After Thursday's emergency landing of U.S. Airways Flight 1549, people will likely pay more attention to airline safety for a while.
The Wall Street Journal explains why successful water landings are so rare:
In such emergencies, pilots are trained to bring the airplane in for a smooth landing, just as they would on dry land. They typically would lower the plane's wing flaps and slats, which increase surface area and allow the aircraft to slow down as much as possible.
In order to keep the plane as watertight as possible, pilots are trained to keep the landing gear stowed inside the fuselage.
One of the biggest obstacles to a safe water landing is a jetliner's engines, which hang below the wings on planes such as the A320. Because of their size, the engines could become enormous water brakes at the time of touchdown, potentially forcing the cockpit to hit the water at a steep angle.
In order to overcome this, pilots are taught to keep the airplane's nose as high as possible during landing so that the plane will hit the water at the lowest possible speed, making impact less dramatic.
The fact that the U.S. Airways crash-landing into the Hudson River is survivable is an opportunity to talk about why flight attendants want you to put your seat into an upright and locked position.
AirSpace magazine explains:
There are two main reasons why flight attendants pester people to keep those seats up—to keep injuries to a minimum during a crash and to clear the maximum amount of space for a quick exit.
The science is pretty basic, as explained by Brian Manning, a flight attendant for Mesa Airlines. "When the seat is up, it is locked. When the seat is back, it's not locked. In the event of an emergency, an unlocked seat has more force during impact, and the thrusting forward of that seat can cause passenger injury."
Like a catapult, the farther back the seat, the greater distance your head would travel during an impact, and the more force would be generated. Those three inches can add to the whiplash effect.
Also, Manning notes, people sitting behind a seat that is reclined or unlocked will not be able to brace properly. And yes, there are proper ways of bracing. In the late 1980s the FAA researched various ways to prepare the body for impact [PDF] using test dummies.
