ATIS Question

[ColoPilot]

When you fly to a towered airport the ATIS is only updated once an hour (usually). Two questions -- is the weather data instantaneous when the controller records the ATIS or is it an average of the weather for some previous time?

Also, why not combine realtime AWOS data with the ATIS specific info (runways, ATC comm instructions etc.) so pilots get more accurate wind and weather?

 

[Captain]

ATIS is a taped recording. No ability to 'update' the recording with actual weather. Invent that system and you can make money.

It is NOT an average. Tower controllers make it at around 50 past the hour and give those weather conditions as reported from the weather equipment. If there is a big change then they make a special whenever needed.

 

[oldShar]

AWOS isn't real-time either.
Depending on the airport, could be reports anywhere from every 10 minutes to once per hour (unless something unusual happens, then it updates at that point)

 

[roncachamp]

When you fly to a towered airport the ATIS is only updated once an hour (usually). Two questions -- is the weather data instantaneous when the controller records the ATIS or is it an average of the weather for some previous time?

ATIS is updated once an hour or when there's a significant change to the content, including the weather observation.

Also, why not combine realtime AWOS data with the ATIS specific info (runways, ATC comm instructions etc.) so pilots get more accurate wind and weather?

How would that work? Would the ATIS code change whenever an element of the realtime weather changed? Or would the code change only when the "ATIS specific info" changed? If the code doesn't change with the weather, what would it mean when pilot reported having information ABCDE? The weather may have changed significantly since that ATIS code became current and there's no way to know if the pilot picked up the ATIS two minutes ago or twenty. If the ATIS code changed every time a weather element changed the alphabet could be used within an hour.

 

[alfadog]

AWOS isn't real-time either.
Depending on the airport, could be reports anywhere from every 10 minutes to once per hour (unless something unusual happens, then it updates at that point)

Assuming there are no special observations, an AWOS will automatically issue three reports (METARs) each hour whereas the ASOS is simply once per hour.

Really? The AWOS at Homestead General (X51) updates every minute. I thought that would be the norm. Call 305-247-2971.

Just called KTMB ASOS and it updates every minute also.

 

[jpower]

Really? The AWOS at Homestead General (X51) updates every minute. I thought that would be the norm. Call 305-247-2971.

Just called KTMB ASOS and it updates every minute also.

I think it provides three written METARs per hour. The AWOS definitely updates its "recording" every minute at Bay Bridge W29.

 

[gismo]

How would that work? Would the ATIS code change whenever an element of the realtime weather changed? Or would the code change only when the "ATIS specific info" changed? If the code doesn't change with the weather, what would it mean when pilot reported having information ABCDE? The weather may have changed significantly since that ATIS code became current and there's no way to know if the pilot picked up the ATIS two minutes ago or twenty. If the ATIS code changed every time a weather element changed the alphabet could be used within an hour.

I could see a way to make this work and I agree with Colo that it could be useful. The concept I'm imagining has the normal ATIS message (including observed hourly weather) followed by something like "Automated weather, Wind 340 at 10 gusting 15, scattered clouds at 3 thousand, altimeter 29.99". The biggest downside would be the extra time needed per ATIS cycle but the advantage would be that pilots would know when things have changed since the official report but not so much that a new ATIS was cut. Seems a lot like when the tower provides a wind report that's different than the ATIS.

 

[ColoPilot]

ATIS is updated once an hour or when there's a significant change to the content, including the weather observation.



How would that work? Would the ATIS code change whenever an element of the realtime weather changed? Or would the code change only when the "ATIS specific info" changed? If the code doesn't change with the weather, what would it mean when pilot reported having information ABCDE? The weather may have changed significantly since that ATIS code became current and there's no way to know if the pilot picked up the ATIS two minutes ago or twenty. If the ATIS code changed every time a weather element changed the alphabet could be used within an hour.

The code would change with the ATIS specific info, which should include the altimeter, now that I think about it. As for the rest of the weather, you wouldn't know if the pilot picked it up 2 or 20 minutes ago, but is that any worse than giving the pilot weather info that is 59 minutes old?

Technically it's possible, since many AWOS recordings have both the real time weather and a recorded message.

 

[ColoPilot]

ATIS is a taped recording. No ability to 'update' the recording with actual weather. Invent that system and you can make money.

Actually the AWOS with the real time weather already allows a taped message -- which could be the ATIS...

