PIREP (Pilot Report)

A PIREP (Pilot Report) is a first-hand, in-flight weather observation submitted by a pilot describing the actual atmospheric conditions encountered at a specific location, altitude, and time. PIREPs are the only weather product in the aviation system that represents real-time empirical data from within the air mass — every other product (METAR, TAF, SIGMET, AIRMET) is either a surface observation, a forecast model output, or a remote-sensing inference. The international framework for PIREPs is established in ICAO Annex 3 §5.6 (Reports from Aircraft); in the United States, detailed format and content requirements appear in FAA AC 00-45H (Aviation Weather Services) and FAA Order 7110.10 (Flight Services).

PIREPs are formatted using a standard abbreviated coding sequence: UA (routine PIREP) or UUA (urgent PIREP), followed by /OV (over — location), /TM (time in UTC), /FL (flight level or altitude in MSL), /TP (aircraft type), and then one or more of the following optional but operationally critical elements: /SK (sky condition — cloud bases, tops, cloud type), /WX (flight visibility and weather phenomena), /TA (air temperature in Celsius), /WV (wind direction/speed), /TB (turbulence — intensity, type, altitude range), /IC (icing — intensity, type, altitude range), and /RM (remarks — free text). The ICAO equivalent fields are similar in structure but use slightly different delimiters and are transmitted through the ATS communications system rather than the US FSS (Flight Service Station) network.

The Urgent PIREP (UUA) is reserved for observations of severe or extreme turbulence, severe icing, low-level wind shear (within 2,000 ft of the surface), volcanic ash, tornadoes, waterspouts, funnel clouds, or hail. A UUA is immediately relayed by ATC or FSS to the Aviation Weather Center, which evaluates whether it meets the criteria for a new SIGMET issuance or amendment to an existing SIGMET. This means a single airborne pilot's observation can directly trigger a weather advisory that protects hundreds of subsequent aircraft from the same hazard — making UUAs one of the highest-leverage safety actions available to any pilot.

The ICAO turbulence intensity scale used in PIREPs has four levels: Light (slight erratic changes in altitude/attitude, turbulence that does not materially affect aircraft control), Moderate (similar but of greater intensity — occupants feel definite strains against seat belts, unsecured objects become dislodged), Severe (large abrupt changes in altitude/attitude, aircraft may be momentarily out of control, occupants are forced violently against restraints), and Extreme (aircraft is violently tossed about and practically impossible to control — may cause structural damage). For icing, the scale runs Trace (barely perceptible, no deice/anti-ice required), Light (slight problem if flight is prolonged), Moderate (safety problem if flight is prolonged, requires immediate corrective action), and Severe (rate of accretion exceeds the capability of de-icing/anti-icing equipment — immediate diversion required).

Despite their critical safety value, PIREP submission rates by general aviation pilots remain chronically low. Studies by the FAA and NWS have documented that only a small fraction of GA pilots who encounter reportable conditions actually submit a PIREP, compared to airline crews who submit routinely under Part 121 company requirements. This data gap is operationally significant: when PIREPs are sparse, forecasters rely more heavily on model output, which can miss localized icing layers, turbulence pockets, and actual cloud tops that differ materially from forecast levels.

For flight school operations, PIREPs are relevant in two directions. Incoming PIREPs from other pilots operating in the school's training area — especially UUAs for turbulence or icing — are actionable intelligence for the dispatcher deciding whether to approve a student solo or cross-country departure. An AIRMET Zulu for moderate icing that has no supporting PIREPs is a different operational picture than the same AIRMET backed by three recent UUAs for severe icing from aircraft at the student's planned cruise altitude.

Outgoing PIREPs from school instructors and students are both a safety contribution to the broader aviation community and a curriculum objective. The FAA Instrument Rating ACS (Airman Certification Standards) requires applicants to demonstrate knowledge of PIREP format and the conditions that require an urgent report. Part 141 instrument rating course syllabi must include PIREP training as a ground and airborne lesson component. Schools that encourage PIREP filing as a standard operating procedure — rather than an optional afterthought — produce pilots who arrive at their commercial and ATP certificates with an established habit of airmanship that prevents accidents throughout their career.

Aviatize's smart planning and booking module can display current PIREPs and UUAs along the planned route of each training flight, giving dispatchers and instructors direct access to real-world condition reports from other pilots before approving a departure. When a UUA for severe turbulence or severe icing appears within the geographic bounds of a scheduled lesson, Aviatize can surface that report alongside the booking for rapid human review — reducing the window between hazard encounter and school-level decision from however long it takes to manually check a briefing website to the time it takes to glance at the dispatch screen.

For student training record purposes, Aviatize can log instructor-submitted PIREPs as part of the lesson debrief entry, associating the report with the flight's date, route, aircraft type, and student stage of training. Over time, this builds a school-level dataset of real weather encounters that can be used in safety management reviews, insurance documentation, and curriculum analysis — identifying which routes and seasons produce the most turbulence and icing encounters, and whether students at particular training stages are being exposed to conditions appropriate to their experience level.