How to send mavlink message and command to take off px4 snapdragon flight board?

[seantobe]

Hi there:

I can sucessfully send mavlink message to px4 snapdragon flight board, but I I don't know how to send mavlink message to take off the plane. I tried the PX4 SITL simulator(JMAVSIm), and when it starts, the commander_main function is running which can accept the take off command(22) from QGC. However, when I upload the firmware to snapdragon flight(make eagle_default upload) and run ./px4 mainapp.config, the commander_main function is not running.
If anybody knows how to take off the plane, please let me know. 3Q

BR
SeanH