Transcription
But wind shear, wind shear, and turbulence. So, so, uh, stuff that we're going to go over today. Uh, we're going to talk about an accident review. Uh, this is a big, kind of, uh, watershed accident that made a lot of changes in aviation. Uh, it's unfortunate, but, uh, that that it happened. But on the other hand, there were people that survived. So, uh, there's pluses and minuses, uh, to this unfortunate accident. We'll talk about that, how it affects us in our, our daily flying, especially during areas where you might get, uh, more wind shear. We'll talk about the advanced, uh, ground proximity warning system. That's when you kind of start to use systems like this. It's kind of, they, they abbreviate a JY WIS. So when you're, you're thinking about utilizing this kind of, uh, equipment, or if you have it installed in your aircraft, it's kind of nice, uh, because it will safeguard, uh, a lot of issues or a lot of, um, a lot, a lot of potential wind shear problems that you might have. So I'll show you what it looks like on a screen that you would be, if you were flying the aircraft, what it would look like and how it works. And then, of course, it all comes from the accident we're going to talk about here in a second. Microburst, directly associated with this accident. Also, we'll talk about what it is, what they look like. And I also have a video included today that, that shows an actual microburst within it. Uh, what the nice thing is, is this particular microburst was shown on the outside of, uh, of a downpour from a thunderstorm, where you can actually visualize it, which is a little different, because a lot of times most of the microbursts are contained within it, and so you can't, they're obstructed, so you can't usually see them. So this is kind of cool. Uh, low-level wind shear, we'll touch on that, since it affects absolutely everybody that flies in an airplane, that flies in anything that contains weather and different air masses. So we'll talk about that. Turbulence in general, uh, what it is, where it comes from, how we can avoid it, if we can. Uh, a lot of times it's just, well, just don't fly because you'll hit turbulence somewhere along the way. Uh, and then, of course, mountain waves. Which, living in a, you know, the LA Basin, we're surrounded by mountains, so it's important for us to understand what mountain waves are, uh, where the bad stuff is, and how we avoid it. And if we get caught in it, what to do about it. So, uh, we'll go ahead and start off, uh, this whole conversation on wind shear and turbulence with an accident overview.
Uh, we're going to talk about this flight, Delta Flight 9191. This is a picture of the actual aircraft, uh, that unfortunately crashed. And, uh, we'll look at the details associated with it, because this was a while ago. So this happened way back in 1985. And when this accident occurred at Dallas-Fort Worth, um, it was kind of, as I set this up, it's, it, it might make you scratch your head at first. So this is a really big aircraft, so it's an L-1011. It's got three huge engines and 150,000 pounds of thrust. So that's pretty impressive in and of itself. It was holding 152 passengers and 11 crew, but this thing was capable of holding over, you know, just, just about 300 passengers if it was, it was configured in that fashion. Um, so it can hold a lot of people and a lot of cargo and luggage and all that kind of stuff. So this was essentially lightly loaded for, as far as an L-1011 is concerned. And, uh, so you would think it, the performance of that aircraft would be much better because of that, especially at lower altitudes when you get more performance out of it. An airplane, the, uh, the crew was very experienced. And so, just to make sure I don't misrepresent, I'm, I'll read a couple, uh, or some stats. So the captain, Captain Connors, had logged over 29,300 hours. That's, that's like close to retirement, almost numbers. I mean, that's, those are big, big numbers. And over 3,000 hours of those were in this type of aircraft, uh, which is very important because they, you know, you generate, or you, you get a feel for an aircraft when you start to fly it a lot. And it's, and usually you can anticipate things a lot better than folks that maybe just started flying it. And, uh, so that experience is, is, is valued quite a bit. Um, the flight officer that was sitting in the right seat was, uh, Flight Officer Price. It logged over 6,500 hours, which is still significant, and 1,200 hours in the TriStar. So that's, that's, uh, both these people, uh, were very experienced. So that's really not the issue, uh, with why they, why they crashed, but more about the weather. What we knew at the time this accident happened, and then, of course, for all of us that we're talking about it today, is what have we learned since then, and what are changes that have happened to the system, uh, since this unfortunate crash? So if you were to look, this, this is what's kind of the, the head-scratcher. If you look at the, the weather that was reported on that day, it shows the ADIS, which is that terminal, uh, information system that you get on the airfield itself. It shows that it has 2,000 feet scattered, 6,000 scattered, visibility 10, temperature 101, and the winds were calm. What we're going to see here in a second, and what they didn't anticipate was ready, is this. This is a microburst that comes out of the bottom of a thunderstorm. Generally speaking, it happens towards the end of the life of the thunderstorm as it starts to dissipate. Remember the dissipation phase, right? Towering cumulus, mature, and the dissipating. And in this particular case, as I, I don't know if you'd call it a colorful description of flushing the toilet, but this is pretty much what happens towards the end of a thunderstorm. All the rain and all the mass that's inside that thunderstorm, because the energy is not there keeping it up, will just start to come out of the bottom. So, uh, that's pretty amazing. If we take a little closer look at it and we see, see the winds that are associated with it, that's 116 miles an hour. So that's pretty impressive. And I know they can get upwards to 150, 160 miles an hour. And I'm sure that people aren't walking around clocking that wind speeds coming out of the bottom of thunderstorms, but I'm sure it varies and it can get pretty high. So the difference is when we look at microbursts, are those are portions of this, this event you see right here that are also contained within it. So there's additional microbursts, which we'll see in a video, and it'll make a lot more sense when you see it, um, that can be even more deadly than what you're looking at right now. So the other issue that the L-1011 has is it was an older school jet. Even though it was a bypass turbine, it didn't have the spool-up time. Or, in other words, when you command a certain power setting in this aircraft, the, you know, the systems went through a process that took up to 8 seconds in order to give you what you're asking for. So I push up the throttle, or in this case, the thrust levers, and I wait for a response from the engines. So we'll see actually a video that shows in-cockpit. It, it shows a shot of the plane itself as, as an animation as it's flying on the glide slope. We'll explain that in a sec. Um, and then what the crew was talking back and forth, and you can hear when they push the power up, how, you know, there's that, there's a lag before the actual sound of the engine starting to spool up happens. And it's that gap of time where you didn't get the response as a pilot, uh, for what you're asking for, can lead to an issue if you can't compete against mother nature in this case. So we'll take a look at that a little bit closer. If you want to look at what a different view is of a, a microburst, uh, you can see this shot where it