Taxiway closed by notam due to snow/ice

lsaway said:
In the south, it takes longer to dispatch the workforce and equipment needed to clear snow and ice because we rarely need it. Most of our vehicles don't have snow tires either. It pays to have patience in these conditions.
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Our southern county has about 880mi of paved roads, and the county owns exacly two plow/salt trucks. Most years they stay parked.
 
EdFred said:
Rolling slower will stop faster than locked wheels on snow or ice, and once the wheels are locked, you aren't in control and since most roads around here are crowned, you're most likely going off roadin'.
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Rolling tires = static friction
Sliding tires = kinetic friction

In general static friction > kinetic friction, thus maximum braking is braking just hard enough to NOT lock up the tires. I believe the term is braking at incipient lockup.
 
luvflyin said:
I’m still skeptical. Pretty sure wheels locked will always give you the shortest stopping distance. Dry, wet or ice. I ain’t sayin do it. Stopping under control is almost always better than stopping a little shorter outta control.
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Wheels locked will not give you the shortest distance. Rolling wheels with braking action will. Dynamic friction (wheels locked, tire has broken contact, is sliding on pavement) vs static friction (tire contact patch is not sliding on pavement).

Lots of discussion on this topic on the motorcycle forums. Laying it down intentionally and sliding will not stop you shorter than remaining on the wheels and braking.

EDIT: I could have just said "DITTO" to what Bill posted above.
 
Anti-lock brakes are a scam perpetrated by the same auto makers that are hiding the carburetor that runs on water, man.
 
Salty said:
Anti-lock brakes are a scam perpetrated by the same auto makers that are hiding the carburetor that runs on water, man.
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Well, I bet all carbs would run on water, but would the engine that it is mounted on?
 
Bill said:
Rolling tires = static friction
Sliding tires = kinetic friction

In general static friction > kinetic friction, thus maximum braking is braking just hard enough to NOT lock up the tires. I believe the term is braking at incipient lockup.
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Learned something, thanks!
 
If they were really anti-lock brakes, they'd be amazing. But every anti-lock I've seen are really "fast unlocking and relocking" brakes. Still, they're better than a blind panicked lock, and they are pretty cool on mixed ice/snow and dry pavement. Oh, and they're handy for trucks or anything else that has a screwy front/rear balance.
 
Albany Tom said:
If they were really anti-lock brakes, they'd be amazing. But every anti-lock I've seen are really "fast unlocking and relocking" brakes. Still, they're better than a blind panicked lock, and they are pretty cool on mixed ice/snow and dry pavement. Oh, and they're handy for trucks or anything else that has a screwy front/rear balance.
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And they allow you to steer during full-effort braking, a feature that kept me alive and uninjured one night.
 
Albany Tom said:
If they were really anti-lock brakes, they'd be amazing. But every anti-lock I've seen are really "fast unlocking and relocking" brakes. Still, they're better than a blind panicked lock, and they are pretty cool on mixed ice/snow and dry pavement. Oh, and they're handy for trucks or anything else that has a screwy front/rear balance.
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The theoretical reason that they lock and unlock: if they don't occasionally unlock brakes your reference velocity drifts away from the actual speed over the ground (relying on integrating longitudinal acceleration while the vehicle may be changing it's pitch attitude), and if the reference velocity is off then your slip calculations are off and thus your slip targets are off...

The practical reason that they lock and unlock: wheel/tire/brake combinations are pretty hard to accurately control right at the peak of grip since tire coefficient of friction with the road falls off sharply if you get just a little too much longitudinal slip (especially true with track focused tires and low inertia/carbon fiber wheels). All the while your brake torque vs. pressure is constantly changing with increasing brake pad and rotor temperature. And also the normal load on each tire is constantly changing due to the road surface being non-planar and load transfer from decelerating.
 
The advantage of anti-lock on slippery stuff is not just stopping distance, it's steering. Try steering on ice with your front wheels not rotating.
 
My experience with anti lock brakes is it takes a further distance to stop on ice or slippery snow... so I plan accordingly.
 
PaulS said:
My experience with anti lock brakes is it takes a further distance to stop on ice or slippery snow... so I plan accordingly.
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Compared to dry road, yes.
 
Salty said:
Compared to dry road, yes.
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Negative Salty, on sloppy icy roads. I've slid through stop signs with abs clacking away many times. Down my driveway, same thing. Where locking the wheels would have stopped. On the driveway I've had to hit the ebrake to stop.

