Pilot Reports
Encyclopedia
A pilot report or PIREP is a report of actual weather
conditions encountered by an aircraft
in flight. This information is usually relayed by radio
to the nearest ground station. The message would then be encoded
and relayed to other weather offices and air traffic service units.
Although the actual form used to record the PIREP may differ from one country to another, the standards and criteria will remain almost the same. At a minimum the PIREP must contain a header, aircraft location, time, flight level, aircraft type and one other field.
In recent years, a PIREP will also include *UA or UUA used to identify the PIREP as routine or urgent.
, funnel cloud
, waterspout
, severe turbulence
, severe icing
, hail
, or a low level wind shear
hazard, the identifier "UUA" would be used.
The location (/OV) can be reported in one of three ways: as a direction and distance from a navigation aid (NAVAID), as a direction and distance from an airport, or as the latitude
and longitude
of the aircraft.
The time (/TM) used is the UTC
time that the PIREP is reported.
The flight level (/FL) is reported as either a three digit value that indicates the altitude of the aircraft above sea level in hundreds of feet or can one of three abbreviations: DURD (during descent or on approach), DURC (during climb or after takeoff) and UNKN (unknown).
Aircraft type (/TP) will be the approved ICAO designator, or UNKN if not reported.
Sky cover (/SK) is used to report the cloud
layer amounts and the height of the cloud base. The tops of the cloud layers can also be included, as can more than one layer of cloud. Heights are in hundreds of feet above sea level and are three digits. Abbreviations used in this group are "CLR" (clear), "FEW" (few), "SCT" (scattered), "BKN" (broken) and "OVC" (overcast).
Temperature (/TA) is the air temperature in whole degrees Celsius as a two-digit value, with negative temperatures preceded by a minus (-) sign.
Wind velocity (/WV) must contain both the wind speed and direction. Direction is reported as a three-digit value in whole degrees true and the wind speed in knots also in three digits.
Turbulence (/TB) and the intensity are reported in a PIREP based on the aircraft and occupants reaction to the turbulence. The altitude of the turbulence should be included using three-digit groups. When the top or the base of the turbulence is unknown then the abbreviation BLO (below) or ABV (above) should be used. Turbulence should be reported as LGT (light), MDT (moderate), SVR (severe) or in exceptional cases EXTRM (extreme). Clear-air turbulence
is reported as CAT.
Icing (/IC) is reported by type and the intensity or rate of accretion. The type of ice is reported as "CLR" (clear), "RIME", or "MXD" (mixed). The intensity is reported as "TR" (trace), "LGT" (light), "MDT" (moderate), and "SVR" (severe).
Remarks (/RM) report on other weather conditions that are not covered in the rest of the PIREP may include such things as icing in precipitation, thunderstorms, St Elmo's fire and frontal
conditions. There are many other types of weather conditions that could be reported in a PIREP.
The above explanation of PIREP fields is Canadian. The United States version may also include a weather (/WX) group; and other countries may use other groups and measurements.
.
UACN10 CYQT 192128
YZ WG
UA /OV YSP 090025 /TM 2120 /FL050 /TP BE99 /SK 020BKN040 110OVC /TA -14 /WV 030045 /TB MDT CAT 060-080 /IC LGT RIME 020-040 /RM LGT FZRA INC
Decoded is
Routine Upper Air, Aircraft report from Thunder Bay
, Ontario
issued at 2128 UTC on the 19th
YZ is Toronto
and WG is Winnipeg
. This is the Flight Information Region where the PIREP was issued
Aircraft observation was 25 nmi (46.3 km) east (090 degrees magnetic) of the Marathon
, Ontario
VOR/DME
at 2120 UTC. The aircraft was at 5,000 ft (1,524 m)and is a Beech 99
. The clouds were broken at 2,000 ft (610 m) AMSL with tops at 4,000 ft (1,219 m) and an overcast layer at 11,000 ft (3,353 m) AMSL. The temperature is -14 Celsius and the winds are from the NE (030 degrees true) at 45 knots (83 km/h). There is moderate clear air turbulence between 6,000 ft (1,829 m) and 8,000 ft (2,438 m). There is light rime icing between 2,000 ft (610 m) and 4,000 ft (1,219 m). Note this would indicate that the icing is picked up in the cloud. The remarks section says that light freezing rain was encountered in the cloud.
UACN10 CYXU 032133
YZ
UA /OV YUX 09010 /TM 2120 /FL030 /TP C172 /TB MDT /RM MDT TURB BLO 050 CYKF CYXU
Routine message from London
Ontario, issued at 2133 UTC on the 3rd
The Flight Information Region is Toronto
The aircraft was 10 nmi (18.5 km) east (090 degrees true) of the London VOR at 2120 UTC. The aircraft was at 3,000 ft (914 m) and was a Cessna 172
. The pilot reported moderate turbulence. Then in remarks went on to say that the turbulence was below 5,000 ft (1,524 m) between Kitchener
/Waterloo
and London.
s are required to solicit PIREPs upon request of other facilities or pilots, or when any of the following conditions exists or is forecast in their area:
At least once hourly, terminal controllers must obtain a descent/climb-out PIREP, including cloud information and other related phenomena.
