The Solo Controller communicates with you primarily via its screen. If it displays different message alerts based on the current status of Solo and the Controller. For brief explanations of the various message alerts, consult this article.
calibration
Solo is calibrating your current altitude. Please wait.
calibrating_solo
Solo is calibrating. Please wait until finished for optimal performance.
compass_calibration
Solo is performing a compass calibration. Please wait.
uneven_surface
Solo requires a level surface to take off from. Place Solo on a level surface to clear this alert.
level_error
Solo requires a level calibration. Perform a level calibration in the 3DR Solo app to clear this alert.
compass_error
Solo requires a compass calibration. Perform this calibration in the 3DR Solo app to clear this alert.
calibration_error
Solo encountered a calibration error. Restart Solo to clear this alert.
sensor_error
Solo encountered a sensor error. Restart Solo to clear this alert.
max_alt
You have reached the maximum altitude. Fly lower to clear this alert.

Solo has been disconnected from the app. Make sure your mobile device is on and that your Wi-Fi is connected to the app. Click here for information on connecting to Solo Wi-Fi.
app_connected
The 3DR Solo app successfully connected to Solo.

The controller has been disconnected from Solo and will Return to Home. Objects like buildings and trees can block the communication signals between Solo and the controller. Make sure your line of sight with Solo is unobstructed and that the controller has power.
controller_signal_lost
Solo has lost the controller signal and as a result will Return to Home. Make sure your controller is powered on with enough battery to operate.
signal_recovered
Solo has recovered the controller’s signal. Press the Fly button to regain manual control.
gps_lost
Solo lost GPS connectivity. Make sure nothing is obstructing the signal between your controller and Solo.
gps_ready
Solo has established a GPS connection and will now switch back to Fly.
fly_manual
If you have lost GPS, you will then be placed in Manual flight. Solo does not automatically balance itself in Manual, so you will need to carefully guide Solo to its landing spot.
service_required
Solo needs to be serviced. Use the app to submit a trouble ticket with 3DR Support to clear the alert.
controller_stick_error
Solo encountered a control stick error. If this controller stick error is received in flight, Solo will return home and land. Use the app to submit a ticket with 3DR Support.

Solo has reached 25% battery. Return to Home soon to prevent a crash.

Solo has reached a critical battery charge of only 10%. Return to Home immediately to prevent a crash.

With a 10% charge you have very little time to land. Return to Home immediately to prevent a crash.

Solo has run out of battery and is returning home. If your battery was drained to 0% it is possible irreversible damage has occurred. Recycle this battery just to be safe.

Your controller has reach a low battery charge of 10%. Charge the controller soon to avoid unexpected flight behavior.

Your controller has reached 5% battery. End your flight immediately and charge the controller. If you continue to fly you are in serious danger of crashing.

Your controller is completely out of battery! Solo is returning home for you to try to prevent a crash.