Definition
An ICAO/FAA flight plan equipment suffix indicating the aircraft is equipped with a transponder that has Mode C (altitude reporting) capability but does not have area navigation (RNAV) equipment on board.
Plain English
A code pilots write on a flight plan to tell air traffic control what's on the aircraft. /TP means the aircraft has a transponder that reports altitude, but it does not have GPS or other area navigation gear.
Context Anchor
Seen in coded pilot weather reports, where each slash mark introduces a different part of the report.
Derivation
The suffix is shorthand: T for Transponder, P signaling a specific equipment combination in the FAA's coded list. The slash separates the suffix from the aircraft type designator on the flight plan (e.g., C172/TP).
Why Pilots Care
Filing the wrong suffix can mean ATC offers routings or procedures the aircraft can't actually fly. /TP tells controllers not to expect direct GPS routings or RNAV approaches, only ground-based navigation.
Intuition Check
Do not read /TP as temperature. In this report format, /TP means the aircraft type making the report.
Example Sentence 1
The pilot filed the flight plan as N12345/TP, signaling a Mode C transponder but no RNAV capability.
Example Sentence 2
Knowing the /TP helps pilots judge how relevant the reported turbulence is to their own aircraft.