# How does a pilot file a PIREP?

For what reasons would a pilot want to file a PIREP?

If a pilot wanted to file a PIREP, how would he/she go about filing one?

I'll tackle the "How" first - you call up Flight Service (either on the radio or on the phone after you land) and tell them you have a pilot report. There's a standard format for pilot reports, and if you give all the information in the order it appears on that form it's faster for you and the person taking the report.
If you're filing a pilot report on the ground for conditions you encountered enroute you need to specify the (Zulu) time of your observation (or tell the briefer "20 minutes ago"). In the air it's generally assumed your report is for "now".

Pilots are requested to provide pilot reports for significant deviations from the forecast weather, or for hazardous conditions. Basically we provide them as a courtesy and service to our fellow pilots (like flashing your lights at other cars on the highway if you know there's a speed trap).

Some pilot reports you may want to file in flight are if the Winds Aloft differ from the forecast. If the forecast told you you should have a 10 knot tailwind and you actually have a 5 knot headwind that's pretty significant, and if you tell Flight Service they will pass it along to the weather forecasters and they'll factor it in to their next Winds Aloft calculation. It will also appear in the next pilot's briefing so they'll know the winds in the forecast aren't correct.
Another example is turbulence: If you're encountering continuous moderate chop at 7,000 feet but smooth air at 9,000 feet providing that information could be useful to the next pilot flying through the same area.

A classic example of a PIREP you file after you're on the ground is icing: If there was no icing in the forecast but you've encountered some you should report these conditions. If you're under ATC control you'll obviously tell them, but when you're on the ground you should call Flight Service and file a formal pilot report. Again, the information will be passed to the weather forecasters and the icing AIRMET will be updated, and your PIREP will be passed along to other folks in their briefings to keep them out of the ice.

• Note that you can also submit PIREPS on aviationweather.gov but I've never used that option: There are more hoops to jump through than I'd care to deal with, and IMHO it's faster to just talk to Flight Service. – voretaq7 Sep 27 '15 at 0:19
• I usually just make them directly with approach or center if the frequency is slow, and I usually only include the relevant items. "Seattle Center, Cessna 123 with a quick pirep." "Go ahead." "4500 over LOFAL, winds 320 at 15, overcast 5000." These almost always end up in the system. – egid Sep 27 '15 at 0:22
• @egid yeah that also works (and if you're IFR and the frequency is slow its better than leaving the frequency). Nobody ever talks to the Flight Service guys around here though, it's like visitng Grandpa Simpson in the home, they're so happy to have someone to talk to :) – voretaq7 Sep 27 '15 at 1:55
• like flashing your lights at other cars on the highway if you know there's a speed trap - It's so good to know I'm not the last one on the planet that does that! Nobody in Indiana seems to have a clue about it... :/. Back to your regularly scheduled discussion of aircraft. – FreeMan Sep 28 '15 at 19:42