Spektrum™ AS3X® technology is a part of the groundbreaking SAFE® assisted flight envelope protection system. Designed to work behind the scenes, an AS3X System delivers instantaneous attitude corrections when turbulence, torque, and tip stalls haphazardly interrupt the way you want to fly. The specially tuned benefit makes the aircraft fly incredibly smooth while providing the pilot with the control that feels natural and wholly accurate. You can find this popular feature in a wide range of E-flite® airplanes, HobbyZone® airplanes, and Blade® helicopters.


The purpose of AS3X technology is to enhance the flight stability of all model types. AS3X technology works behind the scenes to help stabilize the aircraft in whatever attitude you command. It uses a sophisticated combination of sensors and exclusive flight control software. Every BNF® airplane or helicopter with an AS3X system is custom-tuned by RC product development experts to deliver the best flying experience possible.

An AS3X system counters outside forces such as wind, turbulence, torque, tip-stall, and more to make your flight smoother. As a result, a model tuned with Spektrum AS3X technology is easier to fly and performs with greater precision.

AS3X does not fly the aircraft for the pilot. It's not autonomous, nor does it interfere with a pilot’s commands. The beauty of AS3X technology is that it takes advantage of onboard sensing to react perceptively faster. Behind the scenes, AS3X is following along with you, calculating an infinite number of possible corrections. All you see is an aircraft that flies smoothly and goes exactly where you point it with greater accuracy. Ultimately, pilot workload is reduced, making it easier for the pilot to focus on aircraft position and maneuver symmetry for a better flight experience through a broader range of conditions.


A model equipped with a well-tuned AS3X system gives a pilot more control.

For a 3D aerobatic model, an AS3X system can make slow speed, and knife-edge maneuvers feel much more stable and precise even when the pitch and roll rates are set extremely high. In a scale park flyer or ultra-micro, it will counter the effects of turbulence on windy days so the plane will track smoother and give the pilot a “locked-in” feeling.

Maybe you're a scratch builder who finds that scaling and CG (Center of Gravity) limitations make it tough to create an agile or realistic-looking model that isn‘t a handful to fly. AS3X technology can help by battling the conditions that interfere with having a smooth flight. The AS3X system never limits your control or interferes with your commands. You always have control. The AS3X system gives a higher level of stability, making a more enjoyable flight possible.

When you buy an "Open Stock"* receiver with AS3X technology, it operates very similarly to a standard receiver out of the box—the AS3X system is inactive.

You don't have to have a computer radio to enjoy AS3X technology. The interface makes it possible to quickly set up many of the features found in computer radios, such as travel adjust, sub-trim, mixing, wing type, and more. Gain adjustments for each axis allow you to fine-tune the appropriate amount of AS3X assistance desired. One of the coolest features is the flight mode capability to program different AS3X settings on a transmitter switch position. That way, you can experiment with different AS3X settings in flight. Always follow the specific recommendations for the AS3X receiver model you choose. Several tutorials on using these features with success are available online.

*Open Stock indicates that it was purchased separately, not as a replacement part or previously installed in an RTF or BNF® model.


I am having trouble with the AS3X App; it keeps crashing on startup.

Make sure you have granted the App the permissions required from your device. This can be found in the App settings menu of your device. The volume of your headphones must be at the full position. It is also important to delete all previous versions of the software and the AS3X named folders and AS3X App cache in your smart device.

Can I enable SAFE technology in an open stock AS3X receiver?

Open stock AS3X receivers do not have SAFE flight assistance capabilities. Receivers with SAFE technology are intended as replacements for specific aircraft and should only be used with that aircraft.

Neither the program nor App will recognize my AS3X receiver.

A suitable power source must power your AS3X receiver for the software to identify, read and write to it. Sometimes, turning the receiver power off and on will help the recognition process. It is also important to register your receiver to download and be notified of firmware updates.

Is it better to adjust rates, expo, direction, and mixing in the receiver or my transmitter?

It depends on the AS3X receiver you have. With some receivers, AS3X works better when the aircraft parameters are set in the receiver through the setup software or App due to hardware constraints. Other receivers with AS3X offer more versatile adjustment options. Always refer to your user manual.

What is the difference between absolute and relative gain?

Absolute and relative are selectable in the gain adjustment menu; absolute is the default. Absolute means that the gain value can only be changed in the app or PC program. Relative means that mixing and changes to the channel from the transmitter will vary the gain value set through the app or PC program.

Where do I start the gain levels?

The rule of thumb is to start with relatively low gain values. You can use the flight mode option to experiment with different levels on the fly. Another option is to find a BNF® airplane with AS3X technology that’s relatively similar. All registered receivers can accept AS3X presets available from the Spektrum.com website. Upload the preset and then use the flight mode option to fine-tune to your liking.