Visible Moisture

[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.

 

[b707guy]

You were "corrected", or busted? IF the instructor/evaluator can specify a value or provide guidance that says you have to have had EAI on, then I'd say he has a leg to stand on and you simply bank that info for later. But it sounds to me like his approach could have been more like "I'd use it because of xxxx in this case" rather than a directive stating that you were wrong for not using it.

Did you descend through that 3000' ceiling to get to that circling approach? If so, EAI probably should have been on and just left on unless RAT or whatever temp you use inflight exceeded your max value.

Another aspect of EAI is that high power settings associated with takeoff and climbout are much more conducive to engine icing than descent and cruising around at lower power settings. I'd bet that a G-IV doesn't require anywhere near takeoff or go around power for a circling approach, but a rejected landing or go around is something that you'd have to consider, and for that reason alone, I probably would have used EAI, given the surface conditions and the fact that I don't have a clue as to G-IV limitations. Incidentally, it would not have been required in my DC-8.

Either way, I stand with what I said up top: Unless you can be shown a set of values stating otherwise, being "corrected" sounds a bit overblown on the evaluators part (or overly sensitive on yours...:laugh.

P.S. Chasmo was posting at about the same time. I agree wholeheartedly about using landing lights to help determine if I'm in "visible moisture". But, that's a technique, not procedure, and secondly, you were in a simulator, not in an airplane. Do newfangled sims these days simulate visible moisture very well?

 

[gear_guy]

No I was not busted. I was debriefed by my sim partner that I should have used it and the instructor agreed. I agreed that it would not have hurt. But he took it a step further and said I was operating outside of the manufacturers reccomendation. Therefore stating a case that it (I) was dangerous. I did use EAI on the approach until I descended below the bases at which point I called for it to be off. One major reason I called for it to be off was that my landing data in the FMS was not computed to include EAI. And yes, if I went missed and had to go IMC I would have turned it back on.

 

[siucavflight]

I have never heard of anything other than visibility less than one mile being the definition of visible moisture. Seems this guy was giving you his opinion rather then the actual limitation.

 

[filejw]

No I was not busted. I was debriefed by my Sim partner that I should have used it and the instructor agreed. I agreed that it would not have hurt. But he took it a step further and said I was operating outside of the manufacturers recommendation. Therefore stating a case that it (I) was dangerous. I did use EAI on the approach until I descended below the bases at which point I called for it to be off. One major reason I called for it to be off was that my landing data in the FMS was not computed to include EAI. And yes, if I went missed and had to go IMC I would have turned it back on.

Glad you gave a better explanation of the Sim profile. To me your answers is your both right.. I do what you did all the time in those conditions. Whats with Sim partner being a critic.. tell him to keep his month shut till your out of the debriefing room...

 

[NCherches]

If in doubt... use it... It is free to use (assuming you don't need the power)