Help! Quick arm for companion logging

I’m trying to make a Pixhawk into a flight data logger onboard an aircraft flown by another controller. To do this, I have disabled all safeties and pre-arm checks. The only thing I can’t figure out is how to have the pixhawk arm with a single increase in throttle.
In the online documentation, ch7 option (and the other channels) have 41 as an option “armdisarm.” This option seems to be disabled and not selectable. If I manual put 41 in. Nothing happens.
Is there any custom firmware that can do this easily.
I’m trying to avoid the standard arming sequence and don’t want to log all of the time.
Any advice?

Ray, have you looked into this? This is for plane only but since you are only using Pixhawk as a data logger …

Thanks for the reply.
Yes, I have looked into that. That means that it arms the motors immediately.
Does this provide any added benefit over setting LOG_DISARMED to 1, logging everything?