WAS MECHANICAL FAILURE A POSSIBILITY IN JET CRASH?

An investigation into the crash of USAir Flight 5050 focused Saturday on the possibility of mechanical failure, although officials said the rookie co-pilot had punched the wrong cockpit button just before the craft plunged into the East River.

Investigators continued removing pieces of the plane's fuselage from the water off a runway at LaGuardia Airport, National Transportation Safety Board spokesman Ted Lopatkiewicz said. The parts will be examined to determine if there were any mechanical problems in addition to the pilot error, he said.Speaking of the co-pilot's mistake, Lopatkiewicz said, "It may turn out that was unrelated to what happened."

The flight's pilot and co-pilot had their flight licenses suspended for leaving the accident scene and were strongly criticized Friday by federal officials for failing to immediately submit to drug and alcohol testing.