PIREPs explained
What a pilot report is, how to decode one, and why your own PIREPs make the system safer.
A PIREP (pilot report) is a real-time, first-hand observation of weather from an aircraft in flight — the only weather product that confirms what's actually happening aloft, such as cloud tops, icing, turbulence, and in-flight visibility. Forecasts and radar infer conditions; a PIREP reports them.
A coded PIREP has standard fields. For example: `UA /OV KBOS 090030 /TM 1415 /FL060 /TP C172 /SK BKN040-TOP070 /TA 02 /IC LGT RIME /RM SMOOTH`
- UA routine (UUA = urgent), /OV location, /TM time (Z), /FL altitude, /TP aircraft type.
- /SK sky/cloud (broken 4,000 ft, tops 7,000), /TA temperature, /IC icing (light rime), /TB turbulence, /RM remarks.
Urgent PIREPs cover severe icing or turbulence, low-level wind shear, tornadoes, hail, and volcanic ash — things every nearby pilot needs to know now.
PIREPs are invaluable for decisions forecasts can't make for you: *Is the layer really only 2,000 ft thick? Are the tops climbable? Is there ice at my cruising altitude?* And the system only works if pilots feed it. Give a PIREP whenever conditions differ from the forecast — good or bad — by calling Flight Service or ATC. A "negative ice, smooth, tops 6,000" report is as useful to the next pilot as a warning.
*Reference and training only. Use official briefings for flight planning.*