Weather
Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the troposphere, just below the stratosphere. Weather refers, generally, to day-to-day temperature and precipitation activity, whereas climate...
conditions encountered by an aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
in flight. This information is usually relayed by radio
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
to the nearest ground station. The message would then be encoded
Encoder
An encoder is a device, circuit, transducer, software program, algorithm or person that converts information from one format or code to another, for the purposes of standardization, speed, secrecy, security, or saving space by shrinking size.-Media:...
and relayed to other weather offices and air traffic service units.
Although the actual form used to record the PIREP may differ from one country to another, the standards and criteria will remain almost the same. At a minimum the PIREP must contain a header, aircraft location, time, flight level, aircraft type and one other field.
In recent years, a PIREP will also include *UA or UUA used to identify the PIREP as routine or urgent.
Mandatory
- UA or UUA used to identify the PIREP as routine or urgent (Note: in Canada this is indicated by the prefix to the PIREP: "UACN01" for an urgent PIREP or "UACN10" for a normal PIREP).
- /OV location of the PIREP, in relation to a NAVAID, an aerodrome or geographical coordinates
- /TM time the PIREP was received from the pilot. Coordinated Universal Time.
- /FL flight levelFlight levelA Flight Level is a standard nominal altitude of an aircraft, in hundreds of feet. This altitude is calculated from the International standard pressure datum of 1013.25 hPa , the average sea-level pressure, and therefore is not necessarily the same as the aircraft's true altitude either...
or altitudeAltitudeAltitude or height is defined based on the context in which it is used . As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The reference datum also often varies according to the context...
above sea levelSea levelMean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...
at the time the PIREP is filed. Essential for turbulence and icing reports. - /TP aircraft type. Essential also for turbulence and icing reports.
Optional (at least one is required)
- /SK sky cover
- /TA ambient temperature. Important for icing reports.
- /WV wind velocityVelocityIn physics, velocity is speed in a given direction. Speed describes only how fast an object is moving, whereas velocity gives both the speed and direction of the object's motion. To have a constant velocity, an object must have a constant speed and motion in a constant direction. Constant ...
referenced in terms of True North (ICAO), or magnetic north (in the United States). - /TB turbulenceTurbulenceIn fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic and stochastic property changes. This includes low momentum diffusion, high momentum convection, and rapid variation of pressure and velocity in space and time...
. Intensity, whether it occurred in or near clouds, and duration. - /IC icingAtmospheric icingAtmospheric icing occurs when water droplets in the atmosphere freeze on objects they contact. This can be extremely dangerous to aircraft, as the built-up ice changes the aerodynamics of the flight surfaces, which can increase the risk of a subsequent stalling of the airfoil...
- /RM remarks
- /WX flight visibility and weather.
Body
The message identifier "UA" is used when the PIREP contains non-hazardous weather information. If the PIREP contains a report of a tornadoTornado
A tornado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as a twister or a cyclone, although the word cyclone is used in meteorology in a wider...
, funnel cloud
Funnel cloud
A funnel cloud is a funnel-shaped cloud of condensed water droplets, associated with a rotating column of wind and extending from the base of a cloud but not reaching the ground or a water surface. A funnel cloud is usually visible as a cone-shaped or needle like protuberance from the main cloud...
, waterspout
Waterspout
A waterspout is an intense columnar vortex that occurs over a body of water and is connected to a cumuliform cloud. In the common form, it is a non-supercell tornado over water. While it is often weaker than most of its land counterparts, stronger versions spawned by mesocyclones do occur...
, severe turbulence
Turbulence
In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic and stochastic property changes. This includes low momentum diffusion, high momentum convection, and rapid variation of pressure and velocity in space and time...
, severe icing
Atmospheric icing
Atmospheric icing occurs when water droplets in the atmosphere freeze on objects they contact. This can be extremely dangerous to aircraft, as the built-up ice changes the aerodynamics of the flight surfaces, which can increase the risk of a subsequent stalling of the airfoil...
, hail
Hail
Hail is a form of solid precipitation. It consists of balls or irregular lumps of ice, each of which is referred to as a hail stone. Hail stones on Earth consist mostly of water ice and measure between and in diameter, with the larger stones coming from severe thunderstorms...
, or a low level wind shear
Wind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
hazard, the identifier "UUA" would be used.
The location (/OV) can be reported in one of three ways: as a direction and distance from a navigation aid (NAVAID), as a direction and distance from an airport, or as the latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
and longitude
Longitude
Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....
of the aircraft.
