Piloting Checks
Source GM Core pg. 236
Many actions related to vehicles call for the pilot to attempt a piloting check. The skills a pilot can use for a piloting check are listed in the vehicle's stat block, but most vehicles use Piloting along with others determined by their propulsion. The creature piloting a vehicle when an encounter begins can usually roll an appropriate piloting skill for that vehicle for initiative.
The GM sets the DC of the piloting check using a standard DC for the vehicle's level, with adjustments based on the circumstances. Generally speaking, an action that would move a vehicle through difficult terrain increases the DC to a hard DC for its level, and moving through greater difficult terrain increases the DC to incredibly hard. Other factors, such as turbulent winds for a wind-powered vehicle, monsters threatening the creatures in a motorized vehicle, or rough seas for a water-based vehicle, could all increase the DC of a vehicle's piloting checks.
The GM sets the DC of the piloting check using a standard DC for the vehicle's level, with adjustments based on the circumstances. Generally speaking, an action that would move a vehicle through difficult terrain increases the DC to a hard DC for its level, and moving through greater difficult terrain increases the DC to incredibly hard. Other factors, such as turbulent winds for a wind-powered vehicle, monsters threatening the creatures in a motorized vehicle, or rough seas for a water-based vehicle, could all increase the DC of a vehicle's piloting checks.