WEBVTT 00:00:16.610 --> 00:00:19.390 PHILIP GREENSPUN: We're going to talk about meteorology. 00:00:19.390 --> 00:00:25.240 So as pilots, we're just trying to understand the basics. 00:00:25.240 --> 00:00:27.280 And in terms of passing the exam, 00:00:27.280 --> 00:00:31.340 you don't need to be a physicist. 00:00:31.340 --> 00:00:34.210 You just mostly are trying to learn 00:00:34.210 --> 00:00:40.060 stuff that will help you fly within the VFR weather minimums 00:00:40.060 --> 00:00:44.230 and predict when those minimums aren't likely to be met 00:00:44.230 --> 00:00:46.990 or when there's going to be really serious hazards, 00:00:46.990 --> 00:00:48.550 such as thunderstorms. 00:00:48.550 --> 00:00:51.160 All right, this will be on the test. 00:00:51.160 --> 00:00:54.620 You have to memorize all of this. 00:00:54.620 --> 00:00:55.710 Well, you kind of do. 00:00:55.710 --> 00:00:57.530 Anyways, they want you-- 00:00:57.530 --> 00:01:04.310 you will have to learn some of this stuff for the exam. 00:01:04.310 --> 00:01:07.730 In reality around here, almost all airspace 00:01:07.730 --> 00:01:09.380 is at least class echo. 00:01:09.380 --> 00:01:10.680 That's controlled airspace. 00:01:10.680 --> 00:01:13.880 It means controllers could give you a clearance 00:01:13.880 --> 00:01:17.180 to fly on instruments and separate you 00:01:17.180 --> 00:01:19.340 from other aircraft. 00:01:19.340 --> 00:01:22.500 So they want you to be well separated from clouds, 00:01:22.500 --> 00:01:26.870 1,000 feet above, 500 feet underneath, 2,000 horizontally. 00:01:26.870 --> 00:01:31.700 That way, if an aircraft under IFR comes out of the clouds, 00:01:31.700 --> 00:01:34.550 there'll be some time for the two of you 00:01:34.550 --> 00:01:36.740 to see and avoid each other. 00:01:36.740 --> 00:01:39.960 You can see the weather minimums are different in class Golf 00:01:39.960 --> 00:01:41.150 airspace. 00:01:41.150 --> 00:01:43.670 And, actually, in uncontrolled airspace 00:01:43.670 --> 00:01:47.870 like up in Alaska, if you're flying on instruments, 00:01:47.870 --> 00:01:50.200 you don't have a clearance. 00:01:50.200 --> 00:01:52.170 So you'll say, well, how is that possible? 00:01:52.170 --> 00:01:54.462 You can be instrument rated, have an instrument capable 00:01:54.462 --> 00:01:57.633 airplane, and fly from airport to airport in the clouds. 00:01:57.633 --> 00:02:00.300 But the air traffic controllers, they can't give you a clearance 00:02:00.300 --> 00:02:03.450 and guarantee you separation from other aircraft 00:02:03.450 --> 00:02:04.830 because they don't have radar. 00:02:04.830 --> 00:02:06.288 They don't even have the authority. 00:02:06.288 --> 00:02:08.610 It's not controlled airspace. 00:02:08.610 --> 00:02:11.190 I've done some flying up there in little airplanes, 00:02:11.190 --> 00:02:13.780 and you have to be very patient. 00:02:13.780 --> 00:02:15.780 Another interesting thing to notice about this-- 00:02:15.780 --> 00:02:17.850 we'll talk about it more again later-- 00:02:17.850 --> 00:02:20.250 is notice how class Bravo airspace 00:02:20.250 --> 00:02:25.140 has lower minimums than ordinary class Echo airspace. 00:02:25.140 --> 00:02:30.237 So we have to be 1,000 feet from the clouds here. 00:02:30.237 --> 00:02:32.070 Here we just have to be clear of the clouds. 00:02:34.860 --> 00:02:38.340 Why are the minimums reduced right around Logan Airport 00:02:38.340 --> 00:02:42.558 and JFK and LAX than they are-- 00:02:42.558 --> 00:02:44.808 AUDIENCE: Because everyone's in contact with the tower 00:02:44.808 --> 00:02:47.178 so the tower knows where everyone is. 00:02:47.178 --> 00:02:48.720 PHILIP GREENSPUN: Yeah, great answer. 00:02:48.720 --> 00:02:51.720 So her answer is that air traffic control 00:02:51.720 --> 00:02:54.840 is in contact with everybody in class Bravo airspace 00:02:54.840 --> 00:02:56.183 and knows where they are. 00:02:56.183 --> 00:02:57.600 And in fact, they're on clearances 00:02:57.600 --> 00:03:00.042 in class Bravo airspace, so they're being told what to do. 00:03:00.042 --> 00:03:00.750 Fly this heading. 00:03:00.750 --> 00:03:01.860 Fly that heading. 00:03:01.860 --> 00:03:03.490 Maintain this altitude. 00:03:03.490 --> 00:03:04.740 Great answer. 00:03:04.740 --> 00:03:07.260 All right, so how do we know if the weather minimums are 00:03:07.260 --> 00:03:09.120 going to be maintained? 00:03:09.120 --> 00:03:12.010 Let's talk about weather theory. 00:03:12.010 --> 00:03:14.670 So raise your hand if you're a science major here 00:03:14.670 --> 00:03:16.570 as opposed to engineering? 00:03:16.570 --> 00:03:18.210 Where are the smart scientists? 00:03:18.210 --> 00:03:21.660 All right, Francis. 00:03:21.660 --> 00:03:24.930 So the science approach to this task 00:03:24.930 --> 00:03:34.160 would be to say if we could just assume that humans are only 4 00:03:34.160 --> 00:03:39.970 inches tall, then we could build some really great aircraft. 00:03:39.970 --> 00:03:42.120 And we'll get into that in a moment. 00:03:42.120 --> 00:03:43.100 Just think about that. 00:03:43.100 --> 00:03:46.570 If you're a scientist, how much flexibility 00:03:46.570 --> 00:03:50.440 can you have compared to being an engineer? 00:03:50.440 --> 00:03:55.960 All right, so let's look at the atmosphere that we do have. 00:03:55.960 --> 00:03:59.920 Mostly, the troposphere tops out around 40,000 feet 00:03:59.920 --> 00:04:02.140 according to this chart. 00:04:02.140 --> 00:04:05.200 And that's where most of the water vapor 00:04:05.200 --> 00:04:08.500 is and, therefore, most of the weather, also 00:04:08.500 --> 00:04:11.650 the higher temperatures. 00:04:11.650 --> 00:04:16.630 You can see it actually does get warm again way up high 00:04:16.630 --> 00:04:18.940 in the thermosphere. 00:04:18.940 --> 00:04:21.500 This is in kilometers on the left. 00:04:21.500 --> 00:04:25.550 So you can see that part of the earth that we're flying through 00:04:25.550 --> 00:04:30.280 is really just, I don't know, probably around 20 kilometers 00:04:30.280 --> 00:04:32.110 and down. 00:04:32.110 --> 00:04:32.990 What did I say? 00:04:32.990 --> 00:04:37.690 Said he could go up to 65,000 feet in this F-22. 00:04:37.690 --> 00:04:40.820 So that's what? 00:04:40.820 --> 00:04:43.830 That's a little over 10 miles. 00:04:43.830 --> 00:04:47.110 Yeah, it's about 20 kilometers, somewhere in that neighborhood. 00:04:47.110 --> 00:04:49.850 Anyway, so not too many people are going higher 00:04:49.850 --> 00:04:56.370 than just the bottom 0 through 20 on this chart. 00:04:56.370 --> 00:04:59.580 All right, who's concerned about global inequality? 00:04:59.580 --> 00:05:02.140 Raise your hand. 00:05:02.140 --> 00:05:03.440 Awesome. 00:05:03.440 --> 00:05:09.930 Well, you'll be pleased to know that so is the FAA. 00:05:09.930 --> 00:05:17.550 And this figure here shows you why it's warmer at the equator 00:05:17.550 --> 00:05:19.130 than up at the North Pole. 00:05:19.130 --> 00:05:20.880 There's the same amount-- 00:05:20.880 --> 00:05:24.630 we're missing a little bit of tilt here, but that's OK. 00:05:24.630 --> 00:05:27.090 There's the same amount of incoming solar radiation, 00:05:27.090 --> 00:05:30.815 but it gets spread out over a larger portion of the earth 00:05:30.815 --> 00:05:31.565 up near the poles. 00:05:34.550 --> 00:05:39.350 All right, so this is where guys like Francis have it easy. 00:05:39.350 --> 00:05:41.510 If you want to understand something, 00:05:41.510 --> 00:05:46.670 you just say, well, you know, I've got an earth, 00:05:46.670 --> 00:05:49.400 and it's pretty much the same as the existing earth. 00:05:49.400 --> 00:05:51.810 It just doesn't have any water on it. 00:05:51.810 --> 00:05:54.800 And it doesn't rotate, and it's not 00:05:54.800 --> 00:05:57.270 tilted with respect to the sun. 00:05:57.270 --> 00:05:58.977 So now I'll do my analysis. 00:05:58.977 --> 00:06:00.060 And I'll publish my paper. 00:06:00.060 --> 00:06:02.640 And I'll get tenure, and your problem is solved. 00:06:06.520 --> 00:06:07.020 Let's see. 00:06:07.020 --> 00:06:08.270 What would happen here? 00:06:08.270 --> 00:06:11.700 In a non-rotating, non-tilted waterless earth, 00:06:11.700 --> 00:06:14.700 it would get hotter at the equator, 00:06:14.700 --> 00:06:17.340 and the air would rise up from the heat. 00:06:17.340 --> 00:06:19.710 So we can see that here. 00:06:19.710 --> 00:06:23.760 So we would have low pressure right there at the equator. 00:06:23.760 --> 00:06:25.850 And then the air would circulate up, 00:06:25.850 --> 00:06:28.736 and we would have high pressure up at the polls. 00:06:28.736 --> 00:06:31.206 Does that makes sense to everybody? 00:06:31.206 --> 00:06:32.760 All right, great, problem solved. 00:06:32.760 --> 00:06:35.160 We can go home. 00:06:35.160 --> 00:06:37.940 Unfortunately, as engineers, we have 00:06:37.940 --> 00:06:41.130 to deal with the real world a little bit more. 00:06:41.130 --> 00:06:44.540 So if we're spinning around the Earth, 00:06:44.540 --> 00:06:49.150 We're going to end up with these three cells 00:06:49.150 --> 00:06:54.220 and in each hemisphere. 