You have until February 23rd to mark the number on the outside of your drone.
FAA will require drones to display registration numbers externally
FAA will require drones to display registration numbers externally
The FAA website still states the marking can be in the battery compartment as long as a tool isn't required to remove the cover.
As of 2/13/19 all US pilots have 10 days to comply. Apparently the rule change was not announced due to public safety concerns.
Federal Register :: Public Inspection: External Marking Requirement for Small Unmanned Aircraft
Thanks for providing the link.
That said this rule change and the reason stated for it sounds a little weak to me. If someone is going to put a bomb or chemical/biological agent in a drone do you really think they are going to put a registration number on it or use their own registration number? If all registration numbers are external how hard would it be to steal a registration number and put it on a drone? If the registration number is on the bottom of the drone in many cases someone is going to have to handle the drone to get to the registration number.
The comment period is still open, but on the other side you have "Members of the law enforcement and security communities have expressed concern..."
This new rule says the number has to be legible, but I do not see a definition of "legible" or what size the number needs to be.