engine lip ice in flight

kidicarus5897 · 07-03-2008, 01:48 PM

with temp around 10*C and moisture in the air, why is there not an (or is there) an ice detector on the engine intake? Temp can drop up to 10* and moisture can freeze on the lip well before the ice detectors detecte ice, if at all. Obviously this isn't an issue, but por que?

Yariv · 07-03-2008, 02:37 PM

there's no detector, but there is a system that automatically turns on engine a/i when these conditions are true. it's called - a pilot.

tat<10*c
sat>-40
moisture

kidicarus5897 · 07-03-2008, 03:33 PM

Quote:

Originally Posted by Yariv

there's no detector, but there is a system that automatically turns on engine a/i when these conditions are true. it's called - a pilot.

tat<10*c
sat>-40
moisture

So everytime you fly around with a temp of 10* TAT you turn on the engine lip anti-ice? You'd be the first

optimus_prime · 07-03-2008, 07:33 PM

Quote:

Originally Posted by Yariv

there's no detector, but there is a system that automatically turns on engine a/i when these conditions are true. it's called - a pilot.

tat<10*c
sat>-40
moisture

If the SAT is -40, I think its too cold for any ice to actually attach itself to anything. And TAT, well that's just SAT with an adjustment for air friction so it really shouldn't matter.

As far as the 10 degrees in flight with visible moisture. Well it all depends on which temp you are talking about. And yes if the auto mode isn't kicking in, then you are the back up to flip the switch.

Yariv · 07-03-2008, 08:14 PM

I don't think I'm the first. and it's a required procedure at other airlines, not that it matters, but it should be at every airline since ice doesn't know what airline you're flying for...

>-40 sat, is where moisture can exists. colder means dry.

<10*c because there is a 10*c temp drop in the intake bringing the temp down to 0*c. it's tat in flight.

don't forget moisture must be present.

what part of this do you disagree with?

optimus_prime · 07-03-2008, 08:28 PM

Quote:

Originally Posted by Yariv

<10*c because there is a 10*c temp drop in the intake bringing the temp down to 0*c. it's tat in flight.

So you are telling me that if you are at FL370 and somehow the TAT is at 10 degrees you are going to turn on the engine anti-ice on?

FLAPS 9 · 07-03-2008, 08:54 PM

Quote:

Originally Posted by Yariv

there's no detector, but there is a system that automatically turns on engine a/i when these conditions are true. it's called - a pilot.

tat<10*c
sat>-40
moisture

I disagree...we all know that with drop in pressure on the upper surface of the wing (which is associated with a drop in temperature) which only occurs in flight (not on the ground) might not be exactly ten degrees but is an insignificant difference from the drop in the intake. The ice detector being shaped like a wing (also being subject to the change in pressure and temperature) makes all parts of the aircraft including the part detecting ice...the SAME TEMPERATURE! So why then do we ever use the OVRD switch? Only on operations on the ground where the wing and stab are not subject to the change in pressure and temperature and in flight when the ice detectors fails.

kidicarus5897 · 07-03-2008, 09:04 PM

I disagree with turning on the engine ICE in the air without any mention in any manual, however I do agree that at times it may be necessary. The fact that it is done at other airlines does not help those of us at this airline that are unaware of that fact, but it does imply that it might be something we should be doing. I have never heard of lip ice being a problem so I guess that is why we don't have a procedure. The question I have is why? Physics-wise at least. So you are telling me that you have turned on the engine lip air in flight based on the temp being close to 10*c. Does anyone else do that on a regular basis?

kidicarus5897 · 07-03-2008, 09:07 PM

Quote:

Originally Posted by optimus_prime

If the SAT is -40, I think its too cold for any ice to actually attach itself to anything. And TAT, well that's just SAT with an adjustment for air friction so it really shouldn't matter.

As far as the 10 degrees in flight with visible moisture. Well it all depends on which temp you are talking about. And yes if the auto mode isn't kicking in, then you are the back up to flip the switch.

TAT is pretty much all that matters in flight................besides the SAT limitation

FLAPS 9 · 07-03-2008, 09:09 PM

Quote:

Originally Posted by kidicarus5897

I disagree with turning on the engine ICE in the air without any mention in any manual, however I do agree that at times it may be necessary. The fact that it is done at other airlines does not help those of us at this airline that are unaware of that fact, but it does imply that it might be something we should be doing. I have never heard of lip ice being a problem so I guess that is why we don't have a procedure. The question I have is why? Physics-wise at least. So you are telling me that you have turned on the engine lip air in flight based on the temp being close to 10*c. Does anyone else do that on a regular basis?

See my explanation above!