IF anyone expected a quick decoding of the flight data recorder and the cockpit voice recorder of the crashed Saudia and Kazakh airplanes to arrive at some quick conclusions like a thriller, the wait is going to be awfully long. The reasons are not far to seek. The inquiry committee headed by Justice R. Lahoti of the Delhi High Court, set up to investigate the worst-ever aviation crash in the nation, is just about beginning to work. The committee which has till February 15, 1997 to submit its conclusions, visited the Delhi air traffic control (ATC) last week for an on-the-spot study of the situation in which controllers work.