ATIS v. ASOS v. AWOS

midwestpa24

midwestpa24

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midwestpa24
I feel the need to post this to help inform. As an airport operator I feel there is some misinformation about the information available on each of these systems.

ATIS: Automated Terminal Information System
ATIS is usually only found at towered airports, and is a recording giving the winds and pertinent NOTAMs and other information pilots may need about the airport.

ASOS: Automated Surface Observation System
ASOS is a automated machine owned by the National Weather Service that provides current weather information. It does not have the ability to give out NOTAMs or any other information.

AWOS: Automated Weather Observation System
AWOS is similar to an ASOS, but is usually owned by the state or the airport. It provides most of the same information as an ASOS. Some new ones do have the ability to add voice information to the broadcast regarding NOTAMs, but not all.

This comes to light, because I've had many pilots at my ASOS equipped airport tell me, "Well that NOTAM wasn't on the ATIS." It is very important to understand the capabilities and the limitations, and why these three information sources are not the same.
 
Thanks! - nowhere have I seen this explained so clearly and logically.
 
I've seen a bit of what you have. AWOS vs ASOS, especially since they are so similar and there are multiple flavors with varying capabilities, is not that big a deal.

But I've heard a fair number of pilots tune into an AWOS or ASOS broadcast and refer to it as "getting the ATIS." It may well just be a universal generic term in their minds (like "Kleenex" meaning "facial tissue") but it is important to understand there are major differences.
 
Actually, AWOS and ASOS are two government programs that define weather reporting stations. Indeed ASOS is developed and operated by NWS. AWOS is defined by the FAA but the stations are built by a number of people, some under contract to the FAA and some just built to program standards and available commerically from a half a dozen approved providers.

ASOS has a secondary use for collecting data for non-aviation purposes at the NWS.
 
flyingron said:
ASOS has a secondary use for collecting data for non-aviation purposes at the NWS.
Click to expand...

You are correct, but I was trying to keep it simple. I have just run into too many issues of pilots depending on the ASOS for NOTAM information, such as closed runways.
 
midwestpa24 said:
I feel the need to post this to help inform. As an airport operator I feel there is some misinformation about the information available on each of these systems.

ATIS: Automated Terminal Information System
ATIS is usually only found at towered airports, and is a recording giving the winds and pertinent NOTAMs and other information pilots may need about the airport.
Click to expand...
I applaud the information you are teaching to us ignorati. I would add one specific, even if your ATIS description covers this with "other information pilots may need".

ATIS also gives us runway(s) in use. For safety purposes, that is a little (!) more important than "other information pilots may need." I recommend you edit your post to include this. And Thanks!

-Skip
 
Do any of these include in their specs a requirement to
a) make the reports available online?
b) by telephone?

I was using a superAWOS (the ones on unicom, activated by mic clicks) which was available by telephone but never online.
 
IAITA. It's all in the acronym. Terminal Information. Surface Observation. Weather Observation.
 
Skip Miller said:
I
ATIS also gives us runway(s) in use. For safety purposes, that is a little (!) more important than "other information pilots may need." I recommend you edit your post to include this. And Thanks!
Click to expand...
And the approaches in use, handy in the bigger terminals.
 
Additional things reported on an ATIS:

WX (including hazardous) PIREPS, braking action, LASHO, shortened runways, VFR arrival freqs, LLWS alerts, bird activity, taxiway closures, MANPAD alert, laser events, and possibly, read back of hold short instructions.
 
Here is a complete detail of the differences between ATIS, AWOS and ASOS/AWSS: http://greggordon.org/flying/CFIIPTSIIIA1AWOS.htm

Essentially,
ATIS is essential but routine noncontrol information in high activity terminal areas plus a weather summary which is often older than ASOS/AWOS information.
ASOS/AWSS is the primary surface weather observing system of the U.S.
AWOS is a secondary U.S. weather observing system (predecessor to and being replaced by ASOS/AWSS)
 
You are probably preaching to the choir. The pilots I've come across who referred to AWOS as ATIS, when corrected, expressed the sentiment that they didn't care.
 
Walboy said:
Another practical difference depending on your location:

ATIS: wind direction is relative to magnetic north
AWOS: wind direction is relative to true north
Click to expand...
Are you sure? I had read that AWOS reports winds relative to magnetic north.

Another key thing that people may get confused about more easily is that not all towered airports have ATIS. So don't assume you will get NOTAMs and other ATIS information from the weather broadcast just because there is a control tower.

And if you need the NOTAMs while in the air, call FSS. That's what they're there for: flight service. That never fully sunk in for me until I was watching Ice Pilots NWT and realized that they talk to FSS all the time, because doing so helps ensure successful flights. A habit we can probably all improve.
 
