1 00:00:16,178 --> 00:00:17,470 PHILIP GREENSPUN: Welcome back. 2 00:00:17,470 --> 00:00:19,600 I hope you've got your coffee. 3 00:00:19,600 --> 00:00:21,520 I see somebody has a muffin. 4 00:00:21,520 --> 00:00:23,170 They'll be in a carb coma, Francis, 5 00:00:23,170 --> 00:00:26,960 I'm relying on you to answer all the hard questions. 6 00:00:26,960 --> 00:00:29,080 That's not authorized. 7 00:00:29,080 --> 00:00:34,220 All right, so multi-engine jets-- 8 00:00:34,220 --> 00:00:37,320 the piston twin, the good news is, 9 00:00:37,320 --> 00:00:38,820 when both engines are spinning, it's 10 00:00:38,820 --> 00:00:41,290 easier to fly than a single. 11 00:00:41,290 --> 00:00:43,530 Because you don't need as much right rudder 12 00:00:43,530 --> 00:00:44,740 or really any right rudder. 13 00:00:44,740 --> 00:00:47,290 It doesn't have all those left turning tendencies, 14 00:00:47,290 --> 00:00:49,170 necessarily. 15 00:00:49,170 --> 00:00:52,770 The training and rating, especially the Seminole, 16 00:00:52,770 --> 00:00:54,320 which has counter-rotating props-- 17 00:00:57,030 --> 00:01:00,120 all your training for a multi-engine airplane 18 00:01:00,120 --> 00:01:02,550 is flying around on one engine. 19 00:01:02,550 --> 00:01:04,050 Because flying around on two engines 20 00:01:04,050 --> 00:01:05,200 is pretty much the same. 21 00:01:05,200 --> 00:01:07,020 So basically, almost all the flight time 22 00:01:07,020 --> 00:01:10,350 that you accumulate during your multi-engine training 23 00:01:10,350 --> 00:01:14,160 will be with one engine pulled back to idle or, in some cases, 24 00:01:14,160 --> 00:01:15,780 stopped altogether. 25 00:01:15,780 --> 00:01:21,090 You have six power levers in a twin-engine piston airplane, 26 00:01:21,090 --> 00:01:25,200 two for throttle, two for mixture, and two for prop. 27 00:01:25,200 --> 00:01:29,700 You may also have cowl flaps to bring more or less cooling air 28 00:01:29,700 --> 00:01:30,960 into these piston engines. 29 00:01:34,040 --> 00:01:35,850 By FAA certification requirements, 30 00:01:35,850 --> 00:01:37,610 as I think I mentioned earlier, there 31 00:01:37,610 --> 00:01:39,190 is no required climb rate. 32 00:01:39,190 --> 00:01:43,020 It may be a truly crummy airplane on one engine. 33 00:01:43,020 --> 00:01:45,390 So that's why people say that second engine 34 00:01:45,390 --> 00:01:48,990 either takes you to the scene of the accident. 35 00:01:48,990 --> 00:01:51,940 One engine expert, Mike Bush, he said-- 36 00:01:51,940 --> 00:01:54,190 he came to appreciate the Cirrus parachute. 37 00:01:54,190 --> 00:01:56,940 It's not like having that extra engine out there 38 00:01:56,940 --> 00:01:59,270 on the wing trying to kill you all the time. 39 00:01:59,270 --> 00:02:03,390 It just waits there quietly until you need it. 40 00:02:03,390 --> 00:02:06,020 Piston twins have an illustrious history. 41 00:02:06,020 --> 00:02:09,840 Here is a Aero Commander piston-driven 42 00:02:09,840 --> 00:02:14,023 twin that was actually Eisenhower's Air Force One. 43 00:02:14,023 --> 00:02:16,440 This also tells you something of the growth of government. 44 00:02:16,440 --> 00:02:18,660 When Eisenhower was president and wanted 45 00:02:18,660 --> 00:02:20,400 to go to a smaller airport, this is 46 00:02:20,400 --> 00:02:25,480 how he would go, in an airplane designed for about six people. 47 00:02:25,480 --> 00:02:27,280 OK, this is probably what you'll be flying, 48 00:02:27,280 --> 00:02:28,980 which is the Piper Seminole. 49 00:02:28,980 --> 00:02:32,160 It is unusual in that the props counter rotate. 50 00:02:32,160 --> 00:02:34,410 And that has some advantages that are 51 00:02:34,410 --> 00:02:37,040 beyond the scope of this talk. 52 00:02:37,040 --> 00:02:41,640 It's a design from the '70s based on designs from the '50s. 53 00:02:41,640 --> 00:02:42,870 Where the problems happen-- 54 00:02:47,110 --> 00:02:48,130 so have a look here. 55 00:02:50,930 --> 00:02:55,550 Can anybody immediately see what one problem might be? 56 00:02:55,550 --> 00:02:58,460 I'd say, the left engine quits, and you 57 00:02:58,460 --> 00:03:00,198 have to manipulate these. 58 00:03:00,198 --> 00:03:00,740 What happens? 59 00:03:03,788 --> 00:03:05,177 AUDIENCE: [INAUDIBLE] 60 00:03:05,177 --> 00:03:07,410 PHILIP GREENSPUN: You're manipulating the controls 61 00:03:07,410 --> 00:03:11,040 for the good engine instead of for the failed engine 62 00:03:11,040 --> 00:03:12,600 inadvertently. 63 00:03:12,600 --> 00:03:17,250 So it's just an interface that's overly complex 64 00:03:17,250 --> 00:03:18,450 given human frailties. 65 00:03:18,450 --> 00:03:21,090 So, what do you have to do if an engine quits? 66 00:03:21,090 --> 00:03:25,320 You don't want the drag of that propeller 67 00:03:25,320 --> 00:03:31,090 out there that's not being driven by the engine. 68 00:03:31,090 --> 00:03:32,952 So you push all of the levers forward 69 00:03:32,952 --> 00:03:35,160 and try to get maximum power out of your good engine. 70 00:03:35,160 --> 00:03:37,980 Push everything forward. 71 00:03:37,980 --> 00:03:41,730 You'll have to put in some rudder to correct the yaw, 72 00:03:41,730 --> 00:03:44,430 because the airplane is going to be pulled 73 00:03:44,430 --> 00:03:46,890 to one side or the other depending on which 74 00:03:46,890 --> 00:03:48,570 engine is still running. 75 00:03:48,570 --> 00:03:53,640 And then there's the old adage, dead foot, dead engine. 