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| · | Amelia Earhart's final flight |
| 0:00 | · | - [Derek] As the sun rose on July 2nd, 1937, Amelia Earhart knew she was in trouble. |
| 0:07 | · | Over the radio, she called, "We must be on you but cannot see you. Gas is running low. |
| 0:13 | · | Been unable to reach you by radio. We are flying at 1,000 feet." |
| 0:18 | · | Beneath her was water in every direction as far as the eye could see. |
| 0:24 | · | She got herself into this predicament through a series of unfortunate events and bad decisions. |
| 0:30 | · | Many of them could have been avoided with a better knowledge of physics. But even so, |
| 0:36 | · | there was one thing she could have done in this moment, one switch she could have flipped |
| 0:41 | · | that would likely have saved her life and changed history. |
| 0:48 | · | This video is sponsored by KiwiCo. More about them at the end of the show. |
| 0:54 | · | Amelia Earhart was vying to become the first female pilot to fly around the world. - I hope to accomplish something |
| 1:00 | · | really scientifically worthwhile for aviation. - And she wasn't taking any shortcuts. |
| 1:06 | · | Other successful circumnavigations had followed a northern route, mostly staying close to land. |
| 1:13 | · | But Earhart's route would be the longest by following a path close to the Equator. |
| 1:19 | · | This meant the last part of her journey was the hardest, crossing the full width of the Pacific Ocean. |
| 1:26 | · | The starting point for this crossing was Lae, a city on the eastern side of New Guinea. |
| 1:32 | · | At the time, it was one of the world's busiest airports, a hub of traffic from Asia and Australia. |
| 1:39 | · | At 10:00 a.m. on a hot July day, Earhart piloted her Lockheed Electra down the runway |
| 1:44 | · | and took off on what would be her final flight. |
| 1:52 | · | The Pacific Ocean is huge. It's way bigger than the Atlantic. I mean, if you look at the globe from that side, |
| 2:00 | · | you see almost no land. The problem was, in 1937, |
| 2:05 | · | most planes could only fly a maximum of a few thousand kilometers, so Earhart removed everything unnecessary from her plane. |
| 2:14 | · | She ripped out the insulation to reduce weight, but that made the engine noise so overwhelming |
| 2:20 | · | she had to communicate with her navigator sitting right beside her using written notes. |
| 2:26 | · | She packed almost nothing, telling her husband, "Extra clothes and extra food would have been extra weight and extra worry." |
| 2:34 | · | She replaced the passenger seats with fuel tanks, effectively turning her plane into a flying gas can. |
| 2:42 | · | But even so, the Electra's maximum range was between 6,600 and 7,200 kilometers in perfect weather. |
| 2:50 | · | It could be just enough to reach Hawaii from Lae, or she might come up disastrously short. |
| 2:58 | · | So Earhart needed a place to stop and refuel along the way. Now, it might seem like there's no land here, |
| 3:05 | · | but if you zoom in, there is this tiny island halfway between Australia and Hawaii. |
| 3:12 | · | Howland Island is just over two kilometers long and less than one kilometer wide. |
| 3:18 | · | The US had claimed it as part of the Guano Islands Act of 1856. But in 1937, it was barely inhabited |
| 3:25 | · | with just a handful of colonists. It would be an ideal location to refuel, |
| 3:31 | · | if only it had a runway. Fortunately for Earhart, by the time of her around the world flight, |
| · | Who was Amelia Earhart? |
| 3:37 | · | she was already famous. In 1928, she became the first female passenger |
| 3:43 | · | to cross the Atlantic by airplane. This made her an international celebrity. - [Announcer] She said she could, and she did it. |
| 3:50 | · | (lively music) - [Derek] But she wanted to fly herself, saying, |
| 3:57 | · | "Maybe someday I'll try it alone." So, in 1932, she attempted to pilot a plane solo across the Atlantic |
| 4:05 | · | heading for Paris. She brought with her only a toothbrush, one container of soup and three cans of tomato juice. |
| 4:12 | · | (thunder booms) But storms, ice, and dense fog battered her small plane. |
| 4:20 | · | A seam in the exhaust manifold cracked and flames from the engine spewed out into the night. |
| 4:26 | · | Gas leaked down her neck from a broken tank, and after 14 hours, she landed in a pasture in Northern Ireland. |
