A channel's trim lies outside its minimum and maximum

What ArduPilot says:

• PreArm: RCN_MAX is less than RCN_TRIM
• PreArm: RCN_MIN is greater than RCN_TRIM

Every channel the receiver sends has three calibration values: RCn_MIN, RCn_TRIM (the centre) and RCn_MAX. The trim must lie between the other two. The message gives the channel number where it does not, which cannot come from a normal calibration.

What to do, most likely first

1. Parameters were loaded from another aircraft's file, or only part of a file was written.

   CheckRead the three values of the channel in the message; Parameter Compare & Migrate shows what differs from the file you meant to load.

   FixCalibrate the radio again: it writes all three values for every channel.

2. One of the three values was typed by hand.

   FixSet RCn_TRIM between RCn_MIN and RCn_MAX: the centre for a stick (about 1500), equal to RCn_MIN for throttle.

Parameters to look at

Where to do it:Setup & Tuning GuideParameter Compare & Migrate