Broken AWOS

BobDDuck

BobDDuck

Island Bus Driver
An FO and I were discussing a situation he'd run into last week.

Going into an uncontrolled airport (at night, but that's immaterial), where the weather report was calling for CAVU. 20 miles out, they picked up the AWOS which stated visibility was 1/4 miles. At 10 miles out they had the airport visually and saw the entire runway and terminal complex with no fog or obstructions to visibility. In fact, they saw no fog for miles and miles. For the sake of argument, lets assume that they could not cancel IFR until on the ground per opspecs.

They assumed that they could not land as the reported visibility was too low to start the approach. They held for about 10 minutes until the AWOS was reporting 1 mile and then they landed.

I'm thinking they could have just taken a visual approach and at that point the AWOS reported visibility no longer matters and as long as they maintain visual with the runway they are good to go. Right?
 
BobDDuck said:
An FO and I were discussing a situation he'd run into last week.

Going into an uncontrolled airport (at night, but that's immaterial), where the weather report was calling for CAVU. 20 miles out, they picked up the AWOS which stated visibility was 1/4 miles. At 10 miles out they had the airport visually and saw the entire runway and terminal complex with no fog or obstructions to visibility. In fact, they saw no fog for miles and miles. For the sake of argument, lets assume that they could not cancel IFR until on the ground per opspecs.

They assumed that they could not land as the reported visibility was too low to start the approach. They held for about 10 minutes until the AWOS was reporting 1 mile and then they landed.

I'm thinking they could have just taken a visual approach and at that point the AWOS reported visibility no longer matters and as long as they maintain visual with the runway they are good to go. Right?
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Wasn't there always the part about in flight visibility? If you can see the airport from 20 miles out, it's not 1/4 miles no matter what the damn AWOS says. Just don't crash the plane.
 
Extreme gray area. The awos could be in a patch of ground fog. If the td/dp spread was small, probably the case. At any rate, picture yourself in the hot seat explaining it.
 
I have encountered this exact scenario in a C152. In the flare, I inadvertently went IMC. It was pretty suspenseful.

As for 121 and weather reports, I don't think you can disregard the AWOS, if I remember right. I think it would have to be NOTAM'd OTS and a certified weather observer would have to give you a legal report, but the AWOS has to be officially OTS.
 
I know of a crew that experienced this - they elected to declare an emergency to cover their bases, but the issue was compounded by a diversion and low fuel. There are several regs in 135 that infer that a pilot can use their own observations to aid in judgement, but I'm not sure if it's in 121. I'll look.
 
Rocketman99 said:
Wasn't there always the part about in flight visibility? If you can see the airport from 20 miles out, it's not 1/4 miles no matter what the damn AWOS says. Just don't crash the plane.
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121 and do this and you can be violated unless your OPSPECS provide relief.
 
BobDDuck said:
An FO and I were discussing a situation he'd run into last week.

Going into an uncontrolled airport (at night, but that's immaterial), where the weather report was calling for CAVU. 20 miles out, they picked up the AWOS which stated visibility was 1/4 miles. At 10 miles out they had the airport visually and saw the entire runway and terminal complex with no fog or obstructions to visibility. In fact, they saw no fog for miles and miles. For the sake of argument, lets assume that they could not cancel IFR until on the ground per opspecs.

They assumed that they could not land as the reported visibility was too low to start the approach. They held for about 10 minutes until the AWOS was reporting 1 mile and then they landed.

I'm thinking they could have just taken a visual approach and at that point the AWOS reported visibility no longer matters and as long as they maintain visual with the runway they are good to go. Right?
Click to expand...

I had this same situation at night a while back on a 91 flight. ASOS reported 1/4 mile. I seen the airport, requested the visual approach. I got it. Did not see any fog at all and seen the entire airport. In the flare I went IMC without any warning but landed uneventful.

The Air Ambulance guy behind me canceled IFR and went in VFR. We discussed this after we landed. Do you need 3 miles vis to land when VFR? What about just doing the Visual approach. Its an instrument maneuver right? no minimum vis required?

What about the guy in the Supercub that dont have any radios? can he land if he got the whole airport in sight and 3 miles vis and has no way of knowing the ASOS is reporting 1/4 mile?
 