76 00:03:53,640 --> 00:03:58,510 So if your left foot is flat on the floor 77 00:03:58,510 --> 00:04:00,930 and it's your right rudder that's in, 78 00:04:00,930 --> 00:04:05,010 then you know that it's the left engine that has failed. 79 00:04:05,010 --> 00:04:07,770 Then you try to verify the dead engine 80 00:04:07,770 --> 00:04:09,180 by pulling back that throttle. 81 00:04:09,180 --> 00:04:11,640 So you'll say, OK, I think the left engine's failed. 82 00:04:11,640 --> 00:04:14,420 I'm going to try monkeying with the left throttle. 83 00:04:14,420 --> 00:04:17,670 And if that has no effect on the flight characteristics, 84 00:04:17,670 --> 00:04:20,700 you verify that it's the left engine. 85 00:04:20,700 --> 00:04:24,330 Then you feather the dead engine by pulling the prop control 86 00:04:24,330 --> 00:04:26,210 all the way back. 87 00:04:26,210 --> 00:04:28,680 If you're in a two-pilot crew, you'll 88 00:04:28,680 --> 00:04:30,780 get your co-pilot to verify. 89 00:04:30,780 --> 00:04:34,680 I have my hand on the left prop control. 90 00:04:34,680 --> 00:04:38,970 And you pull that back, close the cowl flaps. 91 00:04:38,970 --> 00:04:41,670 And only now do you have any chance 92 00:04:41,670 --> 00:04:43,470 of getting an actual climb. 93 00:04:43,470 --> 00:04:46,980 So imagine if this engine failed shortly after takeoff. 94 00:04:46,980 --> 00:04:49,020 It's a lot of stuff to do very quickly. 95 00:04:49,020 --> 00:04:50,670 You have to do it all right. 96 00:04:50,670 --> 00:04:52,860 And if you miss even one of these things, 97 00:04:52,860 --> 00:04:56,040 you may not be able to clear obstacles 98 00:04:56,040 --> 00:04:57,300 at the end of the runway. 99 00:04:57,300 --> 00:05:00,420 Now, of course, your typical piston twin, 100 00:05:00,420 --> 00:05:03,698 takeoff is a stressful time for an engine 100% power. 101 00:05:03,698 --> 00:05:05,490 But there's definitely more engine failures 102 00:05:05,490 --> 00:05:06,900 that occur en route. 103 00:05:06,900 --> 00:05:11,160 So the generally negative impression of piston twins 104 00:05:11,160 --> 00:05:13,860 might have to be revised if your primary mission is flying 105 00:05:13,860 --> 00:05:15,570 around the Caribbean islands. 106 00:05:15,570 --> 00:05:17,710 You might, in that case, actually say, well, 107 00:05:17,710 --> 00:05:19,680 I'd rather have that second engine. 108 00:05:19,680 --> 00:05:22,140 Is this within human capability, that sequence 109 00:05:22,140 --> 00:05:24,690 that you just saw? 110 00:05:24,690 --> 00:05:28,140 Yes, in World War II when engines weren't 111 00:05:28,140 --> 00:05:31,740 being made with as much precision as they are now, 112 00:05:31,740 --> 00:05:34,230 it would be ordinary to have one out of four engines 113 00:05:34,230 --> 00:05:37,515 or one out of two engines fail on any given mission. 114 00:05:37,515 --> 00:05:38,640 But they also got it wrong. 115 00:05:38,640 --> 00:05:41,670 There is one very famous guy, Louis Zamperini. 116 00:05:41,670 --> 00:05:44,610 Some of you may have seen a movie about him. 117 00:05:44,610 --> 00:05:47,130 He floated in a raft for 47 days. 118 00:05:47,130 --> 00:05:51,540 I think that was a record at the time for survival at sea. 119 00:05:51,540 --> 00:05:54,660 He was on a four-engined aircraft. 120 00:05:54,660 --> 00:05:57,000 And one engineer quit. 121 00:05:57,000 --> 00:06:00,232 And I think there were about four pilots in the cockpit. 122 00:06:00,232 --> 00:06:02,190 Remember we talked about a flight engineer also 123 00:06:02,190 --> 00:06:03,693 being an airman. 124 00:06:03,693 --> 00:06:05,610 So if we count the flight engineer as a pilot, 125 00:06:05,610 --> 00:06:08,910 there were at least three or four experts up front. 126 00:06:08,910 --> 00:06:13,320 And as a team, they feathered the wrong engine. 127 00:06:13,320 --> 00:06:19,590 So they killed a second engine that was actually good. 128 00:06:19,590 --> 00:06:21,965 And now they had two engines working on only one 129 00:06:21,965 --> 00:06:22,840 side of the airplane. 130 00:06:22,840 --> 00:06:24,850 And it was uncontrollable. 131 00:06:24,850 --> 00:06:27,900 So they went in the water through human error. 132 00:06:27,900 --> 00:06:30,517 And Cape Air has a great track record. 133 00:06:30,517 --> 00:06:32,850 They've had a handful of engine failures over the years. 134 00:06:32,850 --> 00:06:36,242 They fly piston twins all day, every day in the Caribbean 135 00:06:36,242 --> 00:06:37,200 and around New England. 136 00:06:37,200 --> 00:06:38,490 And when they have a problem, usually it's 137 00:06:38,490 --> 00:06:39,448 not a complete failure. 138 00:06:39,448 --> 00:06:42,630 But maybe there's an ugly indication on one engine. 139 00:06:42,630 --> 00:06:44,130 So they'll shut it down. 140 00:06:44,130 --> 00:06:45,900 But they do a lot of recurrent training. 141 00:06:45,900 --> 00:06:48,330 That's what they fly all day, every day. 142 00:06:48,330 --> 00:06:53,820 The typical family airplane doesn't get flown as often. 143 00:06:53,820 --> 00:06:55,830 And the pilot isn't as proficient. 144 00:06:55,830 --> 00:06:59,190 So the capable twins are very inexpensive now, 145 00:06:59,190 --> 00:07:02,800 except for the Beechcraft Baron, which is the most sought after. 146 00:07:02,800 --> 00:07:05,340 They're a little more expensive to insure 147 00:07:05,340 --> 00:07:07,170 than the comparable single. 148 00:07:07,170 --> 00:07:10,290 Just the other day, I got a quote from my local insurance 149 00:07:10,290 --> 00:07:12,900 agency called Plane Insurance. 