The Pirep, the Pilot Report, and the One Weather Product You Do Not Just Read - You Create It for the Airplane Behind You
A pilot report (PIREP) is the one weather product you create, not just read - here's how to decode, use, and file one.
A pilot report (PIREP) is the only aviation weather product that comes from a human being flying in real weather rather than a machine, model, or forecast. It tells you where cloud bases and tops actually are, how rough the ride is, and whether forecast ice is real - information no METAR or TAF can provide. Every pilot is both a consumer and a creator of PIREPs, and the aircraft behind you depends on you to file one.
What Makes a PIREP Different From Other Weather Products
Almost every weather product you review during a briefing is a forecast, a model, or an automated observation. A METAR is an automated station reading the air at one point on the ground. A winds aloft forecast is a computer’s best guess for a grid point hours out. A satellite image shows cloud tops from 200 miles up. All useful, all a step removed from reality.
A PIREP is the exception. It is a human pilot, at your altitude, in weather like yours, telling you the truth - where the bases and tops really are, whether the ride is smooth or violent, and whether that forecast icing layer is actually ice or just gray and harmless.
A machine can report temperature and dewpoint. It cannot tell you the ride got rough at 8,500 feet over the ridge and smoothed out at 10,000. Only a pilot can, and sometimes that pilot is you.
How Do I Read a PIREP?
At first a PIREP sounds like alphabet soup, but it follows a consistent pattern. There are two types:
- Routine PIREP - coded UA
- Urgent PIREP - coded UUA, with an extra “U” on the front
That extra “U” matters. Urgent means a pilot encountered something likely to hurt the next aircraft: severe or extreme turbulence, severe icing, hail, a funnel cloud or tornado, low-level wind shear, volcanic ash, or an aircraft losing control in the clouds. When Flight Service receives a UUA, it goes out to everyone in the area immediately.
The body of the report is built from two-letter fields. Read in order, they form a sentence:
- Location - usually a VOR or fix with distance and bearing (e.g., 40 miles southwest of a VOR)
- Time - in Zulu
- Flight level - the altitude, written in hundreds of feet
- Aircraft type - critical context (more below)
- Sky cover - bases and tops of layers
- Visibility and weather
- Temperature
- Wind
- Turbulence - intensity (light, moderate, severe, extreme) and frequency (occasional, intermittent, continuous)
- Icing - intensity (trace, light, moderate, severe) and type (rime, clear, mixed)
- Remarks - plain-language notes
Why Does the Aircraft Type in a PIREP Matter So Much?
The aircraft type field matters more than most students think. Light turbulence reported by a Boeing 767 means something very different than light turbulence from a Cessna 172. Same air, two completely different airplanes.
Always look at what was flying when the pilot felt it. If a heavy jet called it moderate chop and you’re in a light single, plan for a rougher afternoon than that word suggests.
Don’t skip the remarks, either. That final plain-language field - “tops ragged,” “better ride down low,” “building fast to the west” - is often the most valuable part of the whole report, because that’s where the human actually talks to you.
How Does a PIREP Actually Change a Decision?
Codes on a page don’t make you safer - decisions do. Picture a cool, damp morning. You’re a fresh instrument pilot planning a cross country. METARs along your route report overcast around 3,000 feet, temperature and dewpoint are close, and the freezing level is forecast near 5,000 feet. On paper, that’s a legal flight. You could file, launch, and climb on top.
Before you do, you search for PIREPs along your route and find one: a Cessna 182, 40 minutes ahead at your planned altitude, reported light to moderate rime icing in the climb and said the tops were higher than forecast - closer to 8,000 feet.
Nothing in the METAR told you that. But a pilot in your airplane, in your air, just told you exactly what’s waiting in that cloud. Now the legal flight looks like a very different decision. Maybe you wait two hours for the temperature to rise, find a route where the layer is thinner, or simply don’t go today.
That PIREP cost the reporting pilot 30 seconds on the radio and may have kept you out of an icing situation your aircraft was never certified to handle.
How Do I File a PIREP?
Here’s where most pilots fall short: we’re great at asking for PIREPs and terrible at giving them. Filing one is not a test - nobody grades your grammar, and you don’t need the fields in perfect order.
Key up with Flight Service on the appropriate frequency, or tell the controller you’re working with, and say what you see. For example:
“Cessna one two three four five, level at six thousand, about ten miles north of the airport. Bases of the overcast right at four thousand five hundred, tops around seven thousand, smooth ride, no ice.”
That’s a complete, useful, life-saving report. The specialist will clean it up, format it, and push it to the system. Your job is just to talk.
File good-news reports too. A PIREP saying the ceiling lifted, the ride is smooth, and there’s no ice where the forecast threatened it is enormously valuable - it lets the pilot behind you relax a plan the paper made look scary. Negative reports are real reports. If you climb through a layer forecast to be full of ice and pick up nothing, say so.
When Should I Give a PIREP?
The Aeronautical Information Manual (AIM) asks pilots to report whenever they encounter unexpected weather:
- Cloud bases, tops, and layers that don’t match the forecast
- Visibility changes
- Thunderstorms
- Wind shear
Any time you hit the urgent items - icing, severe turbulence, a funnel cloud - you are strongly encouraged to report immediately, not after you land.
Weather has a shelf life. A PIREP from 20 minutes ago is worth its weight in gold; one from three hours ago is a history lesson. The value decays fast, which is exactly why the report must come from the aircraft that’s in it right now.
What Do Students and Checkride Applicants Need to Know?
On your knowledge test and oral exam, you’re expected to decode a PIREP from one of those alphabet-soup strings. Practice it. The Aviation Weather Center at aviationweather.gov plots PIREPs on the map - click one, read it, and quiz yourself on every field. Do that ten times and the code becomes a sentence.
On the practical test, when the examiner walks you through a weather briefing scenario, they want to see two things:
- You actively went looking for PIREPs as part of building your weather picture - not just METARs and TAFs.
- You’d file one yourself if you encountered something worth passing along.
That answer tells the examiner you understand you’re not just a customer of the weather system - you’re a participant in it. That’s the mature-pilot answer that separates memorization from real safety judgment.
Your Next Step
On your next cross country - beautiful weather or lousy - make one PIREP. Just one. Tell Flight Service or your controller what you see: bases, tops, the ride, any ice. Get the words out once, and the second time is easy. The tenth time is automatic.
Aviation weather works because pilots talk to each other across time. The person ahead of you flew the air you’re about to fly and left you a note. Someday - maybe today - you’ll be the person ahead, and someone 30 miles back will be glad you took 30 seconds to say what the clouds were actually doing.
Key Takeaways
- A PIREP is the only weather product created by a pilot in real weather, not a machine or model - making it uniquely accurate for bases, tops, turbulence, and icing.
- Routine reports are coded UA; urgent reports (UUA) flag life-threatening conditions like severe icing, severe turbulence, and funnel clouds, and are broadcast immediately.
- Always check the aircraft type - the same turbulence feels far worse in a light single than in a heavy jet.
- Negative reports matter: telling the system there’s no ice where it was forecast is as valuable as a warning.
- PIREP value decays fast; file immediately while the weather is still true, ideally within minutes of encountering it.
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