When is the last time you thought about the pitot static system? This week we go back to basics and delve into one of the most important systems on the airplane!
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00:01
Behind the Prop Intro
Clear prop S73 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.
00:23
Bobby Doss
What's up Wally?
00:25
Wally Mulhern
Hey Bobby, how are you?
00:26
Bobby Doss
Fantastic as always. It's been a while since we've done really anything on systems and we got to talking in the hallway with some students the other day about some Pitot static stuff and that led to more questions and more questions and that's normally how we find the content that we want to share with our listeners. So today we are going to talk about the Pitot static system. The students were asking, you know, the proverbial wall E questions around, you know, what am I going to get asked on the checkride? What can I do? What should I. And I think that's pretty simple whatever the P hack and the airplane flying handbook says and know the acs. But it did cartel into a lot of good conversation that we thought we would share with everyone.
01:11
Bobby Doss
So we're going to break it down into three components and probably get off on some tangents as we go, but we're going to talk about the components of the Pitot static system, how each of those components work and then kind of common malfunctions and failures on along with just some common sense that you can incorporate in your flying to be a better pilot. While everybody wants to know, like what, what do people struggle with on checkrides as it relates to this system or these items, these instruments that use the system? What, what do you see private pilots struggle with? Assuming they talk about it more on their checkrides than all the others.
01:50
Wally Mulhern
Yeah, right off the bat, you know, I, I will go through the instrument panel and talk about how each or basically, I don't know if power sources is the right word, but power sources for the flight instruments and typically we have six flight instruments and typically three of them are Pedot static, two of them are vacuum and one of them is electric. That can vary. A lot of, a lot of vacuum systems are going away. You know, with G5s and that sort of things, you could have a turn coordinator that is not electric. It could be vacuum. That's kind of unusual, but we do see that. So right off the bat, a lot of times people just struggle with what system powers.
02:51
Bobby Doss
I, that's not, I say drives. Drives might be the right one there, technically. Yeah. Which drives the system.
02:57
Wally Mulhern
There you go. Yeah, there you go. That's probably a better word because you say power. We think electricity, but yeah, so right off the bat, that's, that is something that most people, I would say most applicants, it's just not on the tip of their tongue. And I, I really kind of think it ought to be. And usually we have a picture of a panel in the room that we're doing the checkride with. And I'll say, well, you know, it's there for them to look at. And if you look at most turn coordinators, it says right on there elec. So that might tell you that it's electrically powered. You look at most attitude indicators and maybe even directional gyros, and it probably says vacuum on there. So the answer is right in front of you. You just gotta look.
03:53
Bobby Doss
Yeah. And I think these systems, specifically the PEDOT static system, the airspeed, the vertical speed indicator, these blockage things we're going to talk about. Right. For an older guy who started flying. Right. None of this stuff made a lot of sense to me. But these systems are very good at what they do. They're, they're still the same thing that was made a long time ago. And almost, I would say every aircraft at some level uses the pressures, static pressure to help understand altitude and if it moves forward, probably airspeed through the pitot. Pitot tube. So let's break down each of the system, each component of the pitot static system, and then talk a little bit about what. And what people should know about them.
04:44
Bobby Doss
So obviously the pitot tube sticks out normally in front of the air, the airfoil, the wing, so that it's not getting disrupted air to it. And very important tool. We also normally see a red thing on that pitot tube. We'll talk about why that red thing is really important later on. But that pitot tube is really getting ram air. So as the aircraft starts moving forward, some pressure from the ram air is going into that tube and telling the airspeed indicator something. How many of those instruments use the ram air, Wally? What, what all instruments use the ram air?
05:28
Wally Mulhern
Well, the airspeed indicator uses the ram air and. Yeah, yeah, and I'll, I'll tell you a kind of a nerdy, funny story about a pitot tube. My father was notorious at his, you know, he was a professional pilot and he was notorious for bringing pieces of airplanes home and giving them to me and teaching me about him. When I, when I was very young, I mean second, third grade, that kind of thing. And he brought a pitot tube home one day and you know, it obviously had a malfunction and was taken off an airplane. And you know, most second graders probably played with normal toys. But that was something I had and I, this was back in the day. I don't know if they still do show and tell in school or not.
