The Pilot Report, the Coded UA and UUA, and Why the One Weather Product Written by Pilots Is the One Students Never File

A pilot report (PIREP) is the only aviation weather product created by a human being who was actually flying through the conditions in real time - not a forecast, not a model, not an automated sensor. It comes in two forms: a routine UA report and an urgent UUA report, and it’s built from short two-letter coded fields covering location, time, altitude, aircraft type, and the actual weather. Learning to read PIREPs sharpens every go/no-go decision, and learning to file them makes you a contributing member of the aviation safety system.

What Is a PIREP and Why Does It Matter?

Almost every weather product in your briefing is either a prediction or a machine reading. The Terminal Aerodrome Forecast (TAF) is a forecast. The winds aloft are a model output. The METAR is mostly an automated station reporting what a sensor measured a few feet off the ground. All useful - but none of them can tell you what the air actually feels like at 4,500 feet over the ridge you’re about to cross.

Only the pilot report does that. It’s the single piece of aviation weather that comes from a pilot who was up there, in it, right now, and told the system what happened. It is, quite literally, weather written by pilots, for pilots.

The FAA and the National Weather Service don’t just appreciate PIREPs - they depend on them. When a forecaster is deciding whether to issue an AIRMET for icing or upgrade a SIGMET for turbulence, one of the biggest things they’re waiting on is a pilot to confirm the condition is real. The forecast says icing is possible. A PIREP says icing is happening. That second sentence is the one that changes decisions.

How Do You Read a Coded PIREP?

A PIREP arrives in a coded format that looks intimidating but is really just a checklist. Once you see its shape, you can’t un-see it.

The report opens with one of two labels:

• UA - a routine pilot report noting the conditions aloft.
• UUA - an urgent report. That double U means the pilot encountered something serious: severe turbulence, severe icing, hail, a funnel cloud, low-level wind shear, or volcanic ash. When you see UUA, sit up straight.

After the label, the report is built from fields, each with a two-letter tag:

• OV (Over) - the location, usually relative to a navaid or airport. You might see a VOR identifier followed by a radial and distance - for example, the 360 radial at 15 miles, meaning 15 miles due north of that station.
• TM (Time) - given in Zulu (UTC), four digits. This tells you how fresh the report is. A turbulence PIREP from ten minutes ago is gold; one from three hours ago should be taken with a grain of salt.
• FL (Flight Level) - altitude in hundreds of feet. FL045 means 4,500 feet. Altitude is everything with a PIREP - turbulence at 8,000 tells you nothing about your ride at 4,500.
• TP (Type of aircraft) - the field students skip, and the one you should never skip. Moderate turbulence in a Boeing 737 is a completely different animal than moderate turbulence in a Cessna 172. The aircraft type calibrates everything reported after it.

Then come the actual weather fields:

• SK (Sky) - clouds, bases, and tops.
• TA (Temperature) - in Celsius, which helps you find the freezing level.
• WV (Wind) - direction and speed.
• TB (Turbulence) - intensity and type.
• IC (Icing) - intensity and type.

Turbulence and icing are where PIREPs earn their keep, because those are the two things no ground sensor can measure and no forecast can promise.

Finally:

• RM (Remarks) - the pilot’s own plain-language words. This is often the gem: “Broke out on top at 6,200, clear above,” or “Lost 15 knots in the shear on short final, go around.” A remark from someone who was just where you’re going can be worth more than the rest of your briefing combined.

How Do You Use a PIREP to Make a Go/No-Go Decision?

A string of two-letter codes means nothing until you use it to decide something. Here’s a realistic scenario.

You’re planning a morning flight - a 120-mile cross-country, you and one passenger in a Cessna 172. The TAF at your destination calls for marginal VFR with ceilings around 2,500, and there’s an AIRMET Sierra out for mountain obscuration along your route. It’s legal, but it’s not comfortable, and you can’t tell whether that ceiling is really 2,500 or lower and lumpier than the forecast admits.

So you go hunting for pilot reports along the route, and you find one:

• UA - routine.
• TM - 40 minutes old.
• TP - another Cessna 172, so it’s your airplane, your performance, your eyeballs.
• FL - 4,500 feet.
• SK - bases at 2,200, tops at 4,000.
• RM - “Smooth on top, occasional buildups to the west, breaks in the deck over the valley.”

