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Common Aviation Frequencies: A Pilot’s Communication Guide

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Common Aviation Frequencies: A Pilot’s Communication Guide

It is no secret that new pilots are often more than a little nervous and hesitant about getting on the radio. They worry about not remembering what to say and how to say it when they finally key up the mic, but even if you get those variables right, it still does you no good if you are not on the correct frequency. That is why an important hurdle of using your radio is understanding and learning common aviation frequencies.

You have your aircraft’s main radio and a handheld radio as a backup. You have reviewed your ATC communication skills and studied your copy of Aviation Radio Communications Made Easy. You are all ready to turn that radio on and get cleared for takeoff. There is just one problem – what frequency are you supposed to be on?

While no one expects pilots to memorize all the aviation frequencies, it is certainly helpful to know the most common ones and how the frequencies are laid out within the bands. A high-level understanding of the types of aviation radio signals your aircraft can receive will also go a long way towards developing your knowledge on the topic.

Types of Aviation Radio Signals

Aviation radio frequencies are found in the low frequency (LF), medium frequency (MF), high frequency (HF), and very high frequency (VHF) bands. These frequencies may be used for voice communications or for navigation.

Low Frequency (LF)

Historically, when aviation radio was first starting out, most air navigation transmissions took place on the low frequency band from 200 KHz to 415 KHz. As reliable higher frequency systems were developed, most of the low frequency air nav beacons were shut down. Today, some low frequency beacons remain and are used for instrument landings. Others were kept operational as backups in case of primary navigation system failures. Low frequency is useful even when other forms of communication fail because its long wavelengths are less affected by terrain and it can bounce off the ionosphere to travel long distances around the world.

Medium Frequency (MF)

Aviation radio is allocated a small portion of the medium frequency spectrum in a band from 2850 to 3000 KHz. Most planes have radio direction finders onboard that get a bearing by focusing in on a medium frequency transmission.

High Frequency (HF)

In the past, high frequency bands were typically used for domestic voice communications. That traffic has since shifted to the very high frequency (VHF) band. High frequency continues to be used for voice communications for international flights, however, as it can travel a longer distance than VHF.

Very High Frequency (VHF)

Frequencies in the very high frequency band are most widely used for domestic aircraft communications at the present time. Both communication and VOR navigational systems are operated on VHF frequencies.

To support full VHF communications, the FAA recommends that all aircraft with older 360-channel systems should be retrofitted with a 760-channel piece of equipment with 25 kHz channel spacing which is capable of operating in the 118.000 to 136.975 MHz band.

Communication vs Navigation

Signals that are transmitted and received via aviation radio can be of more than one type. In addition to communication (COM) signals, aviation radios are also used for navigation (NAV). Some radios are only capable of COM, while others are dedicated for NAV, and a third variety is configured to be used for both COM and NAV. Some VHF Omnirange (VOR) navigation stations and aircraft navigation beacons transmit voice communications in addition to their navigation functions.

Most Common Aviation Frequencies and Allocations

The Federal Communications Commission (FCC) is an agency that regulates communications including radio in the United States. One of its roles is to allocate all radio bandwidths and frequencies. In the United States, VHF civil aircraft communications are placed in the 100 MHz band and allocated 760 channels within the range from 118.0-136.975 MHz. As a pilot, every frequency you talk on will fall within this range. VOR navigational frequencies are allocated to the range from 108.0 to 117.975 MHz, positioning them just below the communications range.

VHF communications channels usually have 25 KHz of spacing between them, except for flight test stations which are spaced by just 8.33 kHz and the emergency frequency of 121.5 MHz which has 100 kHz of protection around it. The full allocation list covering all 760 channels in the VHF aviation band is posted in FAA advisory circular 90-50D.

While the full allocation listing is interesting to review, from an everyday use perspective it is most helpful to start out with learning the frequency ranges for each type of VHF signal as well as the specific frequencies that you are most likely to use on a regular basis.

The VHF frequency ranges used for aviation are:

Frequency

Allocation

108.000 – 112.000 MHz

Aviation Terminal VOR and ILS Navigation

112.000 – 117.950 MHz

Aviation VOR Navigation

118.000 – 136.975 MHz

Aviation Communication

 

Within the VHF aviation communication frequency range, the most commonly used frequencies and their corresponding allocations include:

Frequency

Allocation

121.500 MHz

Aviation Distress (VHF Guard)

118.000 – 121.950 MHz

Air Traffic Control (Towers and ARTCC’s)

121.3 MHz

Ground

121.7 MHz

Ground

121.9 MHz

Ground

121.975 – 122.675 MHz

FSS

122.0 MHz

En Route Flight Advisory Service (Flight Watch)

122.2 MHz

Universal FSS

122.700 MHz

Unicom (CTAF)

122.75 MHz

Air-to-Air (GA fixed wing)

122.800 MHz

Unicom (CTAF)

122.900 MHz

Unicom (CTAF)

122.950 MHz

Unicom (CTAF) for controlled airports

123.000 MHz

Unicom (CTAF)

123.025 MHz

Air-to-Air (GA helicopters)

123.050 MHz

Unicom (CTAF)

123.3 MHz

Air-to-Air (Gliders and hot air balloons)

123.5 MHz

Air-to-Air (Gliders and hot air balloons)

 

Helpful Hints

Once you have learned the key frequencies, there are a few other helpful hints that can keep you out of trouble and make you sound like a seasoned professional on the air.

CTAF Frequencies

The Common Traffic Advisory Frequency (CTAF) or Unicom frequencies are typically used at nontowered airports. The most common are 122.7, 122.8, 122.9, 123.0. 123.050 MHz with 122.950 being the usual CTAF frequency of choice for airports with a tower.

Pilot-controlled lighting systems (PCL) are used at some smaller, non-towered airports. If you are making a night approach to landing at an airport with a PCL, in most cases, you will activate the system through your radio which is set to the appropriate CTAF frequency. Turn on the lights by keying your mic a specified number of times for the desired lighting intensity.

Ground Frequencies

The most common ground frequencies are 121.3, 121.7, 121.9. All ground frequencies start with 121 and have an odd tenth at the end. Familiarize yourself with the ground frequencies because the tower controller may simply tell you something like “contact ground on point 9” and expect you to know that the full frequency they are referring to is 121.9.

“Finger” and “Fingers”

Select frequencies have been set aside as flight test stations. These frequencies are available to aircraft manufacturers as they conduct test flights. Test flight frequencies are sprinkled throughout the VHF aviation band between 123.125 MHz and 123.575 MHz.

Within this range are 123.4 MHz and 123.45 MHz, colloquially referred to as “Finger” and “Fingers” respectively. In some circles, these frequencies have been used for casual air-to-air communications. This may not be a problem when flying over international waters where those frequencies are not officially designated for another purpose.

Once you start using them over the United States or its coastal waters, however, you could have a very big problem – potentially a $10,000 problem, to be precise. Since the FCC designated both of these frequencies to be used solely for test flight communications, any other use constitutes an illegal transmission, and pilots transmitting illegally could be fined up to $10,000 for each transmission or taken to small claims court for damages caused by interfering with the data transmission during a test flight.

Depending on your location, the likelihood of being prosecuted may not be very high, but it is important to know that the safe and correct course of action if you want to talk to another pilot is to use 122.75 MHz which is the designated air-to-air frequency for fixed wing aircraft. This will keep you out of trouble and show that you are well-versed in the correct aviation frequencies usage.

A great way to learn how to talk on the radio is with Squawk VFR. Pick up your copy today.

Atlanta Flight Squawk VFR - Your Guide to VFR Communications

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  • PilotMall.com Editor