The Pilot Report or PIREP or UA is the actual weather report created by pilots and reported in a standard format when unexpected weather conditions (ex, Icing, Turbulence, thunderstorms, volcanic ash etc..) are observed for improving situational awareness.
The periodic weather reports from the ground stations help to understand the weather changes. However, PIREPs are more efficient to distribute unexpected weather changes or hazards noticed by pilots on air and distribute them to ground stations and which can be notified to other pilots.
Traditionally the PIREPs are transmitted over radio communication or telephone after landing. Recently aircraft are equipped with systems to gather the required meteorological data and transmitted it to ground stations using aircraft data link communications.
Pilots are requested to report the weather conditions when certain weather scenarios are reported or forecasted such as,
Volcanic Ash or Smoke or Haze
Thunderstorms, Turbulence or Icing
Weather changes especially when wind shear observed
In some cases, ATC will request the pilot to share the weather scenario or atmosphere data such as,
cloud bases, tops and layers
flight visibility
precipitation
visibility restrictions such as haze, smoke and dust
wind at altitude
temperature aloft
The automated system equipped in aircraft will be helpful in the above-mentioned case to gather the required data and send it to ground stations.
Format
1. Report Type
PIREPs start with the keyword UA (Routine Report) or UUA (Urgent Report).
UA in PIREP indicates the routine report. The following PIREP is a routine report indicating the cloud top, icing intensity and type and also temperature.
DFW UA /OV CQY/TM 1014/FL170/TP C550/SK TOP220/TA M01/IC TRACE RIME/RM ZFW AWC-WEB/UUA in PIREP indicates the urgent report. UAA PIREPs are issued in case of any hazardous weather observed and may impact flight operations. Especially in the following weather situations,
Tornadoes, funnel clouds, or waterspouts.
Severe or extreme turbulence (including clear air turbulence).
Severe icing.
Hail.
Low-level wind shear. (LLWS PIREPs will be classified as UUA if the pilot reports airspeed fluctuations of 10 knots or more).
UUA /OV CWK180020/TM 1050/FL230/TP C56X/TB MOD TURB/RM KZHU AWC-WEB/2. Location (/OV)
/OV element in PIREP is the location identifier. This element contains either an alphanumeric NAVAID code or 4 letters (ICAO) aerodrome code will be used.
UA /OV CQY/TM 1014/FL170/TP C550/SK TOP220/TA M01/IC TRACE RIME/RM ZFW AWC-WEB/In some cases, the location element in PIREP also contains the 3-digit radials and 3-digit distance values in nautical miles. The following PIREP indicates 315 radial and the distance is 3 nautical miles.
UA /OV KLAN315003/TM 1042/FL040/TP SW4/SK OVC020-TOP043/TA M08/IC LGT RIME 3. Time of Report (/TM)
TM element in PIREP indicates the Time of Report in UTC. The following PIREP denotes the reported time as 1042z.
UA /OV KLAN315003/TM 1042/FL040/TP SW4/SK OVC020-TOP043/TA M08/IC LGT RIME4. Flight Level (/FL)
FL element in PIREP indicates the flight level/altitude in hundreds of feet (MSL). The flight level in the report is essential during turbulence and the icing is observed. The following PIREP indicates the Icing condition observed at the flight of 4000 feet MSL.
UA /OV KLAN315003/TM 1042/FL040/TP SW4/SK OVC020-TOP043/TA M08/IC LGT RIMEIn some cases, the following keywords will be used,
DURC - During Climb (When weather conditions are observed during the climb)
DURD - During the Descent (When weather conditions are observed during descent)
UNKN - Unknown
5. Aircraft Type (/TP)
TP element in PIREP indicates the aircraft type. Icing and turbulence reports must always include the aircraft type.
The following PIREP was reported from the aircraft type Boeing 762.
UA /OV DYE045015/TM 1125/FL335/TP B762/TB MOD/RM ZMEUNKN keyword will be used when the type is unknown.
6. Sky Condition (/SK)
SK element in PIREP indicates the sky condition such as,
Cloud Base and Cloud Top in hundreds of feet. The following PIREP indicates the cloud base at 2600 feet and the top at around 4500 feet.
UA /OV CLE180005/TM 1104/FLDURGC/TP E75X/SK BASES 026 TOPS 045/TA M12 / 035/IC TRACE RM 035 THRU 045Cloud Cover. (/ symbol is used when multiple cloud layers are used). The following PIREP indicates the overcast clouds at 1300 feet and the cloud top observed at 4000 feet.
