Westwind

[C-GGGQ]

By showing them charts and data that tells you exactly how bad of an idea it is. How much performance you are losing by taking off with even 10% of the wing covered in frost.

It's nice to know a plane covered in ice can lose up to 40% of lift and get an additional 60% of drag, or whatever the number of the month is. But that's now what kills pilots. It's the "hmm my wing is covered with frost over the fuel tanks, and there are some chuncks of ice on the leading edge" and then the next day it's something else, a bit more ice. And you always get more and more comfortable in taking on more ice. Because nobody knows how much is too much. And if you look in the books, it's "any ice is too much", which you, and 74% of the pilot population have already disproved.

If you can't guarantee pilots the oppportunity for a proper deice, then give them correct information. Have manufacturers do the tests. Figure out how much is too much, and show that you really shouldn't be taking off with contamination.

You ask for charts and research. The research was done. You even mention the numbers learned. 40% reduction in lift 30% increase in drag etc. So what else do you want? Figure out how much is too much? According to the knumbers above, any frost more than an 1/8th of an inch. So basically any at all. Hense the rule "no contamination is safe" safe doesn't mean "able to take off" you can as mentioned before take off a bit overweight.. in the right conditions. But it's still not safe.
You don't need to guarantee pilots the opportunity for a proper de-ice or even tell them "what tiny amount is acceptable" the whole point is none is acceptable (not possible but acceptable) don't fly. The fact that people break rules means nothing. Bring down the fricken hammer on anyone caught. Permanent loss of license.

[C.W.E.]

t would depend on the lawyers and circumstances of course. But for the sake of argument, hypothetically, I'd probably go after the operator, and if the crew gets sucked into that, so be it.

Now I really feel foolish, I thought I was discussing this with someone who is a pilot and understands the subject.

Oh well I tried.

[shimmydampner]

Digits, I get what you're saying but you're not really thinking it out to it's logical conclusion. If, as you are pointing out, flight crews are already crossing the line in terms of what is legal, the answer is not to simply move the line. The best course of option in terms of safety and liability is zero tolerance. But the flight crews need to be given the tools to ensure that that is achievable. Unfortunately that would be very expensive, whereas operators can send the crews out into less than ideal situations and saddled with all the liability. It's a win win for operators if they're never held to account AND don't have to fork out to provide the necessary infrastructure.

[Diadem]

The current rule and annual training heavily implies you'll die if you take off with even a whiff of ice. That is simply not true.

I don't think that's the case at all, and if that's your interpretation then I think you're misunderstanding it. Everything I've seen from the regulator and my training departments is that the effects of icing can't accurately be known. That might mean the plane flies, or it might mean the plane crashes, but you won't find that out until you're in the air. The point of removing all contamination is that you're returning the aircraft to a known configuration with known performance. If people are flying with contamination, they're test pilots, just the same as if they exceed the limitations of the aircraft; the aircraft might fly just fine, but when lives are at stake is it worth chancing?

[digits_]

You ask for charts and research. The research was done. You even mention the numbers learned. 40% reduction in lift 30% increase in drag etc. So what else do you want? Figure out how much is too much?

That is for a generic airplane with a certain amount of ice on it. I hope you'll agree that a plane with some light frost on top of the fuel tanks will behave differently than a plane that spent a night in freezing rain and has an inch of ice everywhere.

And yes, exactly, I want to show pilots how ice affects the plane in their specific situation. I truly believe that if you could show pilots in an easy to understand figure (for example by comparing it to weight penalties) what the expected performance hit is, that the amount of pilots taking off contaminated would be reduced drastically.

Even the 40%/30% is a bit abstract. How does that affect the airplane, what known performance penalty can I compare that to? It sounds bad, but no idea if it actually is that critical.

According to the knumbers above, any frost more than an 1/8th of an inch.

Does that mean that less than 1/8th of an inch is ok then? That's not a rhetorical question to annoy you, it is really a question I would like to get answered.

The fact that people break rules means nothing. Bring down the fricken hammer on anyone caught. Permanent loss of license.

Respectfully, I disagree. If 74% gets caught breaking a rule, maybe there is something wrong with the rule or how it is enforced.

