1 00:00:00,399 --> 00:00:04,080 If you’re driving a car, it’s pretty easy to know if there's a bumpy road ahead. 2 00:00:04,080 --> 00:00:07,649 Because you can see the road, and it’s bumpy, and sometimes there’s a sign that says “hey, 3 00:00:07,649 --> 00:00:08,910 the road’s bumpy.” 4 00:00:08,910 --> 00:00:10,030 But what if you’re flying a plane? 5 00:00:10,030 --> 00:00:13,420 It’s not like there’s anywhere to plant a sign, and rough air moves around. 6 00:00:13,420 --> 00:00:17,350 So how do pilots, dispatchers, and air traffic controllers forecast turbulence? 7 00:00:17,350 --> 00:00:22,220 And how do they know when to— Uhhhh, attention HAI viewers, this is your 8 00:00:22,220 --> 00:00:23,220 captain speaking. 9 00:00:23,220 --> 00:00:28,269 I’m getting reports of light infotainment up ahead, so I’m gonna turn on the “fasten 10 00:00:28,269 --> 00:00:33,149 seatbelt sign” and ask that you remain seated for the duration of the video. 11 00:00:33,149 --> 00:00:36,301 Turbulence is what happens when funky air currents push on the wings or body of a plane 12 00:00:36,301 --> 00:00:38,290 and make it pitch, roll, or yaw. 13 00:00:38,290 --> 00:00:43,490 The FAA categorizes it with four intensity levels: light, moderate, severe, and extreme. 14 00:00:43,490 --> 00:00:47,100 At cruising levels, there’s light turbulence in about three percent of the atmosphere, 15 00:00:47,100 --> 00:00:50,350 moderate in about one percent, and severe in a few tenths of a percent. 16 00:00:50,350 --> 00:00:53,140 So it’s not super common, but it still sucks. 17 00:00:53,140 --> 00:00:59,570 From 2009 to 2021, 30 airline passengers and 116 crew members were seriously injured during 18 00:00:59,570 --> 00:01:01,600 turbulence, which airlines have to report. 19 00:01:01,600 --> 00:01:05,400 They do not have to report the minor injuries and indignities wrought by turbulence, such 20 00:01:05,400 --> 00:01:08,592 as, uh, I dunno, spilling your little cup of apple juice on your lap and then having 21 00:01:08,592 --> 00:01:11,650 the person next to you point and laugh and say “hahaha, lap-ple juice,” just as a 22 00:01:11,650 --> 00:01:14,470 hypothetical and not something that happened to this video’s writer. 23 00:01:14,470 --> 00:01:17,270 Oh also, turbulence has been estimated to cost airlines up to $500 million a year in 24 00:01:17,270 --> 00:01:19,000 damage, delays, and injuries, so: bad. 25 00:01:19,000 --> 00:01:24,070 There are basically four types of turbulence: wake, mechanical, thermal, and clear-air. 26 00:01:24,070 --> 00:01:27,520 And even though they’re all atmospheric bumpies, they’re caused by different stuff, 27 00:01:27,520 --> 00:01:29,920 so you need different forecasting methods to avoid each. 28 00:01:29,920 --> 00:01:34,590 The first is wake turbulence, which mostly affects planes coming in for a landing. 29 00:01:34,590 --> 00:01:37,630 Much like a boat in water, a plane in the air leaves a wake behind it, only instead 30 00:01:37,630 --> 00:01:41,479 of swirly water waves, it’s swirly air waves, and if you try to water-ski in it, you’ll 31 00:01:41,479 --> 00:01:42,479 die. 32 00:01:42,479 --> 00:01:43,659 The bigger the plane, the bigger the wake. 33 00:01:43,659 --> 00:01:45,659 It’s easy to predict: see a plane? 34 00:01:45,659 --> 00:01:47,369 The wake turbulence is behind it. 35 00:01:47,369 --> 00:01:52,100 Avoiding it is pretty easy too, since an adjustment of about 50 feet, or just over 15 meters, 36 00:01:52,100 --> 00:01:53,710 is enough to get out of the way. 37 00:01:53,710 --> 00:01:57,899 Also, the FAA has separation rules that ensure safe distances between planes, sort of like 38 00:01:57,899 --> 00:02:01,310 a restraining order—if it were keeping a plane away from turbulence instead of keeping 39 00:02:01,310 --> 00:02:03,640 me away from the Wendover guy’s house. 40 00:02:03,640 --> 00:02:07,159 Next up: mechanical turbulence, which is turbulence caused by stuff. 41 00:02:07,159 --> 00:02:10,060 Buildings, mountains, buildings on mountains… 42 00:02:10,060 --> 00:02:13,370 all these things obstruct and redirect the wind, creating eddies in the troposphere that 43 00:02:13,370 --> 00:02:15,590 shake aircraft like a Polaroid picture. 44 00:02:15,590 --> 00:02:18,980 One type of mechanical turbulence is called “mountain wave:” If you’ve got decently 45 00:02:18,980 --> 00:02:22,690 fast wind moving perpendicular towards a mountain range, it’ll bounce over the top and kick 46 00:02:22,690 --> 00:02:26,590 up rotors of air way higher than the mountains themselves, sometimes all the way into the 47 00:02:26,590 --> 00:02:27,590 jet stream. 48 00:02:27,590 --> 00:02:30,860 Sometimes, this kind of turbulence is actually visible thanks to rotor clouds in the eddies 49 00:02:30,860 --> 00:02:34,560 and lenticular clouds over the tops of the mountains, but ideally, you know about it 50 00:02:34,560 --> 00:02:35,769 before you see it. 51 00:02:35,769 --> 00:02:39,540 Long before a flight takes off, atmosphere nerds model where there’s most likely going 52 00:02:39,540 --> 00:02:41,739 to be mountain wave and other types of turbulence. 