I recently listened to a BBC documentary about transatlantic travel that started with the correspondent’s experience on a flight from the U.S. to Europe. She was on a United Airlines flight, listening to live air traffic control audio on the in-flight entertainment system. It was the middle of the night, dinner was over, and most of the cabin was asleep. They were about half way through the journey, right in the middle of the North Atlantic Ocean and at least a thousand miles away from the nearest airport. It’s a lonely part of the planet – just blackness out the window, apart from the potential glint of a moon-lit iceberg. Then, interrupting the static on the radio frequency, she heard an Irish voice: “Shanwick radio, United 924 good morning.”
If you have stayed up during the short night on one of these eastbound flights, as I’ve done many times, you’ll know the scene. If you look on the flight map on the seatback screen, you’ll be past the Labrador Sea and a bit east of the southern tip of Greenland – 60 degrees north, 30 degrees west. If you are unfortunate enough to be awake, you’re probably uncomfortable and perhaps disturbed by the snoring strangers (very) nearby.
This is a far cry from how transatlantic travel once was. The pond, as they say, has been a quite formidable barrier to travel, trade and war for all but the last 75 years. In 1938 the first commercial transatlantic flight safely landed in New York after a long, bumpy, and slow twenty-five hour journey from Berlin. The airplane was a Focke-Wulf Fw 200 Condor with four not-so-reliable piston engines and a cruise altitude of about 12,000 feet. Navigation was shaky and weather forecasting didn’t exist. This was likely not a pleasant ride over the stormy North Atlantic.
Today, tens of thousands make the same crossing each day in airplanes that fly at three times the speed and altitude and have engines that almost never fail. Oceanic navigation is straightforward with GPS and highly accurate internal reference units that measure the airplane’s 3-dimensional accelerations in order to calculate its speed and position. But still, even with the technical precision, the ocean is a big and rather intimidating place. If you pay attention, it’s hard not to feel some respect for the situation – just jet fuel and a century of engineering holding you and your “chicken or beef” above the cold water.
The “voice in the night” that our BBC correspondent heard over the air traffic control frequency was from the Shanwick Oceanic Control center in Prestwick, Ireland. Here a small group of five or ten controllers monitor the hundreds of aircraft that make the transatlantic crossing every day. Over the ocean there is no radar to monitor air traffic like is used over land. The airplanes are also too far away from the control center to use normal radio frequencies and instead must switch to static-filled high frequency channels (which, if you’re curious, reflect off of the very top of the atmosphere and can travel around the entire planet).
Twice a day, the two oceanic control centers – Shanwick and Gander – plan a series of North Atlantic tracks for airplanes to follow across the ocean. These tracks are designed to minimize the crossing time by steering airplanes into optimal wind conditions. The jet stream at 30-40 thousand feet blows from west to east and is commonly over 100 mph; eastbound flights want the strongest tailwind possible and westbound flights want the weakest headwind they can find.
At certain times of the day, the North Atlantic can be a busy place, relatively speaking. Airplanes are “fed” into the track system 10 minutes apart, about 50-60 miles at normal speeds. Because there is no radar control and minimal radio communication, established procedures are in place for emergencies; if an airplane must leave the track or change speeds, the pilot will turn 90 degrees perpendicular to the track, fly a set distance, and then turn back and fly parallel to but in between tracks.
Today, the oceans are no barrier; crossing them is efficient, reasonably comfortable, and far safer than walking. Yet I still find it to be an eerie moment, up above the dark water, so far away from everything human. I think this is what our correspondent felt as well, and why she was so fascinated by the voice breaking through the static – that there is someone out there expecting you as you hurtle through the night.