Look at what you just learned that no forecast gave you. The ceiling is real and a little lower than advertised - 2,200 instead of 2,500. The tops are only at 4,000, so an instrument-rated, current pilot could climb through a thin layer into smooth air. There are breaks over the valley, meaning a VFR option exists down low if you stay in the right place. And the buildups are to the west, telling you where the trouble is and isn’t. One 40-minute-old report from a pilot in your same airplane just turned a vague, nervous decision into an informed one.

How Do You File a PIREP on the Radio?

Reading PIREPs is only half the job. Filing them is the half almost nobody does - and there are never enough of them. Whole regions, altitudes, and hours pass with the system blind because pilots experience weather and say nothing.

Here’s the good news: giving a PIREP is one of the easiest radio calls you’ll ever make. You do not need the codes - that’s the controller’s job. You describe what you saw in plain English, and they build the coded report for you.

Who do you call? Flight Watch as a dedicated service no longer exists, but you have plenty of options:

• Any air traffic controller you’re already talking to - approach, center, or tower.
• Flight Service on the radio.
• On the ground, file through Flight Service or directly in your electronic flight bag (EFB) app.

What do you say? Walk through the same fields you learned to read, just out loud and in order - who and where you are, your altitude, your aircraft type, and the thing you want them to know:

“Skyhawk 523, level 4,500, twenty miles north of the field, encountering light to moderate turbulence and picked up a trace of rime ice in the climb - now clear of it on top at 5,000.”

That’s the whole thing. The controller does the rest.

How Do You Report Turbulence and Icing Accurately?

Precision here is a genuine skill, and it matters.

Turbulence runs on a scale of light, moderate, severe, and extreme - and most pilots go an entire career without legitimately seeing severe. The practical dividing lines, roughly as the Aeronautical Information Manual (AIM) frames them:

• Light - slight, erratic bumps. You feel it, but you’re not fighting the airplane and loose objects stay put.
• Moderate - definite changes in altitude and attitude, strain against the seatbelt, and loose items moving around the cabin. The coffee’s a goner.
• Severe - the airplane is momentarily out of control, with large abrupt changes and occupants thrown hard against the belt. Honest severe turbulence is a UUA (urgent) report - file it the moment you have a free hand.

The most common mistake is calling severe when you mean moderate - adrenaline inflates the estimate. A calibrated, honest moderate is worth more to the system than an exaggerated severe, because if you cry severe over a moderate ride, you make your own future reports worth less.

Icing runs on a scale of trace, light, moderate, and severe - and this is the report forecasters are truly starving for:

• Trace - perceptible but accumulating slowly; not a factor unless you sit in it a long time.
• Light and moderate - accumulating fast enough that you need to act: deice if equipped, or better, change altitude and get out.
• Severe - your deicing equipment can’t keep up. Severe icing is an emergency and always a UUA. Report it and get out of it.

When you report icing, forecasters most want the type (rime or clear) along with the altitude and temperature where you found it - that’s how the freezing level gets pinned down for everyone flying behind you.

Why Should Student Pilots Care About PIREPs?

Your takeaway has two parts.

First, hunt for PIREPs on every cross-country you plan. Make it as automatic as checking the METAR. Read the type, the altitude, and the time, and let a real pilot’s real experience calibrate what the forecast is only guessing at. The Airman Certification Standards (ACS) explicitly expect you to gather and interpret all available weather, and PIREPs are named right in that standard. Examiners want a pilot who synthesizes the actual picture, not one who just recites the forecast.

Second, file your own reports. When you experience something - the ride, the ceiling you broke out of, the ice, the smooth air on top, the layer that sat 2,000 feet lower than forecast - say so. You don’t need the codes or a professional-sounding voice. Every PIREP in the system got there because one pilot decided the person behind them mattered.

Key Takeaways

• A PIREP is the only aviation weather product created by a pilot in flight - the one source that reports what the air actually feels like, not what a model predicts.
• UA means routine; UUA means urgent (severe turbulence, severe icing, hail, funnel clouds, wind shear, or volcanic ash).
• Always read the TP (aircraft type), FL (altitude), and TM (time) fields - they calibrate how much a report actually applies to your flight.
• Filing a PIREP requires no codes - describe conditions in plain English to any controller, Flight Service, or your EFB app, and they build the coded report.
• Report turbulence and icing honestly and precisely - a calibrated “moderate” is more valuable than an exaggerated “severe,” and severe icing is always an emergency.