AIREP: The Automated Position Report, Decoded
An AIREP is what a PIREP looks like when no human types it. The aircraft sends it, so it arrives with the fields in fixed positions and none of the slashes that make a PIREP easy to skim.
That difference is small on paper and awkward in practice, because everything you know about finding a field by its tag stops working.
What an AIREP looks like
An AIREP opens with ARP, which is the marker that tells you what you are
reading.
A typical one runs ARP UAL1303 4405N 11212W 0355 F364 202/065KT TB CONT LGT CHOP IC.
Read left to right. UAL1303 is the callsign. 4405N 11212W is the position.
0355 is the time in hours and minutes Zulu.
F364 is the flight level. 202/065KT is the wind, from 202 degrees at 65
knots.
Then the hazards. TB CONT LGT CHOP is continuous light chop. IC opens the
icing group, and here it is empty, meaning none was reported.
Why the fields have no tags
A PIREP is spoken by a pilot and typed by somebody on the ground. Tags make that work, because a pilot reports whatever they have in whatever order it comes.
An AIREP is generated by the aircraft. The systems know the callsign, the position, the time, the level and the wind, and they always know them in the same order. There is nothing to label because nothing moves.
That makes AIREPs easy for a computer and harder for a person. Without the slashes there is no obvious boundary between one field and the next, so you have to know the order.
The anchors help. The position always has N or S then E or W. The level
always starts with F. The wind always has a slash and ends in KT. Find those
three and the rest falls into place around them.
Reading the position
The position group is the one people find hardest, because it is raw coordinates rather than a fix.
4405N is 44 degrees 5 minutes north. The first two digits are degrees, the
next two are minutes. 11212W is 112 degrees 12 minutes west, with three digits
of degrees because longitude runs to 180.
A PIREP would give this as something like DFW360015, a radial and distance
from a known point. That is friendlier to read and less precise.
Coordinates are better for plotting and worse for a quick mental picture. If you are checking whether a report is near your route, an AIREP usually needs a chart and a PIREP often does not.
The hazard groups
The hazard vocabulary is shared with PIREPs, which is the good news.
TB opens turbulence. IC opens icing. Neither takes a slash, and each runs
until the next marker or the end of the line.
The words inside are the same ones a PIREP uses. CONT and CONS are
continuous. OCNL is occasional. LGT, MOD and SEV are the intensities.
CHOP and CAT are the types.
So TB CONT LGT CHOP decodes exactly as it would in a PIREP: continuous light
chop. The frame changed and the vocabulary did not.
An empty group is still a report. IC with nothing after it means the aircraft
reported no ice, which is worth as much as a NEG in a PIREP.
Where they come from and what they are worth
AIREPs arrive from aircraft with data link, which in practice means airline and larger business traffic.
That shapes what they cover. Lots of reports at cruise levels along busy routes, and very few down low or away from the airways. Oceanic areas are the exception, because there they are often the only reports at all.
They are frequent and consistent. An aircraft sends them on a schedule rather than when something interesting happens, so a run of AIREPs gives you a genuine picture of a level over time.
The trade is richness. A pilot writing a PIREP adds remarks about what the air felt like and where it changed. An automated report has no way to do that.
Reading one against a PIREP
Both end up in the same feed, so you will meet them side by side.
The header is the fastest way to tell them apart. ARP at the front means an
AIREP. UA or UUA means a PIREP, routine or urgent.
That header also tells you something about urgency. An AIREP has no urgent
form, so a severe turbulence encounter reported by data link does not get the
priority handling a UUA would.
So a quiet AIREP feed is weaker evidence than a quiet PIREP feed. Nothing in the automated stream is flagged for attention, however bad it was.
If you find an AIREP with severe turbulence in it, treat it with the weight you
would give a UUA, because nothing else in the system will.
Verdict on AIREP
Read an AIREP as a PIREP with the labels removed. Same hazards, same words, a different frame.
Anchor on the position, the F level and the KT wind, and the fields either
side of them become obvious. Then treat the turbulence and icing groups exactly
as you would in a PIREP, and remember that an empty hazard group is a negative
report rather than a missing one.
Frequently asked questions
What is an AIREP?
An air report downlinked by the aircraft rather than spoken by the pilot. It starts with ARP, carries the callsign, position, time, flight level and conditions, and its fields sit in fixed positions with no slashes.
How is an AIREP different from a PIREP?
A PIREP uses tagged fields opened by a slash, such as OV for location and TB for turbulence. An AIREP has no tags. The fields are identified by their position in the line, so order matters instead of labels.
How do I read the position in an AIREP?
As latitude then longitude. A group like 4405N 11212W is 44 degrees 5 minutes north, 112 degrees 12 minutes west. There is no fix name, because the aircraft reports where it actually is.
What does F364 mean in an AIREP?
Flight level 364, so about 36,400 feet. The F prefix marks the level group, and it is one of the easiest anchors to find when you are working out where the other fields start and end.
Do AIREPs report turbulence and icing?
Yes, using bare TB and IC groups with no slash in front. The hazard words are the same vocabulary a PIREP uses, so CONT LGT CHOP means the same thing in both.