shows his name was Dr. Alfred Maldonado, who's taking his family up to Denver from El Paso, and, uh, took, took this great shot of a microburst coming out of the bottom, uh, of a thunderstorm. And, uh, it's about 4:30 in the afternoon there in Texas. And, uh, this, of course, is as the, the energy starts to wane. But what we need to get back to is the actual accident at Dallas-Fort Worth. And if we look at two different time frames, so, uh, you know, 5:51 at the top, and then 6:05 down below, below it, and you can see it's a short period of time, but in that short period of time, there's a lot more information that wasn't listed in the ADIS when you received it. So if you look at the METAR, right? So the METARs are different from ADIS. ADIS is given over the radio when you're coming in for a landing, and the METAR is something you'd be able to bring up. The beauty of today's, uh, you know, the newer cockpits and, and, uh, ADS-B technology, uh, is that we were able to get METARs instead of just the ADIS today. And we might be able to get this information, which is very valuable. Part of it, though, is what you, what we start to look at, as you see that inside this, it shows cumulonimbus, uh, to the north-northeast, and towering cumulus. Well, so if you just listen to the ADIS, it's a great day. But if you look at the METAR, all of a sudden, like, like, whoa, wait a second, there's some issue out there, and I need to pay attention to it. Now, as these guys were flying, they could see these thunderstorms, and you'll hear it in the video I'm going to show here in a sec, and they make comments about some of the stuff that's coming out of the thunderstorms, like lightning, which, of course, is not necessarily a good thing when you're heading straight for it. Um, but what this doesn't tell you that we get today is in today's, uh, you know, like if you use ForeFlight or Garmin Pilot, or if you have this information on your G1000, uh, what you'll be able to see is not only see the thunderstorm, but you'll also see the direction that the thunderstorm is heading. That's super important, because if you're coming in on final, there's a thunderstorm on your left, and it's moving towards you, because you can see that on your, your display, you know, you might make a little bit different decision about whether or not you wanted to continue. But if you look at the second one, we notice that it says special, and we'll see that in the second half of the semester when we talk about METARs, but it is listed separately, and it is an update. And if you look at this update, we can see that it is moving, uh, towards it, and it's becoming more violent. So more lightning, cloud and cloud, rain showers, heavy intensity. In other words, it's starting to kind of dissipate. There's a lot of wind shear causing a lot of lightning. So it's a very active thunderstorm as it kind of gets to the end of its lifespan, right? So keeping that in mind and understanding like, what actually happened in this case, is that thunderstorm did move over the top of the runway, and these guys ended up flying straight at it. So listen to the, uh, in the video, listen to them, uh, talk back and forth. It's very professional. So as far as like sterile cockpit and that kind of stuff, uh, it's very important to, to hear that. Even when they're flying into crappy conditions, they still maintained a professionalism as they tried to, to keep that plane flying. As it continued on, you'll notice that the airplane is coming down on a glide slope. So for those of you who are not familiar, glide slope will give you vertical guidance. In other words, allow you to come down towards the, uh, runway, in addition to the localizer, which is kind of a beam that comes out from the runway that allows you to maintain the centerline and come straight in towards the runway. So you get vertical and horizontal guidance in an ILS or precision approach, and this is what they're on. But since we're looking at the side, all we see is the glide slope portion, which is what's important to us. And you will notice that the airplane will go up or down based upon the performance that they get, as the plane reacts to the weather that's in front of them. After this, we're going to talk about, I'll show you a picture of where that performance happens, so it'll help you visualize a little bit more. So we go ahead and play this. Uh, this was done in a courtroom, and so this is the video that they used at the time, uh, which has a lot of great information. So listen carefully. There's a lot of chatter because air traffic control, it's Dallas-Fort Worth, it's a busy airspace, so there's a lot of stuff going on. But focus on, and you, you can read the, the, the, uh, the transcripts as it goes along.
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Coming out that 101 I you Haven 963 American 619 cross 6 cross thank 762 in a barrel lose it all of a sudden there it is P it up push your way up where pull up pull up pull [Music] up.
All right, so this was a, a pretty unfortunate accident. There was a lot of stuff that was going on, uh, in this approach. Um, but as far as the, uh, crew is concerned, they were very professional and flew it correctly, uh, for how they flew aircraft back then. Now, a lot of changes have happened since this accident, and, uh, which is good for everybody. And this accident continues to be used today in simulators with professional pilots, uh, to make sure that this doesn't happen again with anyone, because, you know, mother nature's tricky. You know, all of a sudden, you can have stuff pop up that you didn't anticipate. And as long as you've been trained for it, you can react a lot faster, uh, than these guys did, which is, it has nothing to do, like, against them. Uh, it's just that's the way they were trained back then. You see the biggest difference in some of the recovery techniques that are used today in comparison. Uh, when you push the, the thrust levers forward or the throttle, which you're familiar with in a 172s and Pipers and stuff, um, the difference is in a jet, you only go to about 100%. You think, well, wouldn't that be normal? That's like all you get. Well, in a jet, you actually get more than 100%. So their engines are rated for a certain amount of horsepower, but they're capable of creating more than that horsepower. The catch is, you're not supposed to go there unless it's an emergency, see, like this. Um, so you can hear initially where he says to push the, the, the thrust levers up, as he did, but then responded back and said, push you way up. In other words, he's allowing him to go, uh, and max it. It's called max thrust. Put as much as you can into this airplane to, to pull yourself out of this particular scenario. So, uh, anyway, the end result, of course, is that it did crash. We'll talk about the results of the crash here in a second. Um, but what can we do to avoid that kind of scenario ourselves? Looking at what happened during that accident, we can see as they were going down that glide slope, which is represented by the light blue line in this graphic, um, they started to get a positive, uh, reaction from the, the, the downburst that was coming out of the thunderstorm. So because of that positive, uh, aerodynamic advantage that you get, it starts climbing, right? So you can see that the aircraft starts to go up or above that glide slope, which is fine. Normally, you think, oh, okay, no worries, I'll just, uh, just come on back down. Uh, and to do that, generally speaking, you don't push the nose over because you'll go too fast. It's just reduce the power a little bit, and it'll just settle down. Which, if you watch the video, that's exactly what he did. He did a really good job on maintaining that glide slope on the way in. Unfortunately, because it's a thunderstorm and he was caught in a microburst, he