| 4:33 | · | Her face was so covered in grease, a farmhand couldn't tell if she was a man or a woman. |
| 4:39 | · | He asked if she had flown far. "From America," she replied. - I wish I could have done it faster. |
| 4:46 | · | - [Derek] These adventures brought her into the orbits of powerful people, like the First Lady, Eleanor Roosevelt. |
| 4:52 | · | - And Mrs. Roosevelt, won't you go for a ride tonight over Washington? It's really lovely from the air at night. |
| 4:58 | · | - And using her new connections, she lobbied the president to hire her friend, Eugene Vidal, |
| 5:03 | · | to head the Bureau of Commerce. Vidal had promised Earhart a runway on Howland Island, |
| 5:09 | · | but red tape stalled progress only months before her planned takeoff. So Earhart wrote directly to President Roosevelt. |
| 5:18 | · | She explained that the airstrip funds required immediate approval, writing, "Please forgive troublesome female flyer |
| 5:24 | · | for whom this Howland Island project is key to world flight attempt." The president approved the project four days later, |
| 5:32 | · | and three runways were soon cleared. So she had a place to land, |
| · | The flight plan |
| 5:39 | · | but how would she find this tiny speck of an island in a vast ocean? |
| 5:46 | · | Well, flying with her in the Electra was her navigator, Fred Noonan, and he would calculate the flight plan. |
| 5:53 | · | They knew the direction of Howland, so they could use the onboard compass to set their bearing toward it. |
| 5:59 | · | They knew their air speed and could figure out their ground speed by subtracting or adding the wind, |
| 6:05 | · | and then they could calculate how long it should take to reach the island. This method is known as dead reckoning. |
| 6:13 | · | But they wouldn't aim directly at the island, because if they did that and they didn't see it at the prescribed time, |
| 6:19 | · | they wouldn't know in which direction they were off. So instead, they intentionally picked a point |
| 6:25 | · | either north or south of the island. Let's say they picked south. They estimated the trip would take 18 hours, |
| 6:32 | · | so they would fly through day and night. And once they had traveled for the calculated length of time, |
| 6:39 | · | they could confidently turn north and spot the island. |
| 6:44 | · | Before takeoff, the ground crew estimated they would encounter a headwind of 24 kilometers per hour. |
| 6:50 | · | But just 20 minutes after takeoff, Lae radioed Earhart to warn that the headwinds would be stronger. |
| 6:56 | · | She didn't acknowledge their message. Knowing the correct wind speed was critical |
| 7:02 | · | because it would affect how long it would take to reach the island. If it took longer, Earhart would have to turn later. |
| 7:08 | · | So she couldn't rely on dead reckoning alone to reach Howland. |
| · | How celestial navigation works |
| 7:14 | · | As an independent check on their location, Noonan would take measurements of the sun, moon, and stars. |
| 7:20 | · | This is known as celestial navigation. He had an almanac that listed 58 navigation stars |
| 7:27 | · | and the point on Earth each one would be directly overhead for the day and time of his measurement. |
| 7:34 | · | If they found themselves directly under a navigation star, well, then they would immediately know their position. |
| 7:40 | · | But generally they would not be that lucky, so Noonan would measure the angle above the horizon |
| 7:46 | · | to a navigation star and use that to work out how far away they were from the point on the Earth |
| 7:53 | · | where that star would be directly overhead. So he could trace out a circle on the globe |
| 7:58 | · | of possible locations, and then he would measure the angle to another navigation star |
| 8:03 | · | and draw out a second circle. And now they must be at one of these two circle intersections. |
| 8:11 | · | Normally the circles were so large that only one of the intersections would be a plausible position. |
| 8:17 | · | That way they could continually update their location and adjust bearings as needed. But even with celestial navigation, |
| 8:24 | · | errors could accumulate over long trips. Earlier in the journey, when Earhart crossed the Atlantic, |
| 8:30 | · | they missed their intended airport in hazy conditions. Noonan's calculations were reasonable, |
