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Strategies & Market Trends : 2026 TeoTwawKi ... 2032 Darkest Interregnum -- Ignore unavailable to you. Want to Upgrade?

To: SG who wrote (46202)	2/6/2009 2:38:21 PM
From: Elroy Jetson	1 Recommendation Respond to of 217977

So how exactly does a pilot land in the water? "You want to land the airplane as slow as possible without stalling," says Embry Riddle's Ayers. "You also want to catch both engines in the water at the same time. Hit one wingtip first, and you'll cartwheel the plane." The A320 has one engine mounted below each wing. Ladd says there is a checklist for "ditching" an airplane, but Sullenberger most likely didn't have time to go through it. "We have procedures for ditching, but it's the instinct that got him through it, as well as the training," he says. The pilot most likely kept the landing gear retracted, but he also probably extended the wing slats and flaps. Slats extend the front, or leading edge of the wing, and flaps change the shape of the back, or trailing edge. Extending the slats and flaps changes the aerodynamics of the plane, generating more lift, but also more drag. Engaging the flaps, which are used during takeoffs and landings, allowed Sullenberger to slow the plane down without letting it stall. Stalling is the point at which the wings stop generating lift, the force that keeps the plane in the air. "The pilot had to make a trade-off between going too slow and stalling, and going too fast and crashing," Fanjoy says. "He maneuvered the airplane to maintain the best glide speed," referring to the range of speeds where the airplane is still maneuverable and hasn't stalled. "If the whole airplane entered the water at once, it would be much harder to control," Ayers says. Setting the tail of the plane into the water first is key, Ladd says. That lets the water slow the plane down. "The idea is to make the landing as soft as you can at as slow a speed as possible. If the nose is too low and going too fast, you risk flipping the plane tail-over-nose." Floating Down The River After setting down in the river, the airplane floated on the surface long enough to allow all of the passengers to safely exit. While large jets aren't specifically engineered to float, they do have features that can be employed in the case of a water landing. Mary Anne Greczyn, communications manager at Airbus, says a "ditch switch" is standard equipment on all modern Airbus and Boeing aircraft. The switch, which is mounted on an overhead panel in the cockpit, can be pushed by the pilot to close off openings on the outside of the plane before it hits the water. "The switch closes off the outflow valve and the avionics ventilation ports — anyplace air would go in or out," Greczyn says. Where air cold goes, so can water to flood the plane, so "it closes off openings below a theoretical float line." Pilot Ladd says that while the ditch switch is useful, opening the main doors and emergency exits on the plane to let passengers out would negate any impact that closing the valves would have, once the plane is down. Fuel and air in the wings also probably kept the plane afloat for as long as it was, Ladd says. Since fuel and air are less dense than the river water, the wings helped buoy the plane. And because the wings are located slightly forward of the center of the fuselage, the front of the plane was slightly propped up while the tail began to sink. The pilot of the US Airways flight, Sullenberger, also flew the F-4 for the Air Force from 1973 to 1980, and Ladd and Ayers, both military fliers themselves, say his military training no doubt helped him navigate Thursday's emergency. And Sullenberger was also a glider pilot, which undoubtedly brought valuable skills to the crisis. "Every glider landing he's ever made has been a power-off landing, and every power-off landing you make can't hurt, so that gave him a lot of training," Ayers says. "Everything he had done over his professional piloting career contributed to his success here." npr.org