ADS-B Weather as Substitute for AWOS/ASOS ?

M

Minshall

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TedM
I've just upgraded and now have ADS-B in/out in the aircraft. Now I'm wondering ... prior to flying an approach, do I really need to tune the radio to get weather, or can I just check my ADS-B weather? Compared to ATIS, the ADS-B is much more timely, so me thinks this might be a legal and appropriate substitute.

Thanks in advance - I love learning from you guys/gals.
 
AWOS/ASOS updates much more frequently than ATIS. I look at the ADS-B but always listen to the latest info from the station on the airfield.
 
ADSB is an hourly METAR, kinda like ATIS...


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Your title says awos/asos but text says atis.
I think you do need to check atis when there is one, for operational (vs weather) info.
 
Yes, you need to check ATIS or AWOS/ASOS as available.

ADS-B is a fine tool for planning ahead. But it has some limitations.

ATIS: The ADS-B weather is usually the same as that on the ATIS, and can often even be more recent than the ATIS, as the ATIS is recorded usually once per hour unless conditions change. However, the ADS-B is not going to have anything about that runway that just closed, or the taxiway closures, or the fact that even though the wind is from the south, they are still landing to the north due to various reasons. So yes, you still need the ATIS, even if it's not for the actual weather information.

AWOS/ASOS: These are far more current than the ADS-B weather. Sometimes the ADS-B weather is over an hour old, where the AWOS/ASOS is pretty much up-to-the-minute (you may occasionally hear references to the "minute weather", that's what they're talking about). Most of us have seen the wind shift or the cloud layers change dramatically or some other big change take place over just 15 minutes or so - so the ADS-B weather might not have updated yet.

So, in summary, use the ADS-B weather when you're far out from the airport to get an idea of what you might be able to expect. But once you're within range, get the ATIS/AWOS/ASOS weather (and other information).
 
Let'sgoflying! said:
Your title says awos/asos but text says atis.
I think you do need to check atis when there is one, for operational (vs weather) info.
Click to expand...

Exactly. You always need to check ATIS where available. I often use ADSB for long range checks before ATIS is available.

I've gotten in the habit of using ADSB instead of ASOS/AWOS. Haven't researched possible pitfalls. I'm sure they will be covered here shortly.


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Bill Watson said:
I've gotten in the habit of using ADSB instead of ASOS/AWOS. Haven't researched possible pitfalls. I'm sure they will be covered here shortly.
Click to expand...

The main pitfall is that ADS-B is updated every 15-60 minutes, whereas ASOS/AWOS is updated every minute. Thus, you could miss a significant weather change.

I remember working with a Commercial student. We were practicing Power-off 180 degree landings. We were the only ones in the pattern. The first few he did great, landing right on the target. The he started to land long, missing the target completely - hundreds or even a thousand feet off. After a few attempts like that, we just happened to decide to check the AWOS again. Sure enough, the wind had switched completely around, 180 degrees, in the 20 or 30 minutes we were in the pattern.

If you were coming in and using ADS-B for weather, you might not have received the update yet.
 
Put another way, the ADSB info is a metar which is issued hourly and matches the atis where there is one. If there is more current info when you arrive, awos or asos, use it...


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RussR said:
The main pitfall is that ADS-B is updated every 15-60 minutes, whereas ASOS/AWOS is updated every minute. Thus, you could miss a significant weather change.

I remember working with a Commercial student. We were practicing Power-off 180 degree landings. We were the only ones in the pattern. The first few he did great, landing right on the target. The he started to land long, missing the target completely - hundreds or even a thousand feet off. After a few attempts like that, we just happened to decide to check the AWOS again. Sure enough, the wind had switched completely around, 180 degrees, in the 20 or 30 minutes we were in the pattern.

If you were coming in and using ADS-B for weather, you might not have received the update yet.
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That's what windsocks are for. ;)

I had something similar happen once. I flew from home base where the wind was out of the east at something like 10 Kt to an airport about 20 miles west that had no wx reporting. I entered the westbound downwind and after turning base and final towards the east I found myself almost halfway down the 3000 ft runway while still at least 50 ft AGL. Then I noticed the windsock pointed straight out with the tail pointing east. Flew a nice teardrop and got to taxi speed in the first 500 ft using the 20 Kt headwind to my advantage.
 
