Does every international flight have more than one flight route in the flight plan?

For example, after the incident with MH-17, most of the flights were diverted from that route. Were the alternate routes already planned or were they chosen at that moment? If they were chosen at that moment, who planned the new routes?

  • $\begingroup$ I believe that many flight plans include alternate airports, to be used in the event of emergency (not the same as an alternate flight plan). Someone who knows more than me might care to comment. $\endgroup$ Jan 16, 2015 at 16:55

1 Answer 1


Each airborne flight has only one flightplan, which was submitted for that particular flight. The routing is embedded into that flightplan and only that one routing is valid for that flight.

In case the routing is no longer available for the next flight due to airspace closure via NOTAM or airways being restricted by time of flight / day of flight, another routing will be used for that flight and submitted in the flightplan.

In case the routing needs to be changed for an already airborne flight, a new IFR clearance is read to the crew en-route, which alters the existing flightplan.

Alternate routings are usually managed by the airline's dispatch / planning centre and the best routing for a specific flight is created by the dispatchers, taking into account weather, NOTAMS, restrictions and many other factors.

En-route changes to a flightplan are made by ATC units and their data processing centres, if an impromptu change needs to be made due to airspace closures or other restrictions coming into effect which were unforseen.

  • $\begingroup$ Unless things have changed since I retired, a flight using the North Atlantic track system doesn't have its route across the North Atlantic embedded in the flight plan. The aircraft will be given the route in terms of lat/long just before entering the MNPS (Minimum Navigation Performance Specifications) airspace. $\endgroup$
    – Terry
    Mar 4, 2015 at 17:21
  • $\begingroup$ They are then cleared to the expected NAT entry fix and get the rest of the NAT when approaching the Oceanic boundary. I have however also seen aircraft with full routing across the NAT on clearance delivery. I'll try to get some citable sources. When did you retire @Terry? $\endgroup$ Mar 4, 2015 at 17:29
  • $\begingroup$ My last flight was July 30, 1999, so I'm sure things have changed considerably. $\endgroup$
    – Terry
    Mar 5, 2015 at 0:35

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