I prefer abs on dry pavement, and it's usually good on slop. But sometimes you get caught by surprise and I curse it.
 
PaulS said:
Negative Salty, on sloppy icy roads. I've slid through stop signs with abs clacking away many times. Down my driveway, same thing. Where locking the wheels would have stopped. On the driveway I've had to hit the ebrake to stop.

I prefer abs on dry pavement, and it's usually good on slop. But sometimes you get caught by surprise and I curse it.
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I’m not sure how you can compare. It would be nigh impossible to duplicate the conditions twice in a row.

If true, I’d say your brakes were not functioning properly.
 
PaulS said:
I've been driving in crap a long time Salty, many cars. Here is an article, one of many on the subject.

https://www.yourmechanic.com/article/driving-with-abs-in-snow-and-ice
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There are a few things wrong with this article:1) ABS absolutely works on ice (at least modern/recent ABS software) 2)ABS on snow might or might not be better than a skilled driver - it will depend on the surface condition, tire, driver, and the ABS software/calibration. About the only time that the driver is going to be able to beat ABS is if the surface is deep snow without many/any other tracks in it (i.e. you can build a wedge of snow in front of all 4 tires - also, some ABS software/calibrations are able to sense the right conditions and do this for you) and the ABS software and calibration are not well developed. In all other cases, without ABS the driver has to reduce brake pressure on all 4 tires whenever one tire starts to lock vs. ABS only has to reduce pressure on the one tire that started to lock and the others can keep decelerating the vehicle at full capacity.

TLDR: Densely packed snow -> ABS is going to win, slush -> ABS is going to win, patchy snow/pavement -> ABS is going to win, patchy ice -> ABS is going to win, ice -> ABS is going to win, deep virgin snow -> you might be able to beat ABS, but you will not be able to steer/turn at the same time.
 
Matthew Johnson said:
There are a few things wrong with this article:1) ABS absolutely works on ice (at least modern/recent ABS software) 2)ABS on snow might or might not be better than a skilled driver - it will depend on the surface condition, tire, driver, and the ABS software/calibration. About the only time that the driver is going to be able to beat ABS is if the surface is deep snow without many/any other tracks in it (i.e. you can build a wedge of snow in front of all 4 tires - also, some ABS software/calibrations are able to sense the right conditions and do this for you) and the ABS software and calibration are not well developed. In all other cases, without ABS the driver has to reduce brake pressure on all 4 tires whenever one tire starts to lock vs. ABS only has to reduce pressure on the one tire that started to lock and the others can keep decelerating the vehicle at full capacity.

TLDR: Densely packed snow -> ABS is going to win, slush -> ABS is going to win, patchy snow/pavement -> ABS is going to win, patchy ice -> ABS is going to win, ice -> ABS is going to win, deep virgin snow -> you might be able to beat ABS, but you will not be able to steer/turn at the same time.
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Yeah, all I said was abs can take longer to stop on icy roads. I've lived it over and over. You adjust your driving for it, either consciously or unconsciously. Or you crash.
 
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Getonit said:
The airport I am based at has closed the taxiway to the hangars, I assume due to snow and ice, maybe 2-3 inches. I am not concerned about the safety aspect of it as I have plenty of experience dealing with it, summary is go slow and plan ahead. Runway is open, tower is open. I need to go somewhere Saturday morning and I don’t need to be held up by some moronic southern airport administrator. Can I legally ignore this? I am 100% sure I can’t, but wanted to see what the brain trust here thinks.
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Hmmm…. So the airport administrator is a moron because he is from the South?……
 
Getonit said:
All right, this is why people don't bother asking questions on the internet. I am not some cowboy moron with an anti-authority attitude, glad someone just got done reading the FOI's. I did contact the administration and miracle of miracles they responded, saying it would be reopened by close of business today but I don't know if I trust their competence quite frankly. I suspect they closed it to allow the workers to clear ice/snow, I get that need to keep planes out of the way, however did they close it to protect me from myself? That is where I take exception. What is to prevent me from taking off in zero-zero, TSTM nearby, gusty winds, etc. I don't need some government nanny who isn't even a pilot telling me what is safe and what is not. Flame away people.
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Hmm…. so if you were a cowboy that means that you WOULD be a moron, implying that cowboys are all Morons?…….
 
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