06:19
Bobby Doss
But I have a box in my office. I do it very often.
06:23
Wally Mulhern
Back in the 60s, 70s, we used to go to school and we'd have show and tell and you got to stand up in front of the class and show something that you had or tell something. And I can remember taking a pitot tube to school. I, I was probably in second grade and doing show and tell and teaching everybody all about pitot tubes.
06:47
Bobby Doss
Interesting. Well, it turns you into a great pilot and a career pilot to say the least. Yeah, but that, yeah, a broken open tube is very interesting. You, you can see the heater elements and the other components that are built into that pitot tube. Right. A pitot tube is made up of both the ram air inlet, we'll call it a hole. They have a drain hole in the back and they've got a heater element that is controlled by a switch most often in the cockpit there with the pilot can control it and makes it work. Right. We'll talk about the errors or the blockages that occur. But you know, we're up at, Even in a Cessna, you're 5,000ft on a 50 degree day invisible moisture. You might be in some conditions that would cause that to get ice on it.
07:37
Bobby Doss
And it would be very important to make sure that was clear and didn't have ice in it because we would ultimately see some problems with our airspeed indicators and maybe multiple, you know, we've been chasing a problem lately with the digital airspeed indicator and a backup airspeed indicator. And it, you know, it's not always obvious what the, where the blockage is. It could be deep inside that system somewhere, which would be causing inconsistencies amongst multiple indicators inside the cockpit for the pilot. We also have the actual dial inside the cockpit, which is the airspeed indicator, obviously interpreting the information that it's getting from the pitot tube. And, and the static port. We have the static port, which some planes have one, some planes have two. I don't think I've ever seen three.
08:26
Bobby Doss
But surely there's somebody out there that's got multiple static ports and Then there's an alternate static in most of the trainers that we have at our school, I would think, in today's world. Wally, do you see a plane ever that doesn't have an alternate static inside the cockpit?
08:44
Wally Mulhern
Yeah, I'm sure there are. Offhand it. I, I don't think of any, but I'm sure there are some.
08:54
Bobby Doss
And then the other two instruments inside the cockpit are the vertical speed indicator and the altimeter that are using the static port to read the outside pressure of the aircraft and then doing something with that information. So I'll let you. You're much smarter than me. I'll let you describe how the vertical speed indicator and the altimeter work, Wally, using the static port information.
09:23
Wally Mulhern
Well, they basically measured the difference. Difference in pressure. You know, the vertical speed, you know, is probably an instrument that we don't use a whole lot as maybe VFR pilots. But it is a very nice instrument to have, especially on a, you know, when you start flying instrument conditions, to have an idea of what rate of descent you're going to want on an approach to how, you know, just have a good idea of what you're doing. You know, I talk a lot about electrical failures on check rides, instrument check rides, and we talk about if all else fails and we had to come down without our electrical system, you know, that vertical speed becomes very important. So, you know, again, as VFR pilots, it's probably not something we're looking at a whole lot, but instrument conditions, very much so.
10:33
Wally Mulhern
Now, what you got to know that a lot of times it lags a little bit. So, you know, I can remember my first instructor telling me it was a history book, the vertical speed indicator was a history book. Rather than telling you what's happening right now, the other time you might use it is maybe on steep turns. I had a situation with a student was actually doing some teaching the other day, and the. The young man was struggling with steep turns, and I just covered up the panel and said, look out the window. And he was amazed. He said, wow, I've never done that. And it's a lot easier to look outside. So I know I'm not talking about pitot static systems, but as it relates to the vertical speed indicator, well, we.
