AIM ¶ 4-2-2 — Radio Technique
AIM 4-2-2 radio technique: listen before transmitting, prevent stuck mics, and master pilot-controller communications for your checkride and written test.
In Plain English
AIM 4-2-2 lays out best practices for using your aircraft radio so you communicate clearly without stepping on other transmissions. While not a regulation, these are recommended techniques every student pilot should know cold for the oral and checkride.
Key points from the paragraph:
- Listen before transmitting. After changing frequencies, pause and verify the frequency is clear. Often ATIS or just monitoring will give you the info you need.
- Think before keying. Know what you'll say. For long transmissions like a flight plan or IFR position report, write it down first.
- Mic technique: Hold the microphone close to your lips, pause briefly after keying so the first word isn't clipped, and speak in a normal, conversational tone.
- Wait after transmitting — the controller may be writing, switching transmitters, or working another frequency.
- Watch for a "stuck mic." An unintentional open transmitter blocks the frequency for everyone. If your assigned frequency is blocked, follow the en route IFR radio frequency outage procedures to reestablish contact.
- Stay within radio range. VHF is line-of-sight, and higher altitudes extend range. Remote VOR sites may transmit but not receive your call.
AIM Source Text
FAA AIM ¶ 4-2-24-2-2. 4-2-2. Radio Technique
Listen before you transmit. Many times you can get the information you want through ATIS or by monitoring the frequency. Except for a few situations where some frequency overlap occurs, if you hear someone else talking, the keying of your transmitter will be futile and you will probably jam their receivers causing them to repeat their call. If you have just changed frequencies, pause, listen, and make sure the frequency is clear. Think before keying your transmitter. Know what you want to say and if it is lengthy; e.g., a flight plan or IFR position report, jot it down. The microphone should be very close to your lips and after pressing the mike button, a slight pause may be necessary to be sure the first word is transmitted. Speak in a normal, conversational tone. When you release the button, wait a few seconds before calling again. The controller or FSS specialist may be jotting down your number, looking for your flight plan, transmitting on a different frequency, or selecting the transmitter for your frequency. Be alert to the sounds or the lack of sounds in your receiver. Check your volume, recheck your frequency, and make sure that your microphone is not stuck in the transmit position. Frequency blockage can, and has, occurred for extended periods of time due to unintentional transmitter operation. This type of interference is commonly referred to as a “stuck mike,” and controllers may refer to it in this manner when attempting to assign an alternate frequency. If the assigned frequency is completely blocked by this type of interference, use the procedures described for en route IFR radio frequency outage to establish or reestablish communications with ATC. Be sure that you are within the performance range of your radio equipment and the ground station equipment. Remote radio sites do not always transmit and receive on all of a facility's available frequencies, particularly with regard to VOR sites where you can hear but not reach a ground station's receiver. Remember that higher altitudes increase the range of VHF “line of sight” communications.
Oral Exam Questions a DPE Might Ask
Q1What should you do immediately after switching to a new ATC frequency?
Per AIM 4-2-2, pause, listen, and make sure the frequency is clear before transmitting. Keying your mic over another transmission jams receivers and causes the call to be repeated.
Q2What is a "stuck mic" and what should you do if your assigned frequency is blocked by one?
Per AIM 4-2-2, a stuck mic is unintentional transmitter operation that blocks a frequency, sometimes for extended periods. If your assigned frequency is completely blocked by this interference, use the procedures for en route IFR radio frequency outage to establish or reestablish communications with ATC.
Q3Why might you hear a VOR ground station but be unable to reach its receiver?
Per AIM 4-2-2, you must be within the performance range of both your radio and the ground station. Remote radio sites — particularly VOR sites — don't always transmit and receive on all available frequencies, and VHF communications are line-of-sight, so higher altitudes increase range.
Related Paragraphs in AIM Chapter 4