Definition
The title of a specific instrument approach procedure: an Area Navigation approach to Runway 15R that requires Required Navigation Performance (RNP) capability. The 'Z' is a chart identifier letter used to distinguish this approach from other RNAV approaches to the same runway (such as RNAV (RNP) Y RWY 15R or RNAV (GPS) X RWY 15R). RNP approaches require aircraft and crew authorization to fly to defined lateral and vertical containment standards, often including curved (RF) path segments not flyable on a basic GPS approach.
Plain English
This is the name of one particular approach chart. It tells you the approach uses GPS-based navigation, demands a higher level of navigation accuracy than a basic GPS approach, lands on Runway 15R, and is the 'Z' version because the airport has more than one approach to that runway.
Context Anchor
Seen at the top of an instrument approach chart and in the aircraft's procedure list when selecting an approach before arrival.
Derivation
RNAV stands for Area Navigation -- flying along any path you choose rather than directly station-to-station. RNP stands for Required Navigation Performance -- a stated accuracy the aircraft must meet and monitor itself. The letters Z, Y, X (working backward from Z) are chart identifiers used when more than one approach of the same general type serves the same runway. 15R means Runway 15, the right-hand runway when two parallel runways share that heading.
Why Pilots Care
Pilots must identify the exact procedure they are cleared for so they load and brief the correct lateral and vertical path, minimums, and missed approach routing.
Intuition Check
Do not treat the Z as part of the runway name or as a difficulty rating. It is only a procedure identifier used when more than one approach of the same general type serves the same runway.
Example Sentence 1
Approach cleared us for the RNAV (RNP) Z RWY 15R, so we briefed the curved final segment before the initial approach fix.
Example Sentence 2
ATC issued a clearance for the RNAV (RNP) Z RWY 15R, so the crew verified the required RNP value and missed approach instructions.