Part 121 Weather Scenario

[C150J]

Hi guys, here's a scenario:

You're approaching your destination airport. It's late and the tower has suspended class D operations for the night. You tune in the advertised ATIS frequency (which states that it turns into an ASOS when the tower is closed) only to discover that there is no weather information.

Obviously, at this point, you need to find an alternative source of the CURRENT weather. According to our FOM, we need an ATIS, ASOS, AWOS, or certified weather observer to relay the information when conducting an IFR approach. You ACARS for the current weather and get a METAR-style response containing "A02," indicating that it is an automated report. It contains all the information required (time, winds, clouds, visibility, altimeter setting). You then ask ATC (center) for the weather, and they also give you the current weather at the destination field. It's down to minimums, and you verify the altimeter setting one more time before intercepting the glideslope.

For you veterans out there, was everything done acceptably? No NOTAMs indicated that the ASOS was OTS and center, as well as the ACARs weather provider, had current information.

Thanks!
J.

 

[jtrain609]

I'm not a veteran, but I'd say yes, you did everything correctly.

Your ACARS will relay ASOS/AWOS information just as well as the ATIS over a radio frequency, it's simply a different means of receiving the data. You've double checked it against what the center has, and in the end if things go to pot you go missed and head to your alternate eh?

Here's where I think things get sticky; the ASOS needs to be reporting that the approach is at or above miniums at the exact instant you cross the marker while inbound on the approach. If, for some reason, the weather dropped below it between the ACARS message got to you, and when you crossed the marker, it could be grounds for a violation. At least that's what I was told in one of my air carriers ground school courses.

Now WOULD you get dinged on it if that in fact happened? Couldn't tell you. I'd say you had done your due dilligance and fulfilled the letter and intent of the guidelines in the FOM, personally. Would your POI? Who knows.

 

[kellwolf]

Hi guys, here's a scenario:

You're approaching your destination airport. It's late and the tower has suspended class D operations for the night. You tune in the advertised ATIS frequency (which states that it turns into an ASOS when the tower is closed) only to discover that there is no weather information.

Obviously, at this point, you need to find an alternative source of the CURRENT weather. According to our FOM, we need an ATIS, ASOS, AWOS, or certified weather observer to relay the information when conducting an IFR approach. You ACARS for the current weather and get a METAR-style response containing "A02," indicating that it is an automated report. It contains all the information required (time, winds, clouds, visibility, altimeter setting). You then ask ATC (center) for the weather, and they also give you the current weather at the destination field. It's down to minimums, and you verify the altimeter setting one more time before intercepting the glideslope.

For you veterans out there, was everything done acceptably? No NOTAMs indicated that the ASOS was OTS and center, as well as the ACARs weather provider, had current information.

Thanks!
J.

That sounds up and up to me, and I'd have no problems landing with that. More importantly, I'd feel confident that I could defend myself if the CP or the FAA asked why I landed when the I couldn't get the ASOS over the radio. As long as said report is less than an hour old.

Example: We have/had an issue with our DTW-ITH flight. Tower closes at 10ish, but the flight is scheduled to arrive at 10:58. So, the last ATIS issued is at 9:53, making it more than an hour old by the time we get there. That's fine, they have ASOS. Except the winds are missing on the ASOS. Now, you can get a report on winds and sub that in if there's an airfield 5 nm away. There isn't. So, we had a LOT of either diverts or cancellations based on that. So, the company finally ponied up to get an official weather observer to hang out until the flight gets there so they can rely the wind info over the ops frequency.

 

[jtrain609]

ASOS is instant weather eh? ATIS is for the previous hour. You need the ASOS within the minute you cross the marker to be technically legal.

 

[C150J]

That sounds up and up to me, and I'd have no problems landing with that. More importantly, I'd feel confident that I could defend myself if the CP or the FAA asked why I landed when the I couldn't get the ASOS over the radio. As long as said report is less than an hour old.