| 8:36 | · | but small errors put them off course. Luckily, in Africa, there were plenty of other places to land safely. |
| 8:43 | · | The same could not be said for Howland. |
| 8:48 | · | So, for the flight across the Pacific, Earhart commandeered three US Navy and Coast Guard ships. |
| 8:54 | · | The Itasca would be stationed at Howland Island, the Ontario would be halfway along the route, |
| 9:00 | · | and the Swan was positioned midway between Howland and Hawaii. The Itasca would send out smoke signals |
| 9:07 | · | as Earhart approached to help her spot the island. But even more importantly, |
| 9:12 | · | all ships were equipped with radio. Now, in 1937, radio was still fairly new tech. |
| · | Invention of radio technology |
| 9:20 | · | German physicist Heinrich Hertz discovered radio waves in the late 1880s. He excited electrons to oscillate back and forth |
| 9:27 | · | in his transmitter, and a few meters away his receiver was a loop of wire with a small gap in it. |
| 9:34 | · | When Hertz looked at it through a microscope in the dark, he saw faint sparks jumping across the gap. |
| 9:41 | · | The sparks were strongest when the receiving loop was flat. If it was vertical, then no sparks were observed. |
| 9:48 | · | This demonstrated that radio waves are transverse waves with electric and magnetic fields |
| 9:53 | · | oscillating perpendicular to each other and perpendicular to the direction of the wave motion. |
| 9:59 | · | When the receiving loop was aligned with the direction the wave was traveling, the changing magnetic field through the loop |
| 10:05 | · | induced an EMF that created the spark. But if the loop was facing the transmitter, |
| 10:11 | · | then there was no change in magnetic flux through the loop, and so no spark was observed. |
| 10:18 | · | Now, Hertz couldn't see the future he had ushered in. He said, "I do not think |
| 10:23 | · | that the wireless waves I have discovered will have any practical application." |
| 10:28 | · | But within a few years, people started sending messages using radio. And by the 1920s, radio entertainment broadcast took off. |
| 10:36 | · | Ships and planes routinely used radio to send Morse code, and some, including Earhart, |
| 10:41 | · | could send and receive voice messages. In fact, Earhart had five radio antennas around the plane, |
| 10:50 | · | each for a specific purpose. The largest antenna could be reeled in and out like a fishing line behind the plane. |
| 10:57 | · | It was 76 meters long, which was necessary to efficiently send and receive Morse code |
| 11:03 | · | via the 4 or 500 kilohertz radio waves used by ships and remote stations. |
| 11:09 | · | Ideally, an antenna should be at least 1/4 of the wavelength of the radio wave it's transmitting or receiving. |
| 11:15 | · | This improves the efficiency of the conversion from electrical energy to radiated electromagnetic energy. |
| 11:22 | · | Earhart's trailing antenna was only around 1/8 of the wavelength. But it was connected to a high-power transmitter, |
| 11:29 | · | so its signals could still be detected over 1,000 kilometers away. Next were two antennas for voice communications |
| 11:36 | · | on higher frequencies. A transmitting V antenna on the roof of the plane and a receiving antenna along its belly. |
| 11:44 | · | Higher frequencies were useful for two reasons. First, they require smaller antennas, |
| 11:49 | · | which save weight and can be better accommodated on small sparse planes. And second, high frequency radio waves |
| 11:56 | · | can travel long distances by bouncing off a layer of the atmosphere called the ionosphere. |
| · | Radio waves explained |
| 12:02 | · | Starting about 50 kilometers above Earth's surface, radiation from the Sun splits electrons off molecules |
| 12:09 | · | forming a layer of ions and free electrons. Radio waves with certain frequencies |
| 12:15 | · | interact with these free electrons and are effectively reflected back to Earth. It's as if they've bounced off |
| 12:21 | · | a big wobbly mirror in the sky. This effect is called skipping |
| 12:26 | · | and it scatters radio waves all over the place. These radio waves can then reflect off the ocean |
| 12:32 | · | and back off the ionosphere, making multiple hops to travel thousands of kilometers. |
| 12:39 | · | During the daytime, the intense radiation from the sun means the ionosphere starts lower in denser atmosphere. |