ended up in, in, in looking at, I'm sorry, he then went into the thunderstorm, which is represented by number three. And when that happened is when all that action started happening where they were trying to put more power into the aircraft, try to climb out of it. And unfortunately, the two to six, five feet per minute gust that's pushing them straight down towards the ground, the airplane was unable to be able to recover from something like that. It was pretty dire. They were just too close to the ground. Um, it's kind of like when you learn stalls. The reason why you learn stalls is to avoid stalls. But if you have a stall too close to the ground and it starts to enter into a spin, that's probably it for you. So that's why we learn a lot of these techniques is to avoid getting into them in the first place. So in this case, of course, they had lost all, all ability to, you know, go around or, or get away from the microburst. They hit the ground. And when they did that, they, they hit first, just prior to the airport, uh, uh, environment, uh, where they hit through that air, that, uh, parking lot wasn't there at the time. Um, but they hit the park, or the, the ground, uh, but they touched down lightly, which is surprising. So when they did the accident investigation, they noticed that the tires that were down, of course, uh, they, when they touched the ground, they touched the ground lightly. In other words, they were flying this thing essentially all the way to the ground. They were trying to recover, and they were doing a pretty good job, but mother nature was a little too strong in this case. And because of it, they eventually hit in front of it, that road. They hit a car as they crossed over the top of that. That's how low they were. And, uh, after they hit the car, that veered off to the left, hit these, these tanks, and at that point, they have fuselage actually separated. And that was probably, I guess, the only good part about the accident was the separation of the fuselage, because the people in the back of the aircraft survived because their portion of the fuselage kept sliding past where, you know, the fuel tanks had exploded, and so enabled them to survive. So, uh, pluses and minuses to this accident. Um, but, uh, this is unfortunately what had happened. So what were the outcomes from this? That's pretty amazing. So they had 152 passengers, like we had talked about, and only 24 passengers survived, and three crew members, uh, because of this accident. NASA sent out like this memo, right? Said, well, we got to do something, something about this. Duh, right? So, because of that, they created this wind shear and detection avoidance system, which is today pretty, pretty gnarly. Uh, it's, I mean, this thing is, this is some good stuff. And I'll show you a picture of what it looks like here in a second. 94, so you can see the progression. Ground-based radar. So remember when we looked at those RD88s, those big golf ball-sized things that are up on Saddleback Mountain locally, right? That was one of them. That's Doppler. And the second thing that they did was they had terminal radar, or terminal Doppler, that was installed in about 24 airports across the country. That still exists today. And what those do is they can not only see the thunderstorm, but they can kind of parse out, uh, differences, uh, as specific as wind speeds, like right when they happen. And then they can issue, uh, wind alerts, like immediately, which is pretty amazing. So that coupled with the information that you get in the cockpit, which I'll show you here in a second, is some pretty powerful, uh, pieces of technology to keep people from this type of accident in the future. And in 96, of course, uh, airborne wind shear detection was created. And as it progressed, uh, it turned into what you see here today. So this is just an example of what it looks like in an aircraft. Uh, this, this is what's called a wind shear caution. And if you look at, if you, if you're not used to glass, you kind of have to adjust. There's a lot of, a lot of crap on the screen, right there, right? Um, but the middle portion that's colored, uh, with blue on the top, brown on the bottom, that's your attitude indicator. And above, like, right in the center, if you work, work your way straight up, you'll notice that there's a little numbers on the side. In this case, there's a 10. So where that 10 is located is a line, meaning 10 degrees nose up. And it has eyebrow lights. So those little, like feathers that are sticking up, those are the eyebrow lights. And it tells you, in this case, it's a caution. And with it being a caution, it now basically tells the pilots, it's time for you pilots to make a decision. Do you go around, or do you continue? Because you know why this caution is generated. That's important. We used to get this a lot going into Colorado Springs, and it would be a typical positive, uh, uh, performance that we were getting. We knew why we were getting it. And most of the time, we would just say, continue. If it was, uh, a big enough difference, we'd most likely go around, because, hey, we all want to live to fly another day, right? Now, who cares if we have to go around? We use a little bit of gas, and, uh, we give it another shot. Hopefully, it's just a gust that happened temporarily and won't be there again. And then if it doesn't work out the second time, it's like, you know, we're out. So that's the caution. It's, you have to make a, that's the heads-up, and you have to make a decision. The next one is called a warning. And with a warning, that's like, okay, they put it in red, saying, guess what? This is bad. And it's right around the same place, but you notice that the line is a little bit lower. It's in red. It shows the same kind of eye lights, but it's configured just a little bit different to be more prominent on that screen. It also makes a lot of things on the pilot's display. It, it reduces the intensity of everything else, so it focuses, allows you to focus directly on those eyebrow lights. And what that is, is as you're flying the aircraft, and you get into a wind shear warning scenario, you immediately go around. The autopilot is automatically disconnected. So you're flying the aircraft, and you pitch the nose up till you meet that eyebrow light, that bar. So you just pitch it up till you hit that, and you just hold it there, because that's your maximum angle of attack that you can achieve based upon your power, all that kind of stuff, because the computer's reading all the data as you're going through the wind shear, and it makes sure that this is the best, best angle of attack to give you the best climb that's going to get you out of this or keep you from hitting the ground. That's super important. So, in other words, if they were able to do that or see that in the L-1011, they could have immediately pitched up to this attitude and held it and had something to focus on to avoid hitting the ground, which is the way they train today. Um, and I was able, as an example, to get out of this same scenario flying a, a Caravan, which only has 675 horsepower versus, you know, 15,000 pounds of thrust, and, uh, you can still pull it off. So pretty amazing. I did crash, by the way, the first time they did it, because they didn't tell me they were doing it, and I just got hammered, and I turned into, I think, a bug on the ground. But using the proper techniques today, you can pull it off. Um, I do have a video that I'm, I'm going to show you here in a sec. Uh, luckily, in, in Tuesday's class, we had someone who could speak Portuguese and actually told me what the pilot was saying. So for what, four or five years, I've used this video. I had no idea what these people were saying, except for the occasional English word that would come out. So I go, oh, yeah, now I get it. Um, which was a lot