ICAO Equipment Codes
Summary
An abridged version of this article first appeared in POPA Magazine, Summer 2023, “ICAO Flight Plans.”
Updated 5/18/2024. Read time: 12 minutes
A Part 91 operation equipped with WAAS GPS, ILS, VOR, VHF Comms, ADS-B Out, and no LOAs will likely have the following equipment codes (ForeFlight Format).
FAA Equipment: /G (or /L for RVSM)
ICAO Equipment: B, G, R, S, Z. And if equipped: D, F, W, Y
ICAO Surveillance: B1 or B2, L
ICAO Remarks
PBN/ B2, C2, D2, O2, S2
NAV/SBAS
SUR/260B
CODE/aircraft six-digit hex code
On a return trip from Mexico, I handed our local handler what I thought was the perfect ICAO flight plan. Even if you file your flight plan, the tower submits one of theirs at this airport for you. Someone completely disregarded my attention to detail because what I received back did not resemble the route, flight level, speed, survival gear, equipment codes, or even the color of the aircraft.
Being in Rome and short on time, I decided to do as Romans do and launch with what I was given. Unsurprisingly, it was an uneventful flight with no issues or questions from ATC. So, I wondered why filing correctly matters if the system can handle so much misinformation.
Rural Mexico is one thing, but the more complex, technologically advanced, or congested the area of operations, the more these codes matter. They can make a difference in completing the mission or being excluded from your desired operation.
Details
Correctly entering the details into a flight plan seems basic, but the lack of understanding of what these codes mean leads to much confusion, and it’s hard to get straight answers.
Most discussions quickly devolve into a technical rabbit hole that you don’t know how far it will go, and afterward, you find yourself asking the same question at the beginning: “So what do I put on my flight plan?” It’s compounded by the fact that operators rarely revisit these topics, are in constant flux, and are redefined by FAA and international regulators. And, practically speaking, ATC doesn’t seem to care if you get it wrong.
This article will treat the flight plan as the destination. Instead of laying out every flight plan box, what it means, and all the entry options, this will be a different approach. Most operators don’t want or need to know the technical intricacies but how to correctly complete the flight plan based on their capabilities and operation. A good rule of thumb when filling out the boxes is that you probably don't have it if you don’t know what the equipment is.
ICAO
ICAO is an international qazi-regulatory organization that attempts to harmonize and improve worldwide aviation operations. The FAA has required the ICAO flight plan for IFR operations since 2016.
Moving to the ICAO flight plan took some prodding because the domestic one was simpler. Decades ago, the ICAO plan was more straightforward, too, but it has become rigorously complex with technological improvements. With today’s WAAS GPS, LPV approaches, Sat Comms, Mode-S Transponders, ADS-B, ADS-C, and CPDLC equipment options, it takes a good handle on your aircraft equipment to file correctly.
Entries
There are millions of combinations of ICAO flight plan codes. To simplify, I will assume you are a Part 91 operation in an aircraft capable of flying above FL180, you have already complied with the ADS-B Out mandate, and you use flight planning software to fill out flight plans for you.
Box 10, Aircraft Equipment, and Box 18, Remarks, are the most challenging boxes of an ICAO flight plan. We’re going to skip the self-explanatory parts and tackle the meat of the challenges. The chart below is a guide and reference and will cover most of the situations of 91 operators. Based on the aircraft capability, where you fly, and your FAA LOA Authorizations, the remaining columns specify the codes for Box 10a, 10b, and 18.
Code S is shorthand for L + O + V. If you select Code S, do not use L, O, or V.
8.33 kHz comm spacing adds additional frequency selections and has been required for operations in Europe since 2017. Switching between 25 kHz and 8.33 kHz has been a selectable option in turbine aircraft for a while, especially if the aircraft manufacturer is European.
LOA 052 is optional. No special training or authorization is required to conduct GPS approaches in the US. Other international jurisdictions require both. The FAA started issuing this LOA at the request of operators who were asked to produce evidence of the above by foreign authorities.
If equipped with the required RVSM equipment and a 1090 ADS-B Out, conducting domestic RVSM operations does not require an LOA. However, you still need to jump through some paperwork to verify the accuracy of your ADS-B and submit an RVSM monitoring request.
Locate your six-digit aircraft hex code on an ADS-B Performance report or the FAA registration database.
Further Details
If you made it this far, you have reached level three in our descent into the technical rabbit hole of ICAO flight plans. Some additional equipment options, surveillance details, and PBN explanations follow.
Box 10A: Additional aircraft equipment
A: GBAS Landing system.
GBAS is similar to WAAS and is the future replacement for ILS approaches. WAAS has ground-based GPS stations spaced across the country to improve GPS accuracy and allow for LPV approaches. GBAS does the same thing, but several GPS ground stations are based right on the airfield.