UA /OV KMKG/TM 1122/FLDURGD/TP C700/SK OVC013-TOP040/TA M12/IC LGT RIME*SKC keyword in PIREP indicates the clear sky above the highest cloud layer.
7. Weather Condition (/WX)
WX element in PIREP indicates the Flight Visibility and Weather condition.
/WX FV03SM indicates the Flight visiblity of 3 Statue Miles/WX FV03SM +RA indicates Heavy RainStandard weather symbols will be used in PIREP to indicate the weather conditions.
Refer to the following article to know more about weather conditions,
8. Temperature (/TP)
TP element in PIREP indicates the outside air temperature in 2 digits. The prefix M will be used to denote the negative temperature. The following PIREP denotes the -11 degree celsius.
UA /OV KCOM/TM 1207/FL165/TP BE30/SK BASE140-TOP170/TA M11/IC LGT RIME/RM ZFW AWC-WEB/ 9. Wind Direction and Speed (/WV)
WV element in PIREP indicates the Wind Direction and Speed. The wind direction denotes the from direction (magnetic north) in which the wind is blowing and must be coded in 3 digits.
The wind speed must be entered as a two or three-digit group immediately following the wind direction. The speed must be coded in whole knots using the hundreds digit (if not zero) and the tens and units digits. The wind group always ends with "KT" to indicate that winds are reported in knots.
/WV 28008KT - Wind direction 280 degrees and 08 knots wind speed10. Turbulence (/TB)
TB element in PIREP indicates the Intensity, Type and altitude of the turbulence.
Duration (OCNL, INTMT, CONS) and Intensity (LGT, MOD, SEV, or EXTRM) will be reported together in most cases.
Duration | Meaning |
OCNL | Occasional - Less than 1/3 of the time |
INTMT | Intermittent - 1/3 to 2/3 of the time |
CONS | Continuous - More than 2/3 of the time |
Type includes CAT (Clear Air Turbulence) or CHOP
Turbulence Intensity | Meaning |
Light | Causes slight, erratic changes in altitude and or attitude (pitch, roll, or yaw). |
Moderate | Similar to Light but of greater intensity. Changes in altitude and or attitude occur but the aircraft remains in positive control at all times. It usually causes variations in indicated airspeed. |
Severe | Causes large, abrupt changes in altitude and or attitude. It usually causes large variations in indicated airspeed. Aircraft may be momentarily out of control. |
Extreme | The aircraft is violently tossed about and is practically impossible to control. It may cause structural damage. |
CHOP Intensity | Meaning |
Light Chop | Turbulence that causes slight, rapid and somewhat rhythmic bumpiness without appreciable changes in altitude or attitude. |
Moderate Chop | Turbulence similar to Light Chop but of greater intensity. It causes rapid bumps or jolts without appreciable changes in aircraft altitude or attitude. |
Altitude will be included if it's different from Flight Level (/FL) reported in PIREP
The following PIREP indicates the Continous Light to Occasional Moderate Chop observed.
UA /OV BNA090050/TM 1250/FL320/TP A321/TB CONS LGT OCNL MOD CHOP/RM ZME11. Icing (/IC)
IC element in PIREP indicates the Icing Intensity, Type and Altitude.
Intensity - Contractions such as. TRACE, LGT(Light), MOD (Moderate) and SEV (Severe). If intensity varies then a hyphen will be used to separate the range. NEG will be used if the icing is not observed.
Type - Icing type will be reported as RIME, CLR or MX.
Altitude - Altitude will be reported if it's different from /FL (Flight Level) mentioned in PIREP. ABV or BLO will be used when layers are not defined.
UA /OV FINAL 21L/TM 0906/FLDURD/TP B752/SK BASES 022/IC TRACE RIME12. Remarks (/RM)
RM element in PIREP indicates that the remarks section which will be used to add details about the hazards or more details about weather phenomena.
Remarks include the direction and movement of severe weather situations like Funnel Clouds, Tornados or waterspouts etc. Also, plain language will be used in case of phraseology is not sufficient such as DURC, DURD, RCA, TOP, TOC, or CONTRAILS.
Remarks will be added with element /AWC when the pilot with special training (SKYSPOTTER) reports the PIREP.
UA /OV BFV/TM 0940/FL370/TP A20N/TB LGT-MOD CHOP/RM ZFW AWC-WEB/