of fun. So the word, by the way, uh, that he does say repeatedly, the captain says repeatedly, is essentially, uh, don't change the configuration, or don't change the aircraft. What I want you to be able to see, before I start, is take a look at, so you get an idea of what you're looking at, right? So you can see the captain, uh, on front of his screen. He's got two screens. Two main screens. On the left-hand side is his pilot's flight display, which is what you use to fly the aircraft. And on the right-hand side, with all those colors on it, that's the multifunction display that you use for radar and navigation and all that kind of good stuff. So in combination between the two, you should be able to get to where you want to go. In this particular case, it is showing the radar. So, uh, if you look closely at the radar, you can notice what direction he's going. You're at the very bottom of that screen is where you're represented, which you really can't see it, uh, but you're going towards what's in front of you. So do you guys remember, remember when we were talking about the different colors of a thunderstorm that are represented on the echoes that you receive when you're looking at them? Do you remember what those colors mean? The, the green, yellow, and the red? Yeah, you fly into red, doesn't take the, it doesn't clean it. Doesn't take the bugs off. It takes the wings off. So I'm assuming, uh, it's, it's an assumption, but it is probably a good assumption. They're prepared to land. So, if you look a little bit further over on the panel, you'll see three brightly lit up green lights. That represents the gear. In other words, the gear is down. They're ready to land. They're well below maneuvering speed of this aircraft. So whatever happens as they go fly through it, there's a really good chance that the airplane will, will weather, you know, it'll, it'll be able to take it, uh, because they're well below maneuvering speed, so they won't overload or go over the load factor of the aircraft. So that should be okay. Um, but as we watch through, you'll see a couple things happen. You'll see, of course, the captain immediately shove the thrust all the way forward, which was not done in the original accident. And he will give max thrust. He'll immediately pitch the aircraft because he'll have an indicator, which you really can't see, uh, which is those eyebrow lights, which he'll be able to, you know, make get all the way through that. And then eventually, the computers are smart enough. Actually, the eyebrow lights will disappear when you're out of the windshield. They'll just disappear. You just continue to fly the plane. When all that disappears, then you start to configure the aircraft. In other words, pull the gear up, reduce the flaps, all that kind of stuff. And then you just do a regular go-around, essentially. But before you do that, whenever you get into a scenario like this, you do not touch anything. You just fly the aircraft. And that's what you're going to see this, this guy do. Uh, it's, it's really cool. So here we go. Go ahead, firewall. That's 15, 15, five F.
All right, so there's quite a bit of stuff going on there. Uh, hopefully I explained it so you kind of understood what was happening. Uh, there were a couple of red lights that were blinking on the dash. That was essentially telling whoever was flying the airplane that you're, you are now overpowering the engines. In other words, you put too much power in, which is okay, because right, this is an emergency. Uh, what will happen to the airplane after this? So after they come around and they land, um, the airplane's engines will have to be inspected because of the additional power that you put into the system. We'll just keep talking about microbursts and, uh, in this case, this is a great study slide, by the way, where it talks about what a micro, like what happens inside the thunderstorm that causes all this stuff to happen. So you have really dry air that goes into the thunderstorm, you get a lot of evaporation, and a lot, a lot of stuff happens, right? So you get a lot of friction and thunder and lightning and all that kind of stuff. But eventually, what happens is it starts to affect the buoyancy within the thunderstorm, and then it just, it just all starts to come back down. So most microbursts are, uh, not as wide, uh, as you'll see in, in a video coming up, uh, as the, the total kind of deluge that's coming out of the bottom of it. So 2.2 miles or less. It was mentioned by the guy who did the, the, uh, tornadoes, right? Mr. Fujita, who actually coined the term microburst, which is pretty amazing. So I guess if you study thunderstorms, you start seeing stuff like this, and that was, that was, that was definitely his life. So, uh, with a microburst, this hopefully will help you visualize a little bit better. But just keep in mind, though, when a microburst happens, it doesn't always happen straight down. It can come down on an angle, which you'll see in a video here in a second. So keep in mind, even though this is kind of the, the perfect scenario, uh, uh, just, just know that, of course, it can come out on different angles because it's wind, right? It can kind of do different things. Um, anyway, you can see how the core comes down, it starts to spread out, creates that vortex ring. It's that vortex ring that your airplane will start to, uh, uh, be affected by if you're low enough, let's say going towards the airport, like the L-1011 was. And as you can see, you'll start to get a headwind as you first go towards it. That gives you extra performance. Uh, your airplane will start to climb, uh, on, on no reaction of your own. If you change nothing, and all of a sudden you get an increase in airspeed, you will get more lift on the airfoil, so it will climb even if you, if you do nothing, it'll just climb. So you get a positive report, uh, performance. Then, of course, it goes negative when you start to get pushed down. That's one. And then it even gets worse because when you get through it, you think, yes, I'm through the bad stuff, and you get a tailwind. And the effect of a tailwind, of course, is reducing your performance significantly, changing your angle of attack, which means your angle of attack gets greater, and you get closer to or exceed your critical angle of attack, and potentially could stall the aircraft, which is essentially what happened to the L-1011. It didn't have the lift to be able to get out of it, or the altitude to be able to, you know, get the speeds back up so it could fly away. Lot of, lot of complexity there. So what I'm going to show, it's a real brief video on a microburst itself. It's kind of cool to be able to see this so you can visualize it. And of course, just remind yourself, never fly underneath a thunderstorm, because this stuff. Watch how fast the, the rain starts coming out of the bottom of this. So if you're just kind of cruising along in your 172 at 100 knots or whatever, right? All of a sudden, this can happen. So it's kind of an eye-opener. So, so you check it out.
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Photographer and monsoon chaser Brian Snider was taking time-lapse footage of a storm in the Tucson area when he captured this incredible weather event, a wet microburst. Microbursts affect an area of no more than two and a half miles across, and they occur when a cooled, heavier column of air sinks rapidly in the middle of a thunderstorm. As the air hits the ground, it spreads out with great force, often generating winds of over 150 miles per hour. In the case of a wet microburst, it also brings crashing rain, often described as a rain bomb.
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Thunderstorms are frequent and quickly forming at this time of year in Arizona, but to capture a microburst so vividly was a special [Music] event.
