Final answer:
In aviation, the display would switch from HSDH to HSD based on a predefined groundspeed threshold set by the aircraft's computer system, indicating that high-speed hold is no longer necessary.
Step-by-step explanation:
The question pertains to aviation displays, specifically what triggers a change in the display from High-Speed Data Hold (HSDH) to High-Speed Data (HSD) on a Multi-Function Display (MFD). In the context of aviation, these displays provide the pilot with critical information about the aircraft's performance, including speed. The trigger for the change in display from HSDH to HSD would likely be a predefined groundspeed, below which the aircraft's computer no longer considers the high-speed hold necessary and thus changes the display to reflect that. For example, if the threshold were set to 250 knots, then as the aircraft decelerates to below this groundspeed, the display would automatically switch from HSDH to HSD.