00:06:54.220 --> 00:06:56.830 And in this case, you end up still 00:06:56.830 --> 00:06:59.140 with a low pressure at the equator. 00:06:59.140 --> 00:07:02.530 But then you get a high pressure with all the air sinking down 00:07:02.530 --> 00:07:03.700 here. 00:07:03.700 --> 00:07:08.440 And you get still low pressure-- 00:07:08.440 --> 00:07:11.770 you still get high pressure up at the polls and low pressure 00:07:11.770 --> 00:07:12.310 down here. 00:07:18.690 --> 00:07:20.200 See if I got that right. 00:07:20.200 --> 00:07:22.000 High. 00:07:22.000 --> 00:07:23.200 I should be high. 00:07:23.200 --> 00:07:25.725 It says high pressure at 30 degrees North. 00:07:25.725 --> 00:07:27.100 Oh yeah, high, high, that's good. 00:07:27.100 --> 00:07:29.260 And, yes, and low and low. 00:07:29.260 --> 00:07:31.480 All right, we got that right. 00:07:31.480 --> 00:07:34.626 It gets more confusing as you see. 00:07:34.626 --> 00:07:37.750 OK, so the circulation-- one thing 00:07:37.750 --> 00:07:39.400 that the FAA wants you to know is 00:07:39.400 --> 00:07:42.670 that it's heat exchange that drives the weather. 00:07:42.670 --> 00:07:46.120 So the weather is basically a function of the sun heating up 00:07:46.120 --> 00:07:47.080 the earth. 00:07:47.080 --> 00:07:49.270 And then it's not uniform, so the heat 00:07:49.270 --> 00:07:53.320 gets pushed from one part of the earth to another. 00:07:53.320 --> 00:07:56.890 And all of this unequal heating is 00:07:56.890 --> 00:08:01.060 responsible for the altimeter varying, 00:08:01.060 --> 00:08:04.000 for wind blowing around. 00:08:04.000 --> 00:08:07.540 Pretty much every phenomenon that is of interest to pilots 00:08:07.540 --> 00:08:12.730 is caused by heat trying to move from the hotter 00:08:12.730 --> 00:08:16.030 parts of the earth to the colder parts of the earth. 00:08:16.030 --> 00:08:18.020 We'll talk a little bit more about these. 00:08:18.020 --> 00:08:19.870 But notice there's parts of the earth 00:08:19.870 --> 00:08:22.520 that are windier than others. 00:08:22.520 --> 00:08:26.580 Unfortunately, we're in one of the windier parts. 00:08:26.580 --> 00:08:33.140 OK, so you also have to know as a pilot just what an isobar is. 00:08:33.140 --> 00:08:35.980 That's a line of equal pressure. 00:08:35.980 --> 00:08:37.130 And that tells you-- 00:08:39.700 --> 00:08:43.539 that gives you an idea of how the wind is going to move. 00:08:43.539 --> 00:08:46.770 We'll see that in a minute. 00:08:46.770 --> 00:08:49.600 The tighter the isobars, the more dramatic 00:08:49.600 --> 00:08:51.720 the pressure change in a region. 00:08:51.720 --> 00:08:53.330 And it's the pressure gradient force 00:08:53.330 --> 00:08:56.240 that's causing the wind to flow from the high 00:08:56.240 --> 00:08:58.610 to the low pressure. 00:08:58.610 --> 00:09:03.150 So you might think on this chart, 00:09:03.150 --> 00:09:07.460 for example, that wherever you see an L and an H 00:09:07.460 --> 00:09:10.370 that you would just draw a vector of wind from one place 00:09:10.370 --> 00:09:12.110 to the other, right? 00:09:12.110 --> 00:09:13.950 That kind of makes sense. 00:09:13.950 --> 00:09:19.410 However, there is Coriolis force. 00:09:19.410 --> 00:09:21.232 This is for Francis, the science major. 00:09:21.232 --> 00:09:22.440 Francis, what course are you? 00:09:22.440 --> 00:09:26.328 AUDIENCE: I'm course 9, so [INAUDIBLE].. 00:09:26.328 --> 00:09:29.250 PHILIP GREENSPUN: Oh. 00:09:29.250 --> 00:09:33.210 All right, so scientists wear lab coats. 00:09:33.210 --> 00:09:36.360 [LAUGHTER] 00:09:36.360 --> 00:09:40.980 Coriolis force is a fake news force formerly known 00:09:40.980 --> 00:09:42.194 as fictitious. 00:09:46.370 --> 00:09:49.820 So you can see they're throwing the ball straight. 00:09:49.820 --> 00:09:54.060 But because they're on a rotating platform, 00:09:54.060 --> 00:09:58.430 it's apparently curving. 00:09:58.430 --> 00:10:00.680 So camera is mounted to the ground, 00:10:00.680 --> 00:10:02.360 and we'll see the ball going straight. 00:10:05.870 --> 00:10:08.786 They're going to draw you a little dash line at one point 00:10:08.786 --> 00:10:11.040 so you can see the path is actually straight. 00:10:17.670 --> 00:10:18.815 So the ball has an inertia. 00:10:18.815 --> 00:10:20.190 Basically, once it's launched, it 00:10:20.190 --> 00:10:22.800 wants to keep doing whatever it was doing. 00:10:22.800 --> 00:10:27.600 And this guy's white lab coated colleague 00:10:27.600 --> 00:10:29.730 just moves away from where the ball was going. 00:10:39.056 --> 00:10:39.556 Whoa. 00:10:48.240 --> 00:10:50.010 All right, everybody's got that? 00:10:50.010 --> 00:10:51.510 That's Coriolis force for you. 00:10:55.480 --> 00:10:59.620 What happens when we do this on the earth? 00:10:59.620 --> 00:11:00.400 So think about it. 00:11:00.400 --> 00:11:02.260 You have a parcel of air that's moving 00:11:02.260 --> 00:11:04.430 with the earth at the equator. 00:11:04.430 --> 00:11:07.300 If you displace it up to a higher latitude, 00:11:07.300 --> 00:11:11.230 it still has that velocity. 00:11:11.230 --> 00:11:13.690 But now the Earth isn't spinning as fast. 00:11:13.690 --> 00:11:19.060 So it ends up essentially moving a little bit to the right. 00:11:19.060 --> 00:11:22.355 That is the fundamental insight just as you saw in that video. 00:11:22.355 --> 00:11:24.730 You'll have to go home and think about that a little bit. 00:11:24.730 --> 00:11:28.240 But, basically, I think the most effective way 00:11:28.240 --> 00:11:31.150 to think about it is just that a parcel of air that 00:11:31.150 --> 00:11:34.180 was the equator wants to keep moving as if it were still 00:11:34.180 --> 00:11:37.460 at the equator, but it's not there anymore, 00:11:37.460 --> 00:11:41.170 so it moves relative to the underlying earth. 00:11:43.750 --> 00:11:46.420 If you combine the Coriolis force and the pressure 00:11:46.420 --> 00:11:50.050 gradient, then you get the actual wind direction. 00:11:50.050 --> 00:11:53.350 And the trend as seen here-- 00:11:53.350 --> 00:11:55.240 eventually, there's so much Coriolis force 00:11:55.240 --> 00:11:57.640 over so much time that the wind actually 00:11:57.640 --> 00:12:03.495 moves exactly 90 degrees to where you think it should move. 00:12:03.495 --> 00:12:08.920 It flows along the isobars instead of perpendicular 00:12:08.920 --> 00:12:10.520 across them. 00:12:10.520 --> 00:12:15.280 So there you have a couple pressure systems 00:12:15.280 --> 00:12:19.360 and you see that the wind is circulating around these lows 00:12:19.360 --> 00:12:23.890 and highs rather than flowing directly from one to the other 00:12:23.890 --> 00:12:24.670 as you'd expect. 00:12:27.680 --> 00:12:35.180 All right, who would like to become a helicopter test pilot? 00:12:35.180 --> 00:12:37.970 Raise your hand if that sounds like a fun job. 00:12:37.970 --> 00:12:41.900 OK, so when you're developing the manual for your Sikorsky 00:12:41.900 --> 00:12:44.270 helicopter, you've got to go somewhere 00:12:44.270 --> 00:12:46.670 where the wind is calm. 00:12:46.670 --> 00:12:49.340 Where would you all suggest going now 00:12:49.340 --> 00:12:51.693 that you've seen this chart? 00:12:51.693 --> 00:12:52.610 What's your name, sir? 00:12:52.610 --> 00:12:53.260 Sorry. 00:12:53.260 --> 00:12:54.020 AUDIENCE: Jeremy. 00:12:54.020 --> 00:12:56.560 PHILIP GREENSPUN: Jeremy, where do you want to go? 00:12:56.560 --> 00:12:58.550 You're going to take your Sikorsky helicopter 00:12:58.550 --> 00:12:59.967 and you're going to write the POH. 00:12:59.967 --> 00:13:01.220 AUDIENCE: [INAUDIBLE] Florida. 00:13:01.220 --> 00:13:02.390 PHILIP GREENSPUN: Florida. 00:13:02.390 --> 00:13:05.810 Sikorsky, which is headquartered in Connecticut, 00:13:05.810 --> 00:13:07.760 they have a big flight test facility. 00:13:07.760 --> 00:13:10.340 I believe it's in Palm Beach. 00:13:10.340 --> 00:13:12.355 So there you have it. 00:13:12.355 --> 00:13:15.200 They thought just along the same lines as you, 00:13:15.200 --> 00:13:17.540 and they'll be in the horse latitudes. 00:13:17.540 --> 00:13:20.150 There's a whole bunch of-- 00:13:20.150 --> 00:13:22.520 nobody really knows why it's called the horse latitudes. 00:13:22.520 --> 00:13:24.862 One idea is that the ships-- 00:13:24.862 --> 00:13:26.570 since there's no wind in those latitudes, 00:13:26.570 --> 00:13:28.340 they have to find a current, and then they 00:13:28.340 --> 00:13:32.950 get pulled along by the current as if they were on a horse. 00:13:32.950 --> 00:13:36.710 All right, surface friction is a little bit complicated. 00:13:36.710 --> 00:13:38.770 It tends to drag down the wind. 00:13:38.770 --> 00:13:44.060 You'll have to study this vector diagram on your own. 00:13:44.060 --> 00:13:46.300 But, really, from the FAA's point of view, 00:13:46.300 --> 00:13:48.130 they just want you to know mostly 00:13:48.130 --> 00:13:53.920 that the wind 2,000 or 3,000 feet up is 00:13:53.920 --> 00:13:56.200 going to be different from the wind on the surface. 00:13:56.200 --> 00:13:58.020 Because of surface friction, it will 00:13:58.020 --> 00:14:03.046 be less intense and in a slightly different direction. 