Definition
A flight condition in which the aircraft is losing altitude over time, moving from a higher altitude toward a lower one. On instruments, this is indicated by a downward trend on the altimeter, a negative reading on the vertical speed indicator, and a nose-low attitude on the attitude indicator.
Plain English
The airplane is going down — its height above the ground is decreasing.
Context Anchor
Seen in instrument flying, safety-system displays, and warnings that describe whether the aircraft is climbing, level, or moving downward.
Derivation
Descend' comes from Latin words meaning 'to climb down' or 'go down.' In aviation, it keeps that same basic idea: the aircraft is moving to a lower altitude.
Why Pilots Care
Recognising a descent quickly — especially an unintended one — is fundamental to instrument flying. A descent that goes unnoticed can lead to altitude busts, terrain conflicts, or controlled flight into terrain.
Grounding Statement
If the altitude readout is getting smaller over time, the aircraft is descending.
Intuition Check
Do not assume descending means the nose is pointed down. In aviation, descending means altitude is decreasing; the nose position and the aircraft's actual path are not always the same.
Example Sentence 1
The altimeter unwinding and the vertical speed indicator showing 500 feet per minute down confirmed the aircraft was descending.
Example Sentence 2
During the instrument approach briefing, the crew noted the point where the aircraft is descending through the initial approach altitude.