Twenty-four people, among them seven children, were killed on Sunday after their airplane crashed in a river in Brazil. Four people survived the crash, including a 9-year-old boy. The aircraft, which was a twin-engine Embraer turboprop chartered by Manaus Aerotaxis, was carrying 26 passengers and two crew members when it crashed. The pilots of the plane, which had departed from Coari, had supposedly contacted the air traffic control near their destination of Manaus to announce  that they were turning back. The plane, however, then disappeared from radar. The plane made an emergency landing in the river Manacapuru, a branch the  Amazon river in the Brazilian state of Amazonas, 50 miles (80 kilometers) from Manaus.

Based on the paragraph above can we conclude that "It is always a bad sign when planes disappear from radar"?