A pilot report or PIREP is a report of actual flight or ground conditions encountered by an
aircraft
An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, i ...
. Reports commonly include information about atmospheric conditions (like
temperature
Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...
,
icing,
turbulence
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to laminar flow, which occurs when a fluid flows in parallel layers with no disruption between ...
) or airport conditions (like
runway condition codes or ground equipment failures). This information is usually relayed by
radio
Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connec ...
to the nearest ground station, but other options (e.g. electronic submission) also exist in some regions. 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.
Included data
Mandatory
*UA or UUA used to identify the PIREP as routine or urgent (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 (
UTC)
*/FL
flight level
In aviation, a flight level (FL) is an aircraft's altitude as determined by a pressure altimeter using the International Standard Atmosphere. It is expressed in hundreds of feet or metres. The altimeter setting used is the ISA sea level pressur ...
or
altitude
Altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum (geodesy), datum and a point or object. The exact definition and reference datum varies according to the context (e.g., aviation, geometr ...
above
sea level
Mean sea level (MSL, often shortened to sea level) is an mean, average surface level of one or more among Earth's coastal Body of water, bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical ...
at the time the PIREP is filed; it is essential for turbulence and icing reports
*/TP aircraft type; it is essential for turbulence and icing reports
Optional (at least one is required)
*/SK
sky cover
*/TA
ambient temperature; important for icing reports
*/WV wind vector referenced in terms of
true north
True north is the direction along Earth's surface towards the place where the imaginary rotational axis of the Earth intersects the surface of the Earth on its Northern Hemisphere, northern half, the True North Pole. True south is the direction ...
(ICAO), or
magnetic north
The north magnetic pole, also known as the magnetic north pole, is a point on the surface of Earth's Northern Hemisphere at which the planet's magnetic field points vertically downward (in other words, if a magnetic compass needle is allowed t ...
(in the United States)
*/TB
turbulence
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to laminar flow, which occurs when a fluid flows in parallel layers with no disruption between ...
; intensity, whether it occurred in or near clouds, and duration
*/IC
icing
*/RM remarks
*/WX flight visibility and weather
AIREP
Like PIREPs, Aircraft Reports (AIREP) are reports of actual weather conditions of an aircraft in flight. AIREPs are often automated reports generated by sensors onboard the aircraft, contrary to PIREPs, though they can also be reported by pilots. Likewise, a different
encoding
In communications and Data processing, information processing, code is a system of rules to convert information—such as a letter (alphabet), letter, word, sound, image, or gesture—into another form, sometimes data compression, shortened or ...
is used for either type.
Body
The message identifier "UA" is used when the PIREP contains non-hazardous weather information. If the PIREP contains a report of a
tornado
A tornado is a violently rotating column of air that is in contact with the surface of Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, although the ...
,
funnel cloud,
waterspout, severe
turbulence
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to laminar flow, which occurs when a fluid flows in parallel layers with no disruption between ...
, severe
icing,
hail
Hail is a form of solid Precipitation (meteorology), precipitation. It is distinct from ice pellets (American English "sleet"), though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailsto ...
, volcanic ash clouds, a low-level
wind shear
Wind shear (; also written windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical ...
hazard, or any other weather deemed hazardous by the receiving agency, 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
In geography, latitude is a geographic coordinate system, geographic coordinate that specifies the north-south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from −90° at t ...
and
longitude
Longitude (, ) is a geographic coordinate that specifies the east- west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek lett ...
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 be 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
The International Civil Aviation Organization (ICAO ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international sch ...
designator, or UNKN if not reported.
Sky cover (/SK) is used to report the
cloud
In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles, suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may ...
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 delimited with
/
. 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). Cloud cover ranges can be entered with a hyphen, e.g.,
BKN-OVC
.
Flight visibility and weather (/WX) includes both flight visibility and the current flight weather weather phenomenon. Flight visibility is prepended with
FV
followed by two-digit visibility, rounded down. If visibility is reported as unrestricted,
FV99SM
may be used. Flight weather is reported in a similar format as in METAR.
Temperature (/TA) is the air temperature in whole degrees Celsius as a two-digit value, with negative temperatures preceded by a minus (-) sign. In the United States, negative temperatures are preceded by the letter M (M).
