We've had some terrible weather in the Houston, TX area lately... so we decided to discuss that devilish little substance that likes to build up on the wings this time of year. ICE!!
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00:01
Behind the Prop Intro
Clear prop 773 Cherokee number two following twin traffic three mile final one trolley.
Bravo makesford in Runway two five going four mile.
00:10
Nick Alan
This is behind the prop with United Flight Systems owner and licensed pilot Bobby Doss and his co host, major airline captain and designated pilot examiner Wally Mulhern. Now let's go behind the prop.
00:25
Bobby Doss
What's up, Wally?
00:26
Wally Mulhern
Hey, Bobby, how are you?
00:27
Bobby Doss
I am fantastic as always. You know, we have probably had maybe the worst five days of weather in Houston in a long time. Two monsoon storms I think in a matter of 48 hours. We got about 9 inches of rain at the flight school. The airport was almost underwater and the temperature kept dropping, getting colder and colder. And we had a listener reach out and tell us a story that happened to them not too long ago. And we're going to talk a lot about ice today. There's no ice where you're at, is there, Wally?
01:01
Wally Mulhern
There's not, but I'm in beautiful Hawaii. But I did take off yesterday from Houston and on our takeoff we did have our engine. Any ice on? So it was raining and it was below 10 degrees Celsius, which is our marker for when we take off with any ice on.
01:21
Bobby Doss
Wow. So you probably don't use that very often leaving Houston, Texas, but it's not something we really think about much about. Think much about here. And I think that's what the listener was reaching out for. Like, hey, this happened to me. I want y' all to talk about it and try to help other people, maybe not make the same mistake that I made. And hopefully it helps everybody out. So the listener reached out and said he's got this great story to tell and we tried to encourage him to be on the show and he decided to take a pass. He has a thick accent and decided he would let us tell his story. So Dominic, thanks for letting use your story and hopefully we keep making good shows if people keep giving us content. So pretty typical GA pilot, in my opinion.
02:08
Bobby Doss
Did a bunch of flying in 2011 and 2012. Actually went to this flight school, United Flight Systems here in Spring, Texas. And life happened, kids happened, people started growing up. I think his flight that he talks about, his daughter was with him. They were going on a college visit. So she's probably part of the reason why he stopped flying back in those days. And during COVID he got the dream back, was able to get into the aircraft again, wrapped up his private pilot certificate and then did what some do and bought him, bought an airplane. He bought A Mooney and put a bunch of fancy equipment in that Mooney and he started flying, building time. And Wally gave him his instrument checkride actually and loves the show, talks highly of the show and wanted us to tell the story.
03:00
Bobby Doss
So it wasn't very long ago, maybe a month or so couple weeks he took his daughter and we're going to fly to Arkansas for a college visit. And on that trip he did all of his normal cross country planning, knew the weather, looked at a number of weather sources and he knew that it was going to be 40ish degrees in his destination. And weather looked good along the way. Weather briefer said it looked good along the way and they took off. I think depending on where he went. Arkansas exactly. That's probably two and a half, three hour flight from Houston, Texas assuming that the winds were fairly calm and along the flight, no issues, everything going good, flying around 8,000ft ish and gets to kind of the Texas border and starts to make a descent just north of, just north of Texas.
04:03
Bobby Doss
And noticed on that descent that there was a little bit of ice accumulating in the windshield and he thought that was odd. Knew, knew that they were on the descent to 40 degrees and didn't figure it was a problem. Kind of in and out of a little bit of moisture. And then all of a sudden he has a dyne on in his Mooney he said and the dynon just went nuts, went berserk. And a bunch of the numbers were not showing numbers that weren't realistic. Low airspeed. And it took him a minute to really get his, get a handle on the situation. He reflected that it could have been really bad. But all of a sudden the dynon warned him to turn on pitot heat or check his pitot heat.
