What avionics are required?

When you visit pilot groups on the web, you find that there is frequently uncertainty about exactly what avionics you need to have in your aircraft to be legal – particularly when flying IFR. You would expect it to be straightforward to find out, but that’s not always the case.

In this post I will list the various requirements with reference to the relevant regulations. I’m only discussing what the legally mandated minimal equipment is. In many situations it would be prudent to have more equipment than the legal minimum. That’s up to each pilot to decide.

You might find that the AIP in some countries have additional requirements over and above what I list here. If they do, you can actually disregard those additional requirements. Read my post on national vs. EASA regulations for more information.

Let’s go through each of the three main types of avionics (communication, navigation and surveillance) in turn. I will also say a few words about autopilots and ELTs.

Communication

In brief: In airspace where radio communication is required, you need one COM radio with 8.33 kHz channel spacing.

In airspace where radio communication is required (RMZ or airspace class A-E for IFR or B-D for VFR) the aircraft has to be equipped with one COM radio with 8.33 kHz channel spacing. Otherwise no radio is required. Any additional radios can have either 8.33 or 25 kHz channel spacing.

In particular this means that if a COM radio is not required, then all radios in the aircraft can have 25 kHz channel spacing. Obviously, with such radios you are not allowed to use 8.33 kHz-spaced channels even if it would be technically possible. (E.g. the 8.33 kHz-spaced channel 118.005 uses the same frequency as the 25 kHz-spaced channel 118.000.) Fortunately the emergency channel 121.500 is a 25 kHz-spaced channel so if nothing else a 25 kHz COM radio can be used for emergency communications. Also, some ground stations are still using 25 kHz-spaced channels.

This is actually EASA’s official interpretation of the rules. They have explained the underlaying regulations in great detail in this letter, written as response to questions from Eurocontrol.

Note that it is not permitted to make new installations of 25 kHz radios in aircraft. (Ref. EU regulation 1079/2012, article 4, paragraph 2.)

Navigation

In brief: The aircraft only has to be equipped with the navigation equipment you actually expect to need during the flight. In any case, when flying IFR in PBN airspace you need PBN equipment. You must have enough separate boxes so that if any one piece of equipment fails, you can still conclude the flight safely.

The primary rule here is NCO.IDE.A.195. It states that:

  • If the flight can be carried out solely by visual navigation (“reference to visual landmarks”) then no navigation equipment is needed. (Oddly enough, this applies to IFR as well as VFR!) Otherwise
  • The aircraft has to be equipped with the navigation equipment that you need to follow your ATS flight plan. (Note that this applies to VFR as well, when there are no visual landmarks, e.g. over large areas of water, on top or possibly flights by night.)
  • If you intend to make an instrument approach in IMC, then the aircraft has to be equipped with the navigation equipment needed for the intended instrument approach procedure.
  • If you fly IFR in PBN (Performance-Based Navigation) airspace, then the aircraft must have a navigation equipment installation (typically a GPS navigator) that meets the appropriate PBN specifications. (The “appropriate” PBN specifications in Europe are RNAV 5 (“Basic RNAV”), occasionally RNAV 1 (“Precision RNAV”) and – for instrument approaches – RNP APCH. )
  • The aircraft must have enough equipment redundancy so that the flight can be concluded safely (but not necessarily according to plan) if any one piece of navigation equipment fails.

In the case of PBN, note that the installation of the navigator must meet the performance specifications – it is not enough that the navigator itself does. The Guidance Material to NCO.IDE.A.195 explains in detail how you can tell what specifications your installation meets. Typically a navigator box comes with an STC (Supplemental Type Certificate) including a supplement to the Pilot’s Operating Handbook that describes what specifications are met by an installation done according to the STC.

How do you know if you fly in PBN airspace and, if so, what specifications are used? Most controlled airspace in Europe today is PBN airspace, but not all. (E.g. not Swedish controlled airspace below FL95.) The AIP should tell you.

The requirement on redundancy means that it might not be ok to fly IFR with a single combination COM/NAV/GPS navigator such as the Garmin GNS 430 or GTN 650 as your only piece of radio navigation equipment. If you have an additional COM radio you could possibly argue that if the navigator fails the flight could be completed by radar vectors to an area with visual conditions. This is something that you have to decide for yourself.

Surveillance

In brief: For IFR you must have a mode S transponder with altitude reporting. For VFR it varies – consult the AIP.

Part-NCO (NCO.IDE.A.200) simply says that you need a transponder according to airspace requirements. These requirements are given in the AIP.

Additionally, EU regulation 1207/2011 (with amendment regulations – in particular 2020/587) states that all aircraft operating under IFR (article 2, paragraph 2) must be equipped with mode S transponders with altitude reporting (article 5 paragraph 5). (Actually only after 7 December 2020 but that date has, of course, passed now.)

This does not necessarily mean that every European country will always enforce the mode S requirement (or possibly even always notice if you are using a mode A/C transponder), but legally mode S is now a requirement for all IFR flights.

Autopilots

In brief: There are no requirements for having an autopilot, VFR or IFR.

I can’t point you to a specific rule as the regulations generally only say what is required and not what is not required. But at least in all of part-NCO, there is no mention that autopilots are required.

Emergency locator transmitters

In brief: If the aircraft is certified with a maximum seating for six passengers, then you can use either an ELT or a PLB (Personal Locator Beacon). Otherwise you need an ELT.

The rules for ELT/PLB are found in NCO.IDE.A.170. There are two main kinds of ELTs: Automatic ELTs which are activated by a crash and survival ELTs which can be carried and manually activated by a crash survivor.

  • An automatic ELT is always acceptable.
  • A survival ELT is acceptable if the aircraft has a first individual Certificate of Airworthiness issued on or before July 1, 2008.
  • A survival ELT is also acceptable in cases where a PLB is acceptable.

There are several additional requirements on the functions and use of ELTs/PLBs. Refer to NCO.IDE.A.170 and its AMC/GM.