| 12:45 | · | And because of this, lower frequency radio waves are more likely to be absorbed than reflected. |
| 12:51 | · | So aviators would typically use the higher 6210 kilohertz to skip their signals during the day, |
| 12:57 | · | and then the lower 3105 kilohertz at night once the bottom of the ionosphere had lifted |
| 13:02 | · | into thinner air. Four hours after takeoff, |
| 13:08 | · | Earhart radioed an update to Lae on her daytime frequency of 6210. She reported her altitude at 7,000 feet |
| 13:16 | · | and speed at 140 knots before concluding with her typical sign-off, "Everything okay." |
| 13:23 | · | But she never acknowledged calls from Lae about the headwind. They radioed again at 11:20 and 12:20, |
| 13:30 | · | but never got a response from Earhart. In all likelihood, she never heard them. |
| 13:36 | · | She did radio six hours into her flight to report stronger headwinds, but she makes no mention of Lae's earlier warnings. |
| 13:44 | · | It's possible the receiving belly antenna was broken, fell off, or something in the receiving electronics wasn't working. |
| 13:52 | · | But her ability to receive voice messages was clearly impaired. |
| 13:58 | · | Nine hours into the flight, Earhart expected to come upon the Ontario. She listened for Morse code Ns on 400 kilohertz, |
| 14:07 | · | but she heard nothing. The original plan was |
| 14:13 | · | that the Ontario would wait for her to radio them to request that they start transmitting. |
| 14:18 | · | But the day before takeoff, Earhart realized she had made a mistake. The Ontario had told her |
| 14:25 | · | they wouldn't be able to receive any high frequency signals, which meant no voice communication. |
| 14:31 | · | So she sent an urgent telegram asking the Ontario to transmit the Morse code Ns repeatedly |
| 14:37 | · | 10 minutes after each hour. The purpose of the Morse code from the Ontario |
| 14:44 | · | was actually to allow Amelia Earhart to make use of her two final antennas. So she had a loop antenna just like this one |
| 14:52 | · | and a sense antenna. These were designed to allow her to locate the source of radio waves. |
| 14:58 | · | This was the final and most critical way that Earhart planned to stay on course and locate Howland Island. |
| 15:04 | · | She wrote, "I doubt if I'd try the flight to tiny Howland Island without it supplementing Fred Noonan's skill." |
| 15:11 | · | Woo. Alright, so I have an antenna here |
| 15:16 | · | and I'm aligning it vertically in this tree. How are we, how are we there? So the Ontario was sending out Morse code signals |
| 15:23 | · | on their antenna, and here we have a transmitter tuned to about 3.6 megahertz. |
| 15:29 | · | I'm gonna put on this blindfold and use the loop antenna to try to locate the transmitter. |
| 15:37 | · | And because I already know where the transmitter is, we'll spin me around a few times to really disorient me. So, Clifford. Oh, sorry. |
| 15:43 | · | - [Clifford] Oh, which way are you going? - Alright. Whoa, I'm a bit dizzy. |
| 15:51 | · | So the radio waves are gonna be emitted in all directions radially away from the antenna, |
| 15:57 | · | the electric field will be oscillating up and down, and the magnetic field will be oscillating back and forth. |
| 16:04 | · | So if I hold up this loop like this sort of parallel to the direction |
| 16:10 | · | that the waves are traveling, then the magnetic field is gonna be changing through the loop. And because of that, |
| 16:16 | · | it's going to create an EMF and current and I can pick that up because I'm tuned to the right frequency here. |
| 16:23 | · | So I got a fairly strong signal. Woo, it's very strong. But if I rotate the loop like that, |
| 16:29 | · | well, now the magnetic field is oscillating back and forth but not changing through the loop itself |
| 16:34 | · | because it's parallel to the loop. And so, in this orientation, I'm gonna get a null reading. |
| 16:40 | · | If I turn it this way, there's a null. But if you turn it 90 degrees, |
| 16:47 | · | now all the magnetic field is passing through this loop and so I can hear a maximum here. |
| 16:53 | · | So this is what Earhart wanted to measure using her loop antenna to detect the repeated N Morse code from the Ontario. |
| 17:00 | · | She would turn it until she found the null and then she would know the direction to the ship. |
