On Guard!

There’s an old adage – “Pilots don’t get lost, they just get temporarily disoriented.”

The good news is that modern radios are very reliable, and pilots don’t normally “lose” their comms either, they just get a bit disoriented about where they are. The most common problem that is seen is with the volume knob!

Really now, it’s not ever a good idea to turn down the volume, especially while you’re out flying around because you’re very likely to forget to turn it back up when you’re ready to chat with the tower about your return to the airport. You’ll think you've had a radio failure. You’ll wish you’d read my article on light gun signals - or you’ll be really glad you did! Meanwhile, after your second or third call to them, the tower will know what you’ve done and be waiting patiently for you to catch on.

But it's noisy out there!

As an instructor, I know how busy the tower frequency can be and what a distraction to teaching all of that chatter is when you’re out working in the practice area. Yet, I never turn down the volume to avoid the intrusion of the radio. I’m far too likely to forget to turn it back up, and I don’t want to teach a student to turn down the radio lest they too forget to turn it back up! So what’s an impoverished flight instructor to do? How about something useful with the radio? Monitor 121.5 MHz!

What's so special about 121.5 MHz?

Do you recognize that frequency? You should, it’s the emergency frequency. The aviation community refers to 121.5 as “Guard” because it is “guarded” by air traffic control (ATC) facilities and by flight service stations (FSS). If you have an emergency, and you can’t think of a local frequency immediately, it’s nice to know you can call on guard and get some assistance. According to the Aeronautical Information Manual (AIM):

“Although the frequency in use or other frequencies assigned by ATC are preferable, the following emergency frequencies can be used for distress or urgency communications, if necessary or desirable:
“121.5 MHz and 243.0 MHz. Both have a range generally limited to line of sight. 121.5 MHz is guarded by direction finding stations and some military and civil aircraft. 243.0 MHz is guarded by military aircraft. Both 121.5 MHz and 243.0 MHz are guarded by military towers, most civil towers, FSSs, and radar facilities…” AIM 6-3-1(h)(1)(2010)

That's a point worth emphasizing! If you experience and emergency while you’re flying with some kind of ATC services, i.e. on flight following or you are on a tower frequency already, you should continue to use your current frequency instead of changing to guard to alert ATC of your problem.

Aside from being readily available to you in the unlikely event that you experience an emergency, there are other good reasons to set your radio to Guard when it’s not needed for other communications. It turns out, there’s very little chatter on it. Usually, the only thing you hear is an occasional radio test or a call to an airliner that an approach or center air traffic controller is looking for because it’s gotten out of range. (Remember, airliners travel very fast, and it’s easy for a busy controller to not have time to call them with a frequency change before they’re out of range of that controller’s radio. The solution, call them on Guard.)

Also, if you monitor Guard, you may just be able to help someone else who has a problem. Seriously, you may be able to help. In August 2009, I was flying with a student and we heard someone announce on Guard that he’d lost his engine over Long Island Sound! I asked him to “squawk 7700”, which he did. It turns out my student and I were nowhere near him, but other planes (also monitoring Guard) were, so the New York radar controller who saw him squawking the emergency transponder code on his radar screen was immediately able to vector several nearby aircraft to his position and summons the Coast Guard. The pilot of that plane landed safely in Long Island Sound and was rescued.

Of course, if you leave your radio on Guard long enough, you too eventually will make a call to a tower, or the local traffic at a non-towered airport “on Guard” frequency at some point. It’s really not a problem, but you’re sure to hear back from at least one other aircraft, who will respond, “On Guard!”

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Article by: Terry Keller Jr.