Right, this is a study, study slide for you, showing the differences between a wet microburst and a dry microburst. You think, well, dry? Well, of course, if it's a thunderstorm, it can do all sorts of stuff that you didn't anticipate. So to look at what a dry microburst looks like, I have a couple of pictures. First, I'll have a description, uh, which shows the thunderstorm in the top, uh, graphic, and it has virga coming out of the bottom. If you haven't seen that term before, it's essentially rain that starts to fall out of the thunderstorm, but it's so hot, it evaporates before it has a chance to hit the ground. So, uh, you'll see it quite a bit as you start to fly across the, the Midwest, and, uh, or just the West towards the Midwest, you'll see virga coming out of the bottom of thunderstorms, and it's really interesting because it's just like, it's like a curtain that just comes down and just stops. H, which is crazy. But you can still get the microburst out of that thunderstorm, it just doesn't have the moisture content. Just so you'd be able to see it. So you can see the vortex ring, just like you get in the wet microburst. And this particular case, we have one that's shown, uh, down at the very bottom, that shows it like in the middle of a field, which is pretty handy. Or you can see the vortex ring portion, but you can't see the rest of it, of course, because there's no moisture. So the terminal Doppler weather radar that we talked about earlier, along with the bigger Doppler radar systems, but they can detect these kind of microbursts and be able to give a heads-up right away to not only ATC in the tower, but also to the aircraft by issuing a warning, which is nice. Um, so the combination between the two, uh, works to keep things pretty safe. They also have, if you want to look it up later on your own time, Garmin has, it's called a GWX 80, which is the Doppler weather radar system that you can actually install in an aircraft. So you don't have conventional radar anymore, and, or just digital radar now, you will have Doppler, which is pretty amazing stuff. Um, so they do have a video on that site for the Garmin GWX 80 Doppler radar, uh, which is actually a really well-made video. Gives you a little idea of how that system works, which is pretty neat.
All right, so wind shear, as we kind of move on. This is pretty typical of the wind shear that we get exposed to here in Southern California, where if you can, if you look at that chart above, shows a, what a Piper, whatever it might be, I think it's actually Denver Airport is what they're trying to imitate in the background. But it shows the altitude of the aircraft, right? So it shows the ground level, and then all the way up to 300 feet AGL. And you can see the differences from a 30-knot headwind as it descends towards the ground to eventually zero, or in the, well, it goes down to two knots. So you have a 28-knot difference from 300 feet down to the ground, which is very significant. Now, for those of you that are flying right now, what can you tell me? Let's say if you're doing an approach, you're probably somewhere around 65 knots, right? If you, what, what's the stall speed of a Cessna 172 or whatever you're flying in a trainer? Just, just, what's a generic stall speed for, in this case, you're configured to land, right? So that'd be a dirty stall. There you go. 40, 44, it's kind of the number. All right, so when you're coming in for a landing, and you're focused on making sure that you have your approach speeds correct, right? So let's say you are continuing to descend towards the runway at 30 knots, 300 feet, sorry, AGL, you're most likely on final. So you start your final with 30 knots of a headwind, and as you descend at maybe 500 feet per minute, right? You're going to go from, uh, 30 knots to two knots. So you're going to lose straight off your airspeed indicator. It's going to go from 65 knots, let's say, if you just lose 20, right? You're down to 45. It'll actually go lower. By the, if you're not paying attention, you will stall this aircraft if you don't do something about it. So that's the, the, the danger of wind shear, especially in this case, low-level wind shear, because it can happen very quickly over a short period of time. And if you're not paying attention to your airspeed indicator and you don't see it, all of a sudden you'll hear the stall warning horn, and you'll be like, well, what happened? I don't know what happened. So it's important as pilots to get in, kind of, the habit of just glancing at it every once in a while as you're continuing on your approach. And if you notice a big change in your airspeed indicator, in other words, if you're 65 knots, you notice it drops 10 knots, like down to 55, you're like, what? Right? It potentially could be wind shear. And a lot of times you can't see the wind shear. So it'll be a different air mass, almost like an inversion. So you'll have one, uh, area of faster moving air that's above, which would be above 30, uh, 300 feet AGL, and then you have the other part that's closer to the surface that's affected by friction and some other things that's slowing the air flow down, reducing your airspeed in your aircraft. So instead of being caught off guard, just glance at it every once in a while as you're doing the approach, and just be aware that this stuff could happen. If you do hear it or experience it, because you're the first one to receive that wind shear, make sure that everybody knows by telling air traffic control, and they usually keep a wind shear alert active for about an hour after it's been first reported. Um, most of the time, other pilots, especially at John Wayne, where you have, you know, the bigger guys coming in, they'll be able to verify that as, as it starts to go away, which is nice. But in this case, uh, wind shear can be both horizontal and vertical. And we kind of already talked a little bit about the vertical, right, as far as the wind shear. And this is more of the horizontal component of it. And this is caused by usually, uh, a different air masses on top of each other, or things like inversion layers. And we do get this in Southern California every once in a while, and you need to be careful when those kind of scenarios happen. Um, typically in the fall and the spring is right around when stuff like this starts to happen, because we get more volatility, if you remember during these seasons of the year. All right.
Um, let's see. So causes of wind shear. So, uh, it just discussed a little bit about this, but, uh, generally it's that, remember that boundary layer I talked about, that under 2,000 feet, all right? So kind of think about that when it comes to wind shear. So if you're, you find yourself 2,000 feet or below, start, just, it's one of those things that you just kind of keep in your back pocket that you're aware of, that it could potentially happen. Can be associated with low-pressure systems and fronts as they start to move through. So, so different air masses that might be competing against each other. Thunderstorms, pretty obvious where you get wind shear from them, right? The jet stream, which we'll touch on here in a second. Inversion layers, which I've discussed. And then, of course, local topography, which I'll actually show you, uh, some good visual pictures of both Catalina and Big Bear as far as how topography will affect wind shear. So low-level wind shear. Here's a chart that you can use to be able to recognize the severity of the wind shear. So when you're looking it up on some of the, you know, you're getting your pre-flight weather, or you may be able to download some of this stuff, it's kind of nice. Um, but it's any, they define it as anything below 2,000 feet, which is that kind of that boundary layer area along the path on, as far as your, like your landing path. So think about, you know, basically when you get into the pattern, and you're kind of going through the, you know, the cross from the base, and of course, the final. So sudden decrease, of course, is very bad, because of course, it's going to get you closer to the stall. And then, of course, it can happen the opposite direction too, that you need to be aware of where the wind shear actually goes up versus down. So keep that in mind. It doesn't always have to just go down, but typically it's, uh, when you're coming into an airport or landing, you have the wind at your nose, right? And as you continue to drop down, at usually what ends up happening is you get a decrease in your, in your wind speed. Here's an example of an aircraft that was taken off and climbing out. So it doesn't always have to happen, of course, when you're landing an aircraft, it can happen when you start to take off. So this person's climbing out of the runway, or climbing away from the runway, and as they continue their climb, they notice that their airspeed starts to drop. Luckily, in this particular case, you know, you just lower the nose to increase your airspeed to compensate for the loss of airspeed you got from the wind shear, and you just accept the fact that you're not going to climb as well. Um, but in this case, he said from the surface to 3,000 feet, so that's pretty significant as far as a wind shear and changing direction of wind. So just be aware of it, which is important. So before we move on, we want to make sure you get a quick quiz to see if you remember some of this stuff. And, uh, we'll, this, this one works directly on your judgment. So here's the question. So I give three different answers, so you get to pick which one you feel is the best answer. So here is the first one, right? Here's the second one, and here's the third choice. We go. Uh, before I start in this, I do have a reference that if you guys want to look it up later on YouTube, it's kind of pretty cool. But it's, it's, it's a Boeing 777 wing test. So if you have Boeing 777 wing test in the, in the guide, you'll, it'll probably pop up a few videos, and it's pretty impressive where I used to show it in class, but it takes a lot of time. So, um, anyway, it shows how much stress a wing can take before it snaps, which, you, as, as a passenger looking out on the wing, that's pretty comforting, because when you see how far this thing has to get jacked up before it breaks, and then, of course, now you're flying in a plane, you look out and you see it moving a little bit, you're like, that ain't nothing. So, uh, it's pretty impressive how much it takes to actually break one of these wings. It's, it's amazing. So anyway, that is totally related to turbulence, because its ability to take turbulence is important, and we'll talk about the different reasons why turbulence could be good or bad. So what is it? It's that, this, it's that turbulent motion. So you have differential heating on the surface, which makes air travel upwards at different rates, which, of course, gives you that bumpy feeling as you're flying along, right? So aircraft design is very important, because they all have different load factors of what they can handle. And the last would be the most important, which is what you will have an effect on the aircraft and how it handles during turbulence by how you respond to the turbulence. So I love using the example of white water to help.