04:52
Bobby Doss
He checked his pitot heat and came out of the layers of clouds, kind of between two layers of clouds and was able to gather himself. He could see the ground through the bottom layer of clouds, but it was still the visibility wasn't great. And he let the pitot heat warm up, let the pitot heat clear the ice off the pitot static or the pitot source. And then everything came back on the dynon system. And he really on the phone call, shared the story. I know he shared it online. I think he's really trying to help people. I think he knows he made a mistake by not turning the pitot heat on sooner. But he said it wasn't on the checklist. It wasn't, you know, from a standpoint of on descent. It doesn't call out check pitot heat.
05:38
Bobby Doss
He thinks there's a number of things that pilots can think about and learn from this mistake or learn from this incident type thing. And that's always used pitot heat, invisible moisture like that. I think. I think he knew that there was 40 degrees on the ground and knew it was probably colder above that. But I don't think he put two and two together and necessarily calculated that it would be icing in that situation, but it did. I think he. His other takeaway to me was that we understand our instruments and what those instruments will report in failure type conditions. The dynon gave him a lot of information he had never seen before, lots of failure stuff. And he's done a lot of studying to be much better with that.
06:22
Bobby Doss
While you and I did a show, it seems like forever ago now called Every Switch, Every Button. And it was all about really understanding all that equipment in your aircraft. And there's a whole nother show we could probably do on the electronic equipment and the readouts and the information that those give us. But he was very much pointed about he's done the study, he knows what all is connected to that system now and what those emergencies would produce on that dynon now. And then really understanding known icing. He got some criticism or feedback on the web that hey, you shouldn't have been flying in that it was known icing. And maybe you shouldn't tell your story like this. But I think he was misinformed about what was known icing. And I'd done a little research since we got to thinking about doing this show.
07:14
Bobby Doss
And there's a letter of interpretation from the FAA and I'll to not mess it up. I'll read it to the section about it. But in this letter of interpretation, known ice in quotes involves the situation where ice formation is actually detected or observed. Known icing conditions in quotes involve instead circumstances where a reasonable pilot would expect a substantial likelihood of ice formation on the aircraft based upon all information available to that pilot. And said that's a good vague FAA answer, Wally, if I've ever seen one or heard one. But it does constitute that if you know it's possibly to be freezing at a level where there's visible moisture, a reasonable pilot would have to think that ice would accumulate or get on the airframe. So good information.
08:16
Bobby Doss
I'm thrilled that he shared the information with us and we figured we would do a little bit more talking about ice on the aircraft and some things to think about what are your thoughts or reactions, Wally, as you hear the full story in detail and take away from it for pilots, I've come up.
08:37
Wally Mulhern
With three thoughts that I just jotted down as I listened to what you had just said. The first thing I want to address is, you know, when people share stories like this, when people are just jumping on them and saying, how stupid could you be? You know, this is ridiculous. All you're going to do is suppress the next person from sharing a story. And these stories, as long as they have a good outcome. Well, I mean, you know, this. In this case, they lived. Yeah, so it was a good outcome. But we're trying to learn. We are trying to keep people from dying in airplanes. And the more stories like this that we can hear, the more research, the more training we can do. It's just better. It's just better for everybody.
09:30
Wally Mulhern
So, you know, to the guy who wants to jump on the social media thread and say, what an idiot you are, I just want to, you know, pull that keyboard away from you. There's an old story about. At my airline, many, many years ago, there was an aircraft accident that didn't have any fatalities or anything, but it was an accident and it was kind of a big deal. And at the end of the day, someone asked the captain, would you have done anything differently if, you know, if you could start over again? He said, yeah, I would have called in sick. You know, no kidding. No kidding. I mean, if you said to this person who shared the story, well, if you had to do it over again, would you have taken the trip?
10:18
Wally Mulhern
Of course he's going to say, no, I wouldn't have taken the trip, because now, you know, I know the outcome. So, you know, we need to encourage people to be open about these things. I really don't feel that the FAA is going to come down on someone like this. You know, I think it's a positive thing when we can tell because we all have these stories. We all have them. And, you know, at some point we become brave and we can come out and say, well, okay, well, I did this one time. And it's good for all of us to hear these stories. You know, the second thing, you know, talking about instrument or systems failures in airplanes, I think when we know exactly what the, what has happened, I think most of us can handle the situation fairly well.
