Failed Pre-Arm Checks (Double Amber) - Troubleshoot

Completed all the options under mandatory in initial setup and all was successful

Result -
1 - Pixhawk LED - double flashing amber (failed pre-arm check)
2 - Safety switch triple flashing green and solid when pressed
3 - GPS - 3D Hold
4 - Flight mode changes to Hold when Auto is selected

What have I missed gentlemen?

searched this board and other boards as well as the obvious Google Search and do not have a ‘SOLVED’ solution.

What Pre-Arm Check is it failing.

David R. Boulanger

I don’t know David - the only abnormal sign I see on the HUD is Bad AHRS and the audio says “… Lock Zero not maintaining 5Hz update”

Is this the boat and are you powering everything up while the boat is floating in the water or while it is stationary on land?


David R. Boulanger

Yes, it is my mapping boat, but the setup I am doing while removed from the boat on land.

Maybe put this on the Arduboat category here and Grant Morphett will see it.

David R. Boulanger

So I guess nobody knows then?

I sure don’t. I do know that with the latest rover code I cannot arm in the water while the boat is moving around in the waves. You could disable the arming checks and give it a careful try but that probably is not suggested. Or just disable the AHRS check and give it a try.

David R. Boulanger

John, What does it say in the mission planner messages tab? Everytime you fail an arm it will give you a little more descriptive response in the messages tab. Also what is your your prearm check config?

Hi Falcon, this is the message I am getting: - GPS: u-blox 0 is not maintaining a 5Hz update

I never saw that Message Tab before, thanks for telling me about that.

I have changed ARMING_CHECK to 72 (GPS lock only, no RC failsafe)

I now get double flashing green - not armed with GPS lock

When switch is pressed it goes solid, but no arming.

When switching to AUTO, it says that it cannot, so goes into HOLD


Made the following changes:
ARMING_CHECK = was 1 (All) changed to 72 (GPS lock only, no RC failsafe)
ARMING_REQUIRE = was 1 (THR_MIN) to 0 (Disabled)

LED = Solid Green (Armed GPS Lock)
Switch = Solid Green (Armed)
Mode = Manual (All works fine) Auto - still won’t go into AUTO forces into HOLD

When you are troubleshooting arming problems, especially with a boat that is not going to fly away, just turn them all off. IF that works, turn them back on one at a time until you find the one causing you grief. There are a lot of them so search the full parameter list for keywords like failsafe.
You have:
Battery voltage, needs to be calibrated or the failsafe will false.
GPS, not just lock but the PDOP must be low enough.
RTL etc etc.
Turn off the safety swtich

Hi Mike,
Yes, I need to go through them one by one.
Thank you