Decoding a PIREP
PIREP: pilot's in-flight weather report. Only report of what the air is actually doing: turbulence, icing, cloud tops. Fields prefixed /.
Report type (first):
| Code | Type |
|---|---|
UA |
routine pilot report |
UUA |
URGENT report |
UUA hazards (TC AC 100-001, "urgent PIREP"; AWH 24.5.1.1.1):
- Severe or extreme turbulence
- Severe icing
- Low-level wind shear
- Hail
- Tornadoes, funnel clouds, waterspouts
- Volcanic ash
TC: urgent PIREPs are for conditions that are "an immediate hazard for all aviation users" (AIM MET 2.1).
The 1,500 ft AGL figure is the METAR/TAF WS group (wind shear), a different product (TC AIM MET, METAR and TAF wind shear groups).
Example:
CYYZ UA /OV CYYZ /TM 1345 /FL080 /TP C172 /SK BKN050 /TA -03 /WV 24030KT /TB MOD /IC LGT RIME
| Field | Meaning |
|---|---|
/OV |
location (station, or bearing/distance from one) |
/TM |
time, UTC |
/FL |
altitude as flight level, hundreds of feet: FL080 = 8,000 ft ASL |
/TP |
aircraft type (here a C172) |
/SK |
sky / cloud layers |
/TA |
outside air temperature, °C (leading - = sub-zero, e.g. -03) |
/WV |
wind (direction/speed), true |
/TB |
turbulence intensity, decoded in turbulence-intensity-and-reporting |
/IC |
icing intensity TRACE, LGT, MOD, SEV (defined in icing-intensity) + type RIME, CLR (clear), MX (rime and clear at once), described in icing (TC AIM MET 2.4, Table 2.4) |
/RM |
remarks (plain language) |
Field notes:
/FLheights are ASL (PIREP and GFA); METAR/TAF are AGL./FLalso takesDURD(during descent),DURC(during climb),UNKN(unknown) when no fixed altitude applies./WVdirection: pilot reports degrees magnetic, converted to true before entry.
Trap: swapping UA (routine) and UUA (urgent), reading /FL080 as 80 ft or 80,000 ft instead of 8,000 ft ASL, or mixing field prefixes (/TB turbulence as /IC icing, /TP type as /TM time).
References
- TC AIM MET 2.1 (PIREP example, fields)
- TC AIM MET 2.4 (icing intensity codes, Table 2.3; icing type codes, Table 2.4)
- TC AIM MET 1.2.2 (PIREP heights ASL)
- FAA AWH 24.5.1.1.1 (urgent PIREP criteria)
- TC AIM MET 2.5 (volcanic ash urgent PIREP)