In regards to Swissair, the smoke/fumes of unknown origin checklist took 20-30 minutes or more to complete. Only at the end did it suggest a diversion if results were not suitable. The checklist was revised after the accident. This is important to consider: NO manufacturer produced checklist takes time of completion into account. NONE OF THEM. This is an issue I discussed extensively when I managed the human factors program at FlightSafety Intl.