| 17:06 | · | Something that's interesting is, if I turn it away, we get another null because again |
| 17:12 | · | there's no magnetic flux passing through this loop. Now, the first time she picked up the signal, |
| 17:18 | · | she would probably be heading straight towards the ship or close enough, so she would know that it's roughly that way. |
| 17:27 | · | But there's a chance that she's gone past it. And if you go past it, well, then you also get a null, |
| 17:33 | · | but the ship is behind you, not in front of you. So that's where the sense antenna comes in. The sense antenna gives you a cardioid pickup pattern |
| 17:41 | · | so it has a single null instead of two nulls, and so that allows you to determine whether it is in front or behind you. |
| 17:49 | · | - [Clifford] If you walk a bit, you'll know if it's getting weaker or stronger. - Alright, I feel like I've picked the wrong direction. |
| 17:57 | · | I'll try the sense antenna to see if I can figure it out. With the sense antenna, |
| 18:03 | · | the only null points directly away from the transmitter, so it's easy to use the sense antenna |
| 18:09 | · | to check which null is correct but then only use the loop when navigating because it gives a sharper null. |
| 18:15 | · | I think using the sense antenna that the transmitter's right in front of me now. |
| 18:22 | · | I'm looking for another null here. Oh, there's a null. |
| 18:29 | · | - [Clifford] Give it a go. - There, there. Definitely louder, louder. |
| 18:39 | · | Oh, it's funny 'cause you move a little bit and then you start hearing signal again. |
| 18:46 | · | This does not feel like I'm walking in the right direction. - [Clifford] Well, that's either the right way to go or it's the wrong way to go. |
| 18:51 | · | - Oh no. (Clifford laughs) - Trying to fly a plane and do this would be very hard, |
| 18:56 | · | especially with the sound of that engine would have been roaring. |
| 19:03 | · | Oh, I feel like it's getting loud. It's really loud here. |
| 19:09 | · | It drops out right there. I mean, there's a null here. And I was convinced this was the right way. |
| 19:16 | · | Yeah, this is a clear null right here. Whoa. Loud, loud, loud. |
| 19:24 | · | I feel like I've gotta be close. (antenna humming) |
| 19:30 | · | It's gotta be like right here. Whoa! Ah! (laughs) |
| 19:37 | · | This worked amazingly well. I had no idea I was that close, that's impressive. |
| 19:43 | · | - On the nail. - That's awesome. Now, aviators could have used where the signal is loudest |
| 19:49 | · | and try to go in that direction, but it's actually easier to get a precise null, |
| 19:55 | · | a point where the signal drops out. The loud section could range for quite a distance |
| 20:01 | · | and so you wouldn't really know where it is, but the null is more precise so that's why they would look for the point where the signal drops out. |
| 20:08 | · | If Earhart could hone in on the Ontario using her radio direction finding loop, that would ensure she was on course |
| 20:14 | · | and eliminate any navigation errors that may have occurred to that point. But her telegram asking the Ontario |
| 20:21 | · | to transmit 10 minutes after each hour didn't make it to the ship in time. |
| 20:26 | · | And since Earhart couldn't talk to the Ontario, they never sent out any signals. |
| 20:32 | · | So they passed like ships in the night. |
| 20:37 | · | By this point, Earhart was around halfway to Howland. With no other landing strips within 1,000 kilometers, |
| 20:44 | · | she would have to find the tiny island or return to Lae now. But multiple delays had already plagued her journey. |
| 20:53 | · | In fact, this was not Earhart's first attempt to fly around the world. Earlier that year, in March of 1937, |
| 21:00 | · | she had taken off from California for Hawaii, heading west instead of east. |
| 21:06 | · | On board were Fred Noonan and another crew member, Harry Manning. |
| 21:11 | · | As a Merchant Marine captain, he was an expert in radio, Morse code, and traditional navigation. |
| 21:17 | · | He was also a pilot. The flight to Hawaii was successful |
| 21:22 | · | thanks in part to Manning using the loop antenna to hone in on a radio beacon on the destination island. |
| 21:31 | · | Three days later, the trio set off for Howland Island. But just as they were taking off, |
| 21:36 | · | the plane drifted to the right. Earhart corrected by throttling back the left motor, |
