UPS 747 had smoke in cockpit before Dubai crash

DUBAI, United Arab Emirates — Pilots on board a UPS cargo plane faced radio problems and smoke in the cockpit as they struggled to maintain altitude before crashing into the desert outside Dubai last week, investigators said Sunday.
What exactly caused Friday's crash remains under investigation. The UAE's General Civil Aviation Authority said in a preliminary report the Boeing 747-400's two-man crew was trying to return to Dubai's main airport — the Mideast's busiest — when the plane went down. Both crew members were killed.
Flight 6 was en route to the UPS hub in Cologne, Germany.
Al-Suwaidi said it was unclear why the plane turned back toward Dubai rather than heading toward an airport in Bahrain, which was responsible for the plane's flight path when crew reported smoke in the cockpit.
A US National Transportation Safety Board team is scheduled to arrive Sunday evening to help with the probe.