The dryden crash happend in 1989. That's 30 years ago, and people are still flying with contaminated wings. You can preach that they have to follow the rules, and you'd be right. Or you could try to alter the way you approach the subject and try to raise more awareness (what I'm suggesting), or you could make deicing more accessible (what TSB is suggestion), or maybe something else. But other than the "any ice is too much and don't even dare to talk about researching it" reply from some posters here, haven't heard any other suggestions. I don't think that "keep doing what you're doing" is a good attitude in this case.

[digits_]

Digits, I get what you're saying but you're not really thinking it out to it's logical conclusion. If, as you are pointing out, flight crews are already crossing the line in terms of what is legal, the answer is not to simply move the line. The best course of option in terms of safety and liability is zero tolerance. But the flight crews need to be given the tools to ensure that that is achievable. Unfortunately that would be very expensive, whereas operators can send the crews out into less than ideal situations and saddled with all the liability. It's a win win for operators if they're never held to account AND don't have to fork out to provide the necessary infrastructure.

No no, you misunderstand. That is not what I'm trying to achieve. I do not want to move the line. I want to show pilots how much the actual amount of ice on the airplane that they are planning on flying will affect them. It is my hope that it will convince some people to not go, whereas today they might attempt it anyway. The end result would always be that they need to deice.

[digits_]

The current rule and annual training heavily implies you'll die if you take off with even a whiff of ice. That is simply not true.

I don't think that's the case at all, and if that's your interpretation then I think you're misunderstanding it. Everything I've seen from the regulator and my training departments is that the effects of icing can't accurately be known. That might mean the plane flies, or it might mean the plane crashes, but you won't find that out until you're in the air. The point of removing all contamination is that you're returning the aircraft to a known configuration with known performance. If people are flying with contamination, they're test pilots, just the same as if they exceed the limitations of the aircraft; the aircraft might fly just fine, but when lives are at stake is it worth chancing?

That does sound more realistic. My reply would be: why not find out and get performance numbers? Even if it is just to show how a terrible idea taking off would be.

Those companies design airplanes that fly at incredible speeds, at incredible weights with an incredible fuel efficiency. I shouldn't be too hard for them to simulate what the effect of different types of ice would be. They don't have to be super accurate, as you are not going to actually use them, but it would give you a good idea of how bad the ice would be, and hopefully open some eyes and wake up some sleepy pilots.

[C-GGGQ]

[

Even the 40%/30% is a bit abstract. How does that affect the airplane, what known performance penalty can I compare that to? It sounds bad, but no idea if it actually is that critical.

According to the knumbers above, any frost more than an 1/8th of an inch.

Does that mean that less than 1/8th of an inch is ok then? That's not a rhetorical question to annoy you, it is really a question I would like to get answered.

The fact that people break rules means nothing. Bring down the fricken hammer on anyone caught. Permanent loss of license.

Respectfully, I disagree. If 74% gets caught breaking a rule, maybe there is something wrong with the rule or how it is enforced.

Less than 1/8th of an inch would be LESS of a reduction but not no reduction in performance. 40% is almost half of your performance. That's seems pretty clear and concise. Cut and dry. Take off with even a TINY amount of light FROST let alone ice (which includes a significant weight component not just drag) ruins your performance by almost half.

Also 74% of pilots SEEING someone break a rule does not equal 74% breaking the rule. That's bad and purposefully misleading statistics usage (not aimed at you digits but at the publisher of that study)

[Diadem]

I want to show pilots how much the actual amount of ice on the airplane that they are planning on flying will affect them. It is my hope that it will convince some people to not go, whereas today they might attempt it anyway. The end result would always be that they need to deice.

Here you go: https://arc.aiaa.org/doi/abs/10.2514/3. ... nalCode=ja Or you could look up all the other studies that have been done by the FAA and EASA. The end.

[ant_321]

Why does it matter how much experience I have in these scenario's and if I have flown a DC3 or not? It doesn't matter. I'm using the results of the TSB survey that said that 74% of pilots have seen airplanes take off with contamination. What would you conclude from that? That the current "any ice is too much" rule is working properly?

You yourself admitted to intentionally taking off with a little bit of ice on the wing. Did you think that was a bad idea? Why did you decide to do it anyway?

Would you still have done it if the manufacturer had info that showed a DC3 covered in XXX mm / inches / ... of ice has the performance of a plane that is twice the MTOW?

I’m sure more than 74% of us have seen an airplane takeoff over weight too. Should transport make charts for how much over max weight we can take off at?

[GARRETT]

Boeing (and their lawyers) have certified that the 737 NG is permitted to safely take off with frost contaminated wings...after a few conditions are met of course.