150 00:07:12,900 --> 00:07:16,380 And we found out that if you look 151 00:07:16,380 --> 00:07:20,040 at a $200,000 aircraft being flown 152 00:07:20,040 --> 00:07:23,940 by a pilot that has 250 hours of experience in type 153 00:07:23,940 --> 00:07:27,135 in that exact aircraft and with a million dollars 154 00:07:27,135 --> 00:07:29,590 of smooth liability, that means no sublimit. 155 00:07:29,590 --> 00:07:31,817 So if there's just one passenger, 156 00:07:31,817 --> 00:07:33,900 they would pay, oh, a million dollars for injuries 157 00:07:33,900 --> 00:07:35,220 to that one passenger. 158 00:07:35,220 --> 00:07:40,200 Some policies have, like, $100,000 per person sublimit. 159 00:07:40,200 --> 00:07:44,310 Anyway, it was about 50% more for the Baron, $3,700 a year 160 00:07:44,310 --> 00:07:46,930 versus $2,500. 161 00:07:46,930 --> 00:07:48,460 So there you have it. 162 00:07:48,460 --> 00:07:51,180 Again, it's not insanely risky. 163 00:07:51,180 --> 00:07:52,770 You can quantify the risk. 164 00:07:52,770 --> 00:07:54,540 The insurance company has. 165 00:07:54,540 --> 00:07:56,340 But it is riskier. 166 00:07:56,340 --> 00:07:58,110 OK. 167 00:07:58,110 --> 00:08:01,800 We have a lot of engineering geniuses in this class and one 168 00:08:01,800 --> 00:08:04,010 physics genius-- 169 00:08:04,010 --> 00:08:04,510 science. 170 00:08:04,510 --> 00:08:05,570 Which one was it? 171 00:08:05,570 --> 00:08:07,710 AUDIENCE: Brain in cog. 172 00:08:07,710 --> 00:08:09,830 PHILIP GREENSPUN: That's close enough to physics, 173 00:08:09,830 --> 00:08:10,600 brain in cog. 174 00:08:10,600 --> 00:08:14,530 It takes a lot of physics to make your neurons fire. 175 00:08:14,530 --> 00:08:18,820 Obviously, my neurons aren't firing very well. 176 00:08:18,820 --> 00:08:22,750 So, what's the limit to a piston engine's power? 177 00:08:22,750 --> 00:08:27,070 Why is it that we can't get 6,000 horsepower out 178 00:08:27,070 --> 00:08:28,100 of our piston engine? 179 00:08:28,100 --> 00:08:29,266 What do you guys think? 180 00:08:29,266 --> 00:08:30,180 AUDIENCE: Cooling. 181 00:08:30,180 --> 00:08:31,555 PHILIP GREENSPUN: Cooling is one. 182 00:08:31,555 --> 00:08:33,400 Sure. 183 00:08:33,400 --> 00:08:33,970 What else? 184 00:08:33,970 --> 00:08:36,520 What's fundamentally limiting our ability to produce power? 185 00:08:36,520 --> 00:08:38,145 Remember, all the power that we produce 186 00:08:38,145 --> 00:08:44,716 is by burning fuel and oxygen. Aziz? 187 00:08:44,716 --> 00:08:45,650 AUDIENCE: [INAUDIBLE] 188 00:08:45,650 --> 00:08:46,870 PHILIP GREENSPUN: Size, yeah. 189 00:08:46,870 --> 00:08:49,600 I think that's a good insight. 190 00:08:49,600 --> 00:08:51,790 It's the size of the cylinder. 191 00:08:51,790 --> 00:08:55,270 You only have so much fuel and air that you can combust. 192 00:08:55,270 --> 00:08:58,150 And once you've blown all of that up, what do you got? 193 00:08:58,150 --> 00:08:59,540 Nothing. 194 00:08:59,540 --> 00:09:02,950 So if you want to know why you should never 195 00:09:02,950 --> 00:09:04,600 be like the Silicon Valley heroes 196 00:09:04,600 --> 00:09:07,630 and never hire anybody over the age of 30, 197 00:09:07,630 --> 00:09:12,370 the inventor of the modern jet engine was only 23 years old, 198 00:09:12,370 --> 00:09:14,920 I believe, at the time that the patent 199 00:09:14,920 --> 00:09:16,910 was filed over in England. 200 00:09:16,910 --> 00:09:21,010 He was a cadet when he conceived of the idea 201 00:09:21,010 --> 00:09:22,850 at the Royal Air College. 202 00:09:22,850 --> 00:09:25,090 And he said, well, look, these pistons-- 203 00:09:25,090 --> 00:09:27,940 no matter how high up you go, no matter what you do, 204 00:09:27,940 --> 00:09:31,390 all you can ever do is burn the volume of air and fuel 205 00:09:31,390 --> 00:09:33,980 that's inside the cylinder. 206 00:09:33,980 --> 00:09:37,810 So, what if we just adapt this gas turbine, which 207 00:09:37,810 --> 00:09:40,660 has already been invented? 208 00:09:40,660 --> 00:09:44,530 It was kind of invented in 1791 but not really practical 209 00:09:44,530 --> 00:09:45,920 to fabricate at the time. 210 00:09:45,920 --> 00:09:47,920 But look, we're just sucking in all of this air. 211 00:09:47,920 --> 00:09:51,310 We can probably get 20 times as much air in if we just 212 00:09:51,310 --> 00:09:53,380 vacuum it in, and suck it into a turbine, 213 00:09:53,380 --> 00:09:55,250 and then light it on fire. 214 00:09:55,250 --> 00:09:57,550 So that was the idea, the fundamental insight 215 00:09:57,550 --> 00:10:00,730 for why a gas turbine is going to be a better machine 216 00:10:00,730 --> 00:10:03,670 for propelling aircraft. 217 00:10:03,670 --> 00:10:05,170 He struggled with funding. 218 00:10:05,170 --> 00:10:08,740 So you can see, the patent was filed in 1930. 219 00:10:08,740 --> 00:10:16,110 And it was only in 1941 that it finally got flown. 220 00:10:16,110 --> 00:10:18,110 And that's a good lesson for you entrepreneurs. 221 00:10:18,110 --> 00:10:20,620 A lot of MIT startups have the characteristic, 222 00:10:20,620 --> 00:10:23,320 but they're a bit too early. 223 00:10:23,320 --> 00:10:27,430 I remember, in 1994, I built the world's 224 00:10:27,430 --> 00:10:30,010 first electronic medical record system that 225 00:10:30,010 --> 00:10:31,700 had a web interface. 