Takeoff
From the start of the takeoff roll to a few hundred feet above the runway. Statistically one of the two most dangerous parts of a flight.
The takeoff is defined around V1, the decision speed. Before V1 the takeoff can be rejected on the remaining runway; after it, the crew are committed to fly and must handle any failure in the air. Rejected takeoffs above V1 are a recurring accident category.
Takeoff accidents also involve performance data (wrong weights, wrong thrust settings, the wrong intersection) and configuration errors such as an incorrect flap setting.
Related terms
Loss of thrust from one or more engines. Whether it becomes an accident usually depends on when it happened and what the crew did next.
From just after liftoff to the cruise level. High thrust, high workload, close to the ground for the first part of it.
Decisions and pressures outside the flight deck (dispatch, loading, scheduling, air traffic services, company culture) that shaped the outcome.