Cruise
Level flight between climb and descent. The longest phase and the one with the fewest accidents per hour.
Cruise accidents are rare but distinctive: structural or pressurisation failures, in-flight fires, upsets from weather or sensor problems, and fuel exhaustion. There is usually more time to work a problem, which is why the ones that end badly tend to involve an event that removed the aircraft's controllability or the crew's information.
Related terms
From leaving cruise level to joining the approach. Workload rises as the aircraft is slowed, configured and briefed.
Fire or smoke aboard in flight. It is time-critical: historically, crews have had well under half an hour from the first smell of smoke.
The aircraft told the crew something untrue — blocked pitot tubes, a failed angle-of-attack vane, disagreeing airspeed or altitude indications.