226 00:10:31,700 --> 00:10:33,700 So that had zero value at the time. 227 00:10:33,700 --> 00:10:38,620 And about 10 years later, that was a multi-billion dollar 228 00:10:38,620 --> 00:10:40,510 idea. 229 00:10:40,510 --> 00:10:44,860 So yeah, Whittle died in relative obscurity in 1996. 230 00:10:44,860 --> 00:10:47,680 So nobody else liked this idea at the time. 231 00:10:50,260 --> 00:10:53,120 I'll let you read that quote-- 232 00:10:53,120 --> 00:10:54,610 not totally wrong, of course. 233 00:10:54,610 --> 00:10:56,620 Because it did take quite a bit of engineering 234 00:10:56,620 --> 00:10:58,480 to make it truly practical. 235 00:10:58,480 --> 00:11:02,950 But that didn't take as long as people thought. 236 00:11:02,950 --> 00:11:05,620 All right, you saw this figure before. 237 00:11:05,620 --> 00:11:10,060 This is the modern turbo jet or turbo fan engine, 238 00:11:10,060 --> 00:11:15,210 where you have this bypass error. 239 00:11:15,210 --> 00:11:23,220 So the outer ring is devoted to air 240 00:11:23,220 --> 00:11:25,890 that really never goes through and gets 241 00:11:25,890 --> 00:11:29,180 burned in the power section. 242 00:11:29,180 --> 00:11:32,813 And that provides a lot of additional propulsion for not 243 00:11:32,813 --> 00:11:33,980 a whole lot of extra energy. 244 00:11:33,980 --> 00:11:37,590 So these are much more efficient than the early pure turbo jet. 245 00:11:37,590 --> 00:11:41,860 So just to remind you, you have the compressor section, 246 00:11:41,860 --> 00:11:44,590 where you have air being squeezed. 247 00:11:44,590 --> 00:11:46,575 Now you introduce some fuel. 248 00:11:46,575 --> 00:11:49,840 It catches on fire from the extreme heat or the igniters 249 00:11:49,840 --> 00:11:51,250 if you're just starting up. 250 00:11:51,250 --> 00:11:53,320 That drives these power turbines. 251 00:11:53,320 --> 00:11:57,220 And some of the spinning from the power turbines 252 00:11:57,220 --> 00:12:00,190 goes back to spin the compressor wheels, as well 253 00:12:00,190 --> 00:12:04,180 as the fan in front, which is kind of like the propeller. 254 00:12:04,180 --> 00:12:07,913 All right, what about having to turbo jet engines? 255 00:12:07,913 --> 00:12:10,330 A lot of people like to see two engines on their aircraft, 256 00:12:10,330 --> 00:12:13,240 especially airline passengers. 257 00:12:13,240 --> 00:12:16,330 If you have an engine failure, what do you do? 258 00:12:16,330 --> 00:12:19,840 The answer is, pretty much nothing. 259 00:12:19,840 --> 00:12:22,690 If it hasn't been done automatically for you already, 260 00:12:22,690 --> 00:12:25,810 you can advance the thrust levers. 261 00:12:25,810 --> 00:12:28,090 If the airplane is the yawing, that sometimes 262 00:12:28,090 --> 00:12:31,870 is automatically corrected for you to a substantial extent 263 00:12:31,870 --> 00:12:33,460 by the yaw damper. 264 00:12:33,460 --> 00:12:35,710 You will step on the rudder to do the natural thing 265 00:12:35,710 --> 00:12:39,950 and bring the nose back pointed to where you want it pointed. 266 00:12:39,950 --> 00:12:42,070 And you'll keep climbing nicely. 267 00:12:42,070 --> 00:12:44,525 You've arranged everything both in terms 268 00:12:44,525 --> 00:12:46,900 of the design of the aircraft and the weight at which you 269 00:12:46,900 --> 00:12:51,250 took off so that, no matter the environmental conditions, 270 00:12:51,250 --> 00:12:52,630 you will be able to climb. 271 00:12:52,630 --> 00:12:54,720 And you will be able to clear the obstacles. 272 00:12:54,720 --> 00:12:55,720 This can be a challenge. 273 00:12:55,720 --> 00:12:58,150 If you're taking off out of a mountainous, high altitude, 274 00:12:58,150 --> 00:13:01,630 hot airport, you're not going to have a full load of fuel 275 00:13:01,630 --> 00:13:04,408 and a full load of people and bags. 276 00:13:04,408 --> 00:13:05,950 But by regulation, you're going to be 277 00:13:05,950 --> 00:13:09,910 able to clear the terrain safely even on one engine. 278 00:13:09,910 --> 00:13:11,840 Why is it so much easier? 279 00:13:11,840 --> 00:13:14,950 You don't have a propeller that'll drag back a wing. 280 00:13:14,950 --> 00:13:19,870 And therefore, there's no urgency about feathering. 281 00:13:19,870 --> 00:13:23,350 You also have a little bit less of the crazy yaw. 282 00:13:23,350 --> 00:13:26,410 Because the engines are, in some aircraft, pretty 283 00:13:26,410 --> 00:13:29,050 close to the fuselage. 284 00:13:29,050 --> 00:13:32,830 So basically, you can still apply that cardinal rule 285 00:13:32,830 --> 00:13:34,270 of flying jets. 286 00:13:34,270 --> 00:13:37,000 If the switch has dust on it, don't touch it. 287 00:13:37,000 --> 00:13:42,028 So you don't have to take immediate action. 288 00:13:42,028 --> 00:13:43,570 All right, if it's turbo jet powered, 289 00:13:43,570 --> 00:13:46,600 though, you do need specific training. 290 00:13:46,600 --> 00:13:51,700 And you have to pass a check ride specific to that aircraft. 291 00:13:51,700 --> 00:13:54,190 So most of you guys, except for Francis, 292 00:13:54,190 --> 00:13:57,940 believe that Captain Sully was all by himself in the A320. 293 00:13:57,940 --> 00:14:01,720 but actually, anything that's more than about a 10 seater 294 00:14:01,720 --> 00:14:03,520 almost always requires two pilots. 295 00:14:03,520 --> 00:14:05,830 And according to the type certificate, 296 00:14:05,830 --> 00:14:10,060 it's not even legal to operate even the larger business 297 00:14:10,060 --> 00:14:12,970 jets with one pilot. 