A PIREP, or pilot report, is a short coded message from a pilot describing what the weather is actually like in the air. Each one starts with a station and a report type, then runs through slash-separated elements for location, time, altitude, aircraft type and conditions. Once you know the thirteen element codes, a PIREP reads left to right in about ten seconds.
Key Takeaways
- Every transmitted PIREP includes elements 1 to 6 (station, report type, location, time, altitude, aircraft type) plus at least one weather element.
- "UA" is a routine report and "UUA" is urgent.
- The report is only as good as its timing and altitude, so read those first.
The Thirteen Elements
This is the format table from the FAA's Aeronautical Information Manual (AIM), Chapter 7. Items 1 to 6 appear in every transmitted PIREP, along with one or more of items 7 to 13.
| # | Element | Code | What it tells you |
|---|
| 1 | Station | XXX | Nearest weather reporting location to the reported phenomenon |
|---|
| 2 | Report type | UA or UUA | Routine or urgent PIREP |
|---|
| 3 | Location | /OV | Position in relation to a VOR |
|---|
| 4 | Time | /TM | Coordinated Universal Time |
|---|
| 5 | Altitude | /FL | Essential for turbulence and icing reports |
|---|
| 6 | Aircraft type | /TP | Essential for turbulence and icing reports |
|---|
| 7 | Sky cover | /SK | Cloud height and coverage |
|---|
| 8 | Weather | /WX | Flight visibility, precipitation, restrictions to visibility |
|---|
| 9 | Temperature | /TA | Degrees Celsius |
|---|
| 10 | Wind | /WV | Direction in degrees magnetic and speed in knots |
|---|
| 11 | Turbulence | /TB | Intensity, using the AIM turbulence criteria |
|---|
| 12 | Icing | /IC | Intensity and type, using the AIM icing criteria |
|---|
| 13 | Remarks | /RM | Anything else, or clarification of an earlier item |
|---|
Decode One, Line by Line
This is a PIREP from the AIM:
KCMH UA /OV APE 230010/TM 1516/FL085/TP BE20/SK BKN065/WX FV03SM HZ FU/TA 20/TB LGT
| Part | Meaning |
|---|
| KCMH | Station: Columbus, Ohio, the nearest reporting location |
|---|
| UA | A routine pilot report |
|---|
| /OV APE 230010 | Over the Appleton VOR, 230 degrees, 10 miles. In plain words, ten miles southwest of Appleton |
|---|
| /TM 1516 | Observed at 1516 UTC |
|---|
| /FL085 | Flight level 085, which is 8,500 feet |
|---|
| /TP BE20 | Aircraft type: a Beechcraft King Air 200 |
|---|
| /SK BKN065 | Broken cloud layer with bases at 6,500 feet |
|---|
| /WX FV03SM HZ FU | Flight visibility three statute miles in haze and smoke |
|---|
| /TA 20 | Air temperature 20 degrees Celsius |
|---|
| /TB LGT | Light turbulence |
|---|
The practical reading: at 1516Z, at 8,500 feet southwest of Appleton, a King Air flew in three miles visibility with haze and smoke, a broken layer at 6,500 feet and light turbulence. If you plan to fly that route around that time, a ceiling at 6,500 feet and three miles visibility is something you need to know.
A Longer Example With Icing
KCRW UV /OV KBKW 360015-KCRW/TM 1815/FL120//TP BE99/SK IMC/WX RA/TA M08 /WV 290030/TB LGT-MDT/IC LGT RIME/RM MDT MXD ICG DURC KROA NWBND FL080-100 1750Z
This one gives a route rather than a single point. The AIM reads it as: from 15 miles north of the Beckley VOR to the Charleston VOR, at 1815 UTC and 12,000 feet, in a Beech 99. In cloud, with rain, a temperature of minus 8 Celsius and wind from 290 degrees magnetic at 30 knots. Light to moderate turbulence, light rime icing, and a remark that the pilot encountered moderate mixed icing during the climb northwestbound from Roanoke, Virginia, between 8,000 and 10,000 feet at 1750 UTC.
Notice how the remarks line adds the detail the codes cannot carry. Always read /RM.
How to Read a PIREP for Planning
- Check the time first. A PIREP from three hours ago describes a different sky. Compare the /TM time with now.
- Check altitude and location. Does the report cover your altitude and route? Turbulence at 12,000 feet says little about 4,000 feet.
- Compare with the forecast. A PIREP is the best way to confirm or contradict an AIRMET, SIGMET or TAF, because it is an actual observation.
- Weigh the aircraft type. A King Air's moderate turbulence may feel worse in a Cessna 172, and icing that a de-iced aircraft shrugs off is a serious problem for one without protection.
When and How to File One
The FAA says air traffic facilities are required to solicit PIREPs when these are reported or forecast: ceilings at or below 5,000 feet, visibility at or below 5 miles, thunderstorms and related phenomena, icing of light degree or greater, turbulence of moderate degree or greater, wind shear, and volcanic ash clouds. Pilots are urged to volunteer reports of those and of cloud bases, tops and layers, flight visibility, precipitation, haze, smoke, wind at altitude and temperature aloft.
Give the report to the facility you are already talking to, such as Flight Service, a center or a terminal controller. If you cannot report by radio, reporting on landing to the nearest Flight Service station or Weather Forecast Office helps. The AIM says not to worry about strict format: the important thing is that the information is relayed so other pilots can use it. If something needs clarifying, the ground station will ask.
A turbulence PIREP should state your location, time in UTC, intensity, whether it occurred in or near clouds, altitude, aircraft type and duration.
Where to Find PIREPs
PIREPs are distributed through the weather system to briefers and forecasters, and you can read current reports on the Aviation Weather Center's website. For a fuller treatment of turbulence and icing terms, the FAA's Aviation Weather Handbook (FAA-H-8083-28) is the reference the AIM points to.
Frequently Asked Questions
What does UA mean on a PIREP?
UA marks a routine pilot report. UUA marks an urgent report, which covers hazards such as severe turbulence, severe icing or wind shear.
What is the difference between a PIREP and a METAR?
A METAR is an observation from a fixed ground station. A PIREP is an observation from a pilot at a particular place and altitude in the air, so it can describe things a ground station cannot see, like cloud tops, icing or turbulence.
Do I have to file a PIREP?
The AIM urges pilots to cooperate and volunteer reports of the conditions air traffic facilities are required to solicit. Format is not strict, and the ground station will ask if something needs clarifying.
How old can a PIREP be and still be useful?
The age that matters depends on the weather, but always compare the report time (/TM) with the current time and treat it as an observation of a past moment rather than a forecast.
Related guides: How to Read and Decode a METAR, With a Worked Example.
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