Definition
A specified altitude in a precision approach or approach with vertical guidance at which the pilot must decide whether to continue the approach to landing or execute a missed approach. To continue, the pilot must have the required visual references in sight and the aircraft must be in a position to land using normal maneuvers. Decision Altitude is referenced to mean sea level (MSL) and is read from the barometric altimeter.
Plain English
On certain instrument approaches, this is the altitude where you have to make a go/no-go call: if you can see the runway environment, you keep going and land; if you can't, you fly the missed approach.
Context Anchor
Seen on instrument approach charts, especially approaches that guide the aircraft vertically toward the runway.
Derivation
‘Decision’ comes from the Latin decidere, meaning ‘to cut off’ — a moment where the choice is made and no longer deferred. ‘Altitude’ comes from the Latin altus, meaning ‘high.’ Together: the height at which the choice is cut off — you either land or go around.
Why Pilots Care
It sets the last safe point to commit to landing or go around, protecting against descent into terrain or obstacles when visual contact is lost.
Intuition Check
Do not read “decision” as a casual judgment call. At DA, the decision must already be made: continue only if the required visual references are visible and landing is safe; otherwise, begin the missed approach.
Example Sentence 1
Approaching DA on the ILS, the captain called 'minimums' and, with the approach lights in sight, continued to land.
Example Sentence 2
At DA the runway was still obscured by fog, so the crew began the missed approach climb.