00:14:03.046 --> 00:14:06.650 OK, vertical circulation of the air. 00:14:06.650 --> 00:14:10.940 I think you're going to be OK if you just remember that warmer 00:14:10.940 --> 00:14:12.575 air is lighter than colder air. 00:14:12.575 --> 00:14:14.450 That's all that you pretty much need to know. 00:14:17.270 --> 00:14:20.640 OK, local wind patterns. 00:14:20.640 --> 00:14:26.250 If you heat up the shore line, the air will rise off the shore 00:14:26.250 --> 00:14:28.930 and pull in air from the ocean during the daytime 00:14:28.930 --> 00:14:30.840 so you get that sea breeze. 00:14:30.840 --> 00:14:34.808 And then at nighttime, the opposite happens, 00:14:34.808 --> 00:14:35.850 so you get a land breeze. 00:14:35.850 --> 00:14:38.980 So there are some of these predictable local weather 00:14:38.980 --> 00:14:39.480 patterns. 00:14:42.240 --> 00:14:44.990 The bigger ones have to do with atmospheric stability. 00:14:47.520 --> 00:14:52.430 If you have a stable atmosphere, meaning 00:14:52.430 --> 00:14:56.120 that a displaced parcel of air tends to get pushed back down 00:14:56.120 --> 00:15:02.390 to wherever it was, then you get these weather characteristics 00:15:02.390 --> 00:15:05.480 where you're not going to be bumped around in your aircraft. 00:15:05.480 --> 00:15:08.360 You're going to have trouble seeing, 00:15:08.360 --> 00:15:11.000 and you're going to see clouds that are basically flat, 00:15:11.000 --> 00:15:16.670 these stratiform clouds here that you see on the right. 00:15:16.670 --> 00:15:18.740 If it rains, it's just going to rain all day. 00:15:18.740 --> 00:15:21.500 It's going to be a typical miserable New England 00:15:21.500 --> 00:15:25.910 day where it rains all the time, or Seattle, I guess, 00:15:25.910 --> 00:15:28.130 is like that as well. 00:15:28.130 --> 00:15:30.620 Well, what about if the air once displaced 00:15:30.620 --> 00:15:33.350 tends to want to keep being displaced? 00:15:33.350 --> 00:15:35.870 If it rises up a little bit, it keeps rising. 00:15:35.870 --> 00:15:38.840 Then you have these clouds with vertical development. 00:15:38.840 --> 00:15:42.182 And the good news is you can see really well. 00:15:42.182 --> 00:15:44.390 You're not going to have an obstruction to visibility 00:15:44.390 --> 00:15:47.720 unless you're in heavy rain. 00:15:47.720 --> 00:15:50.810 And the rain won't be all day, every day. 00:15:50.810 --> 00:15:53.930 It'll be showery, but it'll be very turbulent 00:15:53.930 --> 00:15:56.750 if you get into that cloud or maybe right 00:15:56.750 --> 00:15:58.955 underneath that cloud. 00:15:58.955 --> 00:16:07.200 OK, what about the profile of the atmosphere? 00:16:07.200 --> 00:16:10.470 Let's have a look at this. 00:16:10.470 --> 00:16:11.210 So on the right-- 00:16:14.510 --> 00:16:16.640 I wonder if this is actually my newest 00:16:16.640 --> 00:16:17.840 version of the presentation. 00:16:17.840 --> 00:16:19.010 We'll see. 00:16:19.010 --> 00:16:20.840 I corrected an error. 00:16:20.840 --> 00:16:24.380 On the right, you can see that for every 1,000 feet you go up. 00:16:24.380 --> 00:16:27.230 So we go from 0 to 1,000 feet up. 00:16:27.230 --> 00:16:30.060 The temperature is gone from 18 Celsius to 15, 00:16:30.060 --> 00:16:32.450 so it's lapsed by 3 degrees. 00:16:32.450 --> 00:16:35.981 And the dew point has gone down by half a degree. 00:16:35.981 --> 00:16:37.400 Does that makes sense? 00:16:37.400 --> 00:16:40.070 The air goes up, it's lower pressure. 00:16:40.070 --> 00:16:43.270 This is called an adiabatic process. 00:16:43.270 --> 00:16:45.710 I was not a chemistry major, but I 00:16:45.710 --> 00:16:50.240 think that means that we're not adding or taking away 00:16:50.240 --> 00:16:51.530 heat from the air. 00:16:51.530 --> 00:16:52.980 We're just moving it. 00:16:52.980 --> 00:16:57.530 So the temperature and dew point spread, 00:16:57.530 --> 00:16:59.240 actually does get narrower. 00:16:59.240 --> 00:17:02.780 You can see as we rise up to 5,000 feet that the spread has 00:17:02.780 --> 00:17:06.380 gone down to 2 and 1/2 degrees because the dew point is not 00:17:06.380 --> 00:17:10.529 falling nearly as fast as the overall temperature. 00:17:10.529 --> 00:17:11.404 Does that make sense? 00:17:11.404 --> 00:17:14.990 So I think this conceivably could be an FAA test 00:17:14.990 --> 00:17:21.430 question that the dry adiabatic lapse rate is 3 degrees. 00:17:21.430 --> 00:17:26.589 OK, then the moist air is lapsing only at 2 degrees. 00:17:26.589 --> 00:17:32.690 So this figure shows you going from 0 to 1,000 feet, 00:17:32.690 --> 00:17:36.500 and from 1 to 2,000 feet, we were dropping 00:17:36.500 --> 00:17:39.830 3 degrees per thousand feet. 00:17:39.830 --> 00:17:44.070 After that, we're dropping only 2 degrees per thousand feet. 00:17:44.070 --> 00:17:47.790 And once the temperature dew point spread goes to 0, 00:17:47.790 --> 00:17:50.050 that's when a cloud happens. 00:17:50.050 --> 00:17:52.900 So the air can't hold anymore water vapor. 00:17:52.900 --> 00:17:58.320 And when the temperature and dew point meet, 00:17:58.320 --> 00:18:00.055 the water vapor turns into water, 00:18:00.055 --> 00:18:03.200 and now you've got a cloud. 00:18:03.200 --> 00:18:07.690 All right, so you might ask yourself, well, 00:18:07.690 --> 00:18:10.540 why is this air moving at all? 00:18:10.540 --> 00:18:12.130 Why does it start moving? 00:18:12.130 --> 00:18:15.380 One thing that can start it moving is a mountain range. 00:18:15.380 --> 00:18:19.090 So the air gets pushed by a wind coming 00:18:19.090 --> 00:18:23.050 from the left side of the slide up the top of the mountain. 00:18:23.050 --> 00:18:27.760 And at that point, it will condense into a cloud. 00:18:31.470 --> 00:18:34.000 Just let you absorb that cloud here for a minute. 00:18:34.000 --> 00:18:35.880 Notice also that relative humidity is just 00:18:35.880 --> 00:18:39.340 another way of stating the temperature dew point spread. 00:18:39.340 --> 00:18:41.880 So here temperature and dew point are pretty close, 00:18:41.880 --> 00:18:44.400 10 and 15 or 15 and 10. 00:18:44.400 --> 00:18:47.010 So we've got relative humidity of 80%. 00:18:47.010 --> 00:18:50.610 Over here, they're quite far apart. 00:18:50.610 --> 00:18:53.760 The temperature is 23, and the dew point is minus 2. 00:18:53.760 --> 00:18:57.790 So the relative humidity is low. 00:18:57.790 --> 00:19:01.270 OK, you've heard that there's a cold front coming in 00:19:01.270 --> 00:19:03.040 and we have all these thunderstorms. 00:19:03.040 --> 00:19:03.790 Well, this is why. 00:19:03.790 --> 00:19:07.490 The cold air is denser than the warm air. 00:19:07.490 --> 00:19:09.980 So it pushes the warm air up. 00:19:09.980 --> 00:19:12.490 And at that point, you get clouds forming, 00:19:12.490 --> 00:19:14.860 and you get thunderstorms all along the line 00:19:14.860 --> 00:19:16.860 of the cold front. 00:19:16.860 --> 00:19:19.230 OK, so what if you have stable air? 00:19:19.230 --> 00:19:20.370 Let's have a look at this. 00:19:25.980 --> 00:19:26.750 You end up-- 00:19:30.520 --> 00:19:31.160 Let's see. 00:19:35.770 --> 00:19:46.390 We've gone from 0, to 1, to 2, and we're only 00:19:46.390 --> 00:19:48.370 dropping-- actually, we're not dropping at all. 00:19:48.370 --> 00:19:49.328 And then we're back up. 00:19:49.328 --> 00:19:50.590 This is an inversion. 00:19:50.590 --> 00:19:53.350 OK, so, basically, the air temperature 00:19:53.350 --> 00:19:56.780 is pretty constant as we go up. 00:19:56.780 --> 00:20:11.260 So if a parcel of air rises up into the atmosphere, 00:20:11.260 --> 00:20:16.330 it's not going to be warmer than the surrounding air, 00:20:16.330 --> 00:20:20.340 so it doesn't want to keep rising. 00:20:20.340 --> 00:20:22.920 OK, what if it's unstable? 00:20:22.920 --> 00:20:24.740 So look at this by contrast. 00:20:24.740 --> 00:20:26.210 The environmental air temperature 00:20:26.210 --> 00:20:28.790 is lapsing at a higher than standard rate. 00:20:31.730 --> 00:20:36.250 It's going down 4 degrees Celsius per thousand feet. 00:20:36.250 --> 00:20:40.810 And this parcel of air that was in equilibrium 00:20:40.810 --> 00:20:49.120 down at sea level is still warmer than the surrounding 00:20:49.120 --> 00:20:51.340 air, and, therefore, it wants to keep rising. 00:20:51.340 --> 00:20:53.720 Does that make sense? 00:20:53.720 --> 00:20:58.030 So, basically, if it goes up and it wants to keep going up, 00:20:58.030 --> 00:21:01.090 that's unstable and a perfect situation 00:21:01.090 --> 00:21:05.950 for forming thunderstorms, which we'll talk about shortly. 00:21:05.950 --> 00:21:09.520 Temperature inversion like we saw on that earlier slide 00:21:09.520 --> 00:21:14.560 where it was actually a little bit warmer here, 00:21:14.560 --> 00:21:21.310 that tends to keep air where it is, 00:21:21.310 --> 00:21:23.470 and, therefore, you end up with poor visibility 00:21:23.470 --> 00:21:25.660 and haze because all the stuff that's 00:21:25.660 --> 00:21:27.430 obscuring your visibility is just staying 00:21:27.430 --> 00:21:28.833 underneath the inversion. 