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
In meteorology, clear-air turbulence (CAT) is the turbulence, turbulent movement of air masses in the absence of any visual clues such as clouds, and is caused when bodies of air moving at widely different speeds meet.
The atmospheric region mos ...
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). (Units are measured in MSL - MEAN SEA LEVEL)
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. In the United States, the
Federal Aviation Administration
The Federal Aviation Administration (FAA) is a Federal government of the United States, U.S. federal government agency within the United States Department of Transportation, U.S. Department of Transportation that regulates civil aviation in t ...
launched a program called SKYSPOTTER to train pilots in observing and reporting weather while in flight. Reports submitted by these pilots are annotated with
/AWC
at the end of the remarks section.
The explanations above is mostly north American. 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 Canada
Environment and Climate Change Canada (ECCC; )Environment and Climate Change Canada is the applied title under the Federal Identity Program; the legal title is Department of the Environment (). is the Ministry (government department), department ...
.
*PIREP:
::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 as:
::Routine upper air report from
Thunder Bay
Thunder Bay is a city in and the seat of Thunder Bay District, Ontario, Canada. It is the most populous municipality in Northwestern Ontario and the second most populous (after Greater Sudbury) municipality in Northern Ontario. Its population i ...
issued at 2128 UTC on the 19th of the month
::YZ is
Toronto
Toronto ( , locally pronounced or ) is the List of the largest municipalities in Canada by population, most populous city in Canada. It is the capital city of the Provinces and territories of Canada, Canadian province of Ontario. With a p ...
and WG is
Winnipeg
Winnipeg () is the capital and largest city of the Provinces and territories of Canada, Canadian province of Manitoba. It is centred on the confluence of the Red River of the North, Red and Assiniboine River, Assiniboine rivers. , Winnipeg h ...
: these are the Flight Information Regions where the PIREP was issued
::Aircraft observation was east (090 degrees radial) of the
Marathon
The marathon is a long-distance foot race with a distance of kilometres ( 26 mi 385 yd), usually run as a road race, but the distance can be covered on trail routes. The marathon can be completed by running or with a run/walk strategy. There ...
VOR/
DME at 2120 UTC. The aircraft was at and is a
Beech 99. The clouds were broken at AMSL with tops at and an overcast layer at AMSL. The temperature is −14 degrees Celsius and the winds are from the northeast (030 degrees true) at . There is moderate clear air turbulence between and . There is light rime icing between and . 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.
*PIREP
::UACN10 CYXU 032133
::YZ
::UA /OV YUX 09010 /TM 2120 /FL030 /TP C172 /TB MDT /RM MDT TURB BLO 050 CYKF CYXU
:Decoded as:
::Routine message from
London
London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Wester ...
, issued at 2133 UTC on the 3rd of the month
::The Flight Information Region is Toronto
::The aircraft was east (090 degrees radial) of the London VOR at 2120 UTC. The aircraft was at and was a
Cessna 172. The pilot reported moderate turbulence. The remarks says that the turbulence was below between
Kitchener/
Waterloo and London.
Soliciting PIREPs
In the US,
air traffic controller
An Air traffic controller (ATC) is a person responsible for the coordination of traffic in their assigned airspace. Typically stationed in area control centers or control towers, they monitor the position, speed, and altitude of aircraft and c ...
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
*Visibility at or less than
*
Thunderstorm
A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustics, acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorm ...
s and related phenomena
*
Turbulence
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to laminar flow, which occurs when a fluid flows in parallel layers with no disruption between ...
of moderate degree or greater
*Icing of light degree or greater
*
Wind shear
Wind shear (; also written windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical ...
*
Volcanic ash
Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to r ...
clouds
At least once hourly, terminal controllers must obtain a descent/climb-out PIREP, including cloud information and other related phenomena.
See also
*
AMDAR – aircraft meteorological data relay, a WMO FM-42 code for an automatic meteorological report from an aircraft
*
ACARS – ARINC Communications Addressing and Reporting System
*
SIGMET
*
AIRMET
*
Aeronautical Information Manual
References
External links
FAA Pilot Weather Report*
{{Earth-based meteorological observation
Aviation meteorology
Earth sciences data formats
Aviation publications