Scott Dennstaedt lives in North Carolina. He has touched down in every single state, with the exception of Alaska and North Dakota. Scott is a Certified Flight Instructor – Instrument (CFII), former NWS research meteorologist and founder of AvWxWorkshops Inc. He previously co-owned a 2003 Cirrus SR22 equipped with inadvertent TKS Ice Protection, which he flew for 1 year.TKS for the Cirrus SR22 is now only available as a factory-installed FIKI certified option.
How did you get started in aviation?
I went to school to become a meteorologist, specifically in research area. I got my bachelor’s and master’s degree. Right after getting my bachelor’s I worked in the field of meteorology for about 5 years. I always wanted to fly, so I got into software engineering for 15 years working on airport radar systems, air traffic control systems, and weather radar systems. In the mid-90s I wanted something challenging in my life. I got my PPL, instrument rating and became a co-owner of a turbo Arrow 4, got my commercial. My instructor recommended getting a CFI even though I had no plans to teach. But it would keep me in an airplane with a CFI as I continued to gain more flying experience. So I got my CFI and then CFII to become an instructor. During that time, I realized weather education was a joke from an aviation standpoint. Only the minimum was given to understand weather situations. At that time, the Internet was just blossoming. The FAA was about 10-15 years behind the power curve of all this new weather guidance that’s available on the Internet that helps you make good decisions. That’s when I left my job at Northrop Grumman and became a full-time flight instructor. Successful businessmen and businesswomen making long cross-country trips needed the additional weather training. 15 years later, here we are now. I’m currently working on my PhD.
Why did you choose TKS?
I am a flight instructor. My customers know my background as an aviation weather expert. They want to learn how to fly their airplanes the way that makes the most sense from a safety and efficiency standpoint, given the meteorological situations they are faced with. Usually it’s an icing situation.
The most important thing in general is the ability to have greater dispatch capabilities. It’s unreasonable in some cases to buy an airplane and only fly it in the summertime because there is typically no icing issues. I want to fly from Point A to Point B and have more dispatch authority because I have an aircraft that is able to deal with some limited impact exposure or some limited airframe ice. I think that’s the biggest thing. The other aspect is that it really handles the worst case icing scenario whereas other aircraft might have an accident or incident or loss of control. TKS really keeps the aircraft clean even in the worst icing scenario. I would never recommend anyone to fly in freezing rain or freezing drizzle on purpose. But if you ran into that in an isolated fashion, or you were in a convective scenario where, again, large drops are commonly found, that would be another reason to have TKS over others.
What has TKS done for your mission?
I do more than “let’s get in and go see what happens.” My training starts at preparation—meaning I teach them how to utilize different weather guidance that is available. We characterize the scenario, whether a small drop or large drop icing scenario, lots of liquid water content, layered approach. The real goal is to teach them that. The goal is to say “Okay, this is a safe environment. We’re not dealing with a large drop situation outside of the certified envelope of the airplane. As a result, we can make this plan and go here. We’ve been able to, for the most part, as long as the plan is viable given the altitude requirements and oxygen requirements, to get on top or in-between layers, then we execute it. TKS helps us fly just about every mission we wanted to. We did cancel some flights because the airplane wasn’t certified to fly in those conditions.
The real advantage of TKS is that it protects the entire wing if it’s used within the limitations of the manufacturer. It will help protect runback ice which booted aircraft do not. Once ice starts to collect behind boots, behind protected surfaces, it cannot be moved. Only when you get to warmer temperatures will it be removed. TKS really helps solve that issue. The worst icing scenarios you’ll ever get are typically clear ice scenarios—freezing drizzle and freezing rain. Whether it’s inadvertent or a certified system, TKS helps prevent accumulation in the worst scenarios which are large droplet icing scenarios. Again, you’re not certified to fly in those. But if you inadvertently ran into the situation, I would rather be in an aircraft equipped with TKS than boots. The system is pretty outstanding. I’ve trained thousands of pilots throughout the years and because of my background and expertise, I’ve received spine-chilling phone calls and emails, knowing that they made some really bad decisions. For some, they had an inadvertent system that helped them escape it. In other cases, they got lucky that the airframe still was able to fly and they didn’t hurt themselves. A lot of these were cases that could have been prevented in pre-flight.
