was air france 447 in 2009. it took two days before they found any debris and two years to locate the flight recorders. the cause of this crash, the pilot didn't react. another possibility, a mechanical problem. twa flight 800 went down off the coast of long island in 1995. >> the general area of maintenance is a valid area -- again, everything's on the table, including that. >> this japan airline 747 crashed after its tail broke off. a faulty repair seven years earlier was to blame. this malaysian plane had one past accident. in 2007, its wing clipped another aircraft. it was repaired.