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and produce forecasts. The FAA and NWS

disseminate meteorological observations, analyses,

and forecasts through a variety of systems. In

addition, the Federal Government is the only

approval authority for sources of weather observa-

tions; for example, contract towers and airport
operators may be approved by the Feder


Government to provide weather observations.


Enhanced Weather Information System

(EWINS). An EWINS is an FAA authorized,

proprietary system for tracking, evaluating, report-

ing, and forecasting the presence or lack of adverse

weather phenomena. The FAA authorizes a certific-

ate holder to use an EWINS to produce flight

movement forecasts, adverse weather phenomena

forecasts, and other meteorological advisories. For

more detailed information regarding EWINS, see the

Aviation Weather Services Advisory Circular 00−45

and the Flight Standards Information Management

System 8900.1.

3. Commercial Weather Information


 In general, commercial providers

produce proprietary weather products based on

NWS/FAA products with formatting and layout

modifications but no material changes to the weather

information itself. This is also referred to as

“repackaging.” In addition, commercial providers

may produce analyses, forecasts, and other

proprietary weather products that substantially alter

the information contained in government−produced

products. However, those proprietary weather

products that substantially alter government−

produced weather products or information, may only

be approved for use by 14 CFR Part 121 and Part 135

certificate holders if the commercial provider is

EWINS qualified.


Commercial weather information providers contracted by
FAA to provide weather observations, analyses, and
forecasts (e.g., contract towers) are included in the Federal
Government category of approved sources by virtue of
maintaining required technical and quality assurance
standards under Federal Government oversight.


As a point of clarification, Advisory

Circular 00−62, Internet Communications of

Aviation Weather and NOTAMS, describes the

process for a weather information provider to become

a Qualified Internet Communications Provider

(QICP) and only applies to 14 CFR Part 121 and

Part 135 certificate holders. Therefore, pilots

conducting operations under 14 CFR Part 91 may

access weather products via the public Internet.



4. Preflight Briefing


Flight Service Stations (FSSs) are the primary

source for obtaining preflight briefings and inflight

weather information. Flight Service Specialists are

qualified and certificated by the NWS as Pilot

Weather Briefers. They are not authorized to make

original forecasts, but are authorized to translate and

interpret available forecasts and reports directly into

terms describing the weather conditions which you

can expect along your flight route and at your

destination. Available aviation weather reports,

forecasts and aviation weather charts are displayed at

each FSS, for pilot use. Pilots should feel free to use

these self briefing displays where available, or to ask

for a briefing or assistance from the specialist on duty.

Three basic types of preflight briefings are available

to serve your specific needs. These are: Standard

Briefing, Abbreviated Briefing, and Outlook Brief-

ing. You should specify to the briefer the type of

briefing you want, along with your appropriate

background information. This will enable the briefer

to tailor the information to your intended flight. The

following paragraphs describe the types of briefings

available and the information provided in each



AIM, Preflight Preparation, Paragraph 5

−1−1, for items that are


b. Standard Briefing.

You should request a

Standard Briefing any time you are planning a flight

and you have not received a previous briefing or have

not received preliminary information through mass

dissemination media; e.g., TIBS, TWEB (Alaska

only), etc. 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. The briefer will

automatically provide the following information in

the sequence listed, except as noted, when it is

applicable to your proposed flight.

1. Adverse Conditions.

Significant meteoro-

logical and/or aeronautical information that might

influence the pilot to alter or cancel the proposed

flight; for example, hazardous weather conditions,

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