*edit:added the FCOM text.
Takeoff with CSFF on upper wing surfaces is allowed provided all of ​the following conditions are met:​•​ The CSFF on the wing tank upper surfaces is only within the ​lines defining the permissible CSFF area with no snow, ice or​ ​frost​ on the leading edges or control surfaces​•​ Ambient air temperature is at or above +4°C, +39°F​•​ There is no precipitation or visible moisture (rain, snow, drizzle,​ ​or fog with less than 1 mile visibility)​•​ Tank fuel temperature is at or above -16°C, +3°F.​If all of the above conditions are not​ met, all snow, ice and frost on the ​upper wing surfaces must be removed using appropriate ​deicing/anti-icing procedures.

This goes goes directly against the "any ice is too much" theory.
Hmmm

[goingnowherefast]

They've already decided that some aircraft can legally take off with a specified amount of frost on the underside of the wing in the area of the fuel tanks.

Now you want more?

[Diadem]

Boeing (and their lawyers) have certified that the 737 NG is permitted to safely take off with frost contaminated wings...after a few conditions are met of course.
This goes goes directly against the "any ice is too much" theory.
Hmmm

Then that's a known configuration with calculated performance. As I stated previously, the point of de-icing is to get the aircraft to a known configuration, but if manufacturers start publishing data for specific contamination and allow take offs then that would be equivalent.

[ant_321]

Boeing (and their lawyers) have certified that the 737 NG is permitted to safely take off with frost contaminated wings...after a few conditions are met of course.
This goes goes directly against the "any ice is too much" theory.
Hmmm

The allowance is for frost caused by cold soaking and is quite restrictive. The OAT must be above 4 degrees, no precipitation etc. The only place I’ve ever used it was in the Caribbean. And as was said before Boeing has obviously done the testing for frost “in the box” in very specific conditions and determined that it is ok. Nobody can reasonably expect manufacturers to make 100’s of charts for all the factors that lead to frost/icing. Think of all the combinations of temp, dew point, fuel tank temp, precipitation, wind, etc.

[pelmet]

So if you want to legally takeoff with frozen contamination on the wings, go out and pay for the certification like Boeing did who will then charge the customer for the approval. Otherwise, it is not certified and not legal. I guess that includes on non-certified aircraft as well.

There should be research to show pilots and ground crew how much is too much.

There are too many variables for the regulator to be able to do this. It would be endless so it ain't gonna happen.

Then again, is it illegal to takeoff with non-frozen contamination like the time when I flew an aircraft with a a lot of dead bugs on the leading edge? What if there are dead bugs on the leading edge and the temperature is below freezing so that it is now considered frozen contamination?

[FlyGy]

What if there are dead bugs on the leading edge and the temperature is below freezing so that it is now considered frozen contamination?

One doesn't often see insects flying around in sub-zero temperatures.

[pelmet]

What if there are dead bugs on the leading edge and the temperature is below freezing so that it is now considered frozen contamination?

One doesn't often see insects flying around in sub-zero temperatures.

True, but some operators don't clean their aircraft for months. Seasons change. Also, planes can travel significan distances, you know, like from the Caribbean to Canada or even just a few hundred miles for a GA aircraft.

Anyways, back to the thread subject.

[digits_]

There should be research to show pilots and ground crew how much is too much.

There are too many variables for the regulator to be able to do this. It would be endless so it ain't gonna happen.

I disagree. How does ice affect the airplanes? There is weight, change of shape of the aerofoils and a different texture/friction indexes. Every airplane of the caravan/pc12 generation and newer is exists digitally. Every part is simulated somewhere. Any manufacturer of modern airplanes can tell you exactly how ice would affect the performance.

I am not intimately familiar with certification, but if I remember correctly, at some point you'll have to proof that your data matches reality and a whole bunch of flight tests need to happen. That is not necessary for what I'm asking. I am not asking for certified data to allow pilots to fly with ice on the wings. No, I merely want relatively accurate data to show them what a stupid idea it is to go flying with frost/ice/wet snow/.... on the wings. That can be calculated with the current models that already exist to a great level of accuracy. It will be an eye opener and way more accurate than the one "30% / 40%" number we have now.

What would be easier: forcing 20 manufacturers to simulate data in let's say 20 example scenarios, or get decent deicing equipment installed in every little northern community?

