Definition
A single letter (A, B, C, etc.) added to the end of an instrument approach procedure title to distinguish between two or more approaches of the same type to the same runway, or to identify approaches that do not provide straight-in landing minimums to a specific runway. Suffixes begin with the letter A and continue alphabetically. When a procedure terminates in circling-only minimums (no straight-in runway alignment), the suffix is paired with a runway-independent identifier such as the airport name or a directional reference.
Plain English
It's the letter at the end of an approach name that tells you which version of that approach you're flying. If an airport has more than one approach of the same type to the same runway, each one gets its own letter so pilots and controllers know exactly which chart to use.
Context Anchor
Seen in instrument approach chart titles and clearances, especially when several similar procedures serve the same airport or runway.
Derivation
Alphabetical comes from alphabet, meaning a set of letters. Suffix comes from Latin words meaning “fastened underneath or after.” Together, the term means a letter fastened onto the end of a name.
Why Pilots Care
When a controller clears you for a specific approach, the suffix matters. 'RNAV Y' and 'RNAV Z' to the same runway can have different procedures, minimums, and missed approach instructions. Briefing or loading the wrong chart is a real safety issue.
Intuition Check
Do not treat the letter as a grade, difficulty level, or quality rating. In this context, the letter is simply part of the procedure’s exact name.
Example Sentence 1
Tower cleared us for the RNAV (GPS) Z Runway 27 approach, so I made sure to load the Z chart and not the Y version.
Example Sentence 2
Loading the correct alphabetical suffix in the FMS ensures the aircraft follows the published circling minima.