Definition
An ATC procedure permitting simultaneous independent ILS, RNAV, or GLS approaches to parallel runways whose centerlines are separated by less than 4,300 feet but at least 3,000 feet. Because the runways are closer together than standard parallel approach criteria allow, a high-update radar monitor and a No Transgression Zone (NTZ) between the final approach courses are required, and pilots must comply with specific charted approach procedures and ATC instructions to maintain separation.
Plain English
Two aircraft fly approaches at the same time to two runways that sit close to and parallel with each other. Because the runways are unusually close, controllers use special radar and a protected zone between the approach paths to keep the aircraft safely apart.
Context Anchor
You may see this term in approach procedures, ATC information, or airport operations at busy airports with closely spaced parallel runways.
Derivation
“Simultaneous” comes from a Latin word meaning “at the same time.” “Parallel” means running side by side without meeting. In this term, those words point to the key idea: two approaches happening at the same time to runways that sit side by side.
Why Pilots Care
These procedures increase landing capacity at busy airports during peak periods while preserving safety through enhanced monitoring and immediate breakout instructions if needed.
Intuition Check
“Close” does not mean the aircraft are casually close to each other. It refers mainly to the spacing between the parallel runway centerlines, and the operation is allowed only under specific procedures.
Example Sentence 1
Tower advised that simultaneous close parallel approaches were in use to runways 28L and 28R, so we briefed the breakout procedure before commencing the approach.
Example Sentence 2
The controller issued a breakout instruction when the aircraft on the adjacent approach began to drift inward during simultaneous close parallel approaches.