What do you verify to prove an aircraft is airworthy using the Journey log?

To demonstrate that an aircraft is airworthy using the Journey log, verifying the compass calibration date is essential. An accurate compass is crucial for navigation, and ensuring that it has been calibrated within the required timeframe is part of maintaining the aircraft's airworthiness. This process ensures that navigational aids function correctly and that the pilot can determine their heading accurately, which is vital for safe flight operations.

The other options, while they may provide helpful information about the aircraft's history or operations, do not directly relate to the criteria for airworthiness. For instance, the last owner change may be relevant for ownership records but does not impact immediate operational safety. The last refueling date is significant for assessing fuel management but does not serve as an indicator of the aircraft’s overall airworthiness. Engine hours can provide insights into maintenance schedules but are not as directly related to proving airworthiness through the specific parameters checked in the Journey log.