00:21:28.833 --> 00:21:30.250 It's kind of a common phenomenon I 00:21:30.250 --> 00:21:32.800 think in some of these basins like Los Angeles. 00:21:32.800 --> 00:21:36.035 Talk about an inversion, and ordinary people 00:21:36.035 --> 00:21:38.410 think about that, and hear that term, and worry about it. 00:21:41.140 --> 00:21:44.680 Most frequently-- you're going to I think see this on a test 00:21:44.680 --> 00:21:45.570 maybe-- 00:21:45.570 --> 00:21:53.350 is phenomena having to do with the ground radiating back heat 00:21:53.350 --> 00:21:56.440 into the atmosphere or into space at night. 00:21:56.440 --> 00:21:58.990 Tends to make the ground cold and the air 00:21:58.990 --> 00:22:02.560 right next to the ground cold, whereas the air just slightly 00:22:02.560 --> 00:22:04.750 higher than that, a couple thousand feet up, 00:22:04.750 --> 00:22:07.430 hasn't changed the temperature too much. 00:22:07.430 --> 00:22:12.400 So the terrestrial radiation on a clear still night 00:22:12.400 --> 00:22:15.400 can cause a temperature inversion. 00:22:15.400 --> 00:22:20.380 We talked about this earlier when the temperature and dew 00:22:20.380 --> 00:22:26.130 point meet, and that's when the water vapor will condense. 00:22:26.130 --> 00:22:27.030 Frost. 00:22:27.030 --> 00:22:32.740 When the dew point is below freezing 00:22:32.740 --> 00:22:38.190 and you have a surface that's cold, then you will get-- 00:22:38.190 --> 00:22:40.860 maybe it's cold because it radiated its heat 00:22:40.860 --> 00:22:43.260 back out into space at night, for example. 00:22:43.260 --> 00:22:46.260 That's when you get frost forming. 00:22:46.260 --> 00:22:48.630 And you want to definitely clear that off your aircraft 00:22:48.630 --> 00:22:53.580 before you go anywhere because it messes 00:22:53.580 --> 00:22:58.080 with the smooth flow of the air, so the wing becomes much less 00:22:58.080 --> 00:23:02.220 efficient even if the shape hasn't changed that much. 00:23:02.220 --> 00:23:04.095 All right, let's look at the kinds of clouds. 00:23:07.290 --> 00:23:14.520 You've got basically-- the prefix to the cloud 00:23:14.520 --> 00:23:18.630 tells you what height it is. 00:23:18.630 --> 00:23:21.360 And then the second part of the word 00:23:21.360 --> 00:23:24.930 tells you kind of the shape of the cloud. 00:23:24.930 --> 00:23:29.430 So I'll just let you absorb this a little bit. 00:23:29.430 --> 00:23:34.460 If it says nimbo, yeah, cumulonimbus or nimbostratus, 00:23:34.460 --> 00:23:37.550 that means it's raining. 00:23:37.550 --> 00:23:42.260 Towering cumulus is bad if they talk about that. 00:23:42.260 --> 00:23:43.790 And cumulonimbus is the worst. 00:23:43.790 --> 00:23:48.620 That's just another fancier way of saying thunderstorm. 00:23:48.620 --> 00:23:53.580 OK, so here's your Latin lesson for today. 00:23:53.580 --> 00:23:55.200 Unfortunately, I didn't study Latin. 00:23:55.200 --> 00:23:57.890 It would have been nice when I went 00:23:57.890 --> 00:23:59.810 to Peru to be able to communicate 00:23:59.810 --> 00:24:05.060 with the locals in Latin America. 00:24:05.060 --> 00:24:06.320 OK, that wasn't funny I guess. 00:24:06.320 --> 00:24:09.722 [LAUGHTER] 00:24:12.650 --> 00:24:18.320 If you have low clouds, the main hazard to worry about 00:24:18.320 --> 00:24:20.180 is the icing. 00:24:20.180 --> 00:24:24.800 If the water is supercooled, that's the worst. 00:24:24.800 --> 00:24:27.717 You can usually get a forecast of that. 00:24:27.717 --> 00:24:29.300 You'll get AIRMETs for icing, and they 00:24:29.300 --> 00:24:33.545 might talk about supercooled water is a hazard. 00:24:36.530 --> 00:24:38.720 I guess this might be an exam question. 00:24:38.720 --> 00:24:43.850 Stratus clouds form when moist, stable air flows upslope. 00:24:43.850 --> 00:24:49.310 But just remember stable usually means the flat clouds, 00:24:49.310 --> 00:24:50.740 stratiform clouds. 00:24:50.740 --> 00:24:55.745 And unstable is where you get the cumuliform clouds. 00:25:02.090 --> 00:25:03.230 So same deal. 00:25:03.230 --> 00:25:04.880 Those altocumulus are going to be 00:25:04.880 --> 00:25:13.690 much more turbulent and probably more severe icing potential. 00:25:13.690 --> 00:25:19.390 The high clouds-- it's so cold in the high atmosphere 00:25:19.390 --> 00:25:22.720 that the maximum amount of water that can be stored 00:25:22.720 --> 00:25:25.570 is pretty low, and, therefore, you 00:25:25.570 --> 00:25:28.780 don't tend to get ice when it's below 00:25:28.780 --> 00:25:32.260 say minus 15 degrees Celsius. 00:25:32.260 --> 00:25:35.110 There just isn't a whole lot of moisture to begin with. 00:25:38.790 --> 00:25:41.910 OK, so this is what as a GA pilot 00:25:41.910 --> 00:25:44.608 you're more likely to have to worry about. 00:25:44.608 --> 00:25:46.650 You're probably not going to be up at 25,000 feet 00:25:46.650 --> 00:25:48.360 in your Piper Warrior. 00:25:48.360 --> 00:25:57.038 But you could be underneath a cumulus cloud. 00:25:57.038 --> 00:25:58.830 I will tell you that if you have passengers 00:25:58.830 --> 00:26:01.470 and there is low cumulus clouds, you desperately 00:26:01.470 --> 00:26:02.860 want to get above those. 00:26:02.860 --> 00:26:05.700 So let's say there's a bunch of cumulus clouds at 4,000 00:26:05.700 --> 00:26:07.290 or 5,000 feet. 00:26:07.290 --> 00:26:10.500 You can climb probably to 8,000 or 10,000 feet 00:26:10.500 --> 00:26:13.120 in a light airplane, and that'll be much, much smoother. 00:26:13.120 --> 00:26:16.470 So as soon as you get above the cumulus clouds, 00:26:16.470 --> 00:26:18.750 that's where the air tends to smooth out, 00:26:18.750 --> 00:26:21.180 and it'll be much more comfortable. 00:26:21.180 --> 00:26:23.730 But if it's a towering cumulus cloud, 00:26:23.730 --> 00:26:29.130 they may go up to as high as 60,000 feet down in Texas. 00:26:29.130 --> 00:26:30.660 And you really can't get over them 00:26:30.660 --> 00:26:36.870 in anything short of an SR-71 or maybe last as F-22. 00:26:36.870 --> 00:26:41.970 Even the latest Gulfstreams only go to 51,000, I believe. 00:26:41.970 --> 00:26:44.750 OK, so thunderstorms are the worst hazard. 00:26:44.750 --> 00:26:47.700 Even the airliners get in trouble and thunderstorms 00:26:47.700 --> 00:26:55.790 with hail smashing into the windshield and turbulence that 00:26:55.790 --> 00:26:58.930 can bend stuff. 00:26:58.930 --> 00:27:08.500 So how do you predict if you're flying along-- 00:27:08.500 --> 00:27:10.580 well, if you're preparing to go on a flight, 00:27:10.580 --> 00:27:12.788 how do you predict where the clouds are likely to be? 00:27:12.788 --> 00:27:16.130 One thing you do is look at the temperature dew point spread. 00:27:16.130 --> 00:27:21.255 The FAA tells you to use a lapse rate of 2.5 degrees Celsius 00:27:21.255 --> 00:27:22.880 to figure out where the clouds will be. 00:27:22.880 --> 00:27:28.240 So if there is a 10 degree temperature dew point spread, 00:27:28.240 --> 00:27:30.740 then you should expect the clouds to have 00:27:30.740 --> 00:27:32.480 a base at about 4,000 feet. 00:27:32.480 --> 00:27:33.780 There's a typo in the slide. 00:27:33.780 --> 00:27:34.760 Sorry about that. 00:27:34.760 --> 00:27:37.340 I thought we had the new version in the Dropbox. 00:27:37.340 --> 00:27:42.590 The temperature lapses at 3 for the dry adiabatic air. 00:27:42.590 --> 00:27:43.590 You remember that? 00:27:43.590 --> 00:27:45.415 And the dew point's at 0.5. 00:27:45.415 --> 00:27:46.790 So if we go back to that figure-- 00:27:52.080 --> 00:27:55.690 I think it was our-- yeah. 00:27:55.690 --> 00:27:59.640 Yeah, if we go back here, you remember this? 00:27:59.640 --> 00:28:02.530 We went from 18, to 15, to 12. 00:28:02.530 --> 00:28:05.260 And the dew point, meanwhile, is falling from 3, to 2 and 1/2, 00:28:05.260 --> 00:28:06.430 to 2. 00:28:06.430 --> 00:28:07.270 So that's why. 00:28:10.930 --> 00:28:13.060 It's 2.5 as a rule of thumb. 00:28:13.060 --> 00:28:16.300 That's not great, but you can actually-- 00:28:16.300 --> 00:28:19.843 Just look at METARs around the country, 00:28:19.843 --> 00:28:21.760 and I think you will see because they give you 00:28:21.760 --> 00:28:24.130 the basis of the clouds and the ceilings. 00:28:24.130 --> 00:28:26.260 I think you usually will see that it's 00:28:26.260 --> 00:28:31.810 reasonably close to this formula but almost never spot on. 00:28:31.810 --> 00:28:38.620 OK, this is worth studying. 00:28:38.620 --> 00:28:41.300 I'm not going to cover it completely here. 00:28:41.300 --> 00:28:44.540 But some of these are exam questions. 00:28:44.540 --> 00:28:46.420 Advection fog-- I think I remember 00:28:46.420 --> 00:28:50.590 they like to ask about that, when the warm moist air moves 00:28:50.590 --> 00:28:55.253 over a cool surface along coastlines. 00:28:55.253 --> 00:28:56.420 So I think that makes sense. 00:28:56.420 --> 00:28:58.520 Maybe that's what they're having in California 00:28:58.520 --> 00:28:59.650 a lot of the time. 00:28:59.650 --> 00:29:05.455 They have the fog over the coastal areas. 