As a result, the new approaches coming out are called GLS approaches. They fly just like an ILS and have some advantages. They require less equipment than an ILS (cheaper), can service all runways at an airport vs. only one (cheaper), and have some potentially advantageous features like radius-to-fix waypoints.
Before you get your hopes up, avionics technology is still catching up. You will have to stay tuned because this option is currently not available on GA aircraft, and airports are hesitant to invest in the infrastructure.
B: LPV (Localizer Performance with Vertical guidance)
WAAS-equipped GPS units can fly LPV approaches. They act like ILS approaches but should not be confused with GLS approaches.
Within the US, Part 91 operations do not need any authorization to fly these approaches. Flying abroad, some nationalities require specific training and authorization for LPV approaches. As a result, the FAA can issue an optional LOA for international operations. I have had no issue with this and didn’t pursue the LOA. However, I did bring a copy of my latest aircraft training event showing LPV procedures were completed, just in case.
C: Loran C
You don’t have one.
Introduced in the late 1950s, Loran C is the precursor to GPS. It works similarly but is all ground-based units instead of satellite ones. In the last decade, the system was defunded and scheduled to shut down, but later, it was half-heartedly refunded as a backup system to GPS. Redundancy is great, but good luck finding a serviceable Loran C avionics unit in the civilian market.
F: ADF
ADF used to be included in the standard equipment code (S). Now that it is becoming less common, if you are equipped, you need to select this option individually.
G: GNSS
Aka: GPS. This would be an installed, IFR-certified GPS. No portables. GNSS is a large umbrella term that could include other satellite systems as well, like Galileo (EU), GLONASS (Russia), and BeiDou (China).
H: HF Radio
High Frequency (HF) radios are required for some oceanic flights. If you have it, you know it. You would have paid a lot for it.
I: Inertial Navigation
Like the above, an IRU is very expensive. It’s an onboard position calculator. Think of it as if you are your own personal GPS satellite flying through the sky, and you have an RNAV system independent of any satellites. Mid-sized jets are usually the floor of an IRU option.
Most of the remaining options involve ACARS, CPDLC, and ADS-C. These technologies are trickling down into lighter aircraft, and more widespread use is on the horizon.
ACARS
Revolutionary 40 years ago, ACARS sends text messages to ARINC ground stations, who relay your message to whoever you want. ACARS has enjoyed widespread airline use but is not common on light GA aircraft.
CPDLC
Controller Pilot Data Link Communications is like ACARS. The difference is you are sending text messages to ATC controllers instead of ARINC. There are several different means of sending messages: VHF, HF, or satellites.
Domestically, CPDLC is now live and will replace most cruise radio communications in the future. No LOA for Part 91 operations is required if you have the equipment. CHECK OUT THIS FULL WRITEUP ON STARTING DOMESTIC CPDLC OPERATIONS IN THE US.
ATN CPDLC (VHF-based) is required to fly above FL285 in Europe but with many exemptions. Aircraft with less than 19 seats and 100,000 lbs built before February 5th, 2020, are exempt. If you are exempt, you must add DAT/CPDLCX in the remarks section of your flight plan. Newer aircraft must have the equipment, and operators should apply to the login list. This topic deserves more research if you plan to operate over there, as some countries require login at certain altitudes if equipped, regardless of your authorization status.
Internationally, satellite-based CPDLC has become the preferred communication method in Oceanic airspace, especially the North Atlantic High-Level Airspace (NAT HLA). When properly equipped and authorized, you can unlock higher and preferred routing. Here are the formulas:
As you can see, things quickly get out of hand. Your simple flight department now has a thick pile of LOAs and international operations manuals to manage if you want to access the best routing over the North Atlantic.
Box 10b: Surveillance (aka, transponder/ADS-B)
Quick recap:
Mode A transponders = code only
Mode C = Mode A + altitude
Mode S = Mode C + ADS-B data
Mode S has seven possible flight plan entries depending on the combination of aircraft ID, pressure-altitude, extended squitter, and enhanced surveillance capabilities. ADS-B technology evolved so quickly over the last decade that most of these flight plan codes are for early adopters.
For enlightenment, aircraft ID is your transponder’s unique 6-digit HEX code. The pressure altitude is the same as Mode C altitude. Extended squitter expands the amount of data the transponder can broadcast. And enhanced surveillance is the additional data sent, which includes: bugged altitude, roll angle, true track angle, ground speed, mag heading, IAS/ Mach, vertical rate, and true airspeed.
