Plain English Meaning
The last part of an instrument approach, where the aircraft is lined up with the runway and descending toward landing. If the runway is not in sight at the end of this segment, the pilot must go missed.
Full Definition
The portion of an instrument approach procedure in which alignment and descent for landing are accomplished. It begins at the final approach fix or point and ends at the missed approach point or runway threshold, depending on the procedure.
Context Anchor
Seen on instrument approach charts and in instrument flying discussions, especially when identifying where the final descent toward landing begins.