The mode is Auto, but there is no mission to fly
What ArduPilot says:
- PreArm: No mission library present
- PreArm: Mode requires mission
The flight mode is Auto, which flies the stored mission, and there is none: the aircraft holds only the home position or nothing at all (MIS_TOTAL is 0 or 1). ArduPilot will not arm in Auto with nothing to fly. “No mission library present” is the same failure on a firmware built without missions, when ARMING_MIS_ITEMS asks for mission items.
What to do, most likely first
The mode switch is in Auto, and no mission has been uploaded.
CheckRead the mission from the aircraft in the ground station's Plan screen: it comes back empty.
FixWrite a mission to the aircraft and read it back, or choose another mode to arm in.
The upload did not finish.
CheckArduPilot answers a complete upload with “Flight plan received”; “Mission upload timeout” means it gave up half way.
FixWrite the mission again over a better link, for example USB on the bench.
The mission is erased at every start-up, because
MIS_OPTIONSbit 0 is set.Check“Clearing Mission” is among the start-up messages.
FixUpload the mission after every power-on, or clear bit 0 of
MIS_OPTIONSso that the mission is kept.
Parameters to look at
| Parameter | What it is |
|---|---|
MIS_TOTAL | Total mission commands |
MIS_OPTIONS | Mission options bitmask |
ARMING_MIS_ITEMS | Required mission items |
Where to do it:Mission Energy CheckSetup & Tuning Guide
The code that sends it
PreArm: No mission library present
libraries/AP_Arming/AP_Arming.cpp AP_Arming::mission_checks() · Open in ArduPilot Copter-4.7.1
PreArm: Mode requires mission
libraries/AP_Arming/AP_Arming.cpp AP_Arming::mission_checks() · Open in ArduPilot Copter-4.7.1