Definition
The Normal Operating Zone (NOZ) is the airspace of specified width on either side of a final approach course within which an aircraft conducting a simultaneous parallel instrument approach is normally expected to remain. It is the protected band of airspace centered on each runway's final approach course during simultaneous parallel ILS or RNAV approaches to closely spaced parallel runways.
Plain English
When two aircraft are landing at the same time on parallel runways at a busy airport, each aircraft has its own lane of airspace it is expected to stay inside. That lane is the NOZ. As long as both aircraft stay in their own lanes, they are safely separated from each other.
Context Anchor
Seen in procedures and controller instructions for simultaneous approaches to parallel runways.
Derivation
“NOZ” is formed from Normal Operating Zone. In this use, “normal” means the expected, correct path of flight, and “zone” means a defined area of airspace.
Why Pilots Care
Defines the safe lateral limits that keep two aircraft on parallel approaches from interfering with each other.
Intuition Check
“Normal” does not mean informal or optional here. It means the expected protected area where the aircraft should remain while flying the approach correctly.
Example Sentence 1
During the simultaneous parallel approach into runways 27L and 27R, the crew flew the localizer precisely to remain within the NOZ.
Example Sentence 2
The controller confirmed both aircraft were established in their respective NOZs before clearing them to land.