298 00:14:12,970 --> 00:14:20,340 There is an old FAR 91.5, I believe, 299 00:14:20,340 --> 00:14:24,730 that says there has to be a proficiency check annually 300 00:14:24,730 --> 00:14:28,930 for the pilot in command of a two-pilot aircraft. 301 00:14:28,930 --> 00:14:31,210 And more recently, the regulations 302 00:14:31,210 --> 00:14:34,040 were updated for single-pilot turbo jets 303 00:14:34,040 --> 00:14:36,560 so that a check ride has to be done annually, 304 00:14:36,560 --> 00:14:39,307 which is not really that different from the insurance 305 00:14:39,307 --> 00:14:40,640 requirements of annual training. 306 00:14:40,640 --> 00:14:42,730 They just made it a little more formalized 307 00:14:42,730 --> 00:14:44,830 with FAA bureaucracy. 308 00:14:44,830 --> 00:14:46,960 All right, turbo jets that you might own-- 309 00:14:46,960 --> 00:14:50,350 the single pilot business jet with a straight wing-- 310 00:14:50,350 --> 00:14:52,150 they said initially, the Cessna Citation 311 00:14:52,150 --> 00:14:54,760 was so slow that birds were hitting it from behind. 312 00:14:57,790 --> 00:15:00,700 But sometimes safety and having it 313 00:15:00,700 --> 00:15:03,610 be easy to operate by people of ordinary skill 314 00:15:03,610 --> 00:15:06,010 and people of lower skill levels is better than 315 00:15:06,010 --> 00:15:08,410 getting that last 50 knots of speed. 316 00:15:08,410 --> 00:15:10,930 And that's what Cessna figured out. 317 00:15:10,930 --> 00:15:12,910 So they're still kind of a leader in this area. 318 00:15:12,910 --> 00:15:15,310 They produced the Cessna Mustang, which 319 00:15:15,310 --> 00:15:18,530 you see there at the right. 320 00:15:18,530 --> 00:15:20,900 Some of the Microsoft folks, they spun off 321 00:15:20,900 --> 00:15:22,360 a design called the Eclipse. 322 00:15:22,360 --> 00:15:25,390 It was supposed to have these new cruise-missile-inspired 323 00:15:25,390 --> 00:15:27,540 engines from Williams. 324 00:15:27,540 --> 00:15:28,540 The engines didn't work. 325 00:15:28,540 --> 00:15:31,030 So the 1500 nautical mile airplane 326 00:15:31,030 --> 00:15:35,350 became a 900 nautical mile airplane with a Pratt & Whitney 327 00:15:35,350 --> 00:15:36,730 more conventional designed engine 328 00:15:36,730 --> 00:15:39,100 that's used on some of these other designs. 329 00:15:39,100 --> 00:15:41,500 The Embraer Phenom 100 has the same engines 330 00:15:41,500 --> 00:15:44,050 essentially as the Mustang, same family. 331 00:15:44,050 --> 00:15:45,640 HondaJet has an innovative engine 332 00:15:45,640 --> 00:15:48,430 designed by GE and Honda. 333 00:15:48,430 --> 00:15:51,100 These have all pretty much been business failures. 334 00:15:51,100 --> 00:15:56,830 And the answer to that is the fixed costs of jet ownership 335 00:15:56,830 --> 00:16:02,600 are so high you can't just get a T hangar for $800 a month. 336 00:16:02,600 --> 00:16:06,870 You may have to pay at one of the busier airports 337 00:16:06,870 --> 00:16:11,260 $40,000 a year to have an FBO hangar it for you. 338 00:16:11,260 --> 00:16:14,620 The insurance company will require simulator training 339 00:16:14,620 --> 00:16:15,280 annually. 340 00:16:15,280 --> 00:16:18,190 And you'll probably have to have two pilots 341 00:16:18,190 --> 00:16:20,920 as a practical matter go through training. 342 00:16:20,920 --> 00:16:23,170 Insurance will be expensive, because the whole value 343 00:16:23,170 --> 00:16:23,710 is high. 344 00:16:23,710 --> 00:16:25,990 If you wreck a $5 million airplane or a $10 million 345 00:16:25,990 --> 00:16:29,860 airplane, that's a bad day for the insurance company. 346 00:16:29,860 --> 00:16:34,450 You get charged a lot more for landing fees 347 00:16:34,450 --> 00:16:36,190 and parking at airports. 348 00:16:36,190 --> 00:16:39,483 When you're a little Cessna, they give you a break, 349 00:16:39,483 --> 00:16:41,900 because they don't want you saying anything bad about them 350 00:16:41,900 --> 00:16:43,550 on airnav.com. 351 00:16:43,550 --> 00:16:45,170 But if you show up in a Gulfstream, 352 00:16:45,170 --> 00:16:49,880 they figure you probably have a credit card somewhere. 353 00:16:49,880 --> 00:16:52,100 So yeah, the Mustang, they actually 354 00:16:52,100 --> 00:16:53,930 stopped production of that plane. 355 00:16:53,930 --> 00:16:56,810 The Phenom 100 is still going from Embraer. 356 00:16:56,810 --> 00:17:02,320 But basically, I think the Phenom 300 is-- 357 00:17:02,320 --> 00:17:04,349 it holds about nine or 10 people. 358 00:17:04,349 --> 00:17:07,790 And I think it weighs somewhere in the 15,000 to 20,000 359 00:17:07,790 --> 00:17:10,180 pound range. 360 00:17:10,180 --> 00:17:12,349 At gross, those are the airplanes 361 00:17:12,349 --> 00:17:15,095 that seem to be popular. 362 00:17:15,095 --> 00:17:18,829 The Phenom 300 is about $9 million new. 363 00:17:18,829 --> 00:17:22,650 And $3 to $5 million used applies, including 364 00:17:22,650 --> 00:17:24,349 the things like the Cessna CJ3. 365 00:17:24,349 --> 00:17:28,339 A $3 million plane could be a CJ3. 366 00:17:28,339 --> 00:17:30,590 All right, what about single-engine jets? 367 00:17:30,590 --> 00:17:35,305 The problem is they're more vulnerable to engine failure. 368 00:17:35,305 --> 00:17:36,680 Jet engines are a little bit more 369 00:17:36,680 --> 00:17:40,010 vulnerable to failure from, say, a bird strike or something 370 00:17:40,010 --> 00:17:41,090 than a piston engine. 