Bailed because of frost -- a good call?

Roddie; One comment about your question on if this was a good call or not....

You are the PIC and we all will respect your decision to exercise your personal safety limits.

There are plenty of items that are just waiting to grab you and twist you up into all manner of wrongness. Deciding that the situation is better to stay on the ground is perfectly okay and demonstrates good thinking. Keep that up!
 
AggieMike88 said:
Roddie; One comment about your question on if this was a good call or not....

You are the PIC and we all will respect your decision to exercise your personal safety limits.

There are plenty of items that are just waiting to grab you and twist you up into all manner of wrongness. Deciding that the situation is better to stay on the ground is perfectly okay and demonstrates good thinking. Keep that up!
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:yeahthat:
 
MAKG1 said:
If it's below freezing, I agree. Bad idea.

But it doesn't have to be below freezing to get nighttime frost.

Now, it still may be time consuming and chilly under those circumstances, but it won't make the ailerons freeze.
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It's getting cold, so we have to have this argument every year. Someone from the South, where you can get frost without it being below freezing, will describe using hot water to defrost an airplane and then someone who learned to fly in Nome warns that if you do, your flight controls will be locked up and you'll crash on takeoff.

It's not an appropriate solution for all situations. But where it IS appropriate, it's the decision of the PIC whether or not to do it.

Personally, I prefer to let the sun defrost the airplane, it usually only takes about 30 minutes of sunlight to do it. But if it's overcast and above freezing, I will not hesitate to use hot water from milk jugs + a towel for frost removal. It can add 2-3 hours of flying time to the day and if the conditions are right, it can be done safely.
 
You absolutely made a good call. Frost can significantly reduce takeoff and climb performance. On a short runway or one with obstructions, you might not have made it.
 
scottd said:
True, it's the skin temperature of the surface of the airplane that is important which can get colder than 0°C even though the official air temperature is slightly above that.
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More than slightly.

On a calm, clear night, I'll get frost on the cars with predawn temperatures in the low 40s. It's already happened twice this week....

The penetration length for infrared light through unsaturated atmosphere is thousands of feet, and most of the emitted radiation energy in the atmosphere is IR, so your upward facing surfaces are in approximate thermal equilibrium with atmosphere thousands of feet up. Thermal energy can be exchanged by conduction, advection or radiation. Radiation becomes dominant when the air is not moving.

It's a different equation when there is a low overcast or fog, or if the wind is blowing.
 
MAKG1 said:
More than slightly.

On a calm, clear night, I'll get frost on the cars with predawn temperatures in the low 40s. It's already happened twice this week....

The penetration length for infrared light through unsaturated atmosphere is thousands of feet, and most of the emitted radiation energy in the atmosphere is IR, so your upward facing surfaces are in approximate thermal equilibrium with atmosphere thousands of feet up. Thermal energy can be exchanged by conduction, advection or radiation. Radiation becomes dominant when the air is not moving.

It's a different equation when there is a low overcast or fog, or if the wind is blowing.
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Where does all the heat go, professor?
 
Sometimes you can "defrost" the plane then you're good to go, from your pic looks like that might have been a possibility.

In the end, as a student pilot, you made the right call, safe then sorry!
 
Jaybird180 said:
Weeping Wing?
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That stuff just affects the leading edges, and back a few inches.

What they had on the wings was more snow than ice, so it all pretty much blew away by the time they rotated.

Don't count on that happening with a cessna.

Bad idea to take off with that much stuff on the wings. I wonder if they de-iced it earlier, the snow fell during the taxi and they figured that with the de-ice fluid between the snow and the wing, that it would all break up and fall off? Or they had no clue it was there.

I noticed that there is a section about 2/3 way up the wing where no snow/ice accumulated. Is that a fuel tank area? Do they heat the fuel tanks to keep the jet fuel liquid?
 
dell30rb said:
That stuff just affects the leading edges, and back a few inches.

What they had on the wings was more snow than ice, so it all pretty much blew away by the time they rotated.

Don't count on that happening with a cessna.

Bad idea to take off with that much stuff on the wings. I wonder if they de-iced it earlier, the snow fell during the taxi and they figured that with the de-ice fluid between the snow and the wing, that it would all break up and fall off? Or they had no clue it was there.

I noticed that there is a section about 2/3 way up the wing where no snow/ice accumulated. Is that a fuel tank area? Do they heat the fuel tanks to keep the jet fuel liquid?
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Try to freeze some fuel...any kind of fuel. Let us know how you make out.

The cemeteries are full of pilots who thought "It will just blow off." In the case of frost, think of it as a gazillion little drag fences...not only on the leading edges, but all over the fuselage as well.

Bob Gardner
 
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bobmrg said:
Try to freeze some fuel...any kind of fuel. Let us know how you make out.
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The fuel itself doesn't, the water suspended in jetfuel may freeze out, hence the Prist on turbine aircraft that fly high and dont have fuel heaters (e.g. the PC12).

I believe ice-crystals were the cause for a 777 that came up short in London a couple of years ago.
 
