A Boeing 737 cargo plane carrying five crew members lost contact with air traffic control on Tuesday night while flying over the Arabian Sea near Ormara in Balochistan, Pakistan, Pakistani aviation authorities said.

The aircraft had reported a technical problem during its journey from Sharjah in the United Arab Emirates to Karachi. Radar systems indicated the plane was descending rapidly before communication was lost, according to the Pakistan Airport Authority (PAA).

Flight tracking data from Flightradar24.com showed preliminary information of an initial loss of altitude, followed by a climb, and then a second, sudden and dramatic loss of altitude. The last transmitted data placed the aircraft at 1,100 feet above sea level with a vertical descent rate of 22,400 feet per minute, an unusually steep rate.

Anthony Brickhouse, an aerospace safety consultant, told Reuters, "Anytime you see something major like that, it catches your eye, but it is too soon to say what any of it means without more information."

The PAA has activated a rescue coordination center and launched a sea search to locate the missing aircraft. The plane, manufactured in 1999, was previously a passenger aircraft operated by Aeroflot and Garuda Indonesia before its conversion to cargo use in 2012.

The last major jetliner accident near Karachi occurred in May 2020 when a Pakistani plane carrying 98 people crashed near the airport following an apparent engine failure during landing.

Sources: Deutsche Welle, Geo News, Flightradar24.com, Reuters