Fly_Unity said:
I had this same situation at night a while back on a 91 flight. ASOS reported 1/4 mile. I seen the airport, requested the visual approach. I got it. Did not see any fog at all and seen the entire airport. In the flare I went IMC without any warning but landed uneventful.

The Air Ambulance guy behind me canceled IFR and went in VFR. We discussed this after we landed. Do you need 3 miles vis to land when VFR? What about just doing the Visual approach. Its an instrument maneuver right? no minimum vis required?

What about the guy in the Supercub that dont have any radios? can he land if he got the whole airport in sight and 3 miles vis and has no way of knowing the ASOS is reporting 1/4 mile?
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In the 135 world, the pilot can use his/her own observation for the weather while conducting VFR operations. If you are IFR, then you have to go with the reported weather. Now that I think about it, back in my 1900 days, there was a small uncontrolled field we we went into that had the AWOS inop. We had to get the station manager, a NWS certified observer, to come out and give us reading on unicom.
 
As some others have mentioned, I would be leery of saying "well, the AWOS is reporting 1/4, but I saw the airport 20 miles out so the AWOS must be wrong." When dealing with fog, slant visibility can be much better than the visibility in the flare. Where I'm flying, I often get the airport 20+ miles out and have to shoot an approach because the actual visibility on the runway is less than 1sm.

As far as the legalities of the situation, a smart guy told me that when landing mins are in question, it's like the cop with the radar gun who gives you a speeding ticket. You can plead to the judge all you want to that the cop was wrong, but the cop still has the radar gun. Yeah, it can be wrong, but it's expensive and time consuming to prove it wrong. Take the delay/diversion (unless you're truly out of fuel, as was mentioned before) and if the AWOS is wrong, report it so it can get maintenance.
 
Part 91, 135, 121 are all different animals. Part 91 you can probably get away with it unless you are playing loose with what 1/4 mile visibility really is. 121 and 135, it's a different world. They don't want pilots playing loosy goosey with weather and visibility. If the ASOS says 1/4 mile, does not matter what you think it is. Unless your OPSECs say otherwise you assume it is 1/4 mile visibility. It does not matter what you think it really is.
 
How stupid is this...I was going into SLO one evening (at OO) and the field was reporting 1/2 mile. I could see half of the runway, but I had to do the ILS which took me to the fogged in part of the runway. I could have done a safer approach visually onto the other end and rolled out at relatively low speed into the foggy area, but them's the rules.
 
Bumblebee said:
How stupid is this...I was going into SLO one evening (at OO) and the field was reporting 1/2 mile. I could see half of the runway, but I had to do the ILS which took me to the fogged in part of the runway. I could have done a safer approach visually onto the other end and rolled out at relatively low speed into the foggy area, but them's the rules.
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The rule is there for those 121 pilots who would try to play with the rules- trying to get into an airport where the weather is below minimums by saying the report is inaccurate. I'm sure if one were to do some research on the rule you would probably find it was written with the blood of innocent passengers.
 
yeah...in my case it would have been much better landing on the completely clear end instead of having to do the mins...approach lights continue...runway in sight...landing...lose sight (in the black area) and as switching hand position to TO/GA see paint and land. The nastiest approach I had to do...I should have had the discretion to do the other thing. Or the lawyers should fly the darn approach.
 
Bumblebee said:
How stupid is this...I was going into SLO one evening (at OO) and the field was reporting 1/2 mile. I could see half of the runway, but I had to do the ILS which took me to the fogged in part of the runway. I could have done a safer approach visually onto the other end and rolled out at relatively low speed into the foggy area, but them's the rules.
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Been there. Tower asked for a PIREP. "well, from the time I joined the localizer to the time I crossed the 500' markers, it was perfect VFR."
 
Never landed in a situation like this but I have taken off from MDT on a few occasions when Fog from the river covered the airport, 800RVR. Take off and then just after rotation everything is clear, you can see all of the lights clearly and the airport clearly. Looking down through fog vs horizontally through it makes a huge difference.
 
Pilotforhire587 said:
Never landed in a situation like this but I have taken off from MDT on a few occasions when Fog from the river covered the airport, 800RVR. Take off and then just after rotation everything is clear, you can see all of the lights clearly and the airport clearly. Looking down through fog vs horizontally through it makes a huge difference.
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This is a great observation to share.
 
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