What radio frequencies are used for intercom in formation flying?

Question

What radio frequencies are used for air-to-air intercom in formation flying? I assume there is a difference between military and civil aviation (e.g a group of GA aircrafts flying as a formation).

I found a couple of civil UNICOM frequencies here (e.g. 122.8 MHz, 122.975 MHz, ...). 122.750 MHz (Aviation Air to Air Communications) seems to be what I am looking for (correct?). But what if there is more than one team?

I also wonder if in military or professional formations (aerobatic formations) something outside the Very High Frequency (VHF) Aviation Band is used (to provide better quality, e.g. digital communication).

In this article I can see lot of military frequencies, but not telling me what to use for military formation flying.

Answer 1

For the US, according to section 4-1-11 of the AIM (Designated UNICOM/MULTICOM Frequencies) for private fixed-wing flights you should use 122.75:

Air-to-air communication (private fixed wing aircraft): 122.750

Air-to-air communications (general aviation helicopters): 123.025

Aviation instruction, Glider, Hot Air Balloon (not to be used for advisory service): 123.300, 123.500

I have no idea what the military does and their tactical comms might even be encrypted anyway, but they frequently use UHF instead of VHF, at least in the US.

Nor do I know what to do if you have two formation flights at the same time, but I guess that in reality it's either an air show with some form of semi-official control and perhaps even NOTAMs, or it's something private and in that case people make their own arrangements, e.g. picking some frequency that doesn't overlap with any nearby assigned frequencies. Using 123.45 is apparently common, but definitely not official.

Non-VHF communications for private flights would be regulated by the FCC, not the FAA, and personally I'm not sure if the benefits would be worth the extra equipment and the risk of confusion, but then again I know nothing about formation flying.

There's some useful information from the FAA in this policy order clarifying the use of 121.5 and 123.45. It says that 123.45 is for operational use in oceanic regions, and within the US it's reserved for "non-government flight test operations". There's also an FAA document on requesting temporary frequencies for airshows etc. but it's air to ground only.

Answer 2

The US Military uses UHF frequencies. Each organization has a communication frequency for contact if you need to divert, have an emergency, or need guidance from higher authority. When in formation, they have a tactical (often called 'tac') frequency to talk to the other plane(s). However most communication of a non-tactical nature is done on traffic control frequencies.

ATC handles formations as a single flight. Each member of the flight has a number Lead(1), 2, 3, etc. The Lead does all communications with ATC. If you are directed to, for example, change altitude, the lead plane acknowledges with call sign and 'climbing to FL240' The number two aircraft just responds "Two" and the number three responds with "Three" and so on. If you do not have a tac frequency and you need to have a conversation with another plane, you tell them to go to an informal channel like Winchester or Popcorn. Winchester is 303.0 MHz. These informal channels were used extensively in Viet Nam to discuss what idiots the brass were. Pilots had a code sheet that had a code for common expressions.

Answer 3

For general aviation, 122.75 is the official fixed wing air-to-air frequency designated by the FCC and FAA (and 123.025 is for helicopters). There are also other frequencies allowed based on location (Hawaii, Los Angeles, and the Grand Canyon). Otherwise, you should probably ask around in the area in which you plan to operate. See if there is a frequency that is commonly used. This thread mentions a few frequencies people have used. If you can find the frequencies used for a local air show, that could be a good indication of frequencies that would be free.

Military aviation is going to vary a lot more. Typically UHF is used, but certainly VHF or digital could be used depending on the situation. Refueling tracks have designated areas and frequencies. Performing groups have a set of channels that they use when they fly. For regular formation flying though, it will probably vary more.

RadioReference is a good place to look. 123.45 is listed as "unofficial" air to air and flight test. The military table lists 303.0 as a possibility.

Answer 4

With respect to military aviation, it's going to depend on the radio capabilities of the aircraft involved in the formation. fooot's answer mentions that typically UHF is used. That is sort of true - UHF is generally used for military ATC, RAPCON, etc, but as far as aircraft-to-aircraft, it will depend on the capabilities of the plane.

Many large aircraft have multiple radios, UHF and VHF, as well as digital radios, so depending on the mission, they may use a specified area frequency, or a "local" frequency, or a specific military channel. With smaller aircraft, such as trainers and fighters, they may only have 1 of each (UHF/VHF), so with the need to monitor the controlling agency, that may drive the "formation frequency" to using a VHF.

With regards to specific channels in that article, it will vary from location to location, as different bases/squadrons/aircrafts will have different frequencies designated for formations. So there's no real way to know "in general" - it would be a localism.