11:21
Wally Mulhern
The problem, a lot of times is identifying the problem. Okay, this is happening on the airplane, and I know it's not supposed to do that. What's going on? Is it, you know, do I have an engine problem or is it an electrical problem or is it a flight control problem? I don't know. So, so half the problem is just identifying the problem. That's one thing that he talks about. This is getting some strange readings on the dynon and thinking, geez, what is going on here? So he makes an excellent point in, you know, the fact that we should know what these failures are or what the symptoms are of something. You know, you know, we have, we can use Google now to diagnose medical problems. Hey, my leg hurts and it feels like this.
12:20
Wally Mulhern
And it probably gets you pretty close to the right diagnosis, but you don't really have that in the airplane. You know, when you're trying to troubleshoot, when you're trying to figure out what your problem is. Some, some systems failures are very, you know, when the engine quits. I think most of us know that, okay, the engine quit, let's try to restart it. If it won't restart, let's put it down in a field somewhere. But this is one of those that, gee, what is going on here?
12:53
Bobby Doss
Well, we talk a lot about this on how we train and what's the greater good of how we tr. You know, I talk about this a lot. There's a huge value in the simulator because when you fail something, it fails like it does in real life, right? The, if you take the vacuum system and kill it. Well, the vacuum gauge goes to zero. Really, really quick. How much of us really, how many of us really scan that every time we're looking in the cockpit on a VFR day to see that. But that attitude indicator kind of slowly starts cocking, turning, kind of loses its. Lose loses its rigidity. And it doesn't, you know, it'll make you start feeling sick if you pay attention to it because you know, you're not turning, but you're used to that only moving when it's turning, right?
13:42
Bobby Doss
Well, when we train a lot of times we just put a suction cup over it or a post it note. That's easy to know that the attitude indicator or the vacuum system failed. When we, when we call out as instructors or pilot's vacuum system failure and we cover up the things that are driven by the vacuum system, much like your engine example, that's pretty freaking obvious. But in IMC on a system that he's clearly invested a significant amount of money in that Dynon it starts giving you just a flurry of changing information that doesn't make any sense. That's very odd. That would be very discomforting in imc. I forgot to say it, but they were in daylight conditions. Man, I don't like night IMC at all in a good working aircraft, never mind one that was giving me crazy information.
14:35
Bobby Doss
So daylight was a huge help, no question. But, you know, it's the way we train, and if you have that opportunity to train in something that gives you more of a realistic failure in whatever type of equipment that you use in your aircraft, by all means, jump on that opportunity for sure.
14:52
Wally Mulhern
What you said is the one reason why simulator training is just so incredibly valuable, because you can do that. I mean, what. What does a pitot tube blockage look like, real world? You know, would it be valuable to go out and cover up the pitot tube and go fly a flight? It probably would, but it's dangerous, so we're probably not going to do that. So, you know, that's something you can do in the simulator. Simulator. And you can do that. You know, I. This is a side story, but I remember back in the late 80s, I remember it was raining like crazy in Houston, and I got a call from a friend of mine, and he said, he says, man, we just left the Astros game, and it's flooding down here, and the car stalled out, and I'm at this gas station.
15:49
Wally Mulhern
Can, can you come down and pick us up? And it was. It was about midnight. I got. Got dressed and I went down and I, I picked these people up and we were driving home and my friend said it was. It was a car that had a digital speedometer, which back in the late 80s was kind of the cutting edge of technology. Yeah, it was. And his comment to me was, I knew I was in trouble when the speedometer said I was going 888 miles per hour. And so, I mean, there's. That's just an example of what happens when these instruments, you know, when we have certain failures. But anyway, so that just goes back to know every switch, every gauge. You know, one thing I ask and, and I'm going to give away a secret of what I ask on checkrides.
16:45
Wally Mulhern
And if you're going to take a checkride with me, you'll get this right. And, And I don't care, because I think it is. It is real important. I think, I think a lot of people really struggle with this. First of all, in the aviation world, let's just accept the Fact that the aviation world works on the centigrade system. So let's just get rid of Fahrenheit. Can we just not even use those temperatures? And you're going to see where I'm going with this. I will with my instrument students, with my current commercial, with my privates. You, you know, we talk about a cross country flight and that, that first point that we're going to is usually a couple hundred miles away. And I will, you know, we'll talk about weather.
