Is there any regulation for this? FMS/GNSS data is mandated every 28 days but I have never seen nor can I locate any regulations for EGPWS updates.
There is none, nor is there a cost to have the data base updated, at least there was not a year or so ago. (For Honeywell any how)
For our fleet the display is currently tdb462, my guess is the current DB # is designated by the airline
Nope, the number is from Honeywell.
Enhanced Ground Proximity Warning System – Honeywell Aerospace