| 21:41 | · | but it was too much. The plane turned to the left and the right wing dipped down. Going up on one wheel, the right landing gear collapsed, |
| 21:49 | · | then the left. The plane skidded out on its belly, spinning around to face the way it had come. |
| 22:01 | · | Thankfully, no one was hurt, but the Electra took months to repair. |
| 22:06 | · | And during that time, the seasonal winds shifted. So, on her next attempt, Earhart would have to fly east instead of west. |
| 22:13 | · | And most importantly, Captain Manning left the crew. Officially, the press reported |
| 22:19 | · | that he needed to return to the Merchant Marines, but rumors spread that he had lost confidence in Earhart, |
| 22:25 | · | or that Earhart believed Noonan was a better navigator than Manning and she could operate the radio on her own. |
| 22:32 | · | Whatever the case, when Earhart took off again three months later, she was accompanied only by Noonan. |
| 22:40 | · | And now they had made it 80% of the way around the world. And in the dark of night, |
| · | Earhart makes her critical decision |
| 22:46 | · | Earhart had to make the critical decision whether to keep going or turn back. |
| 22:51 | · | The lack of signal from the Ontario must have been concerning, but maybe they never got her telegram. |
| 22:57 | · | And she knew that at Howland, the Itasca would be transmitting the letter A over Morse code every half hour, |
| 23:04 | · | even if they didn't hear from her. And they could send and receive voice signals. |
| 23:09 | · | They promised to be ready on a range of different frequencies. So she flew on. |
| 23:17 | · | Around 6:15 a.m. local time, radiomen aboard the Itasca heard Earhart clearly. |
| 23:23 | · | "Please take a bearing on 3105. We'll whistle into the mic. We are about 200 miles out." |
| 23:29 | · | She then began to whistle. But the men were confused. |
| 23:35 | · | They expected Earhart to take a bearing on them, not the other way around. And while they had told her |
| 23:41 | · | that they had radio direction finding equipment, the signal needed to be lower frequency, between 270 and 550 kilohertz. |
| 23:50 | · | Her voice frequency would skip off the ionosphere and reflect off the ocean, scattering in all directions. |
| 23:57 | · | So there would be no way to find a null because the signal would be coming literally from everywhere. |
| 24:04 | · | In the Electra, Earhart heard only static. By now, she must have been worried |
| 24:11 | · | that they hadn't heard anything from either ship. Almost blind from the rising sun |
| 24:16 | · | and deaf from the roar of the engines, Earhart twisted the radio dial, listening for Itasca's response. Nothing. |
| 24:27 | · | She may have expected Howland to have a high frequency radio direction finder called an Adcock antenna array. |
| 24:34 | · | These systems solve the skipping problem with five vertical antennas at the corners and center of a square. |
| 24:40 | · | The direction of the radio wave can be calculated from the slightly different arrival times and signal strengths at each antenna. |
| 24:48 | · | But these antennas were massive, so they were really only installed at larger airports. |
| · | Communication failures |
| 24:55 | · | Now, as it happens, there was a portable high frequency radio direction finder on Howland Island, |
| 25:01 | · | but the operator reported that Earhart's transmissions didn't last long enough for him to take a bearing. |
| 25:06 | · | And trying to conserve his low battery, he missed parts of the later transmissions. |
| 25:13 | · | Around 6:45, Earhart again asked them to take a bearing on 3105 kilohertz and report back in a half hour. |
| 25:20 | · | But a bearing taken now and reported back in a half hour would be at best outdated and at worst misleading. |
| 25:28 | · | This confusion likely had to do with time zones. Earhart was using Greenwich Civil Time, |
| 25:35 | · | but the Itasca set their clocks to their current position which was GCT -11.5 hours. |
| 25:41 | · | And to make matters worse, Howland Island used Hawaii Time, which back in those days was GCT -10.5 hours. |
| 25:50 | · | So the three parties attempting a rendezvous on a tiny island in the middle of the Pacific |
| 25:55 | · | were on three different time zones. And crucially, Earhart's hours didn't even line up |