17:40
Wally Mulhern
So I will say, okay, let's pick an airport that is about halfway between here and where we're going. And they'll pull out the chart, whether it's electronic or paper, and they'll say, okay, it's Airport abc. And I'll say, okay, what is the weather right now at airport abc? And of course they'll pull it up and they'll say, well, okay, the clouds are such and such temperature, altimeter winds. And we'll talk about diverting to abc. And I'll say okay, well if were going to divert to ABC Airport based on the current weather, what Runway would we use? And, and that sort of thing. I will then ask them what, where the freezing level is at Airport abc. Okay, and let's talk about lapse rate and freezing level. And this is assuming a standard atmosphere.
18:39
Wally Mulhern
The lapse rate, standard temperature, lapse rate is 2 degrees per thousand feet. So all you've got to do is take the temperature. Let's say the temperature is 12 degrees. Again, we're talking Celsius, 12 degrees. Celsius, 12 divided by 2. I think most, well no, I'm not maybe giving us too much credit, but most people can figure out 12 divided by 2 is 6. So the freezing level is 6,000ft above the ground. So now look at airport elevation of airport ABC, it's 495ft. Think we could say that the freezing level is at approximately 6,500ft. Now there could be inversions, there could be some weird weather phenomena, but a standard atmosphere, I mean a standard lapse rate, the freezing level is going to be at approximately 6,500ft. I watch people pull out calculators to figure this out, you know how.
19:48
Wally Mulhern
Heck, if it's an odd number, just make it an even number. If it's 19 degrees, make it 20 degrees and let's call the freezing level at about 10,000ft. But a lot of people struggle with this.
20:01
Bobby Doss
Yeah, that's an interesting point. I've had debates with people about standard lapse rate. And they're like, oh, the atmosphere is really not standard. But isn't it a really good rule of thumb? Like, would you really risk it over 500ft in an aluminum aircraft? Like, and that. Then that comes to personal minimums for me, right? My personal minimum on ISIS, I tell everyone there is no gray line. It's 10,000ft. I'm not going to get within 10,000ft of the icing levels. And that's pretty much me saying I'm never going to fly when there's visible moisture and freezing temperatures because I don't have to. I don't have to go fly. Wally, you don't have that choice. You know, they make you get in that plane and take people wherever you got to go. But I have that choice.
20:46
Bobby Doss
There's really no reason for me to get in a plane if the icing level is even at 10,000ft, because one, my plane probably can't even get there. But I'm just not gonna go that day to say your personal minimums on icing level is a thousand feet. And then try and cut the, cut that line that thin. That's pretty tough to do if you don't have icing equipment on your airplane. And, and things can change. So have a line, have a hard line and make it a good distance from what would be the known icing level or considerably known icing.
21:20
Wally Mulhern
Right, for sure. And, and you know, to make, what do you, what do we need to make? Ice? We need water and we need freezing temperatures. So if it's a clear day, and it's 2 degrees and it's there in the cloud in the sky between my airport that I'm going from where I'm going to where I'm going. Well, you're not going to get ice. But one thing to consider, you know, a lot of times, say the ceiling, there's a overcast layer of 8,000ft. And you say, well, I'm going to go at 4,500ft. So I'm well below that. That's fine as long as there's no water falling out of those clouds. Because if there's moisture coming out of the clouds, you know, it comes down. You now you've got either water or ice or something hitting your airplane.
22:18
Wally Mulhern
And that could be an issue as well.
22:20
Bobby Doss
No doubt. The. And then there's a whole nother story about super cold droplets that could be very painful for these small aircraft. So let's talk about the ways that ice does impact these aircraft. And we're talking ga, we're not talking your jet engine antifreezing equipment that you have, we're talking 25 to 3,000 pound single engine trainers that we mostly fly in or something we might be all buying. And I think the biggest one has got to be weight. Right. And with something that I know as a young pilot, meaning young in time of playing piloting, I wouldn't have thought of that. But you know, just a thin layer of ice, call it a quarter of an inch over all that aluminum surface, it could create a ton, no pun intended, A ton of weight on an aircraft for sure.
