reply to post by onehuman
Not necessarily. Once they pass out of radar contact after departure then it's up to the plane to report their position. They may have had an idea sonething happened, but until they were supposed to be closer to land and in radar range there was no way to be 100% sure.
China’s state news agency is reporting that the Malaysia Airlines aircraft has lost contact over Vietam while an unconfirmed report on a flight tracking website said the aircraft had plunged 200m and changed course shortly before all contact was lost.