Definition
Instrument approaches conducted simultaneously to two or more parallel runways at the same airport, with each aircraft tracking its own final approach course while ATC ensures lateral separation between adjacent traffic. Depending on runway centerline spacing and available equipment, parallel approaches are categorized as dependent (staggered, with diagonal separation required), independent (simultaneous, with no required staggering), or simultaneous close parallel (using precision monitoring of a defined No Transgression Zone between courses).
Plain English
Two or more aircraft flying instrument approaches at the same time to runways that sit side by side at the same airport. Each aircraft stays on its own approach path, and controllers keep them safely apart from each other.
Context Anchor
Seen in instrument flying and approach control discussions at airports with closely spaced parallel runways.
Derivation
Parallel comes from Greek roots meaning “beside one another.” That helps here because the runways, and the paths leading to them, run side by side rather than crossing.
Why Pilots Care
These procedures increase airport capacity during busy periods while preserving safe separation between aircraft.
Grounding Statement
Picture two airplanes lined up with two side-by-side runways, each staying on its own straight path to its assigned runway.
Intuition Check
Parallel does not mean the aircraft are automatically safe just because the runways are side by side. It means the approach paths are side by side; safety depends on required spacing, monitoring, and each aircraft staying on its assigned path.
Example Sentence 1
Approach Control advised, "Expect the ILS Runway 28L; simultaneous parallel approaches are in use to 28L and 28R."
Example Sentence 2
Pilots must stay on the localizer during parallel runway approaches to avoid drifting toward traffic on the adjacent runway.