Aviation investigators, running out of time to find the "black boxes" with key information on the crash of Air France Flight 447, suspect a rapid chain of computer and equipment malfunctions stripped the crew of automation today's pilots typically rely on to control a big jetliner.

An international team of experts is building a scenario in which it believes a cascade of system failures, seemingly beginning with malfunctioning airspeed sensors, rapidly progressed to what appeared to be sweeping computer outages, according to...