Visible Moisture

[LJ45]

Thats why I said I make my own rules and over the years I've flown with dozens of pilots, world-wide, part 91 135 and 121, who do it all a little differently. No matter what manufacturers say about visible moisture or known icing, no matter what the FAA says via regulation or AIM recommendations, or what any other pilot says.......there's just to much of a wide range of situations where icing can happen. It happens even when it IS NOT supposed to happen.

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You need to pump the brakes a little on this one , examples please!!

 

[avbug]

At 3-1/4sm you wouldn't see a Boeing 747.

Actually, you really would. And will. And do.

over the years I've flown with dozens of pilots, world-wide,

I've flown with enough different pilots through the years, hundreds of different pilots,

So which is it? Dozens, or hundreds?

Thats why I use anti-ice all the time, I probably use it more than anyone I know. I have my own rules. You can't die and you can't get busted or bitched at for using anti-ice when you don't need it, thats for sure.

Clearly you have your own rules, as well as your own ideas, concepts, and quite possibly, your own alphabet or mathematics system, too. Not particularly relevant to the topic at hand.

However...yes, you can die, yo can get busted, and you can get "bitched at" for using anti-ice when you don't need it.

Anti-ice systems used when not needed can make their use ineffective when they are needed. Examples of exhaustable systems include the nose anti-ice on a learjet...use it and lose it. When the alcohol is gone, there's no more. TKS on a mooney or other aircraft...use it and lose it. When it's gone, the weeping wing is no more.

Use the boots when they're not needed, you not only wear out the boots and needlessly deform the leading edge, but can damage the boots, dependin gon the conditions. To say nothing of making them ineffective if used too soon.

You claim 747 experience, but still assert that anti-ice can be used any time without penality? You're not familiar with the potential for leading edge device damage, takeoff performance penalties, etc? Or the fact that wing anti-ice is ineffective with the flaps extended?

Nacelle and engine anti-ice robs power and bleed air, and can deteriorate takeoff performance. It's not "free." Use of anti-ice increases fuel burn. It increases takeoff distance, or can, and it can reduce climb, circumstance-specific.

Use of wing anti-ice or engine-anti-ice at the wrong time can cuase runback with refreezing aft of protected areas. Thus use of anti-ice all the time is inappropriate and potentially dangerous, too. Use of anti-ice when warranted, and when appropriate, yes. Use of anti-ice indisciminately based on your own "rules?" No. Not a good idea, not a safe idea, and inappropriate.

Even when flying in the clear with that temp and vis, its good to just hit the switch. Its free.

Actually no, it's really not...not a good idea, and not free.

 

[Fly91]

Ok, I think I understand now. Disregard the manufacturer reccomendations and make my own rules. Got it!

Yes, I meant to use the recommendations, but then go a little beyond and make yourself a little more safe. Meaning use anti-ice before the recommendations would have you use it.

Ok just kidding. But my real question was not whether it was a conservative choice, but rather was it operating out of the reccomendations of the manufacturer. I think I have my answer. Yes it is conservative and would'nt hurt, but it was not required per FAA or manufacturer.

I think you should have used the anti-ice in that situation, it falls within all manufacturers recommendations I've ever seen. Less than 10c with visible moisture. At the 3sm mark, where your vis ended on that day, thats the moisture you're looking at. So there was visible moisture in your area that you can plainly see with your eyes.

You were at 5c, right? AI "on".

 

[svcta]

So, you're asserting that the air is as saturated at 3 miles vis as it is at 1 mile vis? Question, why concern ourselves with the vis at all? Your logic is flawed because on a clear day I can sometimes see moisture 20 miles away in a shower. Does that mean that because my visibility stopped there that I need A/I? the Feds and most manufacturers it seems all agree that when it gets to a mile or less, icing conditions are present. not before that. Conditions present in the sim as described in the original post do not, by technical definition, meet the criteria for icing conditions. He did the right thing. And sim instructors don't always, every day, every time, give the best advice. They operate in a different world with scripts and rehearsed scenarios.

 

[TheInsider]

That may be the FAA's definition, but if pilots just used that as a guideline, there would be an increase in icing related accidents. Icing in clear air with better than 1sm visibility happens all the time.