 

[Captain]

Actually the AWOS with the real time weather already allows a taped message -- which could be the ATIS...

'Actually'? You corrected me somehow?

-AWOS with the real time weather already allows a taped message -- which could be the ATIS-

I understand each and every word and yet put them all together and I have no idea what you just said.

 

[ColoPilot]

'Actually'? You corrected me somehow?

No disrespect meant, I just thought from your earlier post that you indicated the "real time" weather couldn't be combined with the recorded ATIS and I was pointing out that it is sort of that way with a AWOS system.

Originally Posted by Captain
ATIS is a taped recording. No ability to 'update' the recording with actual weather. Invent that system and you can make money.

 

[Captain]

Post #5 sums it up. AWOS is a broadcasting machine that constantly spews the current weather. ATIS is a human reading the weather and adding active runways and NOTAMS along with a code.

AWOS is nothing like a taped ATIS and I don't see a way to merge the two.

 

[gismo]

'Actually'? You corrected me somehow?

-AWOS with the real time weather already allows a taped message -- which could be the ATIS-

I understand each and every word and yet put them all together and I have no idea what you just said.

I think what he was saying is that AWOS stations (I think this only applies to ASOS BTW) already have the ability to tack a pre-recorded message onto the end of the wx transmission. You've no doubt heard things like "The XXX airport is in a noise sensitive area" or "The calm wind runway is NN" as part of an ASOS transmission and I think ColoPilot is suggesting that this feature could be used to provide a combination of ASOS and ATIS.

That said, I doubt the FAA would want to do it that way and I suspect that it's not all that easy to update the ASOS "taped" message compared to re-recording the ATIS.

 

[ColoPilot]

I think what he was saying is that AWOS stations (I think this only applies to ASOS BTW) already have the ability to tack a pre-recorded message onto the end of the wx transmission. You've no doubt heard things like "The XXX airport is in a noise sensitive area" or "The calm wind runway is NN" as part of an ASOS transmission and I think ColoPilot is suggesting that this feature could be used to provide a combination of ASOS and ATIS.

That said, I doubt the FAA would want to do it that way and I suspect that it's not all that easy to update the ASOS "taped" message compared to re-recording the ATIS.

Thanks! That's what I was trying to say, but not doing a good job. I don't know anything about the mechanics behind ATIS/AWOS/ASOS so that's why I asked.

 

[roncachamp]

The code would change with the ATIS specific info, which should include the altimeter, now that I think about it. As for the rest of the weather, you wouldn't know if the pilot picked it up 2 or 20 minutes ago, but is that any worse than giving the pilot weather info that is 59 minutes old?

Yes. As it stands, if the weather is 59 minutes old it's because nothing has changed enough to warrant a special observation. If the weather changes enough to warrant a new observation a new ATIS is recorded with a new ATIS code. If a pilot reports an old code the controller knows he has old weather. Under your suggestion a pilot can report the current code but have old weather.

 

[ColoPilot]

Yes. As it stands, if the weather is 59 minutes old it's because nothing has changed enough to warrant a special observation. If the weather changes enough to warrant a new observation a new ATIS is recorded with a new ATIS code. If a pilot reports an old code the controller knows he has old weather. Under your suggestion a pilot can report the current code but have old weather.

Good point, I didn't think of that. How much does the weather have to change before a new ATIS is produced? (and is that something I should have known but forgot since the written exam )

 

[roncachamp]

Good point, I didn't think of that. How much does the weather have to change before a new ATIS is produced?

See FEDERAL METEOROLOGICAL HANDBOOK No. 1 Surface Weather Observations and Reports Surface Weather Observations and Reports paragraph 2.5.2 Aviation Selected Special Weather Report (SPECI).

(and is that something I should have known but forgot since the written exam )

Well, METAR/SPECI observations are covered in the various FAA pilot training publications.

 

[airdale]

... why not combine realtime AWOS data with the ATIS specific info (runways, ATC comm instructions etc.) so pilots get more accurate wind and weather?

I just read this thread and don't see what problem needs to be solved. It's never mattered all that much to me whether the wind was 6 Gusting 8 or 8 Gusting 9. Ditto on the wind direction; 340 or 350, who cares? All the numbers are probably different by this much just from one end of the runway to the other.

When something significant changes they cut a new ATIS. For smaller changes, the local controller often gives a wind check to the landing aircraft. The current system is accurate enough for me.