371 00:17:41,090 --> 00:17:45,410 And therefore, you need some way of dealing with the consequence 372 00:17:45,410 --> 00:17:47,330 of having that engine fail. 373 00:17:47,330 --> 00:17:49,800 The Cirrus jet is pretty slow. 374 00:17:49,800 --> 00:17:51,950 So it could actually be landed off the airport, 375 00:17:51,950 --> 00:17:56,010 perhaps, without too much damage. 376 00:17:56,010 --> 00:17:57,470 But it has a parachute in case. 377 00:17:57,470 --> 00:18:01,130 And F-16 and other fighter jets that are single engine, 378 00:18:01,130 --> 00:18:03,920 they obviously have ejection seats. 379 00:18:03,920 --> 00:18:07,080 Twin turboprops-- let's talk about those. 380 00:18:07,080 --> 00:18:09,870 So if you want to land on a short runway-- 381 00:18:09,870 --> 00:18:14,093 we talked about turboprop engines, I think, on day one. 382 00:18:14,093 --> 00:18:16,010 They can produce a tremendous amount of power. 383 00:18:16,010 --> 00:18:18,363 So you can have a much bigger, heavier airplane. 384 00:18:18,363 --> 00:18:20,030 But because they're driving a propeller, 385 00:18:20,030 --> 00:18:21,488 you get to take off and land short. 386 00:18:21,488 --> 00:18:26,790 They developed thrust very effectively at low speeds. 387 00:18:26,790 --> 00:18:29,930 And the prop is a huge drag, so when you land, 388 00:18:29,930 --> 00:18:33,110 it kind of slows down and stops immediately 389 00:18:33,110 --> 00:18:34,730 or almost immediately. 390 00:18:34,730 --> 00:18:40,243 So the King Air from 1964 to the present 391 00:18:40,243 --> 00:18:41,660 with these Pratt & Whitney engines 392 00:18:41,660 --> 00:18:46,790 that were developed in the very end of the '50s, the PT6. 393 00:18:46,790 --> 00:18:49,220 Those have been hugely popular. 394 00:18:49,220 --> 00:18:51,870 When you hit a bird, it's a problem for the bird 395 00:18:51,870 --> 00:18:55,970 but not usually for the propeller. 396 00:18:55,970 --> 00:19:01,100 The King Airs and this ATR, have an auto-feather system. 397 00:19:01,100 --> 00:19:03,350 If one engine loses power, the propeller 398 00:19:03,350 --> 00:19:06,890 will automatically go to this knife-edge configuration. 399 00:19:06,890 --> 00:19:08,810 I should have said what feathering is. 400 00:19:08,810 --> 00:19:10,220 You twist the propeller blades so 401 00:19:10,220 --> 00:19:14,250 that they're edge to the wind instead of flat to the wind. 402 00:19:14,250 --> 00:19:19,700 So you dramatically reduce the drag of the propeller. 403 00:19:19,700 --> 00:19:22,940 So that airplane actually took care of itself 404 00:19:22,940 --> 00:19:25,400 or should have taken care of itself pretty well. 405 00:19:25,400 --> 00:19:27,200 You can read about that crash. 406 00:19:27,200 --> 00:19:29,820 I think it was in Taiwan. 407 00:19:29,820 --> 00:19:32,300 But the pilots decided to take heroic, immediate action-- 408 00:19:32,300 --> 00:19:34,160 or at least, one of the pilots did-- 409 00:19:34,160 --> 00:19:38,180 and shut down the good engine instead of just leaving 410 00:19:38,180 --> 00:19:40,380 well enough alone. 411 00:19:40,380 --> 00:19:42,640 OK, single-engine turboprops-- as these engines 412 00:19:42,640 --> 00:19:44,650 got more refined and more reliable, 413 00:19:44,650 --> 00:19:47,370 if you look at the PT6 design, it 414 00:19:47,370 --> 00:19:49,510 has all kinds of tubes, and hoses, 415 00:19:49,510 --> 00:19:52,930 and vacuum going from one place to another and bleed air. 416 00:19:52,930 --> 00:19:55,480 You'd be surprised that it's as reliable as it is. 417 00:19:55,480 --> 00:19:58,270 But they supposedly don't really have 418 00:19:58,270 --> 00:20:03,250 to be shut down for a problem or fail more than about 419 00:20:03,250 --> 00:20:06,380 once every 300,000, 400,000, or 500,000 hours. 420 00:20:06,380 --> 00:20:13,570 So after that insight, people said, let's just 421 00:20:13,570 --> 00:20:14,830 put one of them in. 422 00:20:14,830 --> 00:20:17,020 And we don't need that second engine. 423 00:20:17,020 --> 00:20:18,990 It'll save a ton of money. 424 00:20:18,990 --> 00:20:21,250 So the Cessna Caravan is a great example of that. 425 00:20:21,250 --> 00:20:23,980 That's that sort of boxy cargo plane 426 00:20:23,980 --> 00:20:27,490 that you saw on floats in the other video. 427 00:20:27,490 --> 00:20:29,650 For personal planes that are pressurized 428 00:20:29,650 --> 00:20:34,410 and more comfortable, the Piper Meridian, which is down here-- 429 00:20:34,410 --> 00:20:39,100 this is my friend Arnold, who is at Hanscom. 430 00:20:39,100 --> 00:20:42,670 He says he funded his airplanes, because he 431 00:20:42,670 --> 00:20:47,210 was practicing during the golden age of gynecology. 432 00:20:47,210 --> 00:20:49,390 And that's what enabled him to afford 433 00:20:49,390 --> 00:20:54,060 his fancy, pressurized Pipers. 434 00:20:54,060 --> 00:20:56,470 The TBM is a French design that's 435 00:20:56,470 --> 00:20:59,090 considerably preferred to the Piper, 436 00:20:59,090 --> 00:21:00,790 but it's a lot more expensive. 437 00:21:00,790 --> 00:21:03,640 And the Swiss Pilatus PC-12 is kind 438 00:21:03,640 --> 00:21:06,640 of a good airplane for a mixture of family use and charter use. 439 00:21:06,640 --> 00:21:11,470 The Piper and the TBM are too small to justify all 440 00:21:11,470 --> 00:21:13,270 the machinery around charter. 