hrmham

Question for the experienced cargo pilots (I have a lot of time to build for my ATP). Now that winter is coming (and icing concerns build) I'm curious about the rough percentage of time that is spent in the soup during the cruise portion of your flights? That is, while I get it that ice build-up can be an issue as you climb through a cloud deck to get to cruise (or on descent), but do you typically find a cruise altitude clear of clouds?

JohnBurke

That really depends on the type of operation and the time of year, location, and altitude. I've never really thought about a percentage of the time. If you're flying freight that keeps you at 15,000' on the backside of the Sierras in winter, or around the great lakes, you'll spend an appreciably greater amount of time in icing conditions than if you're flying at 41,000 on top, or in ice crystals that don't contribute to icing.

I think what you're getting at here is whether operations occur in areas where picking up ice is likely and the answer is yes...and often occur on the ground when deicing is a necessity, too.

It's for this reason that ground deicing and anti-icing is performed, and aircraft have anti-ice measures on airfoils, engine nacelles, propellers, windscreens, etc.

It's that time of year; planning for ice and using ice protection is part of regular operations.

Bons

In my experience in a turboprop that rarely flies above 10k ft icing can get a bit tricky but shouldn't scare you off if properly managed. It's not uncommon to pickup ice the majority of the trip if imc but the key is proper flight planning and de/anti ice ops and finding a good altitude with minimal ice or warmer temps. There is a lot of trial and error with how the airplane will react to the above. I've picked up ice unforecasted and vise versa. Atc is usually extremely accommodating when it comes to ice and your intended flight plan if changing altitudes or re routing. Listen to your captain and ask what, when, where, why during flight planning, pre and post flight and during deicing. Winter is my favorite time to fly! It beats flying around all those pesky summer t-storms😉

No Land 3

I used to fly a C210 in icing conditions every night in Northern California for a now defunct 135 operator. 10,000ft would start to accumulate ice, start pitching up and start descending against my will. The boots worked for crap, but luckily the temperature differential was enough a thousand feet lower to melt the ice, and the airplane picked up speed. I am lucky to still be alive.
With the two type ratings I have, the CL65 and 744, icing isn't even a concern when you follow procedures. I find the summer time thunderstorms require far more grey matter in deciding a course of action to take.

Twin Wasp

As JB said, it varies. What kind of plane are you flying, a CE-208 or a 747? And where? SoCal doesn't know the definition of winter. Detroit is a whole different story. Years ago I was talking to YIP operator looking for Convair check airmen. They also operated DC-6s. They said I could fly the Six but I would have to spend a winter as an FO. Made a lot of sense.

trip

Changing altitude as little as 3K ft will change the icing condition (as in exit it) probably over 75% of the time, doesn't matter what airplane your in. Word of caution>some airplanes will not be able to climb 1-3K after picking up some ice.

Cujo665

It isn't a question of in the soup or not; it's a question of outside air temperature.

Ice forms in a fairly narrow temperature spread. It's simple to climb or descend out of that temperature band in almost all circumstances.

Once you're out of turboprops you'll find that most icing in most modern jets is a non-event.


However, to answer your VMC vs IMC percentage of the time question; I'd say there's a good reason pilots wear sunglasses.

CaptainYoda

Are you flying with deice equipment?
If no, then you should not fly in icing or potential icing.

If, yes

Remember to have an out. I've seen severe icing levels as thin as 1000', I usually try to climb first unless I hear pireps saying worse icing above.



Don't go straight to flying IFR with icing at night without building up experience.



Night time limits your options real fast, especially with a low performance aircraft. The number of airports that are open, have illumination, have personnel on the field, someone to clear the runway, someone to report the conditions. So the number of airports drops by 50-80% depending on location.



Take it easy, maybe fly day IFR into stratus clouds to observe ice build up in an area with known above freezing level below you (and above terrain) and localized challenging weather, instead of doing it with LIFR covering everything east of the Mississippi.



