Is there a small program which will calculate arrival times in UCT?

If I leave point X at 2:00 UCT and head east on a 12 hour flight, I would like to know what time UCT I will arrive at my destination.

44 minutes ago, IanHarrison said:

Is there a small program which will calculate arrival times in UCT?

If I leave point X at 2:00 UCT and head east on a 12 hour flight, I would like to know what time UCT I will arrive at my destination.

Whether or not, there's a calculator I don't know - but I wouldn't be surprised...

But, honestly, it's not that hard to make an estimate of... 

For east-bound flights just add the timezone difference between departure- and arrival airport, to the arrival time.
For west-bound flights, subtract the timezone difference between departure- and arrival airport from the arrival time.

Example:
For instance, a flight from Copenhagen to New York that takes 8 hours and depart at 12.00: 
12.00 (local Copenhagen departure time) + 8 hours (flight time) = 20.00 (local Copenhagen arrival time).
20.00 (local Copenhagen arrival time) - 6 hours (time difference) = 14.00 (local New York arrival time).

Of course, for flights going across the Pacific Ocean, this calculation gets a bit more complicated, as you pass the date-line. I'm too tired to figure it out right now, but perhaps someone of the more capable and intelligent users in here, can come up with something. 🙂

The best way is to convert your departure time to UTC (Zulu) time, and back to local time at your destination. As travelabroad said, you need to know the time zone offset at your departure and destination.

Example: LAX to JFK. In summer, the US Pacific coast is 7 hours earlier than UTC. If your flight is scheduled to depart at 0900 local, you would add 7 hours to get the UTC departure time, which in this case would be 1600Z.

If your flight to JFK will take 5 hours, you would add that to the UTC departure time. So, 1600 + 5 would mean that it would be 2100Z when you land in New York. In summer, the US east coast is 4 hours earlier than UTC, so you would subtract 4 hours from your UTC arrival time to get the local time. 2100 - 4 would mean it would be 1700 (5 PM) in New York when you land. 

There are several web sites that will give the offset between local and UTC time for almost any city, such as: https://www.worldtimeserver.com/time-zones/aoe/
 

The rule of thumb is that when flying eastbound over a significant distance,  the local time at your destination will always be later than your local time at departure. When flying westbound, the local time might be close to (or even earlier than) the local time at departure, depending on how fast the aircraft travels in cruise.

Converting local time to UTC at departure, and back to local time at destination even works when flying west across the International Date Line - the only difference is that the calendar day will advance by one when you cross the date line heading west.