Five by Five, an Aviation Radio Term Explained

five by five radio communication

I can remember the days when I used to play on Microsoft Flight Simulator just so I could connect to Vatsim so I could tell all the virtual air traffic controllers I heard them five by five on the radio transmissions.

It was fun as a teenager being able to pretend to be in mission critical moments of flight and have to make sure communication over the virtual radios were still working. Actually, you would be surprised how much static can happen with poor old computer headsets (before the dawn of Apple ear buds)… the only time I have felt even remotely old on this blog. Literally, I used a big headset and a Toshiba laptop with all the desk flight simulator equipment around me. Yep, I was that kid.

Anyway, I got to thinking one day and questioned what 5 by 5 really meant when it came to radio communication. I had always just assumed it was an aviation term without really digging into what it meant to tell the controller I heard him or her loud and clear. You sometimes hear the term used when listening to controllers on LiveATC frequencies and most times I use it in real life when I’m in a questionable area during a flight that gets not as great of radio signals. Especially being located in Ohio, I find that there are many non-towered fields I fly to and making sure you know how well you can hear other pilots on unicom in the area is a constant task.

I digress.

Wherever you hear the term being used, the question still remains.

What does this five by five talk really mean?

Well like I have stated in previous articles, I am no audiophile but even I can manage to give you a lamens spark notes version of what the term really means. Contrary to what I used to believe, 5 by 5 is a term used to give the other person on the line a rating on the readability (the first number) of their voice, and their signal strength (the second number) of their frequency.

Let’s break it down.

When you report a...ReadabilitySignal Strength
1Not ReadableYou even there?
2Readable but spottyYou're Weak
4ReadableEven Better
5Crystal clear readableBest

That’s the least technical I can get with the break down of one through five identifiers and what they really mean. Quite honestly I always thought it was a fraction. I thought that X out of 5 was how well you received the person on the other side of the radio’s voice and frequency all wrapped into one number over five.

When in-fact it stems from more of the olden days when they used less digitalized radio frequencies and had to wade through the static that comes with transmitting things through the air. The simple way of judging it was by responding in a quick matrix of sorts like this one.

The moral of the story is that both sides of the matrix actually represents two different things. I’m really hoping this wasn’t something I was supposed to learn in private pilot training, because if it was I likely never learned it.

You can still use 5 x 5 though, no one will judge

Although radio communication has gotten perhaps a bit better from back in those old days, it’s still radio at it’s core. Don’t be afraid to use the five by five matrix when responding to other pilots or air traffic controllers in the sky, even if we have come into the era where cars now fly and drones are our new bird strike fear.

At the very least, it’s a fun phrase to spout of to your friends. I do it all the time. Maybe that’s why they all left… guys, hey guys you there?