India, July 8 -- A cargo plane carrying five crew members disappeared off the coast of Karachi late Tuesday night after rapidly descending and abruptly changing course, triggering an urgent multi-agency search across the Arabian Sea, Pakistani aviation officials said.

The Boeing 737, operated by Karachi-based K2 Airways, was flying a cargo route from Sharjah in the United Arab Emirates to Karachi when its crew reported a navigation system problem at 9:18 p.m. local time, according to Pakistan's Civil Aviation Authority. Radar data showed the aircraft descending sharply and making a sudden change in heading roughly three minutes later, before radar and radio contact was lost entirely about 155 nautical miles, some 178 miles, west of Karac...