23:13
Bobby Doss
A lot more than six pounds per wing.
23:15
Wally Mulhern
Right, right. You know, and it's, it's not the way it is a consideration, but we're now really changing the shape of the wing. So, you know, we're, whoever designed that shape of that wing, I mean, some aeronautical engineer, you know, put a curve here and this here and this here and flattened out those rivets to reduce the drag. Now we're putting stuff on that wing and we're just changing the whole shape of the wing.
23:52
Bobby Doss
Yeah, definitely. Drag is a huge problem. Any of that ice on anything, even antennas or, you know, anything sticking out is going to cause both weight and drag for sure. That could be a big problem. Another problem is induction ice. All these planes that have a little something in the front, probably under the bottom side of the cowling there, right below the prop, that probably is the intake, the induction air coming in. Got most of mine, I think have a little aluminum filter with another filter behind that. Right. If you're flying through freezing moisture, it's not going to take much for that to be frozen over. And what's that going to do for your airplane, Wally?
24:39
Wally Mulhern
Well, now you're not getting airflow into the engine.
24:42
Bobby Doss
Yeah. So we need air, gas and spark to make fire in those cylinders. And if we don't have air, we're losing power, significant power. Our mixture could be, you know, the way we have our mixture set up, we might not be getting much air already, depending on what altitude we're at. So we would definitely need to think through that and not fly in icing conditions very long at all in these little planes for sure. What happened to Dominic, the pitot tube, if you get ice really over the inlet, the drain, all of the point, all the ports on a pitot tube, if they freeze up, you're going to see some really awkward things. That are going to blow your mind inside the cockpit and it's not going to be natural and you're going to get really disoriented really quick.
25:32
Bobby Doss
So as he said, don't forget to use the pitot heat, for sure. In any of that. We talk about the shape of the wing, what happens to wings that don't create lift anymore, they create stalled wings. And in the stall with ice on our plane, that's going to be, assuming we're in imc, that's going to be almost impossible to recover from. Many, many sad stories about something similar to that, I'm sure. And then I would say the last one that I think of, I guess, because it's kind of a trick question that we'll probably discuss, is the reduced visibility on the windshield. Right. If we get ice on that windshield, we're not going to be able to see very well. And that brings us to what kind of anti icing systems do we have in the airplane? Wally?
26:21
Bobby Doss
Do we have any in a Cessna 172?
26:24
Wally Mulhern
Yeah, we absolutely do. We usually have three. And again, this is something that we talk about on private commercial instrument checkrides. And I asked the question, you know, what kind of anti icing do we have? And a lot of times it starts out with we don't have any. And then I say, really? And then they go, well, wait a minute. And then they start thinking about it. So the one that we probably think about first is the pitot heat. I would venture to say that this, most of us have maybe never turned the pitot heat on in a small airplane. For those of us who live down here in the south, very possible. But we probably think of that first. The second one that we would probably think about in a carbureted airplane would be carb heat. We probably use that a lot.
27:30
Wally Mulhern
But the one that most people don't really think of is the defroster. Because if you get ice on that windshield, the visibility is going to go to, it's going to go significantly down in a hurry. And you know, I've been in situations where we've had to use it in small airplanes. And really the defroster gives you, if we, from a percentage standpoint, the visible area on a typical windshield. I mean, the defroster probably clears out maybe 15%. So you've got a little hole to look through. But it is, it's better than nothing. It does give you something to look through.
28:14
Bobby Doss
Yeah, that was an interesting question for me when I again, low time pilot, I think. I think I. About the pitot tube. And then you wouldn't get asked that for a while. And the carb heat is obviously a second answer, but the defroster is a big one. And I don't know that just cabin heat alone wouldn't do you some good in a situation like that to maybe break off something on the other windows or whatever. I think I would use all available resources at any point in a situation like that, for sure. Okay, so we talked a little bit about the ways that the ice could impact your airplane. Dominique told us the story of flying inadvertent ice.
