Definition
An instrument approach procedure in which aircraft are cleared to land on closely spaced parallel runways at the same time, with required staggered (diagonal) spacing between aircraft on adjacent final approach courses. ATC ensures a minimum diagonal separation between each aircraft pair, so the approaches are conducted together but the spacing on one final depends on the spacing on the other.
Plain English
Two parallel runways are used for landings at the same time, but the planes on the two runways are not allowed to be side by side. Controllers keep them spaced diagonally so each pair has a safe gap between them.
Context Anchor
Seen in instrument approach procedures and air traffic control operations at airports with parallel runways.
Derivation
"Dependent" comes from Latin dependere, meaning "to hang from" -- one thing relies on another. Here, the spacing of aircraft on one runway depends on the spacing of aircraft on the parallel runway. That dependency is what distinguishes this from independent approaches, where each final is worked separately.
Why Pilots Care
Allows higher arrival rates at busy airports while preserving required separation; loss of stagger or separation can force a go-around.
Intuition Check
Do not read “dependent” as meaning one pilot is following another pilot’s decisions. Here it means the procedure depends on air traffic control keeping required spacing between aircraft on nearby approach paths.
Example Sentence 1
Approach control advised that simultaneous dependent approaches were in use to runways 28L and 28R, so we expected speed adjustments to maintain spacing with the traffic on the parallel final.
Example Sentence 2
During simultaneous dependent approaches the pilot monitored spacing closely because any loss of the required stagger would require an immediate missed approach.