【单选题】

The accident drew renewed attention to the popular but (1) A320. It was the first planeAirbus designed using highly computerized systems that are (2) to curb pilot error and allow crews to land (3) autopilot. Now (4) allAirbus planes—from theA320 to the jumboA340—operate on a " fly by wire" system, which uses electrical impulses (5) cables and pulleys to move the control (6) on the plane’s wings. (7) into the plane’s software also is a protective "envelope" that limits (8) steeply a pilot can climb, dive or band the aircraft.

Still,Airbus has a relatively good safety (9) withA320. Last week’s crash was the seventh accident—the fifth resulting in (10) —involvingA320 since its (11) in 1987.But some of those accidents have raised the question of whether the aircraft’s computer system may be too complicateD、Several of the crashes resulted from pilot’s making errors in (12) the plane’s computerized control or (13) devices. In one (14) 1992 crash near Strassbourg airport, French investigators concluded that anAir Inter plane flew (15) a mountain several miles (16) the runway because the pilots had incorrectly (17) the plane’s descent rate into the computer. The cockpit voice recorder showed that up till the moment of (18) , the pilots had no idea of their mistake. (19) , investigators say, such incidents indicate thatAirbus may need to add or (20) warning devices that tell the pilots when they are dangerously close to the grounD、
A．on
B．with
C．at
D．by