All charts and textual sources such as METAR, TAF, Winds Aloft and Surface Analysis Charts use TRUE North as reference.
ATIS/AWOS/ASOS or any information a controller give you over the radio is MAGNETIC North.

FSS reads from charts and text so they use TRUE North also.
 
As a pilot, Ive never run across a reason to distinguish between ASOS and AWOS. ATIS is different yes.

Question for ya. Does a Class D airport have to have an ATIS?
 
coloradobluesky said:
As a pilot, Ive never run across a reason to distinguish between ASOS and AWOS. ATIS is different yes.

Question for ya. Does a Class D airport have to have an ATIS?
Click to expand...
No. KRAP and KMOT are examples. Both have ASOS. More interesting: are there any class C airports without ATIS?
 
If the Class D doesnt have an ATIS, does it have to have an ASOS or AWOS?
 
Related questions:

1. Do airports with an ATIS always have an ASOS?
2. If yes, does tower use the ASOS to update the ATIS? If no, what do they use?
 
coloradobluesky said:
If the Class D doesnt have an ATIS, does it have to have an ASOS or AWOS?
Click to expand...
They are not the same thing. ATIS is, in essence, a division of labor within a control tower so controllers don''t have to repeat information for every inbound and outbound pilot. If there is an airport with an ATIS broadcast that does not also have an AWOS/ASOS, I haven't come across it yet. Class D airports (almost?) universally have an AWOS or AOS facility.

register@teamandras.com said:
Related questions:

1. Do airports with an ATIS always have an ASOS?
Click to expand...
At this point I think so. Or an AWOS. At one time this was all done by an human weather observer. Then technology came along. Again, I've never come across one that didn't.
2. If yes, does tower use the ASOS to update the ATIS? If no, what do they use?
Click to expand...
So, generally they use it, but there are probably some airports with humans making at least some of the weather calls. If I'm not mistaken, Rocky Mountain Metro (KBJC) still has humans. A telltale clue to the existence of a human can be found the current METAR for that airport:
KBJC 262252Z 30005KT 50SM FEW080 FEW200 05/M18 A2973
 
Tower controllers obtain a certification called Limited Aviation Weather Reporting Station (LAWRS) which permits them to augment the ASOS automation when it differs from their direct observations of a weather situation. They get a username and password for the ASOS computer. The computer starts beeping around 5-10 minutes prior to when it sends the METAR out via "long-line dissemination" -- in other words sending it to a server which makes that METAR available for us to see on Foreflight, AviationWeather.gov, etc. That's typically when they will type in amendments to the METAR string. If they want to later go back and correct something that already went out over long-line dissemination, the METAR will appear with COR, meaning "corrected observation."
 
coloradobluesky said:
As a pilot, Ive never run across a reason to distinguish between ASOS and AWOS. ATIS is different yes.

Question for ya. Does a Class D airport have to have an ATIS?
Click to expand...

Most Class Delta will have ATIS and expect you to have gotten the alphebetical code word prior to contacting ground control. Clearance delivery is usually not present at a Class Delta. The ATIS frequency will be listed among the other frequencies for the airfield in the AF/D. Here is an example from KHND a Las Vegas area Class Delta: https://www.airnav.com/airport/KHND
 
midwestpa24 said:
This comes to light, because I've had many pilots at my ASOS equipped airport tell me, "Well that NOTAM wasn't on the ATIS." It is very important to understand the capabilities and the limitations, and why these three information sources are not the same.
Click to expand...
So....is your ATIS in service? o_O
 
coloradobluesky said:
As a pilot, Ive never run across a reason to distinguish between ASOS and AWOS. ATIS is different yes.
Click to expand...

The one thing I tell my students to remember with ASOS vs AWOS is the the AWOS has multiple types. All ASOS come complete. Airports or private entities can buy various levels of AWOS going from an Altimeter only to ASOS comparable.

Here are also AWSS stations, however their only maybe 20 of them. My old training airfield had one until this year. They were the first attempt by the FAA to create an advanced AWOS. Ours never worked correctly and was a piece of junk. However you knew you were home from the very unique fake male voice.

http://www.allweatherinc.com/programs/faa-awss/
 
midwestpa24 said:
ASOS: Automated Surface Observation System
ASOS is a automated machine owned by the National Weather Service that provides current weather information. It does not have the ability to give out NOTAMs or any other information.
Click to expand...

That's not correct. A local airport has had an advisory about their runway lights after the weather on their ASOS for some time now.
 
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