You understand because a lot of people can visualize, you know, being stuck in white water. Sometimes you just, you can't fight it. You just let it roll, and when it starts to chill out, then you can do something about it. Okay. Uh, in the case of a pilot's response, if you're trying to hold an altitude in really turbulent conditions, you're going to lose. It doesn't work very well because you're fighting it the whole time. The only thing you do is you get sore arms and biceps from trying to push and pull that yoke, uh, trying to keep it at the correct altitude. And you're also stressing the aircraft out. So if you just kind of relax, let everything happen, maintain a level aircraft, in other words, you know, the pointy head forward, keep it level. That's your whole goal in really crappy turbulent conditions is to maintain control of that aircraft. By doing that, if you don't fight it, you're actually, the altitudes that will change is not going to be significant enough. And you can also, if you're under control by ATC, just let them know. And, uh, you know, they're inside a room, right? In a big dark room with all these screens and, and so they're more than happy to say, "Oh, okay, no worries. Uh, just be aware there's other people around your, whatever the case might be." But they'll accept the fact that you're going to get bounced around along with everybody else, most likely, that's around you also. So you can ask them for like block altitudes or, or whatever. So, uh, just as you respond to it, you can actually make the turbulence worse than it is by trying to fight the turbulence instead of just kind of going with it.
So there are three different types of, uh, turbulence. So the first one is low turbulence, which is pretty typical. It's all that stuff you get when you're trying to fly like to Vegas, uh, as you're cruising across the desert, usually in the early afternoons because either you, you know, you got off work or, or you couldn't leave in the early morning or late at night, you'll start to get a lot of this turbulence. The only way to get away from it, of course, is to climb up an altitude. So you get high enough, right? So you get to that, that equilibrium level, right, where, you know, that air mass that was traveling up, which kind of lost energy, starts to come back down. If you can get above that, right? Like above the cloud layer or above that layer, it'll be nice and smooth. Unfortunately, sometimes it's a little bit higher than your aircraft is capable of of getting to. And, uh, you just have to slow the thing down and just accept the fact you're going to get bounced around. So thermal turbulence is probably one of the biggest things you'll deal with, especially in Southern California, uh, as you're flying in the pattern or going, uh, pretty much anywhere, especially during the summer.
Summer. Mechanical turbulence is a big issue also. So we had talked about, uh, let's say, you know, uh, orographic lifting, that kind of stuff. In this case, we have mechanical, uh, turbulence, which is kind of related to it. So as the air flows, let's say, uh, from left to right, as we're looking at that picture of Big Bear, so as it starts to move from the left and the right, don't forget this is a ridge line inside a valley where this airport is located. So as the air is traveling over the top of that ridge line, just like that picture we had earlier where it showed the clouds curving over the top of the ridge line, that Kanda effect, you get the same thing here. So as the air tries to hug, unfortunately, it's trying to hug the, the, the curvature of the ridge line, but it's also getting messed up because it's hitting all the pine trees at the same time, too. So not only is it coming down and giving you a crosswind, it's really, it's a messed up crosswind. And you can actually sit on the ground in Big Bear and watch the wind socks move around because of that kind of reaction. Other things you need to deal with in Big Bear, in this particular case, if you're going directly into the wind, in this case, uh, are the, the, the trees that you're going to have to fly over in order to get to the runway. So you'll get mechanical turbulence of air traveling down the runway and then trying to go up and over that ridge, uh, of trees, uh, both, both the first one and then the second one that's in that neighborhood. And typically, in the case of Big Bear, it has a steeper, uh, descent. Actually, both Big Bear and Catalina have a steeper descent just for this reason, to avoid some of the mechanical turbulence that you'll get as you approach the runway. So, uh, we can obviously see in Big Bear where it can be an issue because of course it's in the mountains. Catalina, on the other hand, might not be so obvious. But if you look at Catalina and visualize the, the wind coming straight down that runway towards you, right, because you always land into the wind, what happens to the wind as it hits that ridge, right? You would think, well, it's going to follow the Coanda effect, right? So it's going to go, drop down on that cliff down towards that road and continue to drop down. That's fine. But don't forget it's an air mass. It's not just the air at the, the surface where you, you know, your tires touched down. It's actually the whole thing is starting to go down. And that's why you have a steeper approach because you're trying to avoid that burble that happens at the end of the runway as you descend towards Catalina. So keep that in mind during your checkout and recognize that you have a steeper descent to avoid, uh, getting into that. So, and you'll notice it when you go in to land there. It's pretty cool. Um, but be very aware of it because there are people that have kind of packed it in and hit that cliff because as they get closer and closer to the runway, there is an illusion at Catalina, which is unique because you feel like you're higher than you really are. And that's why it's really important to know how to read the visual indicator on the airfield to keep your glide slope a little higher. It will feel uncomfortably high when you first fly there. So, and when you're following it, you're doing everything perfect, it just feels a little weird because you do have a steeper approach. But if you're, if you don't follow it and you descend on a flatter approach, unfortunately, if you get caught into this wind, it can kind of pull your aircraft down towards the surface, which of course, it, depending on how hard the wind is blowing, it could be, you know, bad news. So keep that in mind and, uh, know that mechanical turbulence is important to understand and think about the environment, uh, that you're flying in.
