I’ve been doing a lot of flying for work lately, and having spent several hours laid over, often checking the monitors to make sure my flight is still on time, I’ve come to wonder what airports do when a plane crashes?
How do they report it on the monitors?
Happy
In the past, when TV news showed the monitors after a crash, the most common designation was “See Agent”.
I assume that goes up in any unusual situation where the airlines knows that they are going to need to do a lot of handholding. Probably the same thing for a flight that has to land somewhere else because of weather or mechanical trouble.
I remember one crash, which was a flight to Paris, from a photo in a newspaper showing the arrivals board with anulle (sp) displayed.
I’ve seen “Cancelled” on the monitors (not in real life, thankfully, but in newspapers). It seems to be a fairly standard photo in the news - the shocked people in the airport looking up at the monitors. 
The same with trains - after the recent train crash at a level crossing in Berkshire, newspaper reports carried photos of the monitors at Plymouth station (the intended destination of the train), which read “Cancelled”.