00:29:12.270 --> 00:29:15.810 And radiation fog-- also, in the Western deserts, 00:29:15.810 --> 00:29:18.850 oftentimes, there's fog in the morning. 00:29:18.850 --> 00:29:23.160 So I think you're advection fog would be a coastal phenomenon. 00:29:23.160 --> 00:29:26.520 And the radiation fog, something they 00:29:26.520 --> 00:29:32.750 can have in a place like Arizona or Palm Springs. 00:29:32.750 --> 00:29:36.610 OK, the FAA loves this. 00:29:36.610 --> 00:29:39.880 If you see ice pellets, you probably shouldn't be flying. 00:29:39.880 --> 00:29:44.110 But they want you to know that if you do see ice pellets, 00:29:44.110 --> 00:29:47.260 how did they arrive? 00:29:47.260 --> 00:29:50.050 Well, they had to be freezing rain up higher. 00:29:50.050 --> 00:29:52.360 So don't climb in hopes of getting out of the ice 00:29:52.360 --> 00:29:56.050 pellets because then you'll have freezing rain on your airplane 00:29:56.050 --> 00:29:58.960 which is probably the worst kind of icing-related hazard. 00:30:01.580 --> 00:30:04.170 OK, airmasses. 00:30:09.470 --> 00:30:10.790 You can just have a look here. 00:30:13.560 --> 00:30:16.460 If you hear that there's a polar airmass coming in, 00:30:16.460 --> 00:30:18.800 it's going to be cold, not too exciting. 00:30:18.800 --> 00:30:19.890 Might be a question. 00:30:19.890 --> 00:30:21.650 Fronts, they do want you to see-- 00:30:21.650 --> 00:30:23.970 be able to read one of these maps. 00:30:23.970 --> 00:30:25.910 They may occasionally asked you a question. 00:30:25.910 --> 00:30:29.090 So one thing to remember is the cold front 00:30:29.090 --> 00:30:32.260 has the pointy spikes like icicles. 00:30:32.260 --> 00:30:36.140 So if you can remember that, you'll be pretty good. 00:30:36.140 --> 00:30:39.410 There's a cold front. 00:30:39.410 --> 00:30:44.690 Again, you can just read this and study it at your leisure. 00:30:48.115 --> 00:30:49.740 I guess they might want you to remember 00:30:49.740 --> 00:30:54.950 that the front is the boundary between two air masses. 00:30:54.950 --> 00:30:55.560 OK. 00:30:55.560 --> 00:30:57.440 Here's a typical drawing where they'll 00:30:57.440 --> 00:30:59.420 show you the cold fronts and the warm fronts. 00:31:03.070 --> 00:31:05.188 When there is a front, how do you 00:31:05.188 --> 00:31:06.730 know when the front has gone through? 00:31:06.730 --> 00:31:10.000 Well, the temperature's changed and the wind's changed, 00:31:10.000 --> 00:31:10.750 simple as that. 00:31:14.020 --> 00:31:18.250 Here's a little explanation of what you can expect 00:31:18.250 --> 00:31:20.860 when a cold front goes through. 00:31:32.800 --> 00:31:35.792 Everybody is happy with that? 00:31:35.792 --> 00:31:37.610 OK. 00:31:37.610 --> 00:31:43.030 When a warm front goes through, it gets warmer afterwards. 00:31:43.030 --> 00:31:46.520 Yeah, so the warm front produces, as you can see, 00:31:46.520 --> 00:31:53.332 light to moderate rain, drizzle, visibility is bad. 00:31:53.332 --> 00:31:55.040 That's actually the important thing here. 00:31:55.040 --> 00:31:56.960 The visibility gets poor. 00:31:56.960 --> 00:31:59.760 And then it becomes fair and haze, 00:31:59.760 --> 00:32:06.887 whereas the visibility becomes really good after a cold front 00:32:06.887 --> 00:32:07.470 comes through. 00:32:11.850 --> 00:32:16.984 Occluded fronts-- same deal, bad visibility. 00:32:19.720 --> 00:32:20.220 All right. 00:32:20.220 --> 00:32:21.400 Let's talk about hazards. 00:32:21.400 --> 00:32:23.200 This is more important. 00:32:23.200 --> 00:32:34.940 So this is a summary of where heat 00:32:34.940 --> 00:32:39.860 is released into the atmosphere versus absorbed by water. 00:32:39.860 --> 00:32:48.650 So as the water goes, for example, from vapor to liquid, 00:32:48.650 --> 00:32:50.145 it releases heat. 00:32:50.145 --> 00:32:51.770 So that's exactly what's happening when 00:32:51.770 --> 00:32:54.170 it's raining in a thunderstorm. 00:32:56.870 --> 00:33:00.590 And that's not a good thing. 00:33:00.590 --> 00:33:01.550 All right. 00:33:01.550 --> 00:33:08.390 So here's the FAA's chart of a cumulus cloud forming. 00:33:08.390 --> 00:33:11.480 So you can see the lapse rate over here 00:33:11.480 --> 00:33:14.270 in the ambient atmosphere. 00:33:14.270 --> 00:33:19.550 It's going from 28 to 24 down to 21. 00:33:19.550 --> 00:33:25.070 So it is, at least initially, higher 00:33:25.070 --> 00:33:27.050 than standard lapse rate. 00:33:27.050 --> 00:33:30.450 So this warm air-- 00:33:30.450 --> 00:33:31.820 it starts at 28. 00:33:31.820 --> 00:33:34.280 And then it drops only to 25. 00:33:34.280 --> 00:33:36.830 So it's still warmer than the surrounding air. 00:33:36.830 --> 00:33:42.930 So it goes into becoming this big, nasty cloud. 00:33:42.930 --> 00:33:47.270 There's this-- you can see-- if you don't 00:33:47.270 --> 00:33:49.880 want to look at the summaries of weather forecasts, 00:33:49.880 --> 00:33:54.170 you can look at these shards of lifted index. 00:33:54.170 --> 00:33:59.510 Here, it shows the difference between minus 18 and minus 11, 00:33:59.510 --> 00:34:00.200 minus 7. 00:34:00.200 --> 00:34:03.898 That gives you a measure of the thunderstorm potential. 00:34:03.898 --> 00:34:04.940 There are charts of that. 00:34:08.900 --> 00:34:12.620 But as pilots, this is more what we 00:34:12.620 --> 00:34:14.750 deal with on our practical day-to-day basis. 00:34:14.750 --> 00:34:16.760 We just look at the next rad data 00:34:16.760 --> 00:34:20.130 from the radar stations that are strewn around the country. 00:34:20.130 --> 00:34:22.287 And if it's red, we try to find a path around it, 00:34:22.287 --> 00:34:23.870 because there's just not much else you 00:34:23.870 --> 00:34:26.659 can do in a little aircraft. 00:34:26.659 --> 00:34:31.520 It's possible that you could get over this entire front 00:34:31.520 --> 00:34:35.570 if you were in a jet that could climb up 00:34:35.570 --> 00:34:37.610 to 40,000 feet or higher. 00:34:37.610 --> 00:34:40.397 But in a Piper or Cessna or Cirrus, 00:34:40.397 --> 00:34:42.230 you're just not going to be able to do that. 00:34:45.719 --> 00:34:46.350 OK. 00:34:46.350 --> 00:34:51.560 The thunderstorm lifecycle-- this is, I think, 00:34:51.560 --> 00:34:52.850 my favorite test question. 00:34:52.850 --> 00:34:54.650 How do you know that the thunderstorm 00:34:54.650 --> 00:34:56.600 has reached its mature stage? 00:34:56.600 --> 00:35:00.230 Well, it's raining, simple as that. 00:35:00.230 --> 00:35:03.300 If it's raining, it's mature. 00:35:03.300 --> 00:35:09.640 If it's dissipating, you're going to get these downdrafts. 00:35:09.640 --> 00:35:12.040 If it's building, you get updrafts. 00:35:12.040 --> 00:35:17.720 So everything comes up, and then it all comes down. 00:35:17.720 --> 00:35:19.490 OK. 00:35:19.490 --> 00:35:22.267 Look at that nasty thunderstorm. 00:35:22.267 --> 00:35:24.350 You're going to get turbulence right on top of it. 00:35:24.350 --> 00:35:27.630 If you can clear that thunderstorm by 5,000 feet, 00:35:27.630 --> 00:35:29.520 it'll probably nice and smooth. 00:35:29.520 --> 00:35:33.272 So this is your good argument for a plane that can go to 51 00:35:33.272 --> 00:35:35.690 [INAUDIBLE] or 510. 00:35:35.690 --> 00:35:37.020 Airliners don't go that high. 00:35:37.020 --> 00:35:41.640 The latest these jets go much higher than airliners. 00:35:41.640 --> 00:35:42.630 All right. 00:35:42.630 --> 00:35:44.190 The hazard-- we're going to hear more 00:35:44.190 --> 00:35:47.190 about this tomorrow from [? Dojo, ?] 00:35:47.190 --> 00:35:49.950 from the Brazilian Air Force. 00:35:49.950 --> 00:35:59.190 But there is this chart here that shows you how much load 00:35:59.190 --> 00:36:00.290 factor-- that's in g's. 00:36:03.650 --> 00:36:09.200 If you're going pretty fast, you can pretty quickly 00:36:09.200 --> 00:36:12.350 get into the structural damage range. 00:36:15.030 --> 00:36:19.020 So that's why they tell you-- this these lines here are 00:36:19.020 --> 00:36:19.860 basically-- 00:36:23.560 --> 00:36:26.200 this is how many g's you can get on the aircraft 00:36:26.200 --> 00:36:29.800 with either extreme movements on the controls 00:36:29.800 --> 00:36:32.470 or extreme movements that are imposed on you 00:36:32.470 --> 00:36:34.450 by a thunderstorm or something. 00:36:34.450 --> 00:36:37.450 So the takeaway from this diagram 00:36:37.450 --> 00:36:40.840 is slow down if you get into heavy turbulence, 00:36:40.840 --> 00:36:45.630 because then the airplane will stall before it bends. 00:36:45.630 --> 00:36:51.650 And stalling can be corrected by pushing the nose down. 00:36:51.650 --> 00:36:52.150 OK. 00:36:52.150 --> 00:36:54.580 So these are all of the hazards from thunderstorms. 00:36:54.580 --> 00:36:57.710 Again, it's a lot better-- 00:36:57.710 --> 00:36:59.710 in this day and age, there's so much information 00:36:59.710 --> 00:37:02.440 out there and datalink available in the cockpit 00:37:02.440 --> 00:37:05.890 that going through thunderstorms is just much less common 00:37:05.890 --> 00:37:07.060 than it used to be. 00:37:07.060 --> 00:37:11.860 And therefore, don't really have to remember too much, other 00:37:11.860 --> 00:37:15.330 than don't fly through a thunderstorm. 