Here is a simplification: If you are equipped with 1090 ADS-B out to comply with the mandate in 2020, select equipment codes L and B1 (or B2 if you have ADS-B In and Out). Any 1090 ADS-B out transponder for aircraft flying above FL180 has all those above-listed capabilities. Flying below FL180 and only in domestic airspace is where you can get by with the 978 transponders and would file a different code.
Lastly, ADS-C. ADS-B repeatedly broadcasts your information, whereas ADS-C shares your data when it is interrogated (contacted by ATC). The data can flow over radio frequencies or satellites. The satellite-based receivers with LOA FAA authorization are one of the requirements for North Atlantic crossings at FL290-FL410.
Box 18: Remarks
The remarks section of ICAO flight plans holds the remaining space for elaborating on some equipment codes. These are the PBN/, NAV/, SUR/, CODE/ entries, and 14 other less common options.
In reverse order, CODE/ is how the 6-digit Mode-S HEX code you broadcast is linked to your tailnumber in your flight plan. SUR/ if the type of survillence. 1090 ADS-B Out transponders are all SUR/260B. NAV/ specifies the kind of area navigation equipment. NAV/SBAS (Space-Based Augmentation System), i.e., WAAS GPS, is the most common.
Lastly, Performance-Based Navigation (PBN/) drills into the details of the performance of your area navigation (RNAV) units. Understand that RNAV is an umbrella term that includes GNSS (GPS), TACTAN, INS, and LORAN-C navigation systems. All can be used over an area without flying point-to-point over ground stations. WAAS GPS receivers have become the ubiquitous RNAV option due to their reliability, accuracy, and low cost.
Also nested within RNAV is RNP (Required Navigational Performance). RNP = RNAV + pilot alerts when the system loses its position integrity. It is a higher standard of RNAV utilized when navigation accuracy is critical. This can lead to some confusion about how IFR procedures are labeled. For example, the FAA publishes RNAV STARs or approaches. The FAA labels them RNAV to set a lower bar for operators who use different RNAV systems to participate. In other countries, procedures may be labeled RNP instead.
Furthermore, within RNP, there are tiers of accuracy applied to different phases of flight and areas of operation, decreasing from 10nm of accuracy to 0.15nm. While a WAAS GPS is accurate enough for the lowest RNP values, you still need a corresponding LOA to utilize several RNP operations. That is because it is not all about your GPS equipment. At the most precise end, dual GPS units are required for redundancy, backed up by TCAS and a second crew member, and you get into specific training requirements for operators.
Below is the rundown of the different RNAV and RNP terms and corresponding flight plan codes, assuming you have GPS RNAV equipment. Look within the Limitation section of your AFM to see what your aircraft manufacturer certified the aircraft to do.
RNAV 5: Formally called B-RNAV in Europe, it is for point-to-point enroute navigation (Code B2).
RNAV 2: US Q & T routes (Code C2).
RNAV 1: ODP/SID/STAR procedures labeled RNAV, formally called P-RNAV in Europe (Code D2).
RNP 10/ RNP 4: Both are for oceanic operations, and LOA B36 is required (Code A1/L1).
RNP 2: For Enroute operations without navaids, but it’s not currently in practical use in the US. Internationally, it is required along two Tango routes (T9 and T290) off the coast of France. LOA B36 Required (Other Information: NAV/RNP2).
RNP 1: ODP/SID/STARS that require a GPS. This is sometimes confused with RNAV 1 or P-RNAV. Specific RNP 1 procedures may have advanced navigation features such as radius fix turns, meaning curved routes (Code O2).
RNP Approach: RNP 0.3. LNAV, LNAV/VNAV, LPV approaches. GPS approaches are RNP approaches! No LOA is required within the US, but you may want LOA C052 for international operations. (Code S1 for non-WAAS, Code S2 for WAAS).
RNP AR: RNP 0.15 approaches and departures. “Authorization Required” on approach plates. LOA C384 is required (Code T1 with Radius Fixes, Code T2 without).
Technical Resources
Congratulations! You made it through a brief summary of the material. If you want to engage further with the topic or look into acquiring LOAs for your operation, the learning never stops. Below are some resources.
AC 90-105A Approval Guidance for RNP Operations and Barometric Vertical Navigation in the US National Airspace System and in Oceanic and Remote Continental Airspace
AC 90-101A Approval Guidance for RNP Procedures with AR
AC 90-117 Data Link Communications
AC 91-85B Authorization of Aircraft and Operators for Flight in Reduced Vertical Separation Minimum (RVSM) Airspace
NAT Doc 007 North Atlantic Operations and Airspace Manual
AIM Appendix 4. FAA Form 7233-4 – International Flight Plan
Aviate
Verify your flight plan codes and equipment boxes for domestic and international use.
LOOK INTO DOMESTIC CPDLC if equipped.