Btw, this morning I found my plane caked over with several days worth of frost on it. An hour in the heated FBO hangar and an old sweater to wipe down the water fixed the problem.
 
bobmrg said:
Try to freeze some fuel...any kind of fuel. Let us know how you make out.
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It won't freeze but regular diesel begins to thicken to a point where it may clog filters around 10 degrees F get much below that and you need special additives or a different blend.

I know Jet-A with Prist is an additive that prevents thickening at lower temps.

Even the diesel C182 they are coming out with has a way of warming the fuel so it can be certified to run on regular JetA without the additive. I figured big jets probably have a way of heating the fuel too, since they fly where its real cold.
 
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dell30rb said:
I figured big jets probably have a way of heating the fuel too, since they fly where its real cold.
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They do, but its not in the wing. Most are fuel/oil heat exchangers located on the engines. All have different configurations, but same concept.
 
flyingmoose said:
They do, but its not in the wing. Most are fuel/oil heat exchangers located on the engines. All have different configurations, but same concept.
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Do the engines send back warm excess fuel from those heat exchangers back to the tanks? That's how the C182 does it.

Either that or the path to the heat exchanger from the tanks is built very restriction free and they understand the fuel might be a little gelled until it gets to the heat exchanger... Any filters must be downstream
 
weilke said:
The fuel itself doesn't, the water suspended in jetfuel may freeze out, hence the Prist on turbine aircraft that fly high and dont have fuel heaters (e.g. the PC12).

I believe ice-crystals were the cause for a 777 that came up short in London a couple of years ago.
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Ah yes...I recall many times when I stood shivering on a ramp squirting Prist into a Lear tank concurrent with the fuel. Back then it was hard to find an FBO with pre-mixed Prist.

Bob Gardner
 
AuntPeggy said:
Do not fly with frost or ice on the aircraft. At one time the FAA recommended that you could simply "polish" the frost with a towel. They have changed that recommendation. Today, they recommend: Do not fly with frost or ice on the aircraft.
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I trained in Wisconsin, in the winter. If I had not learned to deal with frost on the trainer -- parked on the ramp, in sub-zero weather -- I would never have flown.

The polishing method works fine. Using a gloved hand, rub the frosty surface of the wing in its entirety. This has the added advantage of warming you up. Most of the frost will come off, the rest will be smooth as glass.

Laminar flow wings on a Cherokee, no extra charge! :D

This is one place where a low wing trainer is clearly superior to a high wing. Removing snow and frost from a Cessna wing is a giant PIA.

Sent from my Nexus 7
 
bobmrg said:
Ah yes...I recall many times when I stood shivering on a ramp squirting Prist into a Lear tank concurrent with the fuel. Back then it was hard to find an FBO with pre-mixed Prist.

Bob Gardner
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Back then it was hard to find a Lear Jet without a bunch of Prist "clips" in the bottom of the fuel tanks.
 
Jay Honeck said:
I trained in Wisconsin, in the winter. If I had not learned to deal with frost on the trainer -- parked on the ramp, in sub-zero weather -- I would never have flown.

The polishing method works fine. Using a gloved hand, rub the frosty surface of the wing in its entirety. This has the added advantage of warming you up. Most of the frost will come off, the rest will be smooth as glass.

Laminar flow wings on a Cherokee, no extra charge! :D

This is one place where a low wing trainer is clearly superior to a high wing. Removing snow and frost from a Cessna wing is a giant PIA.

Sent from my Nexus 7
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You mean a low wing without a T-tail! It isn't real fun trying to get the frost off the tail of a DA-40! BTDT!
 
gprellwitz said:
You mean a low wing without a T-tail! It isn't real fun trying to get the frost off the tail of a DA-40! BTDT!
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Uffda! Yeah, that would suck.

Boy, I do NOT miss flying in the upper midwest in winter. Not even a LITTLE. :yikes:
 
gprellwitz said:
You mean a low wing without a T-tail!
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Riddle me this: does the frost on the tail matter at all, assuming the CG is well forward and the tail flies at negative AoA? Note that both C-172 and Cherokee can be loaded so that tail starts flying like a wing. However, on Cherokee, if you hit the utility category envelope, stabilator is guaranteed to fly upside down. In such case, frost is in the high pressure area, and flow separation is not an issue... OR IS IT?
 
zaitcev said:
Riddle me this: does the frost on the tail matter at all, assuming the CG is well forward and the tail flies at negative AoA? Note that both C-172 and Cherokee can be loaded so that tail starts flying like a wing. However, on Cherokee, if you hit the utility category envelope, stabilator is guaranteed to fly upside down. In such case, frost is in the high pressure area, and flow separation is not an issue... OR IS IT?
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Great questions. I presume that it really doesn't matter, but as a student pilot I didn't bother myself with such things. I just scraped all the frost off with my gloves, off over every surface I could reach -- including the stabilator.

Meanwhile, I was melting the fiberglass cowling with one of those little jet engine heaters. :lol:

Looking back, I simply cannot believe I was motivated enough to persevere through that horrible winter.
 