53 00:02:41,739 --> 00:02:46,180 NOAA, for example, uses an algorithm called GTG that accounts for everything from wind 54 00:02:46,180 --> 00:02:50,950 speed to different structures’ eddy dissipation rates to forecast where turbulence might be. 55 00:02:50,950 --> 00:02:54,260 Pilots and dispatchers review these models and use them to pick the safest, smoothest 56 00:02:54,260 --> 00:02:58,030 flight path ahead of time—hopefully avoiding the turbulence entirely, or at least going 57 00:02:58,030 --> 00:02:59,420 through as little as possible. 58 00:02:59,420 --> 00:03:03,690 Those same mapping and charting tools also help them forecast our third type of turbulence: 59 00:03:03,690 --> 00:03:04,690 thermal. 60 00:03:04,690 --> 00:03:06,299 Thermal turbulence is the drama queen. 61 00:03:06,299 --> 00:03:10,560 She’s what happens when warm air meets cool air in the atmosphere, often—though not 62 00:03:10,560 --> 00:03:12,440 exclusively—in the context of a thunderstorm. 63 00:03:12,440 --> 00:03:17,170 Here, we’re talking about big vertical columns of air yanking planes up and down, hail, foreboding 64 00:03:17,170 --> 00:03:19,960 cumulus clouds… stuff you don’t wanna fly through. 65 00:03:19,960 --> 00:03:23,511 On top of all the forecasting tools used to create the flight path before takeoff, pilots 66 00:03:23,511 --> 00:03:26,530 also have some tools to spot thermal turbulence while airborne. 67 00:03:26,530 --> 00:03:30,599 Besides the sometimes-obvious visual cues, they also get real-time weather information 68 00:03:30,599 --> 00:03:32,260 from a radar display in the cockpit. 69 00:03:32,260 --> 00:03:35,870 If it’s showing precipitation, you can bet there’ll be turbulence, and they’ll try 70 00:03:35,870 --> 00:03:37,220 to fly around or over it. 71 00:03:37,220 --> 00:03:40,811 If that’s not possible because going around would burn too much fuel or the turbulence 72 00:03:40,811 --> 00:03:43,510 goes up too high, they’ll aim to go through the lightest part. 73 00:03:43,510 --> 00:03:47,720 This last type is the strong-and-silent one: clear-air turbulence. 74 00:03:47,720 --> 00:03:52,629 It’s the most unpredictable of the bunch, and 75% of the time, it’s in literal clear 75 00:03:52,629 --> 00:03:55,480 air—meaning it’s totally invisible. 76 00:03:55,480 --> 00:03:59,150 Clear-air turbulence, or CAT, as I like to call it, is caused by wind shear, which is 77 00:03:59,150 --> 00:04:03,340 what happens when wind meets other wind moving at a super different speed or direction. 78 00:04:03,340 --> 00:04:06,659 This often happens around curves in the jet stream, and creates patches of turbulence 79 00:04:06,659 --> 00:04:11,430 anywhere from two to ten-thousand feet deep, or about six hundred to three-thousand meters. 80 00:04:11,430 --> 00:04:15,580 Area-wise, they can be in the range of about Rhode Island to Chad—though usually closer 81 00:04:15,580 --> 00:04:20,530 to Rhode Island, and your best tool to spot ‘em is PIREPS: reports from other pilots. 82 00:04:20,530 --> 00:04:23,511 Those can be pretty straightforward: Pilot A tells air traffic control that they just 83 00:04:23,511 --> 00:04:27,280 went through a CAT patch, air traffic control tells Pilot B to navigate around said CAT 84 00:04:27,280 --> 00:04:29,780 patch, buying Pilot B about 20 minutes of adjustment time. 85 00:04:29,780 --> 00:04:33,150 There are also automated versions of this process that collect turbulence data from 86 00:04:33,150 --> 00:04:37,060 all the planes in the air at once and create a sort of crowdsourced turbulence map. 87 00:04:37,060 --> 00:04:40,789 So that’s how the people who plan the flights and fly the planes deal with turbulence. 88 00:04:40,789 --> 00:04:42,670 But what about you, the anxious passenger? 89 00:04:42,670 --> 00:04:46,312 Well, you can learn how to read graphical AIRMETs from NOAA or visit the turbulence 90 00:04:46,312 --> 00:04:49,850 forecast before you fly… or you can just trust the trained professionals operating 91 00:04:49,850 --> 00:04:52,580 your flight and the suite of tools they use to forecast and avoid rough skies. 92 00:04:52,580 --> 00:04:55,520 But whatever you do, pop a lid on that apple juice. 93 00:04:55,520 --> 00:04:59,810 Hey, you know what’s even rockier and more nausea-inducing than turbulence? 94 00:04:59,810 --> 00:05:04,000 Choosing a career without the help of this video’s sponsor: 80,000 Hours. 95 00:05:04,000 --> 00:05:08,120 80,000 Hours is a completely free, nonprofit resource that helps you find a career that’s 96 00:05:08,120 --> 00:05:10,360 a good fit for you and does good in the world. 97 00:05:10,360 --> 00:05:14,250 You’re going to devote 80,000 hours to your career in your lifetime—spent wisely, that’s 98 00:05:14,250 --> 00:05:16,740 enough time to do a lot of good. 99 00:05:16,740 --> 00:05:20,410 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