00:37:15.330 --> 00:37:18.390 Microburst-- however, if you're trying to land and beat 00:37:18.390 --> 00:37:20.465 the thunderstorm, you can actually 00:37:20.465 --> 00:37:21.840 get into a little bit of trouble, 00:37:21.840 --> 00:37:28.380 because the wind right before a thunderstorm or right 00:37:28.380 --> 00:37:36.890 after can be pretty squirrelly and cause you some difficulties 00:37:36.890 --> 00:37:39.350 here. 00:37:39.350 --> 00:37:39.850 Let's see. 00:37:39.850 --> 00:37:41.040 What do we have? 00:37:41.040 --> 00:37:43.330 So here, this airplane is getting a performance boost 00:37:43.330 --> 00:37:45.580 from a strong headwind. 00:37:45.580 --> 00:37:48.040 Now, not much is happening, except that it's 00:37:48.040 --> 00:37:53.270 getting pushed down, maybe faster than the airplane can 00:37:53.270 --> 00:37:54.200 climb. 00:37:54.200 --> 00:37:57.110 And at this point, you're getting a performance reduction 00:37:57.110 --> 00:37:58.145 from this big tailwind. 00:37:58.145 --> 00:38:00.520 So that's reducing-- you might think, well, that's great. 00:38:00.520 --> 00:38:02.390 I'm getting pushed along with a tailwind. 00:38:02.390 --> 00:38:05.810 But if it's suddenly taking away your airspeed, 00:38:05.810 --> 00:38:09.920 then that's not a performance boost. 00:38:09.920 --> 00:38:10.670 All right. 00:38:10.670 --> 00:38:16.280 So the thunderstorm emergency procedures 00:38:16.280 --> 00:38:18.320 are, again, probably a little bit 00:38:18.320 --> 00:38:20.090 less relevant now that we're living 00:38:20.090 --> 00:38:27.380 in this world of constant datalink and NEXRAD data. 00:38:27.380 --> 00:38:31.850 2006, there was a famous accident with a former test 00:38:31.850 --> 00:38:34.580 pilot, Scott Crossfield, who maybe 00:38:34.580 --> 00:38:38.180 didn't get the best advice from air traffic control. 00:38:38.180 --> 00:38:44.060 And I don't think he had datalink in his cockpit. 00:38:44.060 --> 00:38:46.400 The Boeing B 29 bomber crews, they would fly, 00:38:46.400 --> 00:38:51.800 I think, seven or eight hours from an island in the Pacific 00:38:51.800 --> 00:38:53.090 over to Japan. 00:38:53.090 --> 00:38:55.040 And during those eight hours, they 00:38:55.040 --> 00:38:59.140 had satellite data, no data from a ground station. 00:38:59.140 --> 00:39:01.390 So they just had no idea what they were going through. 00:39:01.390 --> 00:39:03.620 And they didn't go as high as the designers thought 00:39:03.620 --> 00:39:06.770 that airplane was designed to go, super high. 00:39:06.770 --> 00:39:09.083 But they were so loaded up with fuel and bombs, 00:39:09.083 --> 00:39:11.000 they couldn't practically climb all that high. 00:39:11.000 --> 00:39:15.410 So they were going at 10-15,000 feet over the ocean. 00:39:15.410 --> 00:39:20.300 And at those altitudes, you can't really see-- 00:39:20.300 --> 00:39:22.820 you may get into an embedded thunderstorm. 00:39:22.820 --> 00:39:27.140 Today's airliners, they go so high that you really are never 00:39:27.140 --> 00:39:29.600 in a position where you blunder into stuff, 00:39:29.600 --> 00:39:33.240 or almost never, because you're in the clear, 00:39:33.240 --> 00:39:35.300 and you can just see the towering cumulus 00:39:35.300 --> 00:39:36.480 and not fly there. 00:39:36.480 --> 00:39:40.290 You just back yourself around them. 00:39:40.290 --> 00:39:42.600 So I guess-- yeah, the final statement 00:39:42.600 --> 00:39:44.640 there is, get-there-itis hasn't been cured. 00:39:44.640 --> 00:39:48.000 So as a pilot, the safest thing you can do 00:39:48.000 --> 00:39:50.850 is really fight that tendency to want 00:39:50.850 --> 00:39:52.740 to complete the mission as planned 00:39:52.740 --> 00:39:55.230 and overcommit to your plan of action. 00:39:55.230 --> 00:39:57.330 All right. 00:39:57.330 --> 00:40:02.010 There are three other categories of turbulence to worry about. 00:40:02.010 --> 00:40:13.540 Probably the worst is due to terrain, like mountains. 00:40:13.540 --> 00:40:18.340 This low level turbulence from thermals is not crazy. 00:40:18.340 --> 00:40:21.430 But as I said, if you get above the clouds, that plane on top 00:40:21.430 --> 00:40:25.190 is going to be in a nice, smooth air. 00:40:25.190 --> 00:40:28.920 Wake turbulence [INAUDIBLE] is also another thing to consider. 00:40:28.920 --> 00:40:30.270 Let's look at that. 00:40:30.270 --> 00:40:42.120 So if you're taking off behind an airplane, so look at that-- 00:40:42.120 --> 00:40:45.120 heavy, slow and in clean configuration. 00:40:45.120 --> 00:40:50.220 So airplanes will tend to retract their flaps, 00:40:50.220 --> 00:40:52.590 and therefore be in a clean configuration 00:40:52.590 --> 00:40:55.080 shortly after takeoff, whereas, if they're landing, 00:40:55.080 --> 00:40:56.112 the flaps are down. 00:40:56.112 --> 00:40:58.320 They're not generating quite as much wake turbulence. 00:40:58.320 --> 00:41:01.500 Although, still if you land behind a Boeing, in your little 00:41:01.500 --> 00:41:02.850 Cessna, you will notice that. 00:41:07.190 --> 00:41:09.500 The solution here-- and I think this 00:41:09.500 --> 00:41:13.190 is a test question-- is you land or take off 00:41:13.190 --> 00:41:17.220 beyond the touchdown point of a large aircraft. 00:41:17.220 --> 00:41:21.870 So if the large aircraft-- 00:41:21.870 --> 00:41:26.820 let's say the large aircraft landed right here in front 00:41:26.820 --> 00:41:28.380 of the laptop on the runway. 00:41:28.380 --> 00:41:30.510 You just fly a little bit higher. 00:41:30.510 --> 00:41:33.290 And you land maybe in the middle of the runway. 00:41:33.290 --> 00:41:36.000 And that way, you can't possibly get into wake turbulence, 00:41:36.000 --> 00:41:38.880 because it will have sunk below that big aircraft's flight 00:41:38.880 --> 00:41:39.840 path. 00:41:39.840 --> 00:41:41.270 Controllers at a towered airport, 00:41:41.270 --> 00:41:45.210 they'll also separate you by the necessary number of minutes. 00:41:45.210 --> 00:41:48.810 They have a bunch of regulations about how much separation 00:41:48.810 --> 00:41:51.630 they have to have between aircraft. 00:41:51.630 --> 00:41:53.500 And then similarly, for liftoff point-- 00:41:53.500 --> 00:41:56.790 so if the big airplane-- 00:41:56.790 --> 00:42:01.290 again, this is not really that much of a practical problem, 00:42:01.290 --> 00:42:04.320 because so little runway is used by light airplanes. 00:42:04.320 --> 00:42:08.610 But if the big airplane rotated and took off and started 00:42:08.610 --> 00:42:11.280 climbing here, well, then you take off 00:42:11.280 --> 00:42:13.740 and start climbing earlier. 00:42:13.740 --> 00:42:16.187 Of course, the climb rate of the big airplane 00:42:16.187 --> 00:42:17.770 is probably a lot better than you are. 00:42:17.770 --> 00:42:20.460 So you've got to think about which way the wind is going 00:42:20.460 --> 00:42:23.290 and maybe try to turn away from it. 00:42:23.290 --> 00:42:25.710 I've only really been stuck in weight turbulence 00:42:25.710 --> 00:42:27.540 once that I can think about. 00:42:27.540 --> 00:42:29.040 It was at Hanscom Field. 00:42:29.040 --> 00:42:32.100 And there was a heavy helicopter that 00:42:32.100 --> 00:42:34.080 was cleared to land on the runway, 00:42:34.080 --> 00:42:36.090 and then transitioned sideways. 00:42:36.090 --> 00:42:37.292 And I was in the Cirrus. 00:42:37.292 --> 00:42:39.000 And I think the controllers didn't really 00:42:39.000 --> 00:42:42.800 think about, well, how much wake turbulence can 00:42:42.800 --> 00:42:44.640 a helicopter generate. 00:42:44.640 --> 00:42:46.530 So I was trying to land. 00:42:46.530 --> 00:42:49.110 And maybe about 200 feet above the ground, 00:42:49.110 --> 00:42:53.820 there was a sharp wing dip that I-- 00:42:53.820 --> 00:42:57.180 the good news is you don't have to be heroic to correct it, 00:42:57.180 --> 00:42:59.490 because, if your airplane is banked, 00:42:59.490 --> 00:43:02.050 the natural tendency is to want to take the bank out. 00:43:02.050 --> 00:43:03.630 So whenever your natural tendency 00:43:03.630 --> 00:43:09.430 is to do the safe thing, that's usually not much of a problem. 00:43:09.430 --> 00:43:09.930 Oh yeah. 00:43:09.930 --> 00:43:13.753 So anyway, here's the FAA question. 00:43:13.753 --> 00:43:14.920 Who wants to give an answer? 00:43:14.920 --> 00:43:15.580 Shout it out. 00:43:15.580 --> 00:43:16.360 A, B, or C? 00:43:24.160 --> 00:43:25.553 AUDIENCE: A. 00:43:25.553 --> 00:43:26.470 PHILIP GREENSPUN: Yay. 00:43:30.620 --> 00:43:31.680 All right. 00:43:31.680 --> 00:43:36.330 So this is a practical issue, especially for anybody 00:43:36.330 --> 00:43:39.960 who wants to fly out west. 00:43:39.960 --> 00:43:41.790 You have the Sierra Mountains. 00:43:41.790 --> 00:43:44.100 You have the Rocky Mountains. 00:43:44.100 --> 00:43:46.680 And you have to be very careful when crossing these mountain 00:43:46.680 --> 00:43:49.530 ranges. 