Riddle me this: does the frost on the tail matter at all, assuming the CG is well forward and the tail flies at negative AoA? Note that both C-172 and Cherokee can be loaded so that tail starts flying like a wing. However, on Cherokee, if you hit the utility category envelope, stabilator is guaranteed to fly upside down. In such case, frost is in the high pressure area, and flow separation is not an issue... OR IS IT?
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Definitely, in IFR training there is long discussions concerning tail icing and tail stalls, which are managed in the direct opposite way that wing stalls are managed.
From AOPA:
www.aopa.org/asf/publications/sa11.pdf
From NASA:
www.youtube.com/watch?v=w1c4-aDB4k8
http://aircrafticing.grc.nasa.gov/courses/inflight_icing/related/3_2_3f_RI.html
From the FAA:
https://www.faasafety.gov/gslac/ALC/course_content.aspx?cID=33&sID=160&preview=true

Doug
 
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zaitcev said:
Riddle me this: does the frost on the tail matter at all, assuming the CG is well forward and the tail flies at negative AoA? Note that both C-172 and Cherokee can be loaded so that tail starts flying like a wing. However, on Cherokee, if you hit the utility category envelope, stabilator is guaranteed to fly upside down. In such case, frost is in the high pressure area, and flow separation is not an issue... OR IS IT?
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To be honest, it was back in 2007. I didn't consider that the frost might be on the high pressure side at the time. For that matter, I never considered it until you just mentioned the possibility! What was going through my mind was that the DA-40 surfaces were laminar flow, and any perturbation could cause problems. Not having any background in aerodynamics, I won't try making determinations about what sorts of deformations in the airplane are okay to fly with. That's one of those areas where I know that I don't know enough to make an informed (and 100% accurate) determination.
Jay Honeck said:
Great questions. I presume that it really doesn't matter, but as a student pilot I didn't bother myself with such things. I just scraped all the frost off with my gloves, off over every surface I could reach -- including the stabilator.

Meanwhile, I was melting the fiberglass cowling with one of those little jet engine heaters. :lol:

Looking back, I simply cannot believe I was motivated enough to persevere through that horrible winter.
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FWIW, the frost was at the dinner stop. We were still planning to fly back home that night. Though there was a good hotel right there if we had problems at Watertown, WI.

douglas393 said:
Definitely, in IFR training there is long discussions concerning tail icing and tail stalls, which are managed in the direct opposite way that wing stalls are managed.
From AOPA:
www.aopa.org/asf/publications/sa11.pdf
From NASA:
www.youtube.com/watch?v=w1c4-aDB4k8
http://aircrafticing.grc.nasa.gov/courses/inflight_icing/related/3_2_3f_RI.html
From the FAA:
https://www.faasafety.gov/gslac/ALC/course_content.aspx?cID=33&sID=160&preview=true

Doug
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While I think that most of these deal with ice accumulated during flight, which would tend to be on the leading edge, rather than frost accumulated at night, which would tend to be on top of the surface, they do tend to support a conservative decision making process!

BTW, FWIW, I wasn't night current at the start of the trip, so I had to do three in the pattern at KRYV before we could head home. So hopefully any problems would have been encountered with only me aboard!
 
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gprellwitz said:
To
While I think that most of these deal with ice accumulated during flight, which would tend to be on the leading edge, rather than frost accumulated at night, which would tend to be on top of the surface, they do tend to support a conservative decision making process!
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True. I did not think about that part of the thread, was just thinking about the issue with tail stalls.

Though here in south florida frost is not an issue.
 
scottd said:
Doug,

Keep in mind, however, that MOST (as in nearly all) icing induced stalls are NOT tailplane stalls in small GA aircraft. They are traditional wing stalls.
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I do not disagree with your statement, but the FAA is putting a lot of emphasis on distinguishing between the two, and the differences in managing them. My guess is they may occur more often then we realize. Unfortunately, I as I have seen in many things in life it often is not the common occurance that gets us in trouble, but the rare unexpected occurance that does.
 
The reality of this is that in real world operations you often have to deal and can't just cancel. The method in which you deal with the frost will vary from airframe to airframe and how severe it may be.

What works fine on a Hershey bar Cherokee might not be a good idea on a Cirrus.
 
My FBO puts all "first A.M. flights" in the hanger to keep them frost\ice free. Is that uncommon? Do need to tip the line guys extravegantly at Christmas?

Shep
 
AuntPeggy said:
What I meant to indicate is that water on frozen hinges can become ice and make them stick.
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It can also run inside the control surface and freeze there, putting it out of balance.

Dan
 
flyingmoose said:
They do, but its not in the wing. Most are fuel/oil heat exchangers located on the engines. All have different configurations, but same concept.
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Our Electras have the hydraulic cooling coils in the fuel tanks. And fuel heater/oil coolers in the nacelles.

Dan
 
Who was the genius who said that clear ice was ok? How do you know it perfectly adheres to the wing and is not changing the shape of the airfoil at all - and what does it weigh and how do you account for it in the W&B?

I swear, the OWT's out there -
 
Not to hijack my own thread, but I passed my checkride today :)
 
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