| 26:01 | · | with the others. Earhart told the Itasca she would be using GCT, but somehow it never made it to the radiomen. |
| 26:10 | · | So, when the Itasca heard Earhart's request, it was 6:45 a.m. But in the cockpit, it was 6:15 p.m. |
| 26:17 | · | So Earhart likely didn't say "in a half hour" but "on the half hour," which for her was only 15 minutes away. |
| 26:25 | · | And also it was a prearranged time that Earhart would be listening for them. |
| 26:30 | · | Earhart was careful to set times she would transmit and times she would listen for the ship |
| 26:35 | · | because she could only power one antenna at a time. And the ships used the same antenna |
| 26:42 | · | for receiving and transmitting, so if they both broadcasted at the same time, they would miss each other's messages. |
| 26:48 | · | If Earhart sent another message at a quarter after the hour, the Itasca blocked it with their own message. |
| 26:54 | · | "Cannot take a bearing on 3105 very good. Please send on 500, or do you wish to take a bearing on us? |
| 27:01 | · | Go ahead please." There was no response. But she couldn't transmit on 500 kilohertz anyway |
| 27:08 | · | because she had removed the long trailing antenna that could transmit lower frequencies. |
| 27:13 | · | Since it could only be used for Morse code, something neither she nor Noonan were particularly well versed in, |
| 27:19 | · | she saw it as dead weight after Manning left. So, after the Hawaii crash, it was removed during repairs. |
| 27:26 | · | So she had no way of sending radio waves that would allow the Itasca to take a bearing on her. |
| 27:33 | · | But she could take a bearing on the Itasca using her loop antenna, if they sent her the right frequency. |
| 27:41 | · | Before the trip, the Itasca had asked Earhart to specify the frequency they should broadcast. Earhart was unsure, |
| 27:47 | · | so she consulted a radio expert in Lae and they recommended the Itasca send Morse code A, |
| 27:53 | · | just repeated dot dashes, on the half hour at 750. But at that time it was typical to talk about radio waves |
| 28:01 | · | using their wavelength, so the expert had meant 750 meters or 400 kilohertz. |
| 28:07 | · | But Earhart made a terrible mistake relaying this plan to the Itasca. She requested the signal be sent on 7,500 kilohertz |
| 28:16 | · | instead of 750 meters or 400 kilohertz. But she did explicitly say, |
| 28:23 | · | "If frequencies mentioned unsuitable, inform me." But no one ever corrected her. |
| · | "Gas is running low" |
| 28:31 | · | At 7:42 a.m., Earhart's voice came through so loud men even went above deck to see if they could hear a motor |
| 28:39 | · | or spot the plane. She said, "We must be on you but cannot see you. |
| 28:45 | · | But gas is running low. Been unable to reach you by radio. We are flying at 1,000 feet." |
| 28:51 | · | On Howland, the high frequency radio direction finder was so low on battery the radiomen didn't even hear Earhart's message, |
| 28:58 | · | much less take a bearing on it. 10 minutes later, Earhart said, "We are circling but cannot hear you. |
| 29:05 | · | Go ahead on 7,500." The Itasca immediately sent As on 7,500 kilohertz. |
| 29:12 | · | In the Electra, Earhart heard the stutter stop of As filling the cabin. The relief of finally hearing something |
| 29:20 | · | must have been overwhelming. She quickly turned her radio direction finding loop to locate the null, |
| 29:26 | · | but the signal never dropped out. The frequency was too high, so the radio waves from the Itasca were reflecting |
| 29:33 | · | and arriving from different directions. Joseph Gurr, a radio mechanic who worked on Earhart's plane, |
| 29:39 | · | later said that they knew there were limitations to high frequencies which had a tendency to skip and bend, |
| 29:45 | · | creating a false radio direction bearing. Without a minimum, she was still lost. |
| 29:53 | · | Earhart frantically called Itasca. "We received your signals but unable to get a minimum. |
| 29:59 | · | Please take a bearing on us and answer with voice." Itasca attempted to explain the problem. |
| 30:05 | · | "Your signals received okay. It is impractical to take a bearing on your voice." No response. Without the belly antenna, |
| 30:12 | · | she probably never heard any of their communications. And it wouldn't have mattered if the Itasca had sent low frequency signals |
| 30:20 | · | because Earhart's loop was tuned to pick up 7,500 kilohertz. |
