Icing Questions

[Steveair]

Preparing for an interview and one of the questions that could be asked is "What you will do if you encounter such and such icing?"

Clear Ice - Climb since warmer air is above.

Rime Ice - ?? Use anti-ice, climb above or below clouds.(?)

Mixed Ice - ??? Same as Rime??

If anyone has any other good ice questions / answers, feel free to share!

Thanks!

 

[DC8 Flyer]

Icing is one of those things that general rules of thumbs could get you into more trouble. Example, if you are putting on ice it may not be the best idea to climb since now the ice has a chance to form on the bottome of the wings and fuselage, etc. where the boots or hot wing cant get it off, but descending might put you in more sever conditions as well as climbing. The best defense is ice protection equipement, lead by knowing what the weather around you is forecast/is doing. That doesnt mean you have to be a meterologist, just have a good idea where the VFR is or the warmer air is, if any.

Also keep in mind most ice protection equipement is meant for moderate icing if that and is meant to get you out of, not stay in it for the whole leg. Of course you get some airplanes with better equipement, hot wings, weeping wings etc, but all and all ice is one of those things that just should be avoided and or gotten out of as soon as possible/practical.

Hope this helps.

 

[imacdog]

Clear ice isn't necessarily an indication of warmer air above. If I don't know for certain where the tops or bases are to get out of the clouds, first thing I will try is climbing. If it gets worse I can always descend. If I were to try descending first and it gets worse, climbing may not be an option any more.

 

[paulsalem]

it gets worse I can always descend. If I were to try descending first and it gets worse, climbing may not be an option any more.

I was always taught that you'll get more ice at the top of a cloud than anywhere else. So it stands to reason that if you try to climb out of the ice it may get worse before it gets better.

 

[imacdog]

From what I have seen, ice accumulation does increase near the top of the cloud, though not significantly more than whatever ice you may already be picking up. If, however, the ice becomes too much to continue the climb, or your plane is at an altitude where it can't climb any more, you always have the option to descend. If, however, you try to descend out of the icing and run into worse conditions and not break out of the clouds, climbing back to better conditions might not be an option any more. In either case, in a plane with no icing protection, if you don't know for sure that you can climb or descend out of the ice, then it's time to turn around.

 

[greygoose]

Clear ice has nothing to do with warmer air aloft. Clear ice forms generally around the freezing level, I have seen it build as close to -10C but that generally starts to be more likely rime or mixed. The only possible sign of warmer air aloft is FZRA, the nice thing about FZRA is that you can climb and the aircraft will clean itself off. The negative side is you need to question how bad or thick is the layer that the FZRA is. Altitude is always your friend in icing conditions. The best thing taught about icing is when you start accumulating it get out of it.

 

[apcooper]

I agree with a lot said here. Usually a 3000 ft change in alt in either direction will get you out of ice. According to the NASA icing research videos, 90% of the time icing layers are < 3000 ft think and 50 mi long. Yes, ice is usually worse near cloud tops, fronts, lows, downwind of large bodies of water and in mountanious terrain. If you do climb in ice you must climb quite a bit faster than Vy otherwise ice will form aft of the protected surfaces. The flight operation manual should give a min speed for flight in ice. FZRA will always be clear ice but clear ice won't necessarily be FZRA. Climbing without a doubt is best in ice since as others have stated, you can always descend after a climb but might not be able to climb after descending.

 

[Lead Sled]

Lot of good stuff. I'd recommend that you dust off your copy of Weather Flying by Capt. Robert Buck. If you don't have the book go to just about any of the larger bookstores and buy it.

'Sled