My pixhawk will not arm in stable mode but it will in altitude mode.
Are you sure? The mode referred to as "Stabilize" is essentially identical to "Altitude Hold", except alt hold uses the altimeter (barometer) to try to maintain altitude. There is no reason you should be able to arm in one but not the other.
When connected to Mission Planner, it will tell you which prearm check is failing; that will answer what if anything is preventing you from arming. I do the same as
@Old Man; I always arm in Stabilize, and generally land in Stabilize too. The trick is that if you are in Loiter, Alt Hold, or another altitude maintaining mode (all of which use the same altitude controller), you need to be aware of the different handling of the throttle stick between those and Stabilize. For the Alt Hold modes, mid stick is essentially 'hover', where stick down is descend and stick up is ascend. If for example your craft is overpowered, switching to Stabilize when just above mid stick could cause you to rocket into the air, so be aware of that if you are switching while under trees or something
Eventually you will get the hang of it, it just takes practice.
And there really is nothing explicitly wrong with landing using Land, or an altitude maintaining flight mode such as Alt Hold or Loiter. You just need to be aware that if the landing detection fails, which can happen if you're wandering a bit and taking awhile to land thus confusing the altimeter, when you yaw left to disarm it can engage the motors and flip. Just be ready to switch quickly to Stabilize as it is guaranteed to idle the motors at minimum throttle. This has only happened a handful of times to me, and only in wind or when I was very uncertain about landing. In the common case, landing with confidence in Loiter is completely fine.
So after arming the pixhawk I need to get it off the ground 7 to 10ft and switch to altitude. After arming I waiting a long time watching the gps led but it never went solid green it only blinked green steady.
Blinking green means you're all set; it will blink blue when not yet ready, or yellow if it is failing prearm check (some of this became easier with APM 3.3, and there are beeps between flight modes, and a "no, sorry" beep with it tried for instance to go to Loiter but can't yet due to lacking GPS fix). If you get an OSD set up (such as minimosd or MAVLink-OSD) it will tell you how many satellites you've got, and this can help you be more predictive about when you're ready to go to Loiter. Mission planner will also help with this, particularly since APM 3.3 (the release of which is imminent).
When switching from Stabilize, once you are in the air go ahead and switch to Loiter provided you had a blinking green. Just be ready to fly manually if it doesn't switch for some reason.
Once you get good at flying in Stabilize, try Drift - it is a blast! It will combine yaw and roll into the right stick (assuming mode 2, or whatever is the non-throttle/yaw stick depending on your tx mode) making turns a lot more graceful. Then when not moving forward, you can use it for just yaw. It will also "brake" when you stop moving, to maintain position when you stop. This is as opposed to Loiter, which will 'coast' until it stops.
Cheers!
