The Basics: At 30,000 feet, airplanes operate on autopilot, with computer software adjusting pitch, power, speed, wing level, and altitude. They stay aloft thanks to engine propulsion, which overpowers air resistance, or drag, and the way air streams over their aerodynamically shaped wings to generate lift. The wing flaps, structures that supplement lift but create drag, would be retracted.
Rolling an airplane, even a big one like an MD-80 (which, by the way, is not recommended by its manufacturer) would involve turning the yoke all the way to one side. The sight certainly would be unusual, but it wouldn?t make for a groundbreaking stunt: In 1955, Boeing chief test pilot Alvin "Tex" Johnson executed two barrel rolls in a Dash 80, the 707 prototype, over Seattle?s Lake Washington as part of the company?s U.S. tour to promote jets as the future mode of air travel. The spectacle worked, notes Boeing historian Mike Lombardi. "Within a month of the barrel roll, the Dash 80 had done its job," he says. "Pan Am ordered 20 of the Dash 80?s offspring?the 707."
Inverting an airplane to regain altitude and balance, as Whitaker does in Flight, would make sense, at least theoretically. Tom Aldag, director of research and development for the National Institute for Aviation Research in Wichita, Kan., explains it like this: If you stick your arm out the window of a moving car and tip your hand up, the air will push it farther up; if you angle it down, the air will push it farther down. When a force pins down a surface (hand or airplane), what?s the last-ditch way to counteract that force? Flip the surface. "In theory, it might work," Aldag says, emphasizing might.
The uncontrolled dive situation certainly complicates things. In the film, Whitaker shouts to his cockpit crew to retract the landing gear, flaps, and speedbrakes, and hit full throttle. But decreasing speed would lessen stress on the airframe, a critical factor. Speedbrakes increase drag and slow the aircraft, says Russ Williams, an experienced test pilot and airline pilot. Flaps do the same, though they?re not designed to deploy at such high speeds. It?d be better to pull back the throttle to power idle while losing altitude, he says.
So now?theoretically?you?re piloting an upside-down airliner. Normally, you?d just keep rolling over until you completed a full 360 degrees, Williams says. Inversion risks engine failure, because fuel pickup tubes draw from the tank?s bottom. But if your airplane had a broken jackscrew and dysfunctional horizontal stabilizer, like Whitaker?s, inversion could help it regain altitude and slow down; its nose would remain stuck pitched down?but now "down" means up, toward the sky. You?d want to increase power if needed, flip, and land quickly; once righted, the airplane would jolt earthward again.
The reaction speed required to execute all that makes this a true Hollywood feat. "If you know what you?re doing, sure, you could roll an airplane," Williams says. "But your timing would have to be pretty perfect to judge all the pitching up and pitching down and touch down at the right attitude."
But airline pilots have a long history of remaining cool under pressure. Consider Sully Sullenberger?or Al Haynes, the captain of United Airlines flight 232, a DC-10 that crash-landed on July 19, 1989, after the catastrophic failure of its tail-mounted engine led to the loss of all hydraulic flight controls. Haynes and his flight crew used the power of the wing-mounted engines to guide the airplane?s descent. (On approach, Haynes stayed calm and collected?he even kept his sense of humor. After air traffic control cleared Flight 232 for an emergency landing at Sioux City, he quipped: "Roger. You want to be particular and make it a runway, huh?") His DC-10 cartwheeled off the runway into a cornfield, but 185 of the 296 passengers and crew on board survived.
No doubt Hollywood wants to craft an exciting visual experience, and Flight definitely achieves that by raising the stakes for Whitaker (in more ways than one, as moviegoers will see). "It?s looking for the dramatic without crossing the line to the ridiculous," says Craig Hosking, a pilot who?s flown at least 300 different types of aircraft and who worked as an aerial coordinator on the film. "Nobody would?ve ever believed you could land on the Hudson River and not hurt a soul. If you?d seen that in a movie, you wouldn?t have believed it."
Kristen Stewart Rupert Sanders Photos BBC 2016 Olympics TD Bank mountain lion hanley ramirez Christian Bale visits victims
কোন মন্তব্য নেই:
একটি মন্তব্য পোস্ট করুন