00:43:49.530 --> 00:43:52.770 If the wind aloft forecast is more than about 30 knots 00:43:52.770 --> 00:43:56.130 for the time that you're planning on crossing, 00:43:56.130 --> 00:43:59.640 you can expect this kind of turbulence on the lee side 00:43:59.640 --> 00:44:02.680 or the eastern side of those mountain ranges. 00:44:02.680 --> 00:44:07.200 So when I've crossed those mountains in light airplanes, 00:44:07.200 --> 00:44:11.100 I have usually done it first thing in the morning basically. 00:44:11.100 --> 00:44:15.420 So I arranged to shut down just short of the mountains 00:44:15.420 --> 00:44:18.330 the night before, and then cross early in the morning 00:44:18.330 --> 00:44:21.330 when the winds are typically calm. 00:44:21.330 --> 00:44:25.470 So you can look for these lenticular clouds. 00:44:25.470 --> 00:44:27.690 But again, if you saw the winds aloft 00:44:27.690 --> 00:44:30.660 forecast that it was going to be blowing 50 knots at 12,000 00:44:30.660 --> 00:44:32.580 feet, you can be pretty sure that it's 00:44:32.580 --> 00:44:36.580 going to be turbulent. 00:44:36.580 --> 00:44:37.080 All right. 00:44:37.080 --> 00:44:43.610 Structural icing-- you can get rime, clear or mixed. 00:44:43.610 --> 00:44:47.720 I'll just let you look through the conditions that 00:44:47.720 --> 00:44:48.380 lead to this. 00:44:56.300 --> 00:45:00.350 Clearing rime-- probably rime icing is more common. 00:45:04.470 --> 00:45:06.760 What happens? 00:45:06.760 --> 00:45:09.713 Everything gets worse about your aircraft. 00:45:09.713 --> 00:45:11.130 Especially if you're on autopilot, 00:45:11.130 --> 00:45:15.890 it's a challenge to recognize when icing is occurring. 00:45:15.890 --> 00:45:18.070 You can be in the air, fat, dumb, and happy 00:45:18.070 --> 00:45:22.110 while the airplane gets iced up. 00:45:22.110 --> 00:45:27.870 So the worst part of it, I guess, is that you can't climb. 00:45:27.870 --> 00:45:30.720 Basically, when your airplane has all this performance 00:45:30.720 --> 00:45:34.630 reduction, you can summarize this all-- 00:45:34.630 --> 00:45:38.070 if it's only moderate icing, basically you 00:45:38.070 --> 00:45:39.570 have an aircraft that can't climb. 00:45:39.570 --> 00:45:41.130 All you can do is descend. 00:45:41.130 --> 00:45:45.900 So a good practical tip is, if you're-- well, first off all, 00:45:45.900 --> 00:45:47.760 the good news is, if you're a VFR pilot, 00:45:47.760 --> 00:45:49.620 like you guys are going to become, 00:45:49.620 --> 00:45:52.020 initially you shouldn't have to worry about icing, 00:45:52.020 --> 00:45:55.200 because it's a phenomenon that occurs when you're in a cloud. 00:45:55.200 --> 00:45:57.840 So you shouldn't be in a cloud if you're a VFR pilot 00:45:57.840 --> 00:45:58.820 to begin with. 00:45:58.820 --> 00:46:01.110 So how did you get ice? 00:46:01.110 --> 00:46:03.300 The exception might be freezing rain, if you somehow 00:46:03.300 --> 00:46:05.410 drive through freezing rain. 00:46:05.410 --> 00:46:08.370 But if you are instrument-rated and you are going somewhere-- 00:46:08.370 --> 00:46:12.960 I'm planning on going to New York next week in the Cirrus. 00:46:12.960 --> 00:46:19.350 So if it's cloudy, even if there's no icing forecast, 00:46:19.350 --> 00:46:22.620 I know that there is a risk of getting ice on the wings. 00:46:22.620 --> 00:46:25.885 So in the wintertime, I just say, 00:46:25.885 --> 00:46:28.260 well look, I'm not going to go unless it's above freezing 00:46:28.260 --> 00:46:30.900 on the surface, because, if I get iced up, 00:46:30.900 --> 00:46:36.330 then inadvertently I need an escape route. 00:46:36.330 --> 00:46:40.200 And if it's going to be above freezing at, say, 3,000 feet, 00:46:40.200 --> 00:46:41.340 well, that's fine. 00:46:41.340 --> 00:46:43.710 I know that I probably won't be able to climb 00:46:43.710 --> 00:46:48.060 if I get moderate icing, but I will be able to descend. 00:46:48.060 --> 00:46:49.920 Even a brick can descend. 00:46:49.920 --> 00:46:53.087 So descend down to 3,000 feet, and all the ice will melt off. 00:46:53.087 --> 00:46:53.920 That would be great. 00:46:53.920 --> 00:46:56.780 But if it's below freezing on the surface, 00:46:56.780 --> 00:47:00.610 then it's basically a no-go. 00:47:00.610 --> 00:47:02.310 I've definitely had icing a few times. 00:47:02.310 --> 00:47:03.360 And it's pretty scary. 00:47:03.360 --> 00:47:09.470 I was out on a day when with an instrument student. 00:47:09.470 --> 00:47:11.270 And it seemed like a perfect day to go 00:47:11.270 --> 00:47:13.700 practice instrument flying. 00:47:13.700 --> 00:47:15.530 There was no turbulence. 00:47:15.530 --> 00:47:17.840 There was just clouds everywhere, 00:47:17.840 --> 00:47:19.747 about 800 feet of ceiling. 00:47:19.747 --> 00:47:21.830 So you could be in the clouds, do real approaches, 00:47:21.830 --> 00:47:25.190 get experience with actual IMC. 00:47:25.190 --> 00:47:27.920 And halfway through the flight, I 00:47:27.920 --> 00:47:31.970 started criticizing this guy for using way too much power. 00:47:31.970 --> 00:47:35.990 The power settings were all off. 00:47:35.990 --> 00:47:37.142 What are you doing wrong? 00:47:37.142 --> 00:47:38.600 And then I looked out on the wings. 00:47:38.600 --> 00:47:40.520 And I saw they were all frosted. 00:47:40.520 --> 00:47:42.020 So we descended. 00:47:42.020 --> 00:47:46.280 We managed to complete an ILS approach into Lawrence 00:47:46.280 --> 00:47:50.750 and pulled the airplane into a warm hangar 00:47:50.750 --> 00:47:53.640 and got it warmed up. 00:47:53.640 --> 00:47:55.790 So actually, as we were as we were flying, 00:47:55.790 --> 00:47:58.480 the FAA issued an AIRMET for icing, 00:47:58.480 --> 00:48:01.370 but the controllers never told us about it. 00:48:01.370 --> 00:48:02.600 All right. 00:48:02.600 --> 00:48:04.370 Requirements for icing formation-- 00:48:08.040 --> 00:48:12.570 near freezing temperatures, minus 10 to 0, is the worst. 00:48:12.570 --> 00:48:16.080 You have to have a surface on which the ice can form. 00:48:16.080 --> 00:48:18.750 And you have to be invisible moisture, basically. 00:48:18.750 --> 00:48:22.530 So again, if you're flying in the clear with your VFR pilot 00:48:22.530 --> 00:48:25.510 certificate, icing should not be a factor for you. 00:48:30.310 --> 00:48:30.810 Yeah. 00:48:30.810 --> 00:48:34.860 So as I said below, go through a cold cloud 00:48:34.860 --> 00:48:37.910 only if you have an escape route of warm air below. 00:48:42.050 --> 00:48:46.550 AUDIENCE: [INAUDIBLE] for the engine [INAUDIBLE] 00:48:46.550 --> 00:48:51.502 as far as getting the icing in the carburetor [INAUDIBLE].. 00:48:51.502 --> 00:48:52.460 PHILIP GREENSPUN: Yeah. 00:48:52.460 --> 00:48:55.960 So the question is, what about icing in the engine? 00:48:55.960 --> 00:48:58.810 So you can get carb ice that we talked about. 00:48:58.810 --> 00:49:02.490 You can get carb ice when it's 50 degrees outside, 00:49:02.490 --> 00:49:05.220 as long as it's humid. 00:49:05.220 --> 00:49:07.440 So it's slightly unrelated. 00:49:07.440 --> 00:49:10.350 The main problem with engines is that you 00:49:10.350 --> 00:49:12.400 can get ice in the induction. 00:49:12.400 --> 00:49:15.930 So if the intake for the engine where it's trying to breathe 00:49:15.930 --> 00:49:19.260 gets iced over, then there's an alternate-- again, 00:49:19.260 --> 00:49:21.870 they're relying on the hero pilot. 00:49:21.870 --> 00:49:24.990 Some airplanes actually, it'll just open automatically, 00:49:24.990 --> 00:49:27.870 the vacuum of trying to suck the air through the intake that's 00:49:27.870 --> 00:49:32.180 not working will cause some backup door to open. 00:49:32.180 --> 00:49:33.930 And a lot of-- 00:49:33.930 --> 00:49:38.310 most IFR-certified aircraft have an alternate air lever that you 00:49:38.310 --> 00:49:44.380 can pull and have air pulled from somewhere inside the-- 00:49:44.380 --> 00:49:47.430 it's a little more protected inside the airframe. 00:49:47.430 --> 00:49:49.280 Does that answer your question? 00:49:49.280 --> 00:49:49.900 AUDIENCE: Yes. 00:49:49.900 --> 00:49:54.290 So I guess you're saying as long as the heat's working 00:49:54.290 --> 00:49:56.723 your [INAUDIBLE]. 00:49:56.723 --> 00:49:58.390 PHILIP GREENSPUN: As long as which heat? 00:49:58.390 --> 00:50:03.873 AUDIENCE: [INAUDIBLE] 00:50:03.873 --> 00:50:05.290 PHILIP GREENSPUN: You're not going 00:50:05.290 --> 00:50:07.660 to get carb icing and airframe icing at the same time 00:50:07.660 --> 00:50:08.230 probably. 00:50:08.230 --> 00:50:11.535 I think, at that point, it's probably too cold. 00:50:11.535 --> 00:50:12.410 I'm not I'm not sure. 00:50:12.410 --> 00:50:14.530 Well, the other issue is you're probably not going 00:50:14.530 --> 00:50:16.420 to fly a carburated airplane into the clouds, 00:50:16.420 --> 00:50:19.600 because the real IFR airplanes that people use to travel, 00:50:19.600 --> 00:50:23.340 like Cirruses and Bonanzas and stuff, 00:50:23.340 --> 00:50:26.910 in challenging conditions, those are almost all fuel injected. 