when Germanwings Flight 9525 crashed in the French Alps. Officials say the co-pilot flew the airplane directly into a mountain on purpose.Now, experts wonder if possibly removing pilots from planes would improve airline safety. Some suggest, at the very least, letting officials on the ground take control of a plane if a pilot is acting strangely in the cockpit.But airplane industry experts warn that the technology has many problems. And they say the tragic crash of the Germanwings flight was an anomaly -- an extremely unlikely event. Each year, more than three billion people around the world take about 34 million flights. Fewer than 10 crashes over the past 30 years were purposely caused by commercial airline pilots.Patrick Smith was a commercial airline pilot for 25 years. He wrote a book called "Cockpit Confidential.'' He says that even the newest airplaneswould need costly re-engineering of their major systems. He says there are also concerns over terrorists taking control of the communications link and hijacking the plane.The United States military already has pilots operating drone aircraft remotely. The pilots are usually based far away from the drones, even on the other side of the Earth. But some experts worry about doing the same for passenger aircraft.Mary Cummings is a former U.S. Navy fighter pilot. She now works as a professor at Duke University in North Carolina. In her words, "the real reason a person wants another human in the cockpit is because they want to believe there's somebody in the front who shares their own fate and thus if anything goes wrong, they will do everything they can to save their own lives.''She and other experts believe cargo planes will be the first aircraft to fly over the U.S. without pilots. They say big cargo companies would go from two pilots to one, with a team of pilots assisting from the ground. Then, all operations would be done by flight specialists on the ground.Airlines would save money on pilot training, pay and retirement costs. They also would save on hotel and travel costs. In addition, ground-based pilots would be able to have normal eight-hour work days, even if their plane is in the air for 12 hours. Ms. Cummings says these changes could take place in 10 or 15 years.Pilots are getting further and further removed from their aircraft. Most aircraft movements other than takeoff and landing are already automated. They are done with the help of computers and other machines. When pilots want to change a flight path, they program the new directions into the plane's computer instead of making the turns themselves.Aircraft manufacturer Airbus is experimenting with the idea of a windowless cockpit. The company is testing a system of cameras and video monitors that would give pilots a wider, more-detailed look at their surroundings.Todd Humphreys teaches aerospace engineering at the University of Texas. He says it would not be hard to go one step further and have the pilots watching those same monitors from a room on the ground."Anything you can control with knobs or buttons, without getting out of your seat, can be done equally well — or even better — on the ground,'' he says.Professor Humphreys argues that pilots on the ground would not have to deal with jetlag or even the dehydration that comes after long flights.In his words, "pilots do not often face extreme challenges" and might not be able to deal with an emergency if it happens. Instead, he suggests having a team of airplane specialists in the room with all the remote pilots who could assist with any emergency. He says this would reduce the number of mistakes by pilots.But many pilots disagree. They say that often pilots must make split-second decisions.In the end, the final decision may come down to passengers. Are travelers more worried about a pilot killing them or stepping onto a plane without a pilot?更多听力请访问51voa.com