11:26
Bobby Doss
Can get fixated on stuff. And I like the history book because it is a delay. And during the research that I did to prepare for the show, because I don't think about the details of all this every day, it said it's about six to nine seconds in the past. So it takes about six to nine seconds for it to, for the calibrated leak to equalize or get to a common pressure change based on the static port and the information that it's getting on the other side of that controlled leak or calibrated leak, which I found very interesting. So if you started to climb, it's going to be six seconds before they begin balancing or begin to share the right information. And if you only climb for 12 seconds, it'd be right for about the first.
12:14
Bobby Doss
It'd be right for six or seven seconds there in the middle. And then start changing your altitude again. It's going to be lagging on that. But very good information. I remember chasing that thing a lot when I was a student pilot trying to learn how to climb and go out to the practice area or come back to the pattern. I think much like a new ifr, pilots probably chasing a track that they're supposed to be on. I think a VFR pilot starts chasing that needle and it's. Because it is history, it's almost impossible to keep up with it for new pilots, for sure.
12:49
Wally Mulhern
Very much so. You know, one thing I have learned to do myself is anytime I get in an airplane, it just bothers me if I look over and I see that the altimeter is way off of field elevation. So the first thing I want to do is the first thing I do. And this is just my technique, it's just the way I do it. This, there's no, you know, this isn't the way you got to do it. First thing I want to do is set my altimeter to field elevation. And if I notice that the altimeter is significantly off of field elevation, it sends up a flag and it says to me, there has been a significant change in the weather since this airplane last flew. Now maybe the airplane hadn't flown in a year, okay, but maybe it hasn't.
13:46
Wally Mulhern
You know, flight schools, we have a good weather day, then we have three days of bad weather and the airplanes don't fly. And then we come back in and the pressure is significantly different. It tells me that the airplane probably hasn't flown in a couple days. And it really kind of affects how I'm going to do the pre flight. Significant change in weather. Maybe we've had a lot of rain and it's going to be. Am I going to be more cognizant of checking the fuel? I'd like to say every time I check the fuel the same way, but there's more. I don't know. I don't, I don't know how to explain it, but maybe my awareness is much higher knowing that.
14:31
Bobby Doss
I was going to say angst. There's a little bit more angst. Anxiety about. Okay, exactly. Could there be water in the fuel? Right, right. Did it start raining when the plane was parked and they didn't put any fuel in it, but the tanks are full. Right. That would be a big problem because that would be a lot of water and some AV gas as well. Yeah, probably. I'm gonna sump that a little bit more closely in that case because the pressure is so far from what it was when that plane was parked, for sure. Right. Well, talking about pre flight, you know, there is, there's a number of things and I've seen, golly, I feel like I've seen everything and somebody's gonna prove me wrong tomorrow, Wally. But you know, I've seen a lot.
15:12
Bobby Doss
We pay a few young men and women to wash our planes. We call them rampers. They move our planes around on the ramp, right. While we try really hard to use a big piece of blue tape or red tape, red painters tape or blue painter's tape. When we wash our planes, we cover up those static ports. Sometimes that gets forgotten, man. I saw, I saw a ramper one time use a clear piece of tape and I lost it because that's extremely dangerous in that world where they, you know, even someone pre flighting might notice a clear piece of tape. But you've surely seen a pito static port covered up with a piece of tape or something. But that big red thing hanging off the pitot tube, have you ever had someone leave that on during a checkride, Wally?
16:00
Wally Mulhern
I have, I have. And we taxied out and he actually took off and he noticed it rolling down the Runway and he elected to take off. So here we are now we're in the air, we're flying and we don't have any airspeed indication. We had air speed because we flew. Right. So, so what do you do in that situation? Well, first of all, I mean, he shouldn't have taken off. So we had a in depth discussion on that and we talked about how when he came back for his next check ride, that we would be evaluating that. Anyway, if you can read between the lines there.
16:54
Bobby Doss
Yes.