00:50:26.910 --> 00:50:29.410 But you do have to worry about induction icing, like I said. 00:50:32.310 --> 00:50:32.810 OK. 00:50:35.740 --> 00:50:37.640 Icing layers are usually pretty thin. 00:50:37.640 --> 00:50:41.050 So if you're in a jet, you just add power and climb up 00:50:41.050 --> 00:50:44.390 another few thousand feet and you're out of it. 00:50:44.390 --> 00:50:47.560 Again, one of the effects of icing 00:50:47.560 --> 00:50:51.940 is to dramatically reduce your climb performance. 00:50:51.940 --> 00:50:55.030 So this best approach of climbing out of it 00:50:55.030 --> 00:50:56.440 is not always available. 00:51:00.380 --> 00:51:05.800 You will end up using more power on the final approach. 00:51:05.800 --> 00:51:09.460 And you'll add speed as well, because the stall 00:51:09.460 --> 00:51:10.480 speed may have gone up. 00:51:10.480 --> 00:51:14.530 And you can't really be sure, since it hasn't 00:51:14.530 --> 00:51:18.170 been quantified and tested. 00:51:18.170 --> 00:51:20.830 You probably won't use flaps. 00:51:20.830 --> 00:51:24.670 And you'll not make severe turns. 00:51:24.670 --> 00:51:28.870 So there's a good NASA video that I encourage you to watch, 00:51:28.870 --> 00:51:34.150 especially as you work on higher performance aircraft and IFR. 00:51:34.150 --> 00:51:37.460 NASA has this great video about icing. 00:51:37.460 --> 00:51:38.410 OK. 00:51:38.410 --> 00:51:41.830 How do the transportation class airplanes handle this? 00:51:41.830 --> 00:51:46.990 One approach is to push antifreeze out onto the wings. 00:51:46.990 --> 00:51:48.370 That used to be called TKS. 00:51:48.370 --> 00:51:51.040 Now, it's called CAV. 00:51:51.040 --> 00:51:52.460 It's just a brand name. 00:51:52.460 --> 00:51:55.540 So if you go to a flight school and you see a modern Cirrus, 00:51:55.540 --> 00:51:58.510 like the SR22s, the leading edges of the wings 00:51:58.510 --> 00:51:59.710 will be metal. 00:51:59.710 --> 00:52:01.660 And they'll have little tiny holes in them. 00:52:01.660 --> 00:52:05.140 And that's for this antifreeze to come out. 00:52:05.140 --> 00:52:08.650 If you have a very light jet or a turbo prop, 00:52:08.650 --> 00:52:12.250 you may have rubber boots on the wings and on the tail surfaces. 00:52:12.250 --> 00:52:15.310 And those inflate to crack the ice off. 00:52:15.310 --> 00:52:18.190 The jets are really the ultimate-- 00:52:18.190 --> 00:52:22.780 the bigger jets all have bleed air. 00:52:22.780 --> 00:52:24.220 Remember, the jets are compressing 00:52:24.220 --> 00:52:27.060 air so much that it becomes really hot even before it's 00:52:27.060 --> 00:52:28.030 burned. 00:52:28.030 --> 00:52:30.490 So you pull the bleed air off the compressor, 00:52:30.490 --> 00:52:34.550 and you run it out into the leading edges of the wings. 00:52:34.550 --> 00:52:37.720 And that just melts the ice off. 00:52:37.720 --> 00:52:46.150 The transporter aircraft, they also heat the windshields. 00:52:46.150 --> 00:52:47.890 So you'll be able to see when you do-- 00:52:47.890 --> 00:52:50.920 if it's not above freezing at the airport, 00:52:50.920 --> 00:52:54.580 you'll have a clear windshield, so you can leave the runway. 00:52:54.580 --> 00:52:58.390 Even in very basic airplanes like a Cirrus, 00:52:58.390 --> 00:53:03.040 if they're IFR-certified, the pedo tube 00:53:03.040 --> 00:53:04.180 is going to be heated. 00:53:04.180 --> 00:53:06.740 There will be pedo heat. 00:53:06.740 --> 00:53:08.810 OK. 00:53:08.810 --> 00:53:11.630 You can learn a whole bunch more about this. 00:53:11.630 --> 00:53:13.310 I think everything you know to pass 00:53:13.310 --> 00:53:15.440 the test is pretty much in the Pilot's Handbook 00:53:15.440 --> 00:53:17.390 of Aeronautical Knowledge. 00:53:17.390 --> 00:53:20.120 There's a little bit in the AIM. 00:53:20.120 --> 00:53:23.480 If you want to dig deeper and understand more of it, 00:53:23.480 --> 00:53:26.150 then I would encourage you to look at these FAA weather 00:53:26.150 --> 00:53:27.790 publications. 00:53:27.790 --> 00:53:31.940 One is about weather theory and one is about information 00:53:31.940 --> 00:53:34.280 that you can get from various sources. 00:53:34.280 --> 00:53:38.450 There's also these videos that I would encourage you to look at. 00:53:38.450 --> 00:53:41.830 One of them is called "Ambushed by Ice" 00:53:41.830 --> 00:53:44.390 and "Into Deep--" these particular links, 00:53:44.390 --> 00:53:47.300 don't write those down, because I fixed them last night, 00:53:47.300 --> 00:53:49.490 but the Dropbox didn't update yet. 00:53:49.490 --> 00:53:52.500 Do they have real-time weather data? 00:53:52.500 --> 00:53:55.700 So the question is, in your basic trainer airplane, 00:53:55.700 --> 00:53:58.770 do they have real-time weather data? 00:53:58.770 --> 00:54:02.300 So let's just talk about East Coast Aero Club 00:54:02.300 --> 00:54:07.010 is a typical higher end flight school. 00:54:07.010 --> 00:54:10.430 About maybe 10 years ago, almost all the aircraft 00:54:10.430 --> 00:54:15.050 had a Garmin IFR-certified GPS put in, a Garmin 430. 00:54:15.050 --> 00:54:18.770 So at that point, you had a really good GPS. 00:54:18.770 --> 00:54:22.700 But they did not have XM weather pulling data from satellites, 00:54:22.700 --> 00:54:25.670 which we'll talk about in a little bit, 00:54:25.670 --> 00:54:30.710 because it's a $500 a year subscription and a $10,000 box. 00:54:30.710 --> 00:54:32.990 So people didn't want to do it. 00:54:32.990 --> 00:54:37.220 With ADS-B, the FAA is now providing some of the same data 00:54:37.220 --> 00:54:41.240 that XM was providing for free, as long 00:54:41.240 --> 00:54:44.380 as you have an ADS-B in transponder. 00:54:44.380 --> 00:54:47.720 And the East Coast Aero-- well, everybody 00:54:47.720 --> 00:54:50.780 has to upgrade to ADS-B by 2020. 00:54:50.780 --> 00:54:52.940 Not everybody has to have ADS-B in, 00:54:52.940 --> 00:54:54.800 but I think East Coast Aero Club's probably 00:54:54.800 --> 00:54:57.830 fairly typical of the better flight schools. 00:54:57.830 --> 00:55:00.980 They've put-- or they're gradually putting in a ADS-B 00:55:00.980 --> 00:55:03.600 in and out transponders in all their aircraft. 00:55:03.600 --> 00:55:05.487 It won't display in the cockpit. 00:55:05.487 --> 00:55:07.820 You'll have to have your phone, your iPad, or something. 00:55:07.820 --> 00:55:11.180 But you'll be able to see-- 00:55:11.180 --> 00:55:13.460 you'll be able to see NEXRAD radar picture. 00:55:13.460 --> 00:55:15.110 You'll be able to get METARs and TAFs. 00:55:15.110 --> 00:55:16.280 You'll get all of that. 00:55:16.280 --> 00:55:16.940 So I think-- 00:55:16.940 --> 00:55:20.120 TINA: But if you don't want to rely on someone else-- 00:55:20.120 --> 00:55:21.440 this is MIT. 00:55:21.440 --> 00:55:23.960 You can actually get that data yourself. 00:55:23.960 --> 00:55:26.810 So when we talk about weather data today, 00:55:26.810 --> 00:55:28.310 we're going to also talk about how 00:55:28.310 --> 00:55:34.160 you can do it yourself, build your own Stratux ADS-B 00:55:34.160 --> 00:55:35.670 receiver. 00:55:35.670 --> 00:55:36.930 And I've actually done this. 00:55:36.930 --> 00:55:38.340 It was really fun to do. 00:55:38.340 --> 00:55:41.210 It's very easy, actually. 00:55:41.210 --> 00:55:45.260 Basically, based on a Raspberry Pi with a couple of antennas, 00:55:45.260 --> 00:55:48.740 with a little cooling fan, you can build a little box that 00:55:48.740 --> 00:55:50.750 can receive that weather data. 00:55:50.750 --> 00:55:53.610 And it actually-- the software is open source. 00:55:53.610 --> 00:55:55.820 And it can sync with your other tools. 00:55:55.820 --> 00:55:58.280 So I have it synced with my Foreflight app. 00:55:58.280 --> 00:56:00.490 So when I'm flying, I plug that in, I 00:56:00.490 --> 00:56:02.030 bring a backup battery for it. 00:56:02.030 --> 00:56:05.420 And it gives me weather data and some other traffic data. 00:56:05.420 --> 00:56:07.573 And we'll be talking about that in a couple hours. 00:56:07.573 --> 00:56:09.490 PHILIP GREENSPUN: Yeah, I should have noticed. 00:56:09.490 --> 00:56:12.560 As Tina said, a lot of flight school customers 00:56:12.560 --> 00:56:15.650 for the last five years would bring little battery powered 00:56:15.650 --> 00:56:21.300 boxes and stick them to the windshield of whatever they're 00:56:21.300 --> 00:56:21.800 flying. 00:56:21.800 --> 00:56:24.920 And they would get a whole bunch of more modern services. 00:56:24.920 --> 00:56:26.780 I personally don't love that. 00:56:26.780 --> 00:56:28.720 When I started out in my flying career, 00:56:28.720 --> 00:56:30.470 I had my big flight bag with all the stuff 00:56:30.470 --> 00:56:32.330 I was going to bring into the airplane. 00:56:32.330 --> 00:56:34.427 And now, I have the philosophy that I 00:56:34.427 --> 00:56:36.260 don't want to bring anything into the CIrrus 00:56:36.260 --> 00:56:37.430 other than a pencil. 00:56:37.430 --> 00:56:41.140 I want everything that I need to be in the panel. 00:56:41.140 --> 00:56:44.150 But yeah, I definitely think, in the older airplanes, 00:56:44.150 --> 00:56:45.950 it's become conventional for people 00:56:45.950 --> 00:56:52.090 to bring some sort of ADS-B receiver and get that data.