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Stuck on top of a layer full of ice

Posted: Thu Jan 16, 2020 3:33 pm
by Colonel
Years ago, I was coming back from someplace east, getting close to CYSH.

I was in the 421, and ATC kindly told me that they had reports of moderate icing
in a solid layer of cloud that I was on top of.

Wonderful. Look up the definition of moderate icing.

The 421 has icing equipment - boots, heated props - but it didn't have a de-icing
plate for the windscreen. It dribbled alcohol on the windscreen like an incontinent
90 year old. I was not a fan.

So, I asked ATC for a descent as low as I could get, before I got to the beacon to do
the full NDB approach, which is all we had back then. I turned up all the heat to
the windscreen, turned on all the heating pads, reduced power, set the cabin pressure
and did a very aggressive descent - this is coming from an aerobatic pilot - to minimize
my time in the icing.

Didn't matter much. I picked up a load, but the good news is that before I reached the
beacon I was in the clear below the layer. I cancelled IFR and turned VFR towards the
airport, continuing to descend to pattern altitude.

While the boots and heating pads did their job, that stupid windshield was solidly iced
over. No plate, remember? I could see out the side window, but zero forward visibility.

Rockie thinks biplanes are stupid, but the good news is that I don't need forward visibility
to fly and land an airplane. Charles Lindbergh flew solo across the Atlantic ocean similarly
configured, you may recall.

So it was time for a Pitts-style approach, looking out the side window. Just before touchdown
I got the shit scared out of me, when the alcohol and heat finally did something, and blew
a chunk of ice off the windshield, so I could actually see a little bit forward for the landing,
but as I say, because I fly stupid airplanes that airline pilots think are useless, it actually didn't
matter if I could see forward.

In retrospect, if I had simply ignored the ice on the windscreen, and driven around the full
procedure approach, that probably would have given the alcohol and heat time to clear a
little bit of ice from the windshield.

However, I think I made the right decision to dive aggressively through the layer to minimize
my time in the icing. Minimum time and maximum speed are good things in ice. My father
said that 300 knots worked.

Did I mention that I saw frost on the roof, for the first time this winter yesterday?

I don't like ice.

Re: Stuck on top of a layer full of ice

Posted: Thu Jan 16, 2020 4:35 pm
by Scudrunner
One moonless night years ago I was heading up into the oil patch in a 1900D, the Stephan Hawkins weather station was calling clear skies, as was the area forecast.

As we descended down through about 8000' heading direct to the strip, I couldn't see anything forward. I thought for a minute it must be localized layer as I should see the airport. Glancing to the side in the moonless black void I could clearly see a few lights on the ground in the far distance.

The other skipper I was flying that night grabbed the flash light from his side pocket and pointed it at the windscreen. yup both sides completely frosted over. The windshield heat was on but wasn't drawing any current, not a breaker popped. We must have picked it up on the decent going through a layer.

I cracked a joke that if this happened to another infamous pilot at our company he would declare and emergency and return to YYC.
We brought her in crabbed a little sideways and kicked it straight in the flair as we picked up the runway lights in the peripheral vision. No big deal other than the passengers got their first impression of what its like taxiing a Pitts into the ramp. :D

Re: Stuck on top of a layer full of ice

Posted: Thu Jan 16, 2020 5:46 pm
by Rosco P Coltrane
Colonel wrote:
Thu Jan 16, 2020 3:33 pm
I don't like ice.
I on the other hand, don't like my rum and Coke to get warm.

Re: Stuck on top of a layer full of ice

Posted: Sun Jan 19, 2020 7:51 pm
by Colonel
Heating is called “Ram Air Temperature Rise” and is calculated (due to adiabatic compression) as follows:

Ram Air Temp Rise (deg C) = velocity(knots true) squared / 87 squared

Examples:

100 knots: 100^2 / 87^2 = +1C
150 knots: 150^2 / 87^2 = +3C
200 knots: 200^2 / 87^2 = +5C
250 knots: 250^2 / 87^2 = +8C
300 knots: 300^2 / 87^2 = +12C
350 knots: 350^2 / 87^2 = +16C
400 knots: 400^2 / 87^2 = +21C
500 knots: 500^2 / 87^2 = +33C
600 knots: 600^2 / 87^2 = +48C
1000 knots: 1000^2 / 87^2 = +132C

You can see why the X-15 melted it's leading edges off, every time it went Mach 6.

Even the elderly C421 would give me 200K or +5C in the descent.

PS If anyone wants oranges, they're dropping off all the trees here, now.

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Dennis doesn’t like oranges much.

Re: Stuck on top of a layer full of ice

Posted: Sun Jan 19, 2020 10:17 pm
by Scudrunner
Taking citrus back this way across the border probably wouldn’t be that big of a deal, but heading south the CBP take that serious.

Reminds me of heading south into Alaska from the Yukon with a lemon for the Salmon we planned on catching.

The border guard spied our bag of goodies for the voyage
(cheaper beer procurement planned stateside for economic reasons).

He took our lemon and my boss said “Oh sorry, we wouldn’t want to ruin the Citrus crop of southern Alaska”

As I attempted to contain my laughter, he starred back at us for a few seconds,
I pondered what I would look like sporting an orange jumpsuit at Gitmo.

Then he politely replied “good luck with the fishing”
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Re: Stuck on top of a layer full of ice

Posted: Wed Jan 22, 2020 5:56 am
by Colonel
Customs is like Christmas. You never know what you're going to get. They must have an entire
course titled "Surprise!" at Customs school.

PS I still have a buttload of oranges. I'll even wash the dogshit off them.

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