Historical Use of 123.4 and 123.45 MHz
Many pilots think it is convenient to use the frequencies 123.4 ("finger") or 123.45 ("fingers") for air-to-air communications and general chatting while flying. Historically this has been popular because such a frequency is easy to remember and often appears unoccupied other than by other pilots chatting. However, as noted by this article in AOPA magazine Technique: What's the frequency? : finding a channel on crowded coms these two frequencies are not licensed for air-to-air communication between private aircraft - they are designated for use by flight test stations.
Regulatory and Legal Restrictions
This matter was discussed in June 2020 on the Pilots of America (PoA) forum at the behest of an equipment manufacturer who was having interference with his testing due to people interrupting his tests with their chats. In typical PoA fashion, this led to a spirited discussion with some contention about whether the manufacturer could claim it was a violation for people to be chatting and what the penalties might be. I decided to investigate the legal and regulatory issues surrounding the use of the "fingers" frequencies for private aircraft air-to-air communication.
Allocation of frequencies for flight test stations.
The Federal Communications Commission (FCC) regulates the use of radio frequencies by users other than the Federal Government within the United States through its regulations in 47 Code of Federal Regulations (CFR) Part 87. The National Telecommunications and Information Administration (NTIA) administers the use of radio frequencies used by the Federal Government. The Federal Aviation Administration (FAA) works with both the FCC and NTIA in developing and administering these regulations.
The FCC allocates frequencies for use by civilians in 47 CFR 87.173. This table states that both 123.4 and 123.45 MHz are allocated to station class FAT, which is flight test stations. Section 47 CFR 87.303 (a) further discusses the use of frequencies for flight test and notes that the fingers frequencies are available for assignment to flight test land and aircraft stations, as are 123.175, 123.2, 123.225, 123.375, and 123.450 MHz. There are 8 additional frequencies which are available for flight test by aircraft manufacturers only.
These allocations are in general not exclusive to the licensee, as noted in 47 CFR 87.41 (b) which states "Frequencies are available for assignment to stations on a shared basis only and will not be assigned for the exclusive use of any licensee."
Can aircraft legally use 123.4 and 123.45 MHz outside of testing?
Since the frequency allocations to flight test are non-exclusive, can an aircraft then still use them for non-test purposes like chatting within the US? The short answer is no. The longer answer is that such use is permitted over the oceans and outside the range of VHF ground stations, but that this will almost never be the case in the continental US.
VHF radios used in aircraft have a station license and the pilot is not required to have an individual operator license. Such a station must however be operated according to FCC regulations as 47 CFR 87.18 (b) states that "Even though an individual license is not required, an aircraft station licensed by rule must be operated in accordance with all applicable operating requirements, procedures, and technical specifications found in this part."
The International Civial Aviation Organization (ICAO) standards in ICAO Annex 10, Volume V, Section 184.108.40.206.1 state that "An air-to-air VHF communications channel on the frequency of 123.45 MHz shall be designated to enable aircraft engaged in flights over remote and oceanic areas out of range of VHF ground stations to exchange necessary operational information and to facilitate the resolution of operational problems." This recommendation for a standard to be adopted by member nations also does not provide for simply chatting but rather for operational information exchange.
Penalties for using fingers as an air-to-air chat frequency.
Given the continued use of 123.4 and 123.45 for air-to-air communications by pilots, what is the penalty if the pilot is caught and the FCC chooses to pursue an enforcement action? There are in general two kinds of penalties in the United States Code would could be enforced.
- Civil Penalty. This type of penalty results from a civil enforcement action by the FCC and consists of a monetary forfeiture. 47 USC 503 provides for these penalties as follows:
(b)(1) Any person who is determined by the Commission, in accordance with paragraph (3) or (4) of this subsection, to have—
- (A) “willfully or repeatedly failed to comply substantially with the terms and conditions of any license, permit, certificate, or other instrument or authorization issued by the Commission.
and states the amounts of the forfeiture:
shall be liable to the United States for a forfeiture penalty.
- (D) “In any case not covered in subparagraph (A), (B), or (C), the amount of any forfeiture penalty determined under this subsection shall not exceed $10,000 for each violation or each day of a continuing violation, except that the amount assessed for any continuing violation shall not exceed a total of $75,000 for any single act or failure to act described in paragraph (1) of this subsection.”
So a person would have to be shown to willfully or repeatedly interfered with a flight test to have a penalty assessed.
- Criminal Sanctions. An offender could also be pursued criminally by the Federal Department of Justice based on a referral by the FCC. 47 USC 501 provides a general penalty of both fines and imprisonment if convicted in a court:
Any person who willfully and knowingly does or causes or suffers to be done any act, matter, or thing, in this chapter prohibited or declared to be unlawful, or who willfully and knowingly omits or fails to do any act, matter, or thing in this chapter required to be done, or willfully and knowingly causes or suffers such omission or failure, shall, upon conviction thereof, be punished for such offense, for which no penalty (other than a forfeiture) is provided in this chapter, by a fine of not more than $10,000 or by imprisonment for a term not exceeding one year, or both; except that any person, having been once convicted of an offense punishable under this section, who is subsequently convicted of violating any provision of this chapter punishable under this section, shall be punished by a fine of not more than $10,000 or by imprisonment for a term not exceeding two years, or both.
47 USC 502 also provides criminal fines which can be assessed by a court:
Any person who willfully and knowingly violates any rule, regulation, restriction, or condition made or imposed by the Commission under authority of this chapter, or any rule, regulation, restriction, or condition made or imposed by any international radio or wire communications treaty or convention, or regulations annexed thereto, to which the United States is or may hereafter become a party, shall, in addition to any other penalties provided by law, be punished, upon conviction thereof, by a fine of not more than $500 for each and every day during which such offense occurs.
Having a criminal penalty of either type would require that a Federal prosecutor conclude the offense was an egregious enough "willfully and knowningly" committed act to merit pursuing it.
Please consult a qualified aviation attorney to advise you on the likelihood of such penalities in a particular case.
Which Frequency to Chat On?
So what VHF frequency can a pilot use to chat with other pilots? Again, the technical answer is there really aren't any assigned to this use.
The frequency 122.75 is assigned as the air-to-air communications frequency by 47 CFR 87.173. However, 47 CFR 87.185 (a) states that "Aircraft stations must limit their communications to the necessities of safe, efficient, and economic operation of aircraft and the protection of life and property in the air, except as otherwise specifically provided in this part". There is no provision elsewhere in that part for just chatting.
Clearly this regulation is often abused on 122.75. The penalties for such use would presumably be similar to that for misuse of the fingers frequencies as outlined in Penalties for using fingers as an air-to-air chat frequency though I have never heard of a case of even a warning being issued by the FCC for this, let alone a penalty assessed.
A Norcal Aviation Review article regarding one person's experience with the FCC after using "fingers" for chatting.
FAA Order 6050B Chg 1 documents the change to the FAA Spectrum Management Regulations and Procedures Manual clarifying the use of 123.45 and 123.4 MHz.