Why do planes crash?

Navigational errors are among the most common causes of plane crashes. Planes are flown into a mountain or the sea out of a variety of reasons. Sometimes weather conditions are bad, in other cases pilots have made bad judgements.

In 1996 a Peruvian airliner crashed into the sea after the computer stopped working. The crew had almost no data left to work with and didn't know at which height they were flying when they hit the water.

In 1977 almost 600 people got killed when two planes were heading at full speed towards each other and collided in heavy fog on the runway in Tenerife. The crash happened after planes had been guided to Tenerife because Gran Canary airport was closed.

In June 2009 an Air France airbus disappeared off the coast of Brazil. Although the wreckage was found after a few days it took investigators almost three years to find out what had really happened to the plane.

Pilots are criticising the way planes are ____. In the past decades the structure of planes has changed. More computers and automated systems are taking over, the pilot often has no alternatives left.

(Adapted from http://www.english.online.at/news-articles/technology)

“Wreckage” in bold type, means