

and

rescue operations benefit from accurate ADS

B

tracking.

Flight Information Services

Broadcast (FIS

B). 

FIS

B is a free service; but is only available to aircraft that can

receive data over 978 MHz (UAT). FIS

B automatically transmits a wide range of weather products with national

and regional focus to all equipped aircraft. Having current weather and aeronautical information in the cockpit
helps pilots plan more safe and efficient flight paths, as well as make strategic decisions during flight to avoid
potentially hazardous weather.

Pilots are encouraged to provide a continuous exchange of information on weather, winds, turbulence, flight
visibility, icing, etc., between pilots and inflight specialists. Pilots should report good weather as well as bad, and
confirm expected conditions as well as unexpected. Remember that weather conditions can change rapidly and
that a “go or no go” decision, as mentioned in paragraph 7

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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.

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6. Inflight Aviation Weather Advisories

a.

Inflight Aviation Weather Advisories are forecasts to advise en route aircraft of development of potentially

hazardous weather. Inflight aviation weather advisories in the conterminous U.S. are issued by the Aviation
Weather Center (AWC) in Kansas City, MO, as well as 20 Center Weather Service Units (CWSU) associated with
ARTCCs. AWC also issues advisories for portions of the Gulf of Mexico, Atlantic and Pacific Oceans, which
are under the control of ARTCCs with Oceanic flight information regions (FIRs). The Weather Forecast Office
(WFO) in Honolulu issues advisories for the Hawaiian Islands and a large portion of the Pacific Ocean. In Alaska,
the Alaska Aviation Weather Unit (AAWU) issues inflight aviation weather advisories along with the Anchorage
CWSU. All heights are referenced MSL, except in the case of ceilings (CIG) which indicate AGL.