| 30:27 | · | So, why didn't the Itasca correct the frequency she suggested? Commander Thompson of the Itasca |
| 30:33 | · | was aware of her radio direction finding limits. He had received messages both from Earhart's husband, George Putnam, |
| 30:40 | · | and the Coast Guard's San Francisco division stating Earhart could only take bearings on frequencies between 200 and 1,500 kilohertz. |
| 30:49 | · | But he either thought Earhart knew more about her radio equipment, or that it wasn't his place to make suggestions |
| 30:55 | · | and take more responsibility for her flight. When she asked the Itasca to tell her if these frequencies weren't suitable, |
| 31:02 | · | she could have been referring to the ship's capabilities rather than her own. The Itasca said they'd be ready |
| 31:07 | · | on the frequencies she wanted and more instead of giving specific suggestions. |
| 31:14 | · | San Francisco's Coast Guard division tried to get Commander Thompson to take more responsibility for Earhart's radio communications |
| 31:21 | · | by suggesting they directly tell Earhart which frequencies to use. But Thompson essentially told them to butt out. |
| 31:28 | · | The Itasca communicated directly with Earhart from then on. |
| 31:34 | · | The radiomen continued to try to reach Earhart, and just before 9:00 a.m., Earhart's voice suddenly burst through again. |
| · | Her desperate final message |
| 31:41 | · | "We are on the line 157-337. We will repeat this on 6,210 kilohertz. |
| 31:48 | · | We are running on line north and south." Her voice was desperate. |
| 31:53 | · | It sounded as if she was about to burst into tears or scream. This was the last message the Itasca heard. |
| 32:02 | · | There are a number of conspiracy theories about what happened to Earhart after that, but the evidence seems clear. |
| 32:09 | · | She ran out of fuel somewhere over the Pacific and crashed into the sea. |
| 32:14 | · | Two hours after her last message, the Itasca left Howland to search north and west for the Electra. |
| 32:21 | · | Other Navy and Coast Guard ships and planes joined the search for over two weeks. |
| 32:26 | · | To that point in US history, it was the most intensive and expensive search and rescue operation, |
| 32:33 | · | costing around $4 million, which is almost 100 million in today's money. |
| 32:40 | · | No one has ever found a trace of Noonan, Earhart, or her Electra. |
| 32:46 | · | All of these mistakes could have been resolved if Earhart had two-way communication, but her belly antenna somehow malfunctioned. |
| 32:54 | · | Some theories suggest it fell off during takeoff in New Guinea, but without physical evidence, it's impossible to say. |
| · | The small detail that could have saved her |
| 33:01 | · | But Earhart did confirm receiving signals on her loop antenna. Her loop could only direction find with lower frequencies, |
| 33:09 | · | but it could receive signals on a wide range. If she had switched to using the loop |
| 33:14 | · | for all communications, she could have received Itasca's voice messages |
| 33:20 | · | and then the Itasca could have requested she take a bearing on a lower frequency, which would have guided her safely to Howland Island. |
| 33:31 | · | When I began researching this video, I expected to find that Amelia Earhart's demise was inevitable. |
| 33:37 | · | That what she was trying to do was just so difficult that nothing could have saved her. |
| 33:43 | · | But instead, I found the opposite. There were at least a half dozen things that if they went differently |
| 33:49 | · | would have allowed her to land safely. So to me, this story comes down to two things. |
| 33:55 | · | Knowledge and responsibility. Earhart lacked knowledge of radio systems, |
| 34:00 | · | which would've allowed her to specify the right direction finding frequency. But Commander Thompson of the Itasca had that knowledge. |
| 34:08 | · | He knew her direction finding limits, but he didn't take on the responsibility to correct her. |
| 34:14 | · | When attempting any challenging endeavor, you need someone with the right knowledge who will also take responsibility for getting things right. |
| 34:23 | · | That's what you need to battle the inherent chaos and disorder of the universe. |
| 34:29 | · | Otherwise, what you get is disaster. |
| 34:38 | · | [ad text redacted] |
00:00 Amelia Earhart's final flight