16:55
Wally Mulhern
So anyway, so here we are. You're, you're in the air. Let's say the, the airspeed just fails, okay? Or in our case, we took off with it having failed, what are you going to do? And, and this is what, you know, the, at this point the check ride was over. So it became a little bit of a teaching moment for him. But we have, most airplanes today now have a gps so we have a ground speed readout. So what I said to him, I says we're going to maintain our Runway heading and we're going to level off and we're going to take a look at our ground speed. And I'll use easy math here, let's say it's 100. I says now we're going to turn crosswind and we're going to turn downwind.
17:51
Wally Mulhern
We're going to turn 180 degrees eventually and we're going to look at the airspeed again. Now if that airspeed when we've made that 180 degree turn or ground speed rather if the ground speed when we make that 180 degree turn is the same, we've got a pretty good idea that we don't have any wind.
18:14
Bobby Doss
Calm day.
18:15
Wally Mulhern
Okay, so if it's, let's say it's 100 on upwind and we make a turn to the downwind and now it's 120, that's a 20 knot split. That tells me that we had a 10 knot headwind when we took off. So that would tell me that my airspeed is probably 110 for 100, I'm upwind, 120 on downwind, split the difference. And that gives you an idea of what your ground speed is. Of course you're going to turn base, you're going to turn final knowing that you've got that headwind again.
19:03
Bobby Doss
Yep. And I think that's something we should all be able to do inside of a plane because you never know. I think we talk about the book knowledge all the time about icing and getting plugged for ice. But I actually think in Houston, Texas it's more likely that a monster mosquito is going to cause you a bigger problem in our aircraft. Something that's going to either create a home or get hit by the plane as we're taking off. That is a bug. Bug flies into the tube or a mud dauber fills it full of mud. Right. Some sort of a burrowing type animal like that or insect. But that's why you got to make sure that pitot tube cover is always on there. You gotta be diligent.
19:48
Bobby Doss
If you fly to fly school and you can't find it because someone didn't, they took it Home on accident or whatever. The school really wants to know because they don't want any issues to be created inside of that system with little bugs that would want to find a nice place to stay dry and warm during the fall to the fall time of year that we're in kind of the almost winter to spring right now. It's perfectly nice for a bird or a bug to get up in those pitot tubes at this point. And that would be a very bad thing for both student and school for sure.
20:24
Wally Mulhern
And, and also don't think because your airplane is a hangar that it's not an issue.
20:30
Bobby Doss
Oh, exactly. Right. Yeah.
20:32
Wally Mulhern
You know, don't have the attitude while I hanger the airplane. I don't need to put that pitot cover on that pitot tube cover on there because that couldn't be farther from the truth. I mean, I, I, you know, I have a couple or have one airplane now and I've had it. Bugs get in it in a hangar and it was uncovered. So I fell into that trap years ago of thinking, oh, it's hangered. I don't need to put the pitot tube cover on it. But guess what?
21:04
Bobby Doss
Maybe more bugs in a hanger just because there's a lot more dryness in there.
21:09
Wally Mulhern
Right.
21:09
Bobby Doss
For bugs to get in there, maybe a little bit of light. You never know. You should definitely put that pitot tube cover on every time and always. And I think I see probably people get lazy with the low wings because it's a little bit more work. It's a little harder to get down there and put that little mast cover on a low wing plane there that, you know, it's kind of more like a, I don't know, a blade. And it is a pitot tube.
21:32
Wally Mulhern
Right.
21:32
Bobby Doss
It's a little harder to get up underneath there and cover that thing up. But super critical if you want to ensure that you don't have any of those issues when you go flying on a given day, for sure. So we talked about tape, we talked about, you know, the pitot tube cover, we talked about bugs. You know, there is the ice thing and there's a lot of errors that could be presented to pilots and some common sense, but it really wasn't common sense to me. When I was a new pilot, I struggled with these high to low, look out below all these pressure sayings, and it didn't really make a lot of sense. And I think I've shared on the show. But whatever it was about a weather balloon kind of made it click for me.
