Definition
A standardized one- or two-letter code filed in the equipment block of an FAA flight plan to indicate an aircraft's navigation, communication, and transponder capabilities. ATC uses the suffix to determine which routes, procedures, and clearances the aircraft is eligible to receive, including RNAV and RVSM operations.
Plain English
A short code on the flight plan that tells air traffic control what your aircraft can do — what kind of navigation gear, radios, and transponder you have on board. ATC uses that code to decide which routes and procedures they can give you.
Context Anchor
Seen when filing an FAA flight plan and when checking whether an aircraft can use certain RNAV departures or routes.
Derivation
A 'suffix' is something added at the end. Here it's the letter added at the end of the aircraft type entry on the flight plan to describe its equipment.
Why Pilots Care
These codes determine whether a pilot can be cleared for RNAV departures, certain routes, or GPS-based procedures without extra restrictions or vectors.
Intuition Check
Do not think of these suffixes as part of the aircraft’s tail number or call sign. Here, the suffix is a flight-plan equipment code that tells ATC what the aircraft is capable of.
Example Sentence 1
Before filing, the pilot checked the FAA flight plan aircraft suffixes table to confirm the correct code for an RNAV-equipped aircraft with a Mode C transponder.
Example Sentence 2
Checking the FAA flight plan aircraft suffixes ahead of time prevented the crew from being assigned a procedure their equipment could not support.