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When ATC Asks: “What’s Your Equipment Suffix?”

For the past few years of flying, I have relied on a dispatcher to file my flight plan and provide the required information to the FAA. Recently, a failure of equipment on my aircraft required me to fly in the Non RVSM airspace at or below FL290. When the controller asked "what's your new equipment suffix?", the First Officer turned to me with a puzzled look. With a blank stare followed by shrugging of shoulders I responded to his implied question with, "let's look it up".

Luckily we where on the ground and had time to look up the suffix for our flight plan, but it would have been easier if I had memorized the suffix for the possible configurations I might encounter. I know others have this same problem because I hear aircraft asking air traffic control for a decent because an equipment failure disqualifies the aircraft to fly in RVSM airspace.

The conversation after the descent to FL290 seems to be the same every time. The air traffic control asks the pilot, "for the flight plan please say your new equipment suffix". After a long pause, the pilot normally responds with a "standby while I look it up". Many times the controller will look up the proper suffix for the flustered pilot.

I see this scenario play out all too often, and I am as guilty as the next pilot for not knowing what suffix to use if my equipment capability changes. After listening to the conversation between the controller and the pilot, I made a determination not to get caught in this situation without know the proper suffix for my aircraft. To help myself and for your reference, I have the codes displayed below.

I suggest you print a copy and carry it with you.  Another suggestion is to note the proper codes for your aircraft anticipating all possible equipment failures, and memorizing the associated suffix for these situations. Next time the controller asks for your equipment suffix, you can respond quickly and with confidence.

FAA Flight Plan Aircraft Suffixes

Effective September 1, 2005


Equipment Capability



No transponder


Transponder with no Mode C


Transponder with Mode C



No transponder


Transponder with no Mode C


Transponder with Mode C



No transponder


Transponder with no Mode C


Transponder with Mode C



LORAN, VOR/DME, or INS with no transponder


LORAN, VOR/DME, or INS, transponder with no Mode C


LORAN, VOR/DME, or INS, transponder with Mode C

ADVANCED RNAV WITH TRANSPONDER AND MODE C (If an aircraft is unable to operate with a transponder and/or Mode C, it will revert to the appropriate code listed above under Area Navigation.)


Flight Management System (FMS) with DME/DME and IRU position updating


Flight Management System (FMS) with DME/DME position updating


Global Navigation Satellite System (GNSS), including GPS or WAAS, with enroute and terminal capability.


/E with RVSM


For more Information:

Aeronautical Information Manual, Chapter 5: Air Traffic Procedures, Section 1: Preflight, Table 5-1-2: Aircraft Suffixes

{ 1 comment… add one }
  • Bob Penkhus January 27, 2018, 6:01 am

    Does your Aircraft suffix change when you install ADSB to an Aircraft that currently flys in RVSM altitudes as a /L designation?

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