Why it's so hard for planes to land on water

But despite that success, landing a plane on the water, known as "ditching," can be extremely dangerous.
This controlled, emergency-landing procedure is very rare, especially on commercial flights.
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Following is a transcript of the video.

Narrator: On January 15, 2009, US Airways Flight 1549 flew into a flock of Canadian geese shortly after taking off from New York's LaGuardia Airport. The plane lost all engine power while flying over Manhattan. Their options? Attempt to land on the Hudson River or crash into one of the densest cities in the US.

Clip: I don't know. I think he said he was going in the Hudson.

Narrator: Thanks to clear conditions, expert piloting, and a quick response from emergency crews, all 150 passengers survived. You may have heard this story before, but it's not the only time something like this has happened. And despite that success, landing a plane on the water is extremely dangerous.

Ditching is a controlled emergency landing on water. It can be caused by almost anything, but usually it's because of engine failure or running out of fuel. Pilots only decide to ditch an aircraft when there is no better alternative. Despite the difficulty, pilots don't undergo extensive training on ditching.

Chesley Sullenberger, the pilot of US Airways Flight 1549, told The Telegraph in 2018: ''The only training we had gotten for a water landing was reading a few paragraphs in a manual and having a brief classroom discussion.''

Carolina Anderson : You really don't practice, not even in the airplane or in the simulator, but most airlines will cover it in training. But it's not something that is mandated for every airplane.

Narrator: That's Carolina Anderson. She's an associate professor of aeronautical science at Embry-Riddle Aeronautical University. Anderson pointed out that it's rare to have to ditch an airplane.

Anderson: It's not something that is very common. You see them in smaller airplanes more often, in big airliners not very often.

Narrator: Planes are usually tested using simulations, rather than actual bodies of water. The aircraft needs to float long enough for passengers to evacuate. But pilots have to worry about more than just the plane. Unlike landing on a runway, there are a lot of variables that are out of the pilot's control.

The most obvious is the waves. The larger the waves, the more dangerous the landing. Pilots try to land parallel to the waves, instead of across them, so the waves don't push the plane around, which could cause damage to the plane, injure passengers, and make evacuating more difficult.

Like in 1956, when Pan Am Flight 6 had to ditch in the Pacific between Honolulu and San Francisco. Upon landing, a wing hit a swell, rotating the plane 180 degrees, damaging the nose, and breaking off the tail. Luckily, everyone survived.

While ditching, pilots have to keep the wings level and maintain an incoming angle that's not too steep to prevent a hard impact. Inside the plane, the passengers will be told to brace for impact. And anything loose in the cabin will need to be tied down. Another huge factor is the weather. Clear conditions give a pilot better control over the aircraft and increased visibility. Pilots balance all of these variables in order to prevent the aircraft from breaking apart. If a plane breaks upon impact, there is a huge risk of flooding.

Anderson: You're not going to float for very long, and if you land too hard, the chances of breaking it are very high because water is going to get in and it's going to start sinking.

Narrator: And if a plane flips over, flooding will occur much faster.

Anderson: Basically, you want to touch down as slow and as soft as possible. If the airplane has retractable landing gear, you want the gear to be up and you want the flaps to be completely down.

Narrator: If the landing is successful, the next step is getting everyone off the plane. Which has to happen quickly, since the Federal Aviation Administration requires planes to be able to be evacuated within 90 seconds.

Thankfully, modern planes are equipped with a bunch of safety features to help passengers if an aircraft is ditched. Commercial planes use rafts and flotation devices like life preservers. They also come with flares and emergency radios. Airplanes are designed so that a water landing won't cause immediate harm to passengers. Many ditching-related deaths are from drowning, not the impact.

But don't let this discourage you from flying. Forced water landings are unlikely to happen, especially on a commercial flight. Whenever flying, you should listen to safety instructions carefully. And always remain calm.