22:16
Bobby Doss
You know, a weather balloon takes off and the balloons pretty small. If you look at pictures on the Google, you can see a weather balloon at altitude that balloons huge. And it really is because those gases inside that balloon have the chance to expand because the air is much thinner up there. And that just put pressure in my mind it just kind of made sense. Right down close to the ground, the balloon's kind of squished by all the other molecules down here. Up in the air everything kind of expands and there's a lot less molecules up there. And that's really what the altimeters reading the vertical speed indicator is with that calibrated leak is managing that for us as well. And then the airspeed is RAM versus that static pressure at whatever altitude we're at. So the system knows what's going on.
23:05
Bobby Doss
So what kind of common errors should we see or expect? And I know you probably get tired of hearing this Wally, but all the listeners want to know like what do people struggle with on checkrides and kind of what's a DPE really trying to evaluate? Obviously it's systems knowledge. But what kind of tips and tricks can we give to the listeners out there that might be taking check rides?
23:27
Wally Mulhern
Well, you know one thing I do with for sure private check rides is I, I talk about their cross country. I say okay, we're going from airport A to airport B and I, you know, this is during the ground portion and I kind of create a, a divert scenario. Let's say we're halfway to airport B and we decide we need to divert. Maybe we just need to go to the bathroom or whatever. It's you know, not an emergency. So we'll pick an airport and you know, I'll use that opportunity to talk about that airport. That's how we talk about, okay, what are the notches that on the, you know, three, six and nine o' clock on the airport, the color of the airport, what type of airspace, Runway length, all that kind of stuff.
24:20
Wally Mulhern
And so I say okay, let's say we land at this airport and we jump in the crew car. Let's say there's not much going on at this airport. We jump in the crew car, we go have lunch and we come back and we get in the airport airplane and the ASOS isn't working so we can't really get the weather. But we look out the window we see there's not a cloud in the sky. The car just told us that it was 75 degrees. We can look at the wind sock and see that it's basically limp. So we know that. And, and we just came in. We know the visibility is really good. So we know the visibility, we know the clouds, we know the temperature, we know the wind. The one piece of the weather puzzle that we don't have is the altimeter.
25:13
Wally Mulhern
And I will say, how do we know the altimeter? And, boy, it's, you know, of course, everybody says, well, I'll look it up on my phone. I say, well, we don't have cell service. And a lot of people really struggle with that. And that goes back to what I just said. Just set field elevation and, you know, whatever it reads is what it reads. If, if I put in 150ft, if that's what field elevation is, and I can look at it and see that the altimeter is 3023.
25:49
Bobby Doss
Yeah, that's one of those things that evaded me as a young pilot. And still, I think due to the fact that I've always got it on my phone or I've always got access to the radio, now I kind of just expect to get it from somewhere else. But it's pretty easy to sit down in the cockpit in the pilot's seat and just turn that dial and figure out what it is that day. You're going to be within a 0.01 or 0.02 of that number almost every time if you know the field elevation. And that's published, so you should be able to get that for sure.
26:23
Wally Mulhern
Yeah. And, and a lot of times we'll. I'll say, well, let's go. Let's go get an airplane and we'll walk out and find an airplane. We'll jump in it and we'll talk about that. And, and eventually they'll get it and they'll say, oh, I think the altimeter is 30225. And I'll say, let's turn on the master switch and let's listen to the ATIS. And lo and behold, altimeter 3026. Okay, 10ft off. So it's really, really close.
26:53
Bobby Doss
Yeah, that's an amazing thing that I don't think I really understood or comprehended probably until my instrument training. But a very easy way to get that number and be accurate to, to. To precision and not just kind of wing it or guess at it. Right, for sure.
27:10
Wally Mulhern
Right, yeah.