Example: We have/had an issue with our DTW-ITH flight. Tower closes at 10ish, but the flight is scheduled to arrive at 10:58. So, the last ATIS issued is at 9:53, making it more than an hour old by the time we get there. That's fine, they have ASOS. Except the winds are missing on the ASOS. Now, you can get a report on winds and sub that in if there's an airfield 5 nm away. There isn't. So, we had a LOT of either diverts or cancellations based on that. So, the company finally ponied up to get an official weather observer to hang out until the flight gets there so they can rely the wind info over the ops frequency.

We have had the same problem with ITH! We finally called the airport manager and they got around to fixing it. ITH also has two different receivers for PCL, so you might roll out on final to see the ALS working, but not the runway lighting... A true headache.

 

[kellwolf]

ASOS is instant weather eh? ATIS is for the previous hour. You need the ASOS within the minute you cross the marker to be technically legal.

Not disputing that, but in our case in ITH, the VISIBILITY is on the ASOS, just not the winds. That's what you need for an ILS.

 

[C150J]

ASOS is instant weather eh? ATIS is for the previous hour. You need the ASOS within the minute you cross the marker to be technically legal.

I think you're right. In this scenario, I should have been more clear. The visibility, our controlling variable for approaches, was a mile above minimums. Ceiling was low, but not controlling.

 

[Polar742]

Hi guys, here's a scenario:

You're approaching your destination airport. It's late and the tower has suspended class D operations for the night. You tune in the advertised ATIS frequency (which states that it turns into an ASOS when the tower is closed) only to discover that there is no weather information.

Obviously, at this point, you need to find an alternative source of the CURRENT weather. According to our FOM, we need an ATIS, ASOS, AWOS, or certified weather observer to relay the information when conducting an IFR approach. You ACARS for the current weather and get a METAR-style response containing "A02," indicating that it is an automated report. It contains all the information required (time, winds, clouds, visibility, altimeter setting). You then ask ATC (center) for the weather, and they also give you the current weather at the destination field. It's down to minimums, and you verify the altimeter setting one more time before intercepting the glideslope.

For you veterans out there, was everything done acceptably? No NOTAMs indicated that the ASOS was OTS and center, as well as the ACARs weather provider, had current information.

Thanks!
J.

If your ACARS has a printer, I'd print what you got and stick it in your little red logbook (if you're oldschool) for 90 days, then toss it.

Not that I've ever done anything similar before.

 

[Copperhed51]

All sounds kosher to me. Did you get the time the weather report you received was put out? That's about the only thing I could see that would ensure it was current. I had a captain get weather that was 3 hours old once and tell me it was fine. I told him we had to go elsewhere. He overruled me and we landed. The next morning he got a call from the Chief Pilot. I didn't get in trouble so oh well. Anyway, I'd say you did everything fine.

 

[C150J]

Did you get the time the weather report you received was put out?

Weather was about 5 minutes old.

 

[jtrain609]

Not disputing that, but in our case in ITH, the VISIBILITY is on the ASOS, just not the winds. That's what you need for an ILS.

Right but you said as long as the report wasn't over an hour old.

Which report? The ASOS or ATIS?

 

[kellwolf]

Right but you said as long as the report wasn't over an hour old.

Which report? The ASOS or ATIS?

ATIS for sure. I can see arguments either way on the ASOS. Any report you get from center is likely gonna be the automated METAR put out around the top of the hour. The ATIS is normally derived from the ASOS and just a controller recording that WX and any significant info affecting the airport. Based on that, I think you'd be safe in arguing that as long as the ASOS is less then an hour old and not trending downward, the FAA would say "Okay." You can also argue that you HAVE to get it at the marker, but by the same token, you should be asking tower for vis every time you fly an ILS when you cross the marker. To me, the only difference is the means the info relayed.

 

[jtrain609]

ATIS for sure. I can see arguments either way on the ASOS. Any report you get from center is likely gonna be the automated METAR put out around the top of the hour. The ATIS is normally derived from the ASOS and just a controller recording that WX and any significant info affecting the airport. Based on that, I think you'd be safe in arguing that as long as the ASOS is less then an hour old and not trending downward, the FAA would say "Okay." You can also argue that you HAVE to get it at the marker, but by the same token, you should be asking tower for vis every time you fly an ILS when you cross the marker. To me, the only difference is the means the info relayed.