[Diadem]

I disagree. How does ice affect the airplanes? There is weight, change of shape of the aerofoils and a different texture/friction indexes. Every airplane of the caravan/pc12 generation and newer is exists digitally. Every part is simulated somewhere. Any manufacturer of modern airplanes can tell you exactly how ice would affect the performance.

I am not intimately familiar with certification, but if I remember correctly, at some point you'll have to proof that your data matches reality and a whole bunch of flight tests need to happen. That is not necessary for what I'm asking. I am not asking for certified data to allow pilots to fly with ice on the wings. No, I merely want relatively accurate data to show them what a stupid idea it is to go flying with frost/ice/wet snow/.... on the wings. That can be calculated with the current models that already exist to a great level of accuracy. It will be an eye opener and way more accurate than the one "30% / 40%" number we have now.

What would be easier: forcing 20 manufacturers to simulate data in let's say 20 example scenarios, or get decent deicing equipment installed in every little northern community?

It doesn't matter whether the manufacturers publish data for literally every single condition if the pilots aren't able to measure things like the coefficient of friction and the ice thickness to a fraction of a millimetre. There are too many variables to reasonably be able to calculate performance when you're not in a test setting.
And there would have to be data for every configuration and STC. Modified your aircraft with a larger engine or a prop with an additional blade? The data is invalid because the propwash is different. You would have to calculate data for thousands of different aircraft models and mods, for thousands of different types of contamination, for every conceivable environmental condition, and then provide pilots with the tools to measure all those things. Or, you just say "No contamination".
If you're really convinced that this is a good idea, start a company to certify aircraft to depart with contamination and see how complicated it is. If you're right, you could make millions!

[digits_]

I disagree. How does ice affect the airplanes? There is weight, change of shape of the aerofoils and a different texture/friction indexes. Every airplane of the caravan/pc12 generation and newer is exists digitally. Every part is simulated somewhere. Any manufacturer of modern airplanes can tell you exactly how ice would affect the performance.

I am not intimately familiar with certification, but if I remember correctly, at some point you'll have to proof that your data matches reality and a whole bunch of flight tests need to happen. That is not necessary for what I'm asking. I am not asking for certified data to allow pilots to fly with ice on the wings. No, I merely want relatively accurate data to show them what a stupid idea it is to go flying with frost/ice/wet snow/.... on the wings. That can be calculated with the current models that already exist to a great level of accuracy. It will be an eye opener and way more accurate than the one "30% / 40%" number we have now.

What would be easier: forcing 20 manufacturers to simulate data in let's say 20 example scenarios, or get decent deicing equipment installed in every little northern community?

It doesn't matter whether the manufacturers publish data for literally every single condition if the pilots aren't able to measure things like the coefficient of friction and the ice thickness to a fraction of a millimetre. There are too many variables to reasonably be able to calculate performance when you're not in a test setting.
And there would have to be data for every configuration and STC. Modified your aircraft with a larger engine or a prop with an additional blade? The data is invalid because the propwash is different. You would have to calculate data for thousands of different aircraft models and mods, for thousands of different types of contamination, for every conceivable environmental condition, and then provide pilots with the tools to measure all those things. Or, you just say "No contamination".
If you're really convinced that this is a good idea, start a company to certify aircraft to depart with contamination and see how complicated it is. If you're right, you could make millions!

What thousands of different types of contamination?

Type, let's narrow it down to: Frost, clear ice, rime ice.
Location: full fueslage, leading edge, full wing, full tail, randomly divided 50% coverage of the wing, randmoly divided 20% coverage of the wings, or whatever seems significant from the simulations
Thickness: you'll have to estimate that yes. Would be easy to fix with a marking somewhere on the wing, I'm sure you could find a small bolt or hook popping out of the wing and put a scale on there if you want. Or measure it with a piece of paper, no big deal

Environmental condition: I wasn't even thinking about freezing precip, but it should be easy to add as well. Freezing precip will most likely create a constant weight increase over the whole plane, so that can be added as an extra factor.

It might take a few weeks of running simulations, but in the end you'll have a rough idea of how screwed you would be if you tried to take off.

Not sure if it is frost or clear ice? Doesn't matter, you can read the table "if this was clear ice we have an equivalent of an additional 4000 lbs on board, if it is frost, we have an additional 2000 lbs on board". Either way, you're not allowed to go anyway, but the danger becomes much more tangible.