27:12
Bobby Doss
So, so what happens? Like, you probably talk through some blockage scenarios, probably more, maybe on instrument check rides or whatever, but, you know, some of this never made sense. But I think if you understand how the systems work, how the tools work, how the airspeed indicator works, then you quickly learn, or understand, maybe not even learn. It's not the road knowledge that makes us good pilots. It's understanding the systems. And if the ram hole, the inlet gets covered up, I'm obviously not going to have any airspeed indication. If the drain hole isn't covered up, it's just going to read zero because the static and the difference is going to be the same. So it's just going to say zero.
27:56
Bobby Doss
But what if the drain holes covered up and the pitot tube is covered up, meaning the inlet for the ram air is covered up, then the pressure is going to be trapped, and that's going to be trapped at some altitude. And we just talked about this, right? So whatever the field elevation was when that got trapped, assuming a bug covered it up, or if we're climbing out at 1,000ft and we hit a big bug or a bird and it covers those two holes up at whatever altitude we're at, that's what's going to be trapped in that system. Assuming it's completely covered up and we're going to have a problem. Right. It's going to act more as an altimeter and in that instance, because it's trapped pressure.
28:39
Wally Mulhern
Right, right. And this is where a simulator is worth its weight in gold. Because I, Other than the, the pitot tube situation, I, I don't know if I've ever really had a Pedot static system malfunction in an airplane. I'm, I'm trying to think. I don't think I ever have.
29:07
Bobby Doss
And that's why the system's so good at what it does and why it's still the system we all use in almost every aircraft we fly.
29:14
Wally Mulhern
Exactly, exactly. But a simulator, you can, you know, the instructor or whoever is operating the simulator can fail certain systems and say, okay, this is what this is. Look, looks like. This is what a blockage of. This looks like. This is what icing would look like. These are the symptoms of it.
29:36
Bobby Doss
And it doesn't have to be the rote knowledge. You can actually climb 3,000 more feet and say, right, oh, now I understand what you mean by altimeter. Because it got. As I went higher, the number got higher, and as I went lower, the Number got lower and I see it and I truly understand what's going on. It's just not me reading it in a book and trying to remember the acronym or the phraseology so that I don't forget that stuff.
30:01
Wally Mulhern
Yeah. And you know, I remember myself as a private pilot, a non instrument rated private pilot. I kind of, I kind of had the attitude of, well, that pitot heat switch doesn't apply to me because I'm not instrument rated. I had the attitude of, well, if I don't fly into a cloud, I'm not gonna need it. But that's not the case because there could be a cloud above with falling precipitation and if the airplane is cold enough, it could freeze on the airplane. So you know that was definitely the wrong attitude to have 40 some odd years ago.
30:43
Bobby Doss
Yeah, you're gonna want that airspeed. I mean it's gonna make it a lot easier to land. If you're a new pilot, you're gonna want that airspeed because we know a combination of that and an electrical failure is going to be a huge emergency for a private pilot. No question whatsoever. For sure.
31:02
Wally Mulhern
Yeah. And don't think it has to be freezing. In fact, I was just in an airplane within the last two days. I don't remember where it was, but the placard said that anytime you're in visible moisture and less than 5, 40 degrees Fahrenheit, that the pitot heat it said must be turned on.
31:22
Bobby Doss
Yeah.
31:22
Wally Mulhern
So you know, in, in bigger airplanes and jets we have this thing called ram rise. And what that is the actual friction of the air going through the pitot tube causes heat. So we'll have two, two temperatures that we look at. One static temperature and that might be minus 56, you know, up at altitude. And then we have total air temperature which is going to be warmer. So it might be minus 38 or something like that. So. And we don't, that's not really an issue with 100 knot airplanes. But, but again, anytime you're anywhere close to freezing, you probably want to get that pitot heat on, you know, with visible moisture. Sure.
32:17
Bobby Doss
If we're up at altitude, call it 5,000ft, visible moisture, 40 degree day. We're going to be in some icing conditions. We want to get out of that in a Cessna for sure. But let's assume the static port does get frozen over. Right. We don't have a piece of tape on there. The static ports frozen we're going to get a lot of abnormal information because all three instruments use the static pressure for information. And like I said earlier, most of our trainers have a, an alternate static. We pull it to check it and when we pull it we normally see things bounce a little bit. It normally is fairly quick vertical speed and the altimeter kind of move a little bit. We know, okay, it released some air or static pressure into that system and it's going to be slightly different.
