Which of the following is a departure restriction for the Omni-directional Departure?

The correct choice refers to the requirement for a minimum climb gradient of more than 3.3%. In the context of omni-directional departures, which allow flexibility in departing any direction from an airport, establishing a specific climb gradient ensures that the aircraft can safely clear any obstacles in the minimum turn radius while maintaining safe navigation. A climb gradient greater than 3.3% provides an added margin for obstacle clearance, particularly in areas where terrain or structure may pose a risk shortly after takeoff.

By implementing this climb gradient, pilots are able to perform safe and efficient departures while adhering to regulatory and safety standards associated with flying from airports with variable departure paths. The other options relate to operational considerations that may not universally apply to omni-directional departures, such as specific runway headings or speed limits, which are often dependent on the selected procedure or route constraints rather than universally applicable to all departures from an airport.