Climbing through a layer is fine IF you consider what happens when you're 500' from the tops and, due to worse icing than predicted, your climb rated drops from 800FPM to 200FPM. Do you push your limits, or admit defeat and retreat to a warmer altitude. Is there a lot of places to land if you can no longer maintain altitude? Is there deicing or a warm hangar below you?



Something that kills a lot of pilots is the lack of a hard limit. They keep pushing their soft limit until they are boxed in a very dangerous situation. Make a hard limit, thickness of icing, IAS/performance loss, gut feeling. Hit the limit, no matter how close you are to your destination, admit defeat and land before you lose control.



Almost every airplane that I've flown there is something that ices up first, a temperature probe on the windshield, an antenna, an exposed bolt, something that gives me an immediate reminder of accumulation. Find it on your airplane.


If you are in icing in level flight, make a note of your airspeed. This is your best indicator of accumulation. Once you lose 5 knots, consider your options NOW. Alternates, altitude changes, ask ATC for help. By the time you've lost 10kts, problems start happening fast and sensory overload and or pilot workload increases beyond safe capacity in 2-5 minutes.



I've flown a LOT of night IFR in icing single pilot.

IT IS NO JOKE!!
A lot of the experience comes from pushing too far and scaring the living poop out of myself for underestimating mother nature.



Press your limits in small steps. Don't allow 3 major problems to happen.

(for instance, LIFR, terrain, and icing)

JohnBurke

It's very much a question of being in the "soup" or not, as well as temperature, as well as speed, as well as atmospheric conditions, as well as aircraft design and capability.

In one of my former lives I flew atmospheric research. One of the keys we looked for was ice production or ice buildup; we made an effort to seek out maximum icing conditions, particularly in thunderstorm penetrations when taking samples or collecting data.

There's a common misconception that ice forms in a narrow range and that a few thousand feet will cure the icing problem. In my experience over the past few decades, this is not true. I've seen many, many times when descent below MEA was impossible and icing conditions existed to MEA and below (often to the surface, especially over mountainous terrain), and well above where I could climb. This can be particularly true of piston and turboprop equipment.

Icing will occur with outside air temperatures above freezing due to several reasons, including supercooled water and freezing rain, local temperature drops to to area pressure changes on the airframe, inaccurate temperature gauges, variability in a parcel of atmosphere, rising or descending air (think orographic lifting, convective activity, etc), and other factors. Icing will occur all the way down to -40C, with the ideal icing range approximately -15C.

Particularly during thunderstorm penetration research, I always picked up my maximum rate of icing around -15C. Icing rate didn't diminish much through 0C and continued up through about 06C in some cases, generally being gone by +10C. It continues with less frequency down through -25C, with liquid water found as low as -40C. I used to fly with the gentleman who discovered liquid water in a research environment at -40C, and not coincidentally one of the first to experience severe icing and airframe damage from hail, at the same time, at -40C. Go figure.

Yes, it's possible that an altitude change of a few thousand feet may remove ice; I've seen that happen. I've seen many more times, however, when making an altitude change of several thousand feet wan't possible, and if possible, woiuldn't remove the icing conditions.

Another popular myth is that ice bridging on boots doesn't exist, and it absolutely does. I've watched it hundreds of times, and there is zero question that it exists. In fact, long ago I lost count of the number of times I popped boots and watched the ice expand outward, change colors as the boots pushed it away, then retracted beneath to leave a hollow shell that continued to build ice as my new leading edge, and coiuldn't be broken by subsequent boot inflations or cycles.

I've seen ice build so rapidly that it couldn't be countered or removed, and have picked up 3/4 to 1" in sixty seconds, and 2-3" in a similarly short period of time. In one case, during a penetration flight, I had to stop the mission and land due to very heavy ice buildup that began to affect controllability and couldn't be removed. I landed at a middle eastern location in the desert, and still had 3/4 inches of ice on the airplane that were peeled off and photographed, more in some areas.

Don't count on it submlimating or being removed by a change of a few thousand feet. Know where your best options are, but also know where they're not. There are a lot of circumstances where the best option is to not be there, and where exiting icing conditions isn't possible.

I think I can count on one hand the number of flights I've had in daylight this year.