All right, so that kind of segues at this point to, uh, mountain waves. So we also need to be, I consider mountain waves quite a bit in Southern California because we're surrounded by mountains. And, uh, these are probably more prevalent over the Sierras than they are in our local mountains, uh, because of typically where the winds are coming from. You know, typically our winds are coming from the west to the east, and of course, the Sierra Nevadas go, you know, fairly north-south. And so of course, it's just going to go straight over the top and create these mountain waves, rotors, and all sorts of nasty stuff. So, uh, you can see in the picture above, which is most likely in your textbook, as the closer it is to the mountain, the worse the, the turbulence will be from the, the, the wind itself. So high velocity wind going over the top, usually around 30 knots or greater, will cause a lot of this nasty stuff to happen. You can see the swells. If you look at them as swells, as the air is traveling over and starts to undulate like that, um, they, they're more abrupt down towards the surface versus as you get up higher in the, uh, atmosphere where it kind of chills out. Think of like water going over the top of a rock. Uh, when the water level is low, there's a lot of white water and turbulence, right? But if you were to raise that level up of the river, of course, it's just going right over the top of the rocks and it's nice and smooth. So same idea here, the more volume you have above wherever the air is blowing, the smoother it's going to be.
All right, uh, good indicator of mountain waves, of course, you'd be able to look up. Let's say you're in Mammoth and you look up and you see clouds like this, you know that there's a mountain wave. And you don't want to fly in mountain waves. It's, it can get pretty nasty. So, uh, we'll see more pictures of lenticular clouds, which is kind of those clouds that are in the middle of that graphic at the top. Uh, we'll see, show you some better pictures of those that happened, uh, from the Sierras.
So the, the jet stream is also another place that we get wind shear. Uh, it is in the upper level. We know it's between two cells, right? The, the polar and the Ferrell cell. And when there's a big temperature differential between those two cells, we get a faster jet stream. And if there's shear within that jet stream, because we now know that it doesn't, it's not just one continuous loop, it can get broken apart or twist and undulate and stuff, right? So when that happens, you can get some pretty nasty, uh, shear associated with it. But understanding the jet stream, why it's there, and how fast it can get could be a plus or a minus to you as a pilot, right? Because we can go faster. The drawback to it is, of course, is clear turbulence because up at that altitude where that normally is, there's usually, you know, there's not a lot of weather that you're looking at. So when you get into the turbulence, it's like, whoa, you know, your, your airplane just drops like 500 feet per minute in a heartbeat. So all your stuff starts to levitate, you know, "Oh, look, there goes my Coke," you know, that kind of stuff. So usually you can't figure, you don't know when cat's going to happen. When it happens, but I will tell you that most of the dispatchers and the weather today can anticipate clear turbulence. So you can completely avoid those places altogether. It's pretty good.
So to give you a little bit more of a visual of what the jet stream looks like, I use this slide to help those that might have trouble visualizing what the jet stream looks like. And of course, this is crushed from Finding Nemo. And in this case, for them to travel long distances underneath the water, well, they weren't in the jet stream. So maybe as we're, we continue this lecture, you'll think about what it's called, uh, in the ocean, uh, but it's a great way in order to enhance some of the, the performance that we get in aircraft if we're going in the right direction. So if you guys remember, hopefully also, what the top is to the tropopause? That's my little side question. Uh, what altitude is, as we continue talking, uh, what altitude is the top of the troposphere or the troposphere where the tropos starts? So go ahead and put that down there if you can think of it as we continue to talk about, uh, the jet stream. Clear turbulence, like what I mentioned before, uh, there is a definition to it. And the definition, according to the FAA, which you'll see on FAA exams, is above 15,000 feet. So normally clear turbulence is associated with the jet stream. And the jet stream is usually, it gets as low as like 25,000 feet in the winter. And then of course, it goes up during the summer, uh, as far as altitude. If you get something above 15,000 feet, you can usually figure out what it is if you're not in the jet stream. But every once in a while, you can get, for whatever reason, could it be, you know, the mountains that you're flying around or whatever the case might be, it's clear and all of a sudden, boom, you get hit clear turbulence. If you can't explain it, that's what it is. And that's what you tell your passengers. Um, anyway, uh, you don't want to get hit by clear turbulence if you can avoid it because it can get pretty nasty, especially if you don't have your seat belts fastened. So that's my other tip for the day. Whenever you're flying in a commercial jet, please keep your seat belt fastened because you never know, it can just happen. So doesn't have to be tight, just relax and just to keep, it's basically to keep you from whacking your head on the top of the ceiling, which is very uncomfortable. And Jeff got a right, 36,000 feet, which is the average for the top of the trop, troposphere.
All right, uh, let's see. So I had asked this question earlier when we were talking about Grush. So the jet stream is a high velocity in the air. What is the ocean's equivalent of the jet stream? What, what's the name of that? And this is totally aviation related. When you hear it, you're gonna go, "Oh, I get it." Gulf Stream. You guys know what a Gulf Stream is, right? So there it is. This is the chart of the Gulf Stream. It's not an older chart, of course. You can see, uh, by looking at the kind of broken out part in the upper left where it actually goes around in a circle. So this is, of course, how they used to sail way back in the day. And somebody figured this out, which is pretty amazing. So the Gulf Stream, right? Gulf Stream. They, they're now at like the Gulf Stream 800 is the newest one. So, and you guys all need a Gulf Stream 800. I've seen them and, uh, they are pretty, pretty awesome. So there's some trivia for you. Feel free to use that, uh, whenever you get to your next social gathering and, uh, whatever.
