How do I contact a Flight Service Station (FSS) in the United States in order to receive weather information or open a flight plan after I've already departed.
For weather (giving PIREPs or asking for a weather report) you want Enroute Flight Advisory Services (addressed on the radio as "Flight Watch").
Flight Watch radio coverage should be available at or above 5,000 feet (though typically you can contact them at lower altitudes without a problem), and is provided between 0600 and 2200 local time (service may be available outside those hours but you will probably have to call Flight Service instead.
Initial calls to Flight Watch should generally take the form:
If calling in to give a PIREP generally adding "With a pilot report" helps the FSS specialist on the other end of the radio know what mode to be in (taking a report versus giving weather information).
For filing and opening VFR flight plans, pushing back your ETA because of a delay, and a few more obscure things which you can find in section 4-1-21 of the AIM you would contact Flight Service (addressed as "region Radio" - e.g. "New York Radio" or "Bridgeport Radio")
The universal flight service frequency is 122.2 (similar to Flight Watch this is supposed to be available above 5000 feet, but often you can talk to someone below that altitude).
Initial calls to Flight Service should take the form:
There's a little catch with Flight Service frequencies: If there is an