441 00:21:16,360 --> 00:21:18,490 All right, so actually, old King Airs 442 00:21:18,490 --> 00:21:20,600 are cheaper than these single-engine airplanes, 443 00:21:20,600 --> 00:21:22,620 but they cost a little more to run. 444 00:21:22,620 --> 00:21:24,370 All right, when you're maintaining a jet-- 445 00:21:24,370 --> 00:21:25,930 I think I mentioned this earlier-- 446 00:21:25,930 --> 00:21:29,950 the manufacturer's guidance will supersede those catch-all rules 447 00:21:29,950 --> 00:21:35,170 of a 100-hour inspection for an airplane operated commercially 448 00:21:35,170 --> 00:21:39,490 or the annual inspection for an airplane operated privately. 449 00:21:39,490 --> 00:21:40,750 It can get expensive. 450 00:21:40,750 --> 00:21:42,790 On one of those Cessna Citation jets 451 00:21:42,790 --> 00:21:45,760 that I mentioned, coming out with $100,000 452 00:21:45,760 --> 00:21:51,040 bill from the annual would not be unexpected. 453 00:21:51,040 --> 00:21:56,935 You usually have a time limit on the whole airframe. 454 00:21:56,935 --> 00:21:59,140 And if it's pressurized, it's getting 455 00:21:59,140 --> 00:22:00,880 expanded and contracted, expanded 456 00:22:00,880 --> 00:22:03,310 and contracted and a little bit of metal fatigue 457 00:22:03,310 --> 00:22:04,030 on every flight. 458 00:22:04,030 --> 00:22:06,170 So you may have a limit on the number of cycles, 459 00:22:06,170 --> 00:22:08,140 the number of times that's happened, 460 00:22:08,140 --> 00:22:10,220 and also on the number of hours. 461 00:22:10,220 --> 00:22:15,380 So a 12,000-hour or 20,000-hour airframe life limit might be 462 00:22:15,380 --> 00:22:15,880 common. 463 00:22:15,880 --> 00:22:18,510 For the Pilatuses, it's 20,000 hours. 464 00:22:18,510 --> 00:22:20,260 And then they have life extension programs 465 00:22:20,260 --> 00:22:23,410 where they tear the whole thing apart and replace 466 00:22:23,410 --> 00:22:26,410 some structures or, at least, look at every structure. 467 00:22:26,410 --> 00:22:29,860 People have extended them out to about 32,000 hours, I think, 468 00:22:29,860 --> 00:22:31,420 now. 469 00:22:31,420 --> 00:22:33,590 There's cycle limits, also, on the jet engines. 470 00:22:33,590 --> 00:22:37,150 So the turbine blades and stuff and disks, every time 471 00:22:37,150 --> 00:22:38,860 they're started and shut down, there's 472 00:22:38,860 --> 00:22:40,570 a huge amount of thermal cycling. 473 00:22:40,570 --> 00:22:43,810 So they say, look, after you've done that 15,000 times, 474 00:22:43,810 --> 00:22:45,400 you got to throw that wheel out. 475 00:22:45,400 --> 00:22:50,830 And that wheel inside the turboprop could be $100,000. 476 00:22:50,830 --> 00:22:53,170 If you guys ever-- 477 00:22:53,170 --> 00:22:55,630 it may seem hard to believe now that MIT has stripped you 478 00:22:55,630 --> 00:22:57,700 of all of your savings, but if you 479 00:22:57,700 --> 00:23:00,190 do have a little bit of money at some future date 480 00:23:00,190 --> 00:23:02,860 and you want to get a type rating for your airplane, 481 00:23:02,860 --> 00:23:04,510 by far the cheapest type rating you 482 00:23:04,510 --> 00:23:07,732 get will be for a big airplane. 483 00:23:07,732 --> 00:23:09,190 So it turns out, if you want to pay 484 00:23:09,190 --> 00:23:11,320 flight safety for the Gulfstream rating, 485 00:23:11,320 --> 00:23:14,020 or a Cessna Mustang rating, or whatever, 486 00:23:14,020 --> 00:23:15,170 those are pretty expensive. 487 00:23:15,170 --> 00:23:16,990 They're relatively rare. 488 00:23:16,990 --> 00:23:20,500 Boeing 737s and Airbus A320s, so many 489 00:23:20,500 --> 00:23:25,030 were made that there's just a wide variety of simulators 490 00:23:25,030 --> 00:23:25,960 all over the world. 491 00:23:25,960 --> 00:23:32,200 And for about $10,000, you can jump in and get your instrument 492 00:23:32,200 --> 00:23:36,700 proficiency back up to snuff, as well as have a lot of fun. 493 00:23:36,700 --> 00:23:39,610 All right, so as a summary, it's a good challenge 494 00:23:39,610 --> 00:23:42,100 to get that multi-engine rating. 495 00:23:42,100 --> 00:23:45,190 I wouldn't recommend practicing it 496 00:23:45,190 --> 00:23:47,920 unless you have an unusual application, like you 497 00:23:47,920 --> 00:23:49,630 live in the Caribbean, and you want 498 00:23:49,630 --> 00:23:50,850 to get from island to island. 499 00:23:53,560 --> 00:23:57,180 If you're nervous and somebody says, 500 00:23:57,180 --> 00:24:01,000 I don't feel comfortable depending on this 501 00:24:01,000 --> 00:24:06,790 five-year-old, 1,000-hour piston engine that's in front of us, 502 00:24:06,790 --> 00:24:10,150 the answer I think these days is it's better to get an airplane 503 00:24:10,150 --> 00:24:14,710 that has a ballistic parachute as your backup than to have 504 00:24:14,710 --> 00:24:17,320 the second engine as a backup. 505 00:24:17,320 --> 00:24:21,910 And while you're formulating your questions, I'll show you. 506 00:24:21,910 --> 00:24:24,490 On the top left is a French design. 507 00:24:24,490 --> 00:24:26,506 That's called a Cri-Cri. 508 00:24:26,506 --> 00:24:27,940 It seats one person. 509 00:24:27,940 --> 00:24:29,555 And it's, I believe, fully aerobatic. 510 00:24:29,555 --> 00:24:31,930 So you can do all kinds of crazy maneuvers in the Cri-Cri 511 00:24:31,930 --> 00:24:33,130 if you want. 512 00:24:33,130 --> 00:24:36,280 Each of those engines might be only 30 horsepower or 15. 513 00:24:36,280 --> 00:24:37,870 You can look it up. 514 00:24:37,870 --> 00:24:39,820 It's a truly crazy design. 515 00:24:39,820 --> 00:24:44,577 Here is an AirCam that's an open cockpit. 