Flying and icing (no boots & tks)

Ibra wrote:

Climb a lot if you can subject to airspace/performance?

If you start picking up ice in IMC climbing will be anywhere from counter productive to impossible.
You will pick up ice on the lower wing surface and crash. Engine may quit due to blocked air intake.

Turn around and abandon the area.

Ibra wrote:

I will just call it off while on the ground preferably

The urge to climb is high but this can be treacherous. You see light above and you think you must not be far from the tops, but sometimes you still have thousands of feet of ice above. And near the tops icing is often the worst. Unless you have a reliable PIREP of cloud tops (almost never in Europe) I would not try climbing.

There is a good FAA safety video about the strategies in icing (I think they name four) but I can’t find it right now.

Say you’re flying in England in a PA28/C172 type SEP. From a club so presumably a PA28-140 or a C172-N from the 1970s…

Temperature on the ground is 2C. Freezing level is 1000ft. You’re flying along at 3000ft and enter IMC, start picking up ice. On the half million chart, the sector MEF (maximum elevation figure) is 1000ft. Add 500 or 1000ft to that and you’re back in the freezing layer. Climbing is not really an option on such an underpowered SEP, you’d have to get to 8 or 9000ft before you get to -15C. Such a climb would take a while and in the meantime you’ll continue to pick up ice… Not to mention the very likely chance of having a CAS just above at 5000ft or so (which arguably in an emergency one would bust, but still adding to the pressure…)

Best course of action? Turn around, descend to MSA, declare emergency. If severe icing is building up, consider a PFL before it’s too late.

All of this from someone who has never experienced icing in flight. Touch wood.

In response to Alpha_Floor – in that situation just don’t go into it in the first place.

If your aeroplane is not FIKI certified then entering cloud with the OAT between zero and minus 15 is (a) risky, (b) probably illegal, and (c) unlikely to look good in the accident report. How accurate is your analogue OAT gauge anyway? How closely can you read it? Wanna look at it and decide it’s reading 1 or 2 degrees above rather than zero so you’re ok? Do you feel lucky?

It’s all about your personal attitude to risk. My attitude is to always have a bailout option – and a solid one, not one that you hope might work.

On Monday the 21st the conditions were much as you describe. I flew from White Waltham to Cardiff and back again later in the day. Bases of scattered/broken layers were about 2,500-3,000ft and generally less than a thousand feet thick. You could see the blue sky through the holes and the thin bits. There was always a hole somewhere not too far away.

I ran along touching the bottoms for a bit, then my confidence increased and I decided to punch up through. The OAT was about minus 5 and this was definitely known icing conditions. I told myself that if I wasn’t on top by 4,000ft or if I saw the slightest trace of ice then I’d be going straight back down at yellow line speed. I’ve never had ice form before, I didn’t particularly want to start now, and I doubt the TB10 can carry much.

Running along the top of it was fun and I did the same on the way home. I am fine with layers when I know how thick they are, but when I’ve no idea I’m very cautious. I always had an out in that I knew there was always 2,500-3,000 of clear air beneath the cloud so I could descend rapidly into that space if required and not have to worry much about terrain.

This was the first time I’ve decided to go through a layer when all the indications suggested there would be ice. It was sobering to learn that someone else going to Cardiff later that day never made it, and it sounds like ice may well have been a factor.

Temperature on the ground is 2C. Freezing level is 1000ft. You’re flying along at 3000ft and enter IMC, start picking up ice.

You should not have departed in that type of aircraft if the surface temp is so low and the cloudbase is such that IMC is likely.

If your aeroplane is not FIKI certified then entering cloud with the OAT between zero and minus 15 is (a) risky, (b) probably illegal,

It is not illegal. In the US, which is the only place “FIKI” has a legal meaning (because it maps onto US weather services), there was a time, many years ago, when the FAA defined “known ice” as any flight in IMC below 0C. They soon changed that, because it was impractical.

This is a good thread to read. Bear in mind that those who tend to worry less about ice temd to be people whose planes are fast (so benefit from aerodynamic heating) and have lots of power (so they can climb fast and high).

One always needs to have a Plan B, and for icing conditions it is usually a descent into warmer air, without hitting terrain. And yes this does limit winter flying – especially in the UK, for IMCR holders who cannot get into Class A and are thus often stuck in IMC at 2400ft or whatever is their legal ceiling.

It is relatively easy to figure out the freezing level as well as the minus 20 degrees Celsius level to be expected. The top of clouds can also be estimated from the infrared cloud top temp satellite images combined with a look at the Gramet chart or Skew-T diagrams. Now you need to have a way out in case ice builds up, which is usually to go down and fly in + temperatures. Once you arrive in air above zero temps, any rime-ice will shed off in minutes and you continue your flight without hitting anything :-)

If the temperature on the ground is near zero, there are not many options left unless you have a FIKI certified aircraft and indeed ideally with lots of power.

Most piston SOPs define icing conditions at 4 degrees C and below, the low pressure at the propeller blades and leading edges, especially tailplane, will potentially result in icing. Some parts of the airframe will have some warming of 1-2oC at puddlejumper speeds, but not the parts you necessarily need for thrust and lift.

A blunt airfoil helps but piston equipment, even FIKI, can be overwhelmed in moderate conditions – moderate for turbine being a lot more than piston. Hard to predict icing, but flying in moderate/severe conditions will make you a believer in turbine and bleed air de icing systems.

Knowledge of the frontal characteristics and positioning is essential, and in nimbostratus the vertical profile of icing conditions can be very extensive, more than 5,000 feet.

Turboprop jobs usually involved demonstrating very good met knowledge at the interview stage, because of the icing risk.

Weeping wing technology has a tendency not to clear the wing tips, which in a high aspect ratio wing like the DA42 creates its own issues.

Snoopy wrote:

If you start picking up ice in IMC climbing will be anywhere from counter productive to impossible.

I’ve certainly gotten out of icing conditions by climbing on top. But that was with the freezing level well above MSA — otherwise I wouldn’t have tried it.