All right, measuring turbulence. This is super important because this chart includes some symbols. And these symbols, you will see again in my tests and with tests from the FAA. So, uh, being able to understand the difference between light, moderate, and severe. When you get to extreme, there is no indicator for that because it's that bad. They figured, well, no one's going to make it through it, so why put an indicator there, right? So turbulence is highly subjective because it's based upon the aircraft that you're going to be flying. So 172s versus a Triple 7 are going to experience the same turbulence in different ways. So, uh, best indicator, of course, is how you feel, which is why this chart is separated into two columns after they show the symbols showing the aircraft's reaction to it. In other words, what happens to the aircraft, choppiness, you know, bouncy, or completely lost control versus the reactions inside the aircraft. So make sure that you focus on these symbols because you will see them again. And go ahead and use this chart, and it works out really well later when you give pilot reports to be able to be familiar with what is light turbulence, what is moderate turbulence. I mean, you can think of like light chop, uh, when they mention that, it's pretty easy to figure out, right? It's just like light chop. Um, and then of course, there's severe, which, you know, when they put a cone head on top of, you know, a big mountain, it's probably not very good. And if you visualize when we start to see, I'll show you here in a second, um, what it looks like when you get, uh, those lenticulars over the top of the mountain, you can visualize that when you look at severe, because that's also where you would get severe turbulence if you flew over the top of that mountain, um, when the wind is going that fast.
So to give you a better visual of what it's like when you get some fairly bad turbulence, I'm going to show you a video. This is also probably one of my favorite videos. It makes me laugh every time. This is getting serious. You can hear the cutlery splashing around. Oh, okay. As you can see, my friend here, hi. It's, oh, oh my God. This makes a roller coaster look like nothing, right? As you can see, holding on to everything for dear life. This is bonkers. Oh, we know everything's spilling. Oh, well, Magic Mountain, who needs the 60th anniversary of Disney? Oh, stuff went in the kitchen. That's all gone. Oh, what do you think it is? I could only assume we're going over the Rockies and the turbulence is out of control. Stuff's flying, plates and stuff are smashing around in the kitchen, and we're up front. Imagine what's going on in the back of the bus. All right, it's co. Okay, it was almost calm there for a second. Hold on. This is, this is insane. This is good. This is, this literally is like an off-road adventure at 38,000 feet. This is crazy. Having fun. [Music] Yet. Doesn't look like we're over the Rockies. Oh, yeah. It turns out we're not over the Rockies. But oh, all right, all righty. How bad do you think that turbulence was? So it wasn't severe, uh, the only reason why it wasn't severe is because you did not lose control of the aircraft. So that's why you have to take both into consideration. When you're talking about the passengers in the back, it's unfortunate that, uh, they, they're getting hammered in the back, uh, with, with that, and they only have one seat belt, which is the only thing keeping them like in their seats. Um, but, uh, in this particular case, you have to take both things into consideration. So, um, anyway, so in this case, we'll go ahead and get a visual of what some of the clouds we're going to look like as I'll show you a picture one in a second. Uh, so we have the Lee wave cloud, which is the lenticular, which looks like a little hat or a long lens or however you want to describe it. Uh, but it is part of the mountain wave where the air is starting to condense and then of course evaporate as it gets towards the other side as it's going back down, you know, and it heats up and the pressure increases. So, uh, there's the big difference. You'll see the rotor cloud that's at the very bottom, uh, typically is what you'll see. This next picture, you'll see a rotor cloud underneath a lenticular cloud. And, uh, that's where some of that severe turbulence will happen. Where's the picture? There we go. So you can see the lenticular cloud looks like a hat or a lens. Uh, the, the, all the, the other clouds that are surrounding it are the rotor clouds are associated with the high winds as it gets messed up as it goes around. I don't know if this illuminates or something, uh, up the Sierras, but it's some pretty, pretty gnarly stuff.
Another picture, uh, is this one. This guy takes some great photos. Um, but in this case, you can see multi-layers. So not only is the air traveling or undulating, right? There's different layers. So as you go up into the atmosphere, right? So some of the air will be traveling, let's say a little bit higher, it'll be traveling faster. So you, you might get more elongated, uh, clouds as you continue to go up higher in the atmosphere. So we can see this in the picture. It's pretty obvious that, uh, this is probably not a good place to fly that day. I can't imagine. Um, and then here's another picture where it actually has multiple lenticular stacked lenticular clouds all, all the way up. So if you're driving up towards Mammoth, you'd be driving underneath these. And they're not thunderstorms. These are just clouds that are caused by the winds. Can they create rain? Well, it's quite possible, right? So there's moisture in it and there's, it's always possible for the most part, though these are caused by the wind of the air condensing and evaporating. That's why they, they're kind of stationary, uh, as you drive underneath them. It's pretty wild looking. So it's kind of cool. Uh, so I like to finish this up with some mountain flying tips. I did quite a bit of mountain flying myself and these come in very handy and they do work. So in valley flying, like if you go into Big Bear, just be aware of when you're crossing over a ridge line, which will be pretty obvious the first time you do it, that you do it not directly, but on an angle, just in case you have to bail. You need to be able to know that you'll be able to maneuver the aircraft to be able to get out, right? And, uh, so that's very important. Uh, that's part of ridgeline flying. But also part of ridgeline flying is, uh, down at the bottom, which is kind of representing if you fly to Mammoth. If you go up the, uh, if you, if you go up like the Sanen Valley, go over the top of Fresno, and then pop over the top into Mammoth, this is what you're going to be flying over the top of. So be aware of the winds as they go over the top of the mountains and the fact that as you get on the other side, there potentially could be rotors as you descend towards Mammoth. So keep that in mind. That's another thing about ridgeline flying, which is important to know. So make sure that the winds are lower the day you fly, uh, to go up there.
Mountain passes. This can happen to all of us that are doing flight training and going out to Banning Pass. So it's a pretty, uh, common place for, for, uh, the instructors to send their students because it's usually that 50 nautical miles long enough to be get a cross country in. And, uh, in this case, as long as you're aware of the winds, and they usually talk to you about it, uh, because you're going between two very large mountain ranges and there's a low point where the, I think it's the 10 freeway cuts through down at the bottom of it. And, uh, I think there's actually like, uh, shopping, there's all stores and stuff down there too. But anyway, the important thing is to understand that's also the area that has all the windmills. And this is why, because the wind is constantly whipping through that valley and, you know, being able to turn these turbines, uh, but it also affects you as a pilot because you'll start to go in and you have wind coming from different directions. Can really mess up your approach. So keep that in mind as you're flying, uh, through that valley. And just accept the fact, anytime I fly through the Banning Pass, I just accept the fact, this can be bouncy. You know, if it's not, it's a bonus. But most of the time, it's probably going to be bumpy.