516 00:24:44,577 --> 00:24:45,910 Although, this one has a canopy. 517 00:24:45,910 --> 00:24:48,790 That's from the Oshkosh seaplane base, a great airplane 518 00:24:48,790 --> 00:24:53,860 for flying low and slow over remote, somewhat wet locations. 519 00:24:53,860 --> 00:24:58,180 Here's an L-39 Czech military trainer. 520 00:24:58,180 --> 00:24:59,620 And there's a company called-- 521 00:24:59,620 --> 00:25:01,330 I think it was called Code 1 Aviation. 522 00:25:01,330 --> 00:25:03,310 They had that at Oshkosh, where they 523 00:25:03,310 --> 00:25:06,910 took a regular American business jet engine out of a Hawker, 524 00:25:06,910 --> 00:25:09,400 and they stuffed it into the L-39 525 00:25:09,400 --> 00:25:12,010 because it's cheaper to operate and maintain it 526 00:25:12,010 --> 00:25:15,770 as a lower fuel burn than the military engines. 527 00:25:15,770 --> 00:25:18,670 So you end up getting a lot longer range out of your L-39 528 00:25:18,670 --> 00:25:19,780 if you want to-- 529 00:25:19,780 --> 00:25:22,030 those L-39s are only a couple hundred thousand dollars 530 00:25:22,030 --> 00:25:22,720 for a nice one. 531 00:25:22,720 --> 00:25:25,360 So you can actually own a jet that's fully aerobatic, 532 00:25:25,360 --> 00:25:26,950 and cool, and look like-- people will 533 00:25:26,950 --> 00:25:32,050 think it's an F-16 for less money than buying a Cirrus. 534 00:25:32,050 --> 00:25:34,380 On the left is the ramp at Teterboro. 535 00:25:34,380 --> 00:25:37,390 I said I was talking about it. 536 00:25:37,390 --> 00:25:39,265 If you're working for Bernie Sanders 537 00:25:39,265 --> 00:25:41,140 and you want to start a revolution in the US, 538 00:25:41,140 --> 00:25:43,690 I would recommend starting it right at the Teterboro 539 00:25:43,690 --> 00:25:46,055 airport and just film the people getting in and out 540 00:25:46,055 --> 00:25:46,930 of their Gulfstreams. 541 00:25:46,930 --> 00:25:47,805 And this is Meridian. 542 00:25:47,805 --> 00:25:51,820 This is the lowest-cost FBO at Teterboro. 543 00:25:51,820 --> 00:25:53,770 And that's what the ramp looks like. 544 00:25:53,770 --> 00:25:57,520 If you want to combine two piston engines in a jet, 545 00:25:57,520 --> 00:26:03,250 I believe each of these of is a Yak-55. 546 00:26:03,250 --> 00:26:07,930 And some airshow performer at Oshkosh glued them together 547 00:26:07,930 --> 00:26:14,700 and put a jet engine in the middle and calls it a Yak-110. 548 00:26:14,700 --> 00:26:15,660 So there you have it. 549 00:26:15,660 --> 00:26:18,047 That combines everything from this talk. 550 00:26:18,047 --> 00:26:18,630 Any questions? 551 00:26:18,630 --> 00:26:21,340 Or should we jump right into night? 552 00:26:21,340 --> 00:26:23,410 Who wants to fly a jet? 553 00:26:23,410 --> 00:26:26,818 Excellent. 554 00:26:26,818 --> 00:26:29,746 AUDIENCE: So you said Cessna Caravans are single engine. 555 00:26:29,746 --> 00:26:32,109 I know they fly those commercially in Hawaii 556 00:26:32,109 --> 00:26:33,075 island to island. 557 00:26:33,075 --> 00:26:34,880 How do you think they justify that? 558 00:26:34,880 --> 00:26:35,838 PHILIP GREENSPUN: Yeah. 559 00:26:35,838 --> 00:26:40,030 The question is, is it OK to fly a single engine over water 560 00:26:40,030 --> 00:26:46,135 in Hawaii in a Cessna Caravan with only one engine? 561 00:26:46,135 --> 00:26:51,550 Well, first of all, the last crash of a Caravan in Hawaii 562 00:26:51,550 --> 00:26:54,430 from an engine failure, they operated it just a few hours 563 00:26:54,430 --> 00:26:58,240 beyond the manufacturer's TBO under a special program 564 00:26:58,240 --> 00:26:59,635 they had approved by the FAA. 565 00:26:59,635 --> 00:27:02,560 They were not doing anything illegal. 566 00:27:02,560 --> 00:27:04,690 Everybody survived the crash. 567 00:27:04,690 --> 00:27:05,860 One person was killed. 568 00:27:05,860 --> 00:27:08,890 Does anybody remember who was killed in that crash, 569 00:27:08,890 --> 00:27:12,510 and what was special about that person? 570 00:27:12,510 --> 00:27:14,010 AUDIENCE: It was a flight attendant. 571 00:27:14,010 --> 00:27:15,718 PHILIP GREENSPUN: Not a flight attendant. 572 00:27:15,718 --> 00:27:22,520 It was a woman who was a state of Hawaii employee. 573 00:27:22,520 --> 00:27:25,250 What was special about her? 574 00:27:25,250 --> 00:27:28,820 She was the person who certified Barack Obama's birth 575 00:27:28,820 --> 00:27:29,930 certificate as genuine. 576 00:27:32,510 --> 00:27:34,970 Think about that. 577 00:27:34,970 --> 00:27:37,670 So anyway, if you really open up the PT6 578 00:27:37,670 --> 00:27:40,170 and the manually would say, no, I'm not going to allow this. 579 00:27:40,170 --> 00:27:41,128 And I think in Europe-- 580 00:27:41,128 --> 00:27:44,510 Europe wouldn't even allow a single-engine charter IFR 581 00:27:44,510 --> 00:27:46,620 until just a year or two ago. 582 00:27:46,620 --> 00:27:48,740 They said, no, this is too much. 583 00:27:48,740 --> 00:27:50,530 So I don't know. 584 00:27:50,530 --> 00:27:51,840 It's a balancing of risk. 585 00:27:51,840 --> 00:27:54,320 I don't think it's an unacceptable risk. 586 00:27:54,320 --> 00:27:58,100 People with Pilatuses, they will go back and forth to Europe 587 00:27:58,100 --> 00:28:00,980 regularly as individuals. 588 00:28:00,980 --> 00:28:04,140 But yeah, maybe there should be a warning to passengers. 589 00:28:04,140 --> 00:28:05,330 We only got one engine. 590 00:28:05,330 --> 00:28:07,510 Thanks for buying a ticket.