Pilot Report (Pirep)

A Pilot Report, or PIREP, is a vital tool for communicating the weather conditions encountered by an aircraft during flight. Traditionally, pilots transmit these reports via radio to a ground station, which shares the information with others. In some cases, reports can also be made by telephone after landing. Nowadays, aircraft equipped with the Aircraft Meteorological Data Relay (AMDAR) system can automatically send weather updates.

The need for PIREPs arises from the presence of hazardous weather, including turbulence, in-flight icing, and thunderstorms. Pilots who experience these conditions play a crucial role in enhancing flight safety by reporting the time, location, and intensity of the threat.

Pilots are encouraged to provide PIREPs in nearly all airspace. In certain regions, air traffic control is required to ask for reports when specific conditions are reported or forecasted. These include ceilings at or below 5,000 feet, visibility at or below 5 miles, thunderstorms, light or greater icing, moderate or greater turbulence, wind shear, and volcanic ash clouds. Pilots should promptly report these conditions along with atmospheric data like cloud bases, tops, and layers, flight visibility, and temperature at altitude.

Once a PIREP is received, the ground station formats the information for distribution. This not only informs other aircraft nearby about the hazards but also assists various agencies. Air Traffic Services (ATS) use the data for weather avoidance procedures, while flight service centers brief pilots and provide inflight advisories. The area control center uses PIREPs to manage enroute traffic effectively and issue hazardous weather information. Additionally, the national weather service may utilize these reports to verify or update aviation forecasts, sometimes triggering advisories based on pilot reports of dangerous conditions.

When submitting a PIREP, pilots must be as accurate as possible. Mandatory details include the location—typically referencing a navigation aid or fix—the time, altitude, and aircraft type, followed by a description of the hazard. For intensity descriptions of icing or turbulence, pilots should refer to the definitions provided by the National Aviation Authority (NAA).

The PIREP is coded for transmission based on specific elements, which include the following: the nearest weather reporting location, report type (routine or urgent), location relative to a VOR, time in UTC, altitude (essential for turbulence and icing), aircraft type, sky cover, weather conditions, temperature, wind direction and speed, turbulence, icing, and any additional remarks.

Here are a couple of examples of PIREPs:

1. KCMH UA /OV APE 230010/TM 1516/FL085/TP BE20/SK BKN065/WX FV03SM HZ FU/TA 20/TB LGT

2. KCMH: Closest weather reporting airport (Columbus, Ohio)

3. UA: Routine PIREP

4. /OV APE 230010: Location ten miles southwest of Appleton VOR

5. /TM 1516: Time 1516 UTC

6. /FL085: Altitude eight thousand five hundred feet

7. /TP BE20: Aircraft type Beech 200 Super King Air

8. /SK BKN065: Base of the broken cloud layer at six thousand five hundred feet

9. /WX FV03SM HZ FU: Flight visibility three miles with haze and smoke

10. /TA 20: Air temperature 20 degrees Celsius

11. /TB LGT: Light turbulence

12. UACN10 CYXU 271338 YZ UA /OV CYYZ 180055 /TM 1338 /FLDURD /TP A319 /TB MDT 200-240 /IC MDT MXD 040-050

13. UACN10: Routine PIREP (Canadian coding)

14. CYXU 271338: Issuing airport (London, Ontario) issued on the 27th at 1338 UTC

15. UA: Routine PIREP

16. /OV CYYZ 180055: Location fifty-five miles south of Toronto Airport

17. /TM 1338: Time 1338 UTC

18. /FLDURD: Altitude – during descent

19. /TP A319: Aircraft type Airbus A-319

20. /TB MDT 200-240: Moderate turbulence between FL200 and FL240

21. /IC MDT MXD 040-050: Moderate mixed icing between 4000 and 5000 feet.