My website avwxworkshops.com is used as a training component, and also has a lot of high temporal and spatial resolution icing guidance available to them. It allows them to clearly see where the worst icing is located along the route, the altitude and the time. Based on that information, they can make really good, educated decisions. It’s not just a matter of looking at a chart and saying “Okay, this is good” but about understanding the big picture. My challenge is to be able to teach pilots how to recognize those situations, to know whether they can challenge the weather and know when they should remain on the ground, which ultimately makes them a better, safer and more confident pilot.
How has the system worked inflight when you’ve activated it?
It’s worked, for the most part, flawlessly. I’ve never had any issues with any of the situations that have occurred that would normally be problematic for other aircraft. I haven’t done a lot of flying in aircraft with boots, so I don’t really have a lot of comparison there. What I’ve seen so far is that it represents a great way to keep ice off the leading edges of the airframe for sure. Certainly it has been stellar at keeping ice off the prop and windscreen. It has been pretty exceptional at removing ice that has already accreted. One of the things I would do with my customer is say we’re going through a thin layer, not very threatening. We’re going to pick up some ice, but we’re not going to use the TKS system until we accrete some amount of ice. Usually it’s a very light icing scenario. As you turn the system on, TKS breaks down the bonds and removes the ice pretty effectively. Obviously that’s not the best way to use the TKS system, but it is effective. One of the questions I always get from all of my students is if it’s just an anti-ice solution. Will it remove ice? A lot of my customers have been told it will not remove ice. Of course that’s not the best approach, but it does a very effective job at removing ice from the airframe in the event that you don’t have it primed and turned on initially.
What are the steps you take to activate anti-ice?
The first thing we do is test the system on the ground to make sure it’s primed and working properly. I always emphasize to all of my students that you do that once a month, even in the summertime. Once we’ve identified on the ground that it’s usable—that there are no issues and it’s flowing evenly throughout the entire TKS panels—then it’s a matter of looking at the situation. If we’re not expecting to get ice until we are 300 miles downwind, I’m not going to turn it on until we reach conditions that could warrant having the system on. The best approach is to save as much TKS. If I know that we are going to encounter icing right away, it will be turned on as soon as we take the runway to depart. If it’s not going to be until we climb out and reach our cruising altitude, then we’ll turn it on in the climb. If we are looking at possibly running into icing 100 miles down the route, then we will effectively manage the weather. Are we in IMC? No. Are we in precipitation? No. There’s no reason to have the system on even if the temperature is below freezing. We may have pitot heat on and such. As soon as we get to a situation where we’re either in IMC, visible moisture, precipitation, and the temperatures are zero degrees or less, then we will turn the system on before we enter those IMC conditions.
If you know that there is likely going to be icing but it’s not forecast, is it still OK to fly with an inadvertent system?
That goes back to what is the legal definition of icing conditions. If you have an aircraft that doesn’t have a certified ice protection system, it’s typically considered a zero tolerance situation, even with inadvertent. This is where the training component comes into play. If you know, for instance, that only 80% of the positive pilot reports get captured in an AIRMET or SIGMET, then there’s 20% that don’t get forecast. That means there are icing situations out there that aren’t being forecast. 20% is a heck of a lot. That’s actually a legitimate number too, because AIRMETs don’t capture convective icing. If you’re dealing with a tall, building cumulus field of clouds, and you’re in the tops of those clouds below freezing, you’re going to pick up some airframe ice. There will be no forecast for that. There are also cases where AIRMETs are for widespread moderate icing. If forecasters don’t believe it’s going to be widespread moderate, only light, maybe occasional moderate, they may not include that particular area in the forecast. When it comes down to it, there are many variables that suggest there could be legitimate icing out there—icing that doesn’t fit. It’s not like the forecaster blew the forecast. This is where I spend a lot of time training pilots about icing, how to use the various products to their benefit and to understand their limitations.
