From Arriba, a witness

ISLAMABAD, July 9 (Reuters) - The family of Faisal Jatoi, a missing Pakistani co-pilot, and four others after their cargo plane crashed into the Arabian Sea, anxiously awaited news of his fate on Thursday as rescuers continued their search.

Jatoi was the co-pilot of a K2 Airways Boeing 737 cargo plane flying from Sharjah, United Arab Emirates, to Karachi on Tuesday evening when it crashed off the southern coast of Pakistan. Pakistani rescuers located the wreckage in a deep-sea search operation on Wednesday.

A relative of Jatoi named Ghulam Nabi Bahrani said the family became worried when they could not contact him, and a Google search showed them the word "crash".

"At that moment, we felt as if Judgment Day had arrived," he told Reuters from his home in Karachi. Jatoi is married and has a two-year-old son.

Bahrani went on to say that the aircraft spent 10 days in Sharjah for maintenance work after a shipment was delivered, waiting for a spare part to arrive from the United States before the crew could embark on the return flight.

The aircraft is a modified Boeing 737-400 cargo plane that was produced 27 years ago.

The Pakistan Airports Authority said the plane reported a navigation problem at 9:18 p.m. Pakistan time (1618 GMT) while en route to Karachi, while data from Flightradar24 showed irregular changes in the plane's altitude before it plummeted.

The wreckage of the plane was found 53 nautical miles (98 kilometers) south of the port of Ormara on Wednesday, while naval and maritime security teams are searching for the plane's black box.

K2 Airways announced that the five people on board were two pilots, an engineer, and a support staff member. Their fate has not been officially confirmed.

Deep water exploration

A Pakistani aviation expert said that the operation to recover the wreckage of the plane could be among the most difficult in Pakistan's modern history, as the water depth in parts of the Arabian Sea ranges from about 2,500 to more than 3,500 meters.

The expert, who asked not to be named because he was not authorized to discuss the matter publicly, added that strong currents, poor visibility, rough seabed topography and changes in sea conditions could complicate efforts to recover the submerged wreckage and the black box.