Thanks for the info - appreciated. All too often, Center asks me if I've got the weather before I'm in range, and then they start descending me just as it's coming in broken. I'll just keep doing it the old way.
 
RussR said:
The main pitfall is that ADS-B is updated every 15-60 minutes, whereas ASOS/AWOS is updated every minute. Thus, you could miss a significant weather change.

I remember working with a Commercial student. We were practicing Power-off 180 degree landings. We were the only ones in the pattern. The first few he did great, landing right on the target. The he started to land long, missing the target completely - hundreds or even a thousand feet off. After a few attempts like that, we just happened to decide to check the AWOS again. Sure enough, the wind had switched completely around, 180 degrees, in the 20 or 30 minutes we were in the pattern.

If you were coming in and using ADS-B for weather, you might not have received the update yet.
Click to expand...
How does the ADSB system get the updates to broadcast them to the unit in the airplane. National Weather Service? Flight Service Stations? Something else?
 
ADSB = metar/speci, so from the FAA


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Keep in mind ATIS is only at airports with an operating control tower.

AIM 4−1−13. Automatic Terminal Information Service (ATIS)

a. ATIS is the continuous broadcast of recorded noncontrol information in selected high activity
terminal areas. Its purpose is to improve controller effectiveness and to relieve frequency congestion by automating the repetitive transmission of essential but routine information.
Click to expand...

Contrary to "selected high activity areas" I believe all operating ATCTs have ATIS. I could be wrong, though. Nonetheless, if ATIS is charted, it is bad form not to obtain it on a timely basis.
 
Current ADS-B (in) provides TIS-B (traffic) and FIS-B weather reports (comrable to mid-to-high-level XM subscription):
  • Aviation Routine Weather Reports (METARs)
  • Non-Routine Aviation Weather Reports (SPECIs)
  • Terminal Area Forecasts (TAFs) and their amendments
  • NEXRAD (regional and CONUS) precipitation maps
  • Notice to Airmen (NOTAM) Distant and Flight Data Center
  • Airmen's Meteorological Conditions (AIRMET)
  • Significant Meteorological Conditions (SIGMET) and Convective SIGMET
  • Status of Special Use Airspace (SUA)
  • Temporary Flight Restrictions (TFRs)
  • Winds and Temperatures Aloft
  • Pilot Reports (PIREPS)
Planned upgrades include:
  • Lightning
  • Turbulence NOWcast
  • Icing NOWcast
  • Cloud Tops
  • 1 minute AWOS – uplinked every 10 minutes
https://www.faa.gov/nextgen/programs/adsb/faq/
 
ATIS is like metar plus. Like runway in use, etc.

If there is an ATIS there is a metar that comes from the same source, the tower. They type one in and record the other. At the same time.

If there is a metar there is official reporting at the airport, whether usually asos or a tower...


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aterpster said:
Keep in mind ATIS is only at airports with an operating control tower.



Contrary to "selected high activity areas" I believe all operating ATCTs have ATIS. I could be wrong, though. Nonetheless, if ATIS is charted, it is bad form not to obtain it on a timely basis.
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Just for your fund of trivial knowledge Manhattan KS has an operating tower but no ATIS. I haven't been there in a couple years so maybe that has changed.
 
Clark1961 said:
Just for your fund of trivial knowledge Manhattan KS has an operating tower but no ATIS. I haven't been there in a couple years so maybe that has changed.
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You're right, it still doesn't.
 
AWOS and ASOS reports are literally one minute (or less) old. ADS-B METAR data can be up to an hour, so unreliable for current winds. AS far as ATIS, these are recorded and only updated when the official weather changes. I've heard ATIS reports that were not updated for over 2 hours.
 
aterpster said:
I believe all operating ATCTs have ATIS. I could be wrong, though. Nonetheless, if ATIS is charted, it is bad form not to obtain it on a timely basis.
Click to expand...

Not even close to ALL towered have ATIS. That's why we get to say "bugdestroyer 666 has the weather at Denton" instead of "bugdestroyer 666 has Mike at Meacham" That would be inflight. On the ground the cool kids get to say "ready to taxi with the numbers" instead of "ready to taxi with Mike"

Oddly, I've never taxied with Mike, Juliet, or Whiskey. Once with my Pappa, but I always called him Dad :)
 
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