[04:50.55][00:00.00]更多听力请访问chinavoa.com [00:05.66]From VOA Learning English, [00:09.41]this is In the News. [00:11.66]The search for a Malaysia Airlines passenger jet [00:15.88]expanded this week. [00:18.00]The airplane, a Boeing 777, disappeared last Saturday [00:23.91]on a flight from Kuala Lumpur to Beijing. [00:27.89]It was carrying 239 people. [00:31.89]At first, the search was along its expected flight path. [00:36.68]But by week's end, crews had expanded the search [00:40.66]across parts of southern Asia [00:43.10]for any evidence of Malaysian Airlines Flight 370. [00:48.31]With satellites and other technology available, [00:52.31]how can a plane as large as the "Triple-7" just disappear? [00:58.26]Air safety expert John McGraw says [01:01.92]it is easier than you may think. [01:05.12]"People are under the impression that every airplane, [01:07.03]even when it's flying across the ocean, [01:08.53]is observed on some kind of radar scope, [01:11.38]with a human being looking at that scope. [01:13.53]And it's just not the case. Radars don't reach that far." [01:16.20]But John McGraw says [01:18.20]there are also a lot of devices inside the Triple-7 [01:23.60]that can help searchers follow its movement. [01:27.66]Systems in the aircraft send altitude, weather conditions, [01:33.47]position and speed to air traffic controllers. [01:38.57]There are also at least three ways the pilots [01:42.46]can communicate with controllers. [01:45.19]Another tool is the flight data recorder or "black box." [01:50.70]If the plane is downed in the ocean, [01:54.00]the black box sends out a signal [01:57.11]that can travel up to three kilometers away. [02:01.12]Many people remember when a French passenger jet [02:06.11]disappeared five years ago. [02:08.47]Air France Flight 447 went missing as it flew from Brazil to Paris. [02:16.24]Its wreckage was eventually found in the Atlantic Ocean. [02:21.69]Air safety expert John McGraw remembers [02:25.54]the National Transportation Safety Board taking action [02:29.54]after the French jet went missing. [02:32.90]He says US officials called for continuous download [02:38.20]of an aircraft's flight data recorder information [02:42.61]in case of emergencies. [02:44.77]"In the past they haven't been able to justify installing [02:47.92]that kind of equipment, because it's expensive, [02:50.21]and because there hadn't been that many accidents [02:53.31]where it would have come into play. [02:54.60]This will certainly provide some additional motivation [02:57.77]and there may be calls to do that." [02:59.52]Malaysia Airlines Flight 370 was last seen [03:03.68]on radar above Vietnam and Malaysia. [03:07.74]Air traffic controllers in both countries say [03:12.00]they did not receive any message [03:14.75]that the plane may have been in trouble. [03:17.51]On Tuesday, Malaysian media reported that the Malaysian military [03:23.32]had noted the aircraft flying toward the country's west coast. [03:28.77]That is far from where controllers lost contact with the plane. [03:34.74]The next day, China released satellite images [03:39.75]showing three large objects floating in waters [03:43.99]between Malaysia and Vietnam. [03:46.85]But China later said it could not confirm the objects [03:52.35]belonged to the missing aircraft. [03:55.01]The Wall Street Journal reported [03:57.72]that the plane could have stayed in the air [04:00.77]for several hours past the time of its last confirmed location. [04:07.17]The newspaper later said that the plane [04:10.65]continued to send information about its engines [04:14.56]and performance to satellites for five more hours. [04:19.85]That suggests Flight 370 could have remained in the air [04:25.42]or was on the ground somewhere. [04:28.82]Why the signals stopped is unclear. [04:32.67]This is a developing story. [04:35.39]For the latest news on the Malaysian airliner, [04:39.39]go to 51VOA.com. [04:42.49]And that's In the News from VOA Learning English. [04:48.54]I'm Steve Ember.

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