I agree but when it is about passing a practical test, using the FAA's own interpretation is the safest way to go. Nothing wrong with imposing stricter criteria when flying the line though, consistent with you company's FOM and the AFM.

 

[satpak77]

only a pilot could turn "visible moisture" into a Phd dissertation

if you see yourself flying in moisture (clouds, water droplets on glass, etc) and its less than 10C, anti-ice on. Period, the end

NEXT TOPIC PLEASE

 

[avbug]

only a pilot could turn "visible moisture" into a Phd dissertation

if you see yourself flying in moisture (clouds, water droplets on glass, etc) and its less than 10C, anti-ice on. Period, the end

NEXT TOPIC PLEASE

It's not nearly so simple, and you've little need to be so dismissive of the topic. Misunderstanding both the definition and the cause and effect can result in loss of certification, and an unsafe flight operation. It may even result in loss of life, and certainly has in the past.

You aptly state that anti-ice should be on in the clouds...but the question at hand is what constitutes a cloud. Whereas the topic is flying a circling approach and not in the clouds, and not with water droplets "etc," then we are left with what you feel is a "Phd dissertation." More to the point, your dismissal of the matter hasn't solved a thing. Use anti-ice, you say...but the conditions in which you assert one should use anti-ice don't exist in this case.

The circling airplane isn't in a cloud, isn't in precipitation...which leaves your dismissive assertion exactly where?

 

[J.Otto]

If its as close as 5+ and 3 miles which is usually an esitmate anyhow (could be higher/lower), just run the anti-ice.

I know it sounds caveman-like but the difference between 1 mile and 3 miles seems fickle. visibility tends to fluctuate anyhow and that 3 mile can quickly turn to less than 1 in a hurry. i dunno. to each his own. 3 miles is quite marginal and most likely contains a good deal of moisture if the visibilty is due to clouds or fog.

 

[semperfido]

some things just don't matter, like in a G550/450. Put the sw in auto and go about your business. go ahead and nit pick.

 

[Gulfstream 200]

some things just don't matter, like in a G550/450. Put the sw in auto and go about your business. go ahead and nit pick.

I'm impressed FIDO - 99% of pilots are such control freaks they simply cant accept that an AUTO function means anything or would ever work!

 

[gear_guy]

some things just don't matter, like in a G550/450. Put the sw in auto and go about your business. go ahead and nit pick.

2 years before delivery of the 450. Until then, the debate continues.

On a serious note, thank you to everyone willing to have the discussion.

 

[Lead Sled]

FWIW, several years ago I had a face-to-face discussion with an engineer from Allied Signal regarding TFE-731 anti-icing usage. He commented that the biggest mistake that they see pilots in the field make is that we don't use anti-icing enough.

Personally, in the DA-50 and DA-900 I use the numbers in the AFM - less than +10C, visable moisture and/or visability less than 1 mile. Recently Dassault gave us a lower temperature limit of -40C as well

LS

 

[chasmo]

The 1 mile in fog has always referred to when you use nacelle anti ice on the ground. It has nothing to do with inflight.
Inflight if you are in clouds, precip ,visible mosture ,etc you need anti ice.
Of course the temperature must be at or less that the manufacture states, usually 10 C or less.

 

[BoilerUP]

The 1 mile in fog has always referred to when you use nacelle anti ice on the ground. It has nothing to do with inflight.
Inflight if you are in clouds, precip ,visible mosture ,etc you need anti ice.

Yes...and the debate at hand is what exactly is the definition of "visible moisture".

Is it 1sm? 3sm? 5sm? 6? 8? Does the observed visibility need to include BR?

Some pilots have their thoughts, while manufacturers have theirs. What's the FAA's definition of "visible moisture"? I haven't been able to find one...

 

[chasmo]

Yes...and the debate at hand is what exactly is the definition of "visible moisture".

Is it 1sm? 3sm? 5sm? 6? 8? Does the observed visibility need to include BR?

Some pilots have their thoughts, while manufacturers have theirs. What's the FAA's definition of "visible moisture"? I haven't been able to find one...

Sorry,I dont know the legal defintion.
But a good guideline on when to turn it on is if your landing lights are reflecting back and you are in the temperature range for icing.