When testing the coupling of double trailers the landing gear of the rear trailer should be?

When testing the coupling of double trailers, the landing gear of the rear trailer should be fully raised and clear of the ground. This ensures that the trailer is properly coupled and that there is no interference with the towing vehicle. Additionally, the landing gear should be checked to confirm that it is securely locked in the up position to prevent any accidental lowering during operation. Proper inspection of the landing gear is crucial for safe towing and maneuverability.