What is a PIREP (Pilot Report) in Aviation?
In modern aviation, staying ahead of changing weather conditions is critical to flight safety and operational efficiency. While forecasts offer predictions based on meteorological models, actual in-flight conditions can deviate significantly. This is where PIREPs—Pilot Reports—become a crucial component of the aviation safety ecosystem.
✈️ Definition of a PIREP
A PIREP (Pilot Report) is a real-time report submitted by a pilot during flight, detailing actual weather conditions encountered. These observations, made from the cockpit, are invaluable for air traffic controllers, meteorologists, flight dispatchers, and other pilots. Unlike weather forecasts, PIREPs provide current, localized, and experience-based information on atmospheric phenomena.
📌 Why Are PIREPs Important?
PIREPs play a key role in aviation safety and operational planning. Their primary benefits include:
- Real-Time Weather Insight: Helps pilots make informed decisions by knowing what lies ahead—such as icing, turbulence, or visibility issues.
- Forecast Validation: Meteorologists use PIREPs to verify, adjust, or improve their models, ensuring better accuracy in future forecasts.
- Air Traffic Control Efficiency: ATC may issue advisories or reroute aircraft based on hazardous weather reported by pilots.
- Flight Planning: Airlines and dispatchers use this data to adjust flight levels, reroute traffic, or delay departures.
🔍 Components of a Standard PIREP
A PIREP consists of standardized codes and fields to ensure consistency. Below is a breakdown of the most commonly used elements:
| Code | Meaning | Description |
|---|---|---|
| UA / UUA | Report Type | UA: Routine / UUA: Urgent (severe weather, volcanic ash, etc.) |
| /OV | Location | E.g., relative to an airport or navigation aid (e.g., 25NM E of JFK) |
| /TM | Time | Report time in UTC |
| /FL | Flight Level | Altitude of the observation |
| /TP | Aircraft Type | Useful for understanding turbulence or icing impact |
| /SK | Sky Conditions | Cloud layers, bases, and tops |
| /WX | Weather | Rain, snow, fog, visibility, etc. |
| /TA | Temperature Aloft | In degrees Celsius |
| /WV | Winds Aloft | Direction and speed |
| /TB | Turbulence | Intensity and altitude range |
| /IC | Icing | Type and severity of ice accumulation |
| /RM | Remarks | Free-text notes (e.g., lightning, clear air turbulence, rotor activity) |
📘 Sample PIREP and Its Interpretation
Interpretation:
- UUA: Urgent report
- /OV DFW180030: 30 NM south of Dallas/Fort Worth
- /TM 1535: 15:35 UTC
- /FL090: 9,000 feet altitude
- /TP A320: Airbus A320 aircraft
- /SK OVC085-TOP110: Overcast clouds from 8,500 ft to 11,000 ft
- /TA M03: Temperature is -3°C
- /TB SEV: Severe turbulence
- /IC MDT RIME 080-090: Moderate rime icing from 8,000–9,000 ft
- /RM LLWS +/-15KT SFC-030: Low-level wind shear, wind speed changes of ±15 knots between surface and 3,000 ft
🧭 How Pilots Submit a PIREP
Pilots can submit PIREPs through:
- Air Traffic Control (ATC) during radio communication in flight
- Flight Service Stations (FSS) via radio or telephone
- Automated systems (ACARS or EFB-integrated apps on newer aircraft)
While filing a PIREP is not mandatory (except in specific commercial operations or training environments), pilots are encouraged to report:
- Unusual or severe weather not indicated in forecasts
- Turbulence, icing, or volcanic ash
- Significant deviations from expected visibility or cloud coverage
- Better-than-forecast conditions, which help others plan accordingly
📅 When Should a PIREP Be Filed?
Common situations where a PIREP is useful or necessary:
- Encountering moderate or greater turbulence
- Observing ice accumulation that affects aircraft performance
- Detecting wind shear or microbursts
- Flying through volcanic ash or smoke
- Finding improved or worse-than-forecast conditions
🛫 Who Uses PIREPs?
| User | Purpose |
|---|---|
| Pilots | Planning enroute altitudes, diversions, or delays |
| Air Traffic Controllers | Adjusting air traffic flows, issuing hazard advisories |
| Meteorologists | Refining forecast models and issuing SIGMETs |
| Dispatchers and Airlines | Making routing and fuel decisions |
| Flight Schools | Teaching weather interpretation and decision-making |
✅ Benefits of Accurate PIREPs
- Enhances collective safety in shared airspace
- Reduces uncertainty in high-risk environments
- Helps develop more accurate weather awareness tools
- Encourages collaboration between pilots and ground services
🔚 Conclusion
A PIREP is more than just a weather update—it’s a vital safety tool. By providing firsthand, real-time insights into atmospheric conditions, pilots improve the safety, efficiency, and predictability of the entire airspace system. Encouraging regular and detailed pilot reports is essential for the continued advancement of aviation safety and weather forecasting reliability.
References
- FAA Aeronautical Information Manual (AIM)
- Skybrary: Pilot Reports (PIREPs)
- AOPA: PIREPs Made Easy
- CFI Notebook: Pilot Reports