28:55
Bobby Doss
Hopefully it never happens to y' all listening, but I think a short checklist of things to think about, a short list of things to put on your list would be obviously pitot heat. If you. If you didn't have ice on your plane 10 minutes ago, five minutes ago, and you start getting ice on your plane, I would think it's a pretty safe bet, not always a for sure thing, but a pretty safe bet that if I turn back, I'm probably gonna be in warmer weather. I think, you know, we live on the coast and I tell this story all the time because it happens. I know what. I know weather pretty well, or I know what weather's coming pretty well because I own a flight school.
29:40
Bobby Doss
But every day, if it's freezing in College Station, which is about an hour and a half from here, car driving, it's going to be freezing here before lunch. Right? So that cold front's always going to come through College Station to Spring, Texas. It's never going to start in the Gulf of Mexico and then come to Spring, Texas. Well, where do we fly? 95% of our flights, we fly northwest, west to northwest, and so things can be nice and warm here. But we're probably flying almost every day into colder weather because the cold fronts naturally come from the north and they're going to come that direction. So we have to be logical and think about that. But if we turn back, we're probably going to get closer to the coast and probably have warmer weather. Use all heating options that you have available to you.
30:34
Bobby Doss
We just talked about those cabin heat defrosters. Any, anything and everything would probably help you. I think the induction ice is one that really, we need an engine. So induction ice and carb heat, whatever we can do to make sure we don't lose any power in our aircraft, and then it is creating a plan to land these aircraft. We ain't got much time to think about it. We ain't got much time to mess around with it. The goal is to come up with a plan to get on the ground as quick as possible. And that's probably doing some flight planning in the cockpit and getting on the ground for sure. The longer you fly in it, the more weight you're going to have, the more drag you're going to have, less performance you're going to have.
31:19
Bobby Doss
I read some other stories preparing for this show where people are flying at 2000ft MSL with ice on their airframe and they got full power and they're barely going 70 knots. Right. And that's a scary situation if you think about what that means. You, you have nothing left before you're going to start stalling hardly in these aircraft. Right. So you're going to need a bigger Runway. You're going to need a lot of things when it is time to land, the all things to be thinking about. And it's not something just because you live in Houston, Texas that you shouldn't think about or some other really hot climate. You never know when it could sneak up and get you.
32:00
Bobby Doss
So do your preparing and make sure you know where the icing levels are and if there's going to be any visible moisture, you got to be aware of it for sure. Anything to wrap up with Wally as we close out this show?
32:14
Wally Mulhern
No, no. You know, the best thing for most of our airplanes that we need to know about icing is don't get in it. But if you do get in it, you know, here are some techniques and you know, for gosh sakes, when, when you're out there and you have incidents, you know, let's keep sharing them because this, that's how we learn. And you know, we can learn, we can read theory, but I think we all learn and enjoy more hearing real world stories.
32:55
Bobby Doss
Yeah, and that's a great point. That's what I'll wrap up with. If something does happen, I don't think you should be afraid or fear the FAA or fear the criticism. Like Wally said, share it. But if you have made a mistake, file a NASA report. By filing a NASA report, you should be doing something to prevent your certificates from being suspended or revoked. As long as these four rules apply. That the violation that you're reporting was inadvertent and not deliberate, that you weren't involved in a crime or an accident, that evidence shows that you did it within a timely manner and that it doesn't get in a bigger situation in the next five years, right?
33:36
Bobby Doss
So by all means file a NASA report if you do something that is at all something that could help others learn from and maybe was a violation, but you didn't do it intentionally and it could save your certificates for sure. And with that sounds doom and gloom. With that we'll say fly safely and stay behind the Prop. Thanks for listening to the show.
34:02
Nick Alan
Thanks for checking out the behind the Prop podcast. Be sure to click subscribe and check us out online@bravetheprop.com behind the Prop is recorded in Houston, Texas. Creator and host is Bobby Doss. Co host is Wally Mulhern. The show is for entertainment purposes only and is not meant to replace actual flight instruction. Thanks for listening and remember, fly safe.