The time (/TM) used is the UTC
Coordinated Universal Time
Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...
time that the PIREP is reported.
The flight level (/FL) is reported as either a three digit value that indicates the altitude of the aircraft above sea level in hundreds of feet or can one of three abbreviations: DURD (during descent or on approach), DURC (during climb or after takeoff) and UNKN (unknown).
Aircraft type (/TP) will be the approved ICAO designator, or UNKN if not reported.
Sky cover (/SK) is used to report the cloud
Cloud
A cloud is a visible mass of liquid droplets or frozen crystals made of water and/or various chemicals suspended in the atmosphere above the surface of a planetary body. They are also known as aerosols. Clouds in Earth's atmosphere are studied in the cloud physics branch of meteorology...
layer amounts and the height of the cloud base. The tops of the cloud layers can also be included, as can more than one layer of cloud. Heights are in hundreds of feet above sea level and are three digits. Abbreviations used in this group are "CLR" (clear), "FEW" (few), "SCT" (scattered), "BKN" (broken) and "OVC" (overcast).
Temperature (/TA) is the air temperature in whole degrees Celsius as a two-digit value, with negative temperatures preceded by a minus (-) sign.
Wind velocity (/WV) must contain both the wind speed and direction. Direction is reported as a three-digit value in whole degrees true and the wind speed in knots also in three digits.
Turbulence (/TB) and the intensity are reported in a PIREP based on the aircraft and occupants reaction to the turbulence. The altitude of the turbulence should be included using three-digit groups. When the top or the base of the turbulence is unknown then the abbreviation BLO (below) or ABV (above) should be used. Turbulence should be reported as LGT (light), MDT (moderate), SVR (severe) or in exceptional cases EXTRM (extreme). Clear-air turbulence
Clear-Air Turbulence
Clear air turbulence is the turbulent movement of air masses in the absence of any visual cues such as clouds, and is caused when bodies of air moving at widely different speeds meet....
is reported as CAT.
Icing (/IC) is reported by type and the intensity or rate of accretion. The type of ice is reported as "CLR" (clear), "RIME", or "MXD" (mixed). The intensity is reported as "TR" (trace), "LGT" (light), "MDT" (moderate), and "SVR" (severe).
Remarks (/RM) report on other weather conditions that are not covered in the rest of the PIREP may include such things as icing in precipitation, thunderstorms, St Elmo's fire and frontal
Weather front
A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorological phenomena. In surface weather analyses, fronts are depicted using various colored lines and symbols, depending on the type of front...
conditions. There are many other types of weather conditions that could be reported in a PIREP.
The above explanation of PIREP fields is Canadian. The United States version may also include a weather (/WX) group; and other countries may use other groups and measurements.
Examples of PIREPs
These examples are taken from the Canadian MANOBS (Manual of Surface Weather Observations) published by Environment CanadaEnvironment Canada
Environment Canada , legally incorporated as the Department of the Environment under the Department of the Environment Act Environment Canada (EC) (French: Environnement Canada), legally incorporated as the Department of the Environment under the Department of the Environment Act Environment...
.
UACN10 CYQT 192128
YZ WG
UA /OV YSP 090025 /TM 2120 /FL050 /TP BE99 /SK 020BKN040 110OVC /TA -14 /WV 030045 /TB MDT CAT 060-080 /IC LGT RIME 020-040 /RM LGT FZRA INC
Decoded is
Routine Upper Air, Aircraft report from Thunder Bay
Thunder Bay
-In Canada:Thunder Bay is the name of three places in the province of Ontario, Canada along Lake Superior:*Thunder Bay District, Ontario, a district in Northwestern Ontario*Thunder Bay, a city in Thunder Bay District*Thunder Bay, Unorganized, Ontario...
, Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
issued at 2128 UTC on the 19th
YZ is Toronto
Toronto
Toronto is the provincial capital of Ontario and the largest city in Canada. It is located in Southern Ontario on the northwestern shore of Lake Ontario. A relatively modern city, Toronto's history dates back to the late-18th century, when its land was first purchased by the British monarchy from...
and WG is Winnipeg
Winnipeg
Winnipeg is the capital and largest city of Manitoba, Canada, and is the primary municipality of the Winnipeg Capital Region, with more than half of Manitoba's population. It is located near the longitudinal centre of North America, at the confluence of the Red and Assiniboine Rivers .The name...
. This is the Flight Information Region where the PIREP was issued
Aircraft observation was 25 nmi (46.3 km) east (090 degrees magnetic) of the Marathon
Marathon, Ontario
Marathon is a town in the Canadian province of Ontario, located in Thunder Bay District, on the north shore of Lake Superior north of Pukaskwa National Park, in the heart of the Canadian Shield.- History :...
, Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
VOR/DME
Distance Measuring Equipment
Distance measuring equipment is a transponder-based radio navigation technology that measures distance by timing the propagation delay of VHF or UHF radio signals....
at 2120 UTC. The aircraft was at 5,000 ft (1,524 m)and is a Beech 99
Beechcraft
Beechcraft is an American manufacturer of general aviation and military aircraft, ranging from light single engine aircraft to business jets and light military transports. Previously a division of Raytheon, it has been a brand of Hawker Beechcraft since 2006....
. The clouds were broken at 2,000 ft (610 m) AMSL with tops at 4,000 ft (1,219 m) and an overcast layer at 11,000 ft (3,353 m) AMSL. The temperature is -14 Celsius and the winds are from the NE (030 degrees true) at 45 knots (83 km/h). There is moderate clear air turbulence between 6,000 ft (1,829 m) and 8,000 ft (2,438 m). There is light rime icing between 2,000 ft (610 m) and 4,000 ft (1,219 m). Note this would indicate that the icing is picked up in the cloud. The remarks section says that light freezing rain was encountered in the cloud.
UACN10 CYXU 032133
YZ
UA /OV YUX 09010 /TM 2120 /FL030 /TP C172 /TB MDT /RM MDT TURB BLO 050 CYKF CYXU
Routine message from London
London, Ontario
London is a city in Southwestern Ontario, Canada, situated along the Quebec City – Windsor Corridor. The city has a population of 352,395, and the metropolitan area has a population of 457,720, according to the 2006 Canadian census; the metro population in 2009 was estimated at 489,274. The city...
Ontario, issued at 2133 UTC on the 3rd
The Flight Information Region is Toronto
The aircraft was 10 nmi (18.5 km) east (090 degrees true) of the London VOR at 2120 UTC. The aircraft was at 3,000 ft (914 m) and was a Cessna 172
Cessna 172
The Cessna 172 Skyhawk is a four-seat, single-engine, high-wing fixed-wing aircraft. First flown in 1955 and still in production, more Cessna 172s have been built than any other aircraft.-Design and development:...
. The pilot reported moderate turbulence. Then in remarks went on to say that the turbulence was below 5,000 ft (1,524 m) between Kitchener
Kitchener, Ontario
The City of Kitchener is a city in Southern Ontario, Canada. It was the Town of Berlin from 1854 until 1912 and the City of Berlin from 1912 until 1916. The city had a population of 204,668 in the Canada 2006 Census...
/Waterloo
Waterloo, Ontario
Waterloo is a city in Southern Ontario, Canada. It is the smallest of the three cities in the Regional Municipality of Waterloo, and is adjacent to the city of Kitchener....
and London.
Soliciting PIREPs
In the US, Air Traffic ControllerAir traffic controller
Air traffic controllers are the people who expedite and maintain a safe and orderly flow of air traffic in the global air traffic control system. The position of the air traffic controller is one that requires highly specialized skills...
s are required to solicit PIREPs upon request of other facilities or pilots, or when any of the following conditions exists or is forecast in their area:
- Ceilings at or below 5000 feet (1,524 m)
- Visibility at or less than 5 miles (8 km)
- ThunderstormThunderstormA thunderstorm, also known as an electrical storm, a lightning storm, thundershower or simply a storm is a form of weather characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere known as thunder. The meteorologically assigned cloud type associated with the...
s and related phenomena - TurbulenceTurbulenceIn fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic and stochastic property changes. This includes low momentum diffusion, high momentum convection, and rapid variation of pressure and velocity in space and time...
of moderate degree or greater - Icing of light degree or greater
- Wind shearWind shearWind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
- Volcanic ashVolcanic ashVolcanic ash consists of small tephra, which are bits of pulverized rock and glass created by volcanic eruptions, less than in diameter. There are three mechanisms of volcanic ash formation: gas release under decompression causing magmatic eruptions; thermal contraction from chilling on contact...
clouds
At least once hourly, terminal controllers must obtain a descent/climb-out PIREP, including cloud information and other related phenomena.
See also
- AMDARAMDARAircraft Meteorological Data Relay is a program initiated by the World Meteorological Organization.AMDAR is used to collect meteorological data worldwide by using commercial aircraft....
-- aircraft meteorological data relay—is a WMO FM-42 code for an automatic meteorological report from an aircraft. - AIREP -- one aircraft report encoded according to the AFMAN manual 15-124 pages 32 through 35.
- ACARS -- Aircraft Communication Addressing and Reporting System
- SIGMETSIGMETSIGMET, or Significant Meteorological Information, is a weather advisory that contains meteorological information concerning the safety of all aircraft. There are two types of SIGMETs, convective and non-convective...
- AIRMETAIRMETAn AIRMET, or Airmen's Meteorological Information, is a concise description of weather phenomena that are occurring or may occur along an air route that may affect aircraft safety...