33:06
Bobby Doss
If you ever have to use it or if you're flying a plane, you should know what the POH says about it. Some are pretty basic and just say, you know, it's going to be 15 or 15ft off or 2 mile, 2 knots off. If that's what the book says, know that information. Some books, Cessna 172s have a pretty involved chart that talks about the different numbers if the windows are open or if the windows are closed, the flaps are down. It's a lot of information that will make those numbers vary if you have to use that alternate static pressure. But you should know that information for the airplane that you're in.
33:43
Wally Mulhern
Yeah. And basically you're using a port that is now inside the airplane and that's the difference. And so is the pressure inside the airplane different from outside the airplane? And it is a little bit not, you know, it's not significant, but it's a little bit different.
34:01
Bobby Doss
I never understood, I read it again today. But it truly is the Bernoulli's principle of the airflow over the fuselage, which creates a little bit of a differing pressure inside the airplane, which does make more sense to me today than it did when I was a 20 hour pilot. But just know it's different and the book will tell you what it's going to be different. If that doesn't work for whatever reason, that alternate static pressure also becomes clogged. You don't have one. There's one fail safe that you can always do. I've always read about it. I don't want anybody to ever try it at my flight school. But it is breaking the glass on the vertical speed indicator.
34:41
Bobby Doss
And really what you're doing by breaking that glass is you're opening the static system to another source of static pressure, which again would be the same pressure inside the cockpit. If you need to use it because you're in an emergency, by all means break the glass. But don't go demonstrate it for someone because those instruments are very expensive and we don't want to break the glass. But if you have to when you break the glass on the vertical speed indicator, you're actually letting static pressure into the system kind of behind the walls of all those other instruments. And you will start to see information that you're expecting to see in those instruments as well.
35:16
Wally Mulhern
And we, and we say the VSI because we figure that is the instrument that is needed the least. So. Because you're probably going to ruin the instrument when you do that. So, so that's why we pick the vertical speed for sure.
35:34
Bobby Doss
Any other tips and tricks you can give the private or instrument students that are days away from checkrides that may. Well, I know they want to impress the dp, but maybe want to impress themselves with the knowledge that they should be understanding before they go in that room.
35:50
Wally Mulhern
No, I mean, it's just a matter of knowing which system drives which instruments and knowing, you know, if we have a PEDOT static problem, what instruments it's going to affect. Is a PEDOT static problem going to affect our heading? No, it's not going to affect our heading. Consequently, you know, we can, you know, what's a vacuum pump failure going to affect? And you know, if we look over and we have zero on the vacuum gauge, is our altimeter still working? Yeah, it is. And you need to know that stuff. You know, we need to know. You know, I'm trying to relate it to something in your car, but, you know, is the radio in your car is working? Is it not working? Is it going to affect your ability to drive to work tomorrow? Well, no, it's not. It doesn't really affect the engine.
36:50
Wally Mulhern
So know what system drives which instruments, you know, an electrical failure. If you have any electrical instruments on your six pack, what you're going to have or what you're not going to have.
37:06
Bobby Doss
But Wally, if their Bluetooth doesn't work tomorrow, they're not gonna be able to listen to the show on their way to the office. That would be detrimental to most of our listeners.
37:13
Wally Mulhern
I would assume that would be very bad. That would be very bad.
37:17
Bobby Doss
All right, well, really good show. We've been wanting to do more kind of teaching or more kind of system type content that helps you guys and girls out there better pilots and safer pilots and know what you need to know. Hopefully you enjoyed the show and as always, stay behind the prop.
37:37
Nick Alan
Thanks for checking out the behind the Prop podcast. Be sure to click subscribe and check us out online@brave.theprop.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.