AS3X (Artificial Stabilization 3 aXis) and SAFE (sensor assisted flight envelope) are two fairly recent Horizon Hobby innovations. But what are they? Read this post for an explanation!

Firstly, all planes equipped with SAFE also have AS3X.

AS3X is a 3 axis gyro system, meaning that if an outside force (like wind) knocks the plane off course, the gyros will compensate for this and put the plane back on course. But, if you move a the sticks of the radio, it will let the plane change to your new course. This system allows a RC plane to fly in heavier winds than without AS3X.

SAFE is the same thing as AS3X, but SAFE has an accelerometer, which brings in self leveling. SAFE also has flight modes and, sometimes, a Panic switch. A switch on your transmitter will activate Panic mode, which automatically brings your aircraft to level flight!

SAFE usually has 3 flight modes: beginner, intermediate, and advanced. Beginner mode has a limited bank angle and self leveling. Intermediate mode has a less limited banking angle and self leveling. Finally, Advanced mode has no bank angle limits and no self leveling.

You can progress through the modes, from beginner to expert, with just a flip of a switch or two (again, depends on the transmitter)!

And, with Panic mode, you don’t have to worry as much as usual about getting the plane into a bad attitude or it getting out of control; just press the Panic button/flip the Panic switch and the aircraft returns to level flight.

To learn more about SAFE and AS3X, visit these two web pages:

AS3X Link


Thanks for reading! As a continuation of my AS3X posts, I will post a review on an AS3X plane and an AS3X mod in the next couple of Sundays.


Update: After flying the Sport Cub S, I have found that, on planes, there is only self leveling in Beginner mode. Quadcopters and helicopters have self leveling in Intermediate mode, but planes do not. Just keep this in mind.

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Joe · February 16, 2015 at 4:24 pm

I have been flying the Horizon Hobby Super Cub for a while and ready to step it up to something with ailerons. Any suggestions on my next plane? I was thinking if the SAFE is something that can help me maybe the Habu 180 or Corsair S – are they out of my league?

    John · February 24, 2015 at 7:31 am

    Firstly, I need to check my comments awaiting moderation more often. For your next plane, I would actually recommend a Parkzone Sport Cub. It is the same size as your Super Cub, has ailerons, and takes the same batteries.

    I do think that SAFE would help since the SC is natually stable, but planes with ailerons aren’t. So you can fly in beginner mode for a day and then move over to expert mode. However, I wouldn’t look at it as a necessity. I went to ailerons with a UM T-28, and I didn’t have much trouble, but SAFE would have been nice.

    If you want to go with SAFE, the Aprentice S comes to mind. Bigger than the SC, doesn’t take the same batteries, but it should handle wind a little better and does have ailerons and SAFE.

    From looking at the Habu, I would say that it wouldn’t be a good aileron trainer. The Hobbyzone Corsair S is intended for first time pilots, so it should be a good aileron trainer (the micro Sport Cub S is made as a first plane, but in reality is also a perfect step up from the Champ, a micro three channel trainer).

    Well, I’ve exhausted my knowledge of the bigger planes. I fly micros since I don’t have room for the bigger ones.. I would recommend that you head over to RCGroups (I’m also there as John234) and make an account there to ask any questions on the ‘normal’ sized planes to ‘normal’ sized plane experts- they should have much more knowlage of regular-sized planes than me!


    (I blame all spelling errors on the iPad keyboard)

      Joe · February 24, 2015 at 9:25 am

      Thanks for the good info John!

        John · February 28, 2015 at 10:21 pm

        You’re welcome!

George Henke · March 2, 2018 at 7:51 pm

I would say the Timber is a great plane for a beginner as it has the same
Insides like the Apprentice 15e and I think that a tail dragged is easier to land and take off. I have them both and like the timber best.

The Ultimate 1S AS3X and SAFE UM Plane List | umFlight · September 11, 2014 at 5:05 pm

[…] have posted before about what AS3X is. To sum it up, AS3X uses a 3 axis gyro to compensate for anything (wind) that […]

Is the Sport Cub S the new Champ? (Part 1) | umFlight · October 19, 2014 at 8:17 am

[…] S took off really well. It tracked perfectly straight. Hand launches with the Panic Button enabled (see my write-up about SAFE) kept the plane going straight as it left my hand. Hand launches were still uneventful with the […]

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