I don't think that's true, actually. The most anal person I've ever met in my life, who taught ground at Amflight, contended that an ASOS is only good for the minute that it's reported. I.E. It's updated once a minute, so it's not good for an hour, it's good for one minute and that's it. After that one minute is up, it's invalid.

I tend to think he's correct.

 

[Orange Anchor]

Regardless, since you have some questions about the legality and the advice here, while probably correct, is not official, I would definitely file a NASA and have the other pilot do also.

In doubt.. FILE!

http://asrs.arc.nasa.gov/report/electronic.html

 

[Stone Cold]

I don't think that's true, actually. The most anal person I've ever met in my life, who taught ground at Amflight, contended that an ASOS is only good for the minute that it's reported. I.E. It's updated once a minute, so it's not good for an hour, it's good for one minute and that's it. After that one minute is up, it's invalid.

I tend to think he's correct.

Seriously?? Do you really do this? Right before you cross the marker you get the ASOS or the official weather from the tower?! Uhuh. Where's the BS flag?!

You are correct for it being a snapshot of the weather at that time, just like the ATIS is a snapshot of the weather at the time they wrote all the information down for the recording. I have never ever heard you must get the new ASOS right before crossing the fix. I want to meet the crew that does this also...checking the weather within the top of the minute of crossing the fix. So, if you check the weather at 15:53:48 and don't cross the marker until 15:54:01, you are illegal, according to what you wrote...

 

[SteveC]

ASOS is instant weather eh? ATIS is for the previous hour. You need the ASOS within the minute you cross the marker to be technically legal.

What's the background for that requirement?

 

[jtrain609]

What's the background for that requirement?

When does an ASOS expire? It's got a time stamp on it, and one minute later it will have another time stamp.

How could you contend that the ASOS transmission you listened to 5 minutes ago is still legal when 5 new ASOS's have been transmitted since then?

 

[jtrain609]

Seriously?? Do you really do this? Right before you cross the marker you get the ASOS or the official weather from the tower?! Uhuh. Where's the BS flag?!

You are correct for it being a snapshot of the weather at that time, just like the ATIS is a snapshot of the weather at the time they wrote all the information down for the recording. I have never ever heard you must get the new ASOS right before crossing the fix. I want to meet the crew that does this also...checking the weather within the top of the minute of crossing the fix. So, if you check the weather at 15:53:48 and don't cross the marker until 15:54:01, you are illegal, according to what you wrote...

I didn't say you were illegal, I said you have no idea what the weather is.

What happens if you get the weather at 15:54 and everything is above minimums, but at 15:57 when you shoot the approach, you are below minimums? You were not legal to shoot the approach, but you probably would have anyway because the weather you got was from 15:54, but you shot the approach at 15:57.

Does it matter in the end? No, it's internet and ground school BS that doesn't even apply to the flying you're doing anymore. Most folks will discount it and say it's a stupid conversation.

But if the FAA was on board, what would be legal?

 

[Stone Cold]

I didn't say you were illegal, I said you have no idea what the weather is.

What happens if you get the weather at 15:54 and everything is above minimums, but at 15:57 when you shoot the approach, you are below minimums? You were not legal to shoot the approach, but you probably would have anyway because the weather you got was from 15:54, but you shot the approach at 15:57.

Does it matter in the end? No, it's internet and ground school BS that doesn't even apply to the flying you're doing anymore. Most folks will discount it and say it's a stupid conversation.

But if the FAA was on board, what would be legal?

You need the ASOS within the minute you cross the marker to be technically legal.

You know what, I started to respond to this, but it's not worth it...

How's the ski bum life treating you?

 

[SteveC]

When does an ASOS expire? It's got a time stamp on it, and one minute later it will have another time stamp.

How could you contend that the ASOS transmission you listened to 5 minutes ago is still legal when 5 new ASOS's have been transmitted since then?

I didn't ask my question clearly enough. What I was wondering was "do I need to have more current weather than the 45 minute old ATIS in order to legally shoot an approach?"