If an aircraft with no DME is being positioned for maintenance, what suffix should be used on the DD Form 175?

In the context of positioning an aircraft for maintenance, the correct suffix on the DD Form 175 is "X". This indicates that the aircraft does not have DME (Distance Measuring Equipment) and therefore cannot provide distance information during the flight. The use of "X" as a suffix effectively communicates to air traffic control and other relevant parties that the aircraft’s navigation capabilities are limited due to the absence of DME.

This designation is important for ensuring proper clearance and routing since it informs controllers of the potential limitations when handling the aircraft's flight plan. Proper suffix usage helps maintain safety and efficiency in air traffic operations, particularly for maintenance flights, which often have specific operational considerations.