I was ferrying a turbonormalized Cirrus SR22 with inadvertent TKS from Richmond, Virginia to Terre Haute, Indiana in July. In West Virginia I flew through some really nasty, building cumulus clouds. They were difficult to avoid. It just about turned me upside down. When I got over Kentucky, I saw another bank of cumulus clouds. I said that I wasn’t going to do the same thing, because the SR22 could get me up to 25,000 feet. I made sure the oxygen was flowing and asked ATC for clearance to 16,000 feet. Of course, as luck would have it they said you can ask the next controller. The next controller said they can give me that clearance in 5 minutes. As I got closer and closer to that bank of cumulus clouds, I realized that even in the best of airplanes it’s going to be difficult to outclimb it. I should have stayed at that altitude and suffered what turbulence I would get. Unfortunately, I chose the wrong decision. I started to climb and from 8,000 feet going up to 13,000 feet it started to collect ice pretty quickly. There’s a lot of runback in that particular situation. At that point I pointed the nose over and was able to tell ATC I couldn’t go any higher. I turned the TKS system on before entering the clouds and noticed it cleared a lot of the runback ice, in addition to clearing ice off the leading edge, pretty effectively. In that case it was an inadvertent situation, not forecast. I’m not proud of it, but that’s the way it ended up being. There are cases where flying through a thin layer of subfreezing clouds where you only expect trace icing, or in a very cold scenario is that you don’t expect liquid water to collect on the airframe, and that’s usually a cold scenario where the clouds are glaciated, meaning all ice crystals. That’s the only time I would climb through or get into visible moisture using an inadvertent system.
When I was a co-owner of a Cirrus SR22 with inadvertent TKS, I did a lot of traveling from Baltimore to Chicago. That’s the Great Lakes Effect. Usually with Great Lakes Effect kind of clouds, at 12,000 feet you can get to the top of most of that. You’re above the clouds, there’s clear air and no real concern. But let’s say your oil temperature or oil pressure says something is wrong. You look at your PFD and it suggests that something is terribly wrong. It could be a sensor, or it could be that something is really happening. Then you have to work your way down through this potential icing layer. It could be some serious ice. In that case, having an inadvertent system is a perfect example of where that protects you. You turn the system on and do what you need to do to handle the emergency, because when the aircraft no longer works properly it’s unairworthy and you’ve got to land as soon as practicable. You use the TKS to safely get on the ground. This situation is one of the best points to having inadvertent TKS.
My goal is always to teach students that they don’t belong in ice unless they have proper equipment. Even if you have proper equipment, you don’t belong in ice you’re not certified to fly in. These are tools that can be used in certain situations. All of them can malfunction. I hear a lot of stories from pilots who have one boot inflate and the other doesn’t. Systems can shut down and put you in a bad situation. Avoiding ice is my general message.
Hope is not a plan. We can’t use previous experiences as future decisions. For example, a pilot could think, “I was able to get through that 3,000 foot stratocumulus deck with no problem. This one is going to be a piece of cake, I’ve done it dozens of times before. I don’t have any certified ice protection system, but I’ve done it before and it’s always worked out fine.” But there’s some issue they didn’t catch that was worse than the other. They fly through one on Wednesday and on Friday fly through another one. They pick up so much ice, a large drop scenario, and they look at themselves thinking what the heck is different? Well it turned out that on Thursday, between the two days, it snowed. It laid a blanket of snow down. Snow keeps clouds above clean. Cleaner clouds typically have larger drops. Add mountains or some orographic effects and you can put yourself into a situation where you are in a large drop scenario with higher liquid water contents. All of those kinds of things need to be understood. You need to know the difference between a clean environment and a dirty environment makes in terms of icing potential. Once you’ve learned those little nuggets of information, you don’t use hope as a plan. You’re making solid decisions.
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