Several days ago, I wrote about a strange occurrence, whereby two American Airlines plane ended up on the same frequency with the same callsign. That’s problematic, since air traffic controllers identify planes with their callsigns, and they’re intended to be distinct.
Well, as it turns out, exactly the same thing happened on another flight a day earlier, and it sure seems like something should be done to address this! There’s a good reason American uses the same callsign for multiple flights, but there’s no good reason for this confusion with ATC communication.
In this post:
Two AA5083 flights end up on same ATC frequency
Every flight has a callsign that’s used with air traffic control, and for commercial aircraft, that’s generally going to be the generic airline callsign plus the flight number. Callsigns are of course unique to a particular flight, because that’s the way that air traffic control communicates with pilots.
That brings us to what happened on Wednesday, August, 12, 2026, involving flight AA5083. For context, this was a flight operated by PSA Airlines, which is a wholly owned subsidiary of American, operating regional jets under the American Eagle branding. Note that while there’s an AA flight number, the callsign is “Bluestreak” rather than “American” (since PSA has its own air operator certificate).
AA5083 is the flight number that American uses between Philadelphia (PHL) and Providence (PVD), and it’s actually a flight number used for both directions of travel. Typically, the same CRJ-700 would operate the flight in both directions, but that’s not always going to be the case, especially if there’s a delay.
That brings us to the flight on August 12, where the inbound flight to Providence was over an hour behind schedule, while the outbound flight to Philadelphia departed on schedule (early, actually).
Below you can see the VASAviation video about how this played out, including a visualization of the path of both planes, as well as the air traffic control audio. As you can see, it’s not just that two planes were in the air at the same time with the same callsign, but they basically flew right past one another.
All parties did a great job handling this situation. The air traffic controller advised the pilots of the duplicate callsign, and made it clear which plane was “outbound” and “inbound.”
Why do some airlines use the same flight numbers for multiple flights?
I think one logical question is why some airlines use the same flight number for multiple flights, including those to and from a destination.
It’s true that this is mostly an issue in the United States, but that’s for a simple reason — a few airlines in the United States are absolutely massive.
Flight numbers are generally limited to four digits (it’s largely an industry equipment limitation, and it’s something that the industry doesn’t consider to be worth addressing), and an airline like American can operate 6,000-7,000 flights per day. The catch is that not all of those flights numbers can be used.
Generally, flight numbers 1 through 2949 are used for mainline flights, 2950 through 6099 are used for regional flights, 9000 through 9999 are used for ferrying and other repositioning flights, and that doesn’t even begin to address codeshare flights. So that explains why we have this issue.
However, what’s supposed to happen is that if there are multiple flights in the air with the same flight number, you’d add a letter to the end of the callsign for that second flight in the air, to differentiate the two.
On my last post about a similar incident, I posed the question of who is responsible for this mistake, and what went wrong. We got a really insightful answer from steve64, which I figure is worth sharing here (note that this is in reference to the previous incident, but the same principle applies here):
I used to work DFW Ops for legacy AA many years ago.
The Dispatcher for the PHX-ORD should’ve “stubbed” that flight. In the Reservation system, nothing changes. But in the Flight Planning System (and thus the Flight Plan sent to ATC) the flight number would be altered.
A 3 digit flight number would simply have a “P” (pronounced “Papa”) suffix added. The system (both AA’s and ATC/FAA) can’t handle more than 4 characters. So on a 4 digit number, the 1st digit gets dropped. 2482 stubbed would be 482P. Double/triple subs can happen. The next letters used are (I think) Romeo & Sierra.
The concept for a “stub” was originally for a flight passing thru a hub, back in the days when flights were actually scheduled “thru.” The inbound would be late but the hub has a spare plane so the outbound could depart on-time as a stub. Now that flight number philosophy has changed (the number doesn’t go “thru” a hub anymore, it’s ‘”out & back,” on return, the plane will go thru the hub but changes flight numbers), stub really apply more at a spoke than the hub.
I think that “stubs are now at the spoke instead of the hub” concept is what tripped the Dispatcher. While PHX is a hub, operationally for flight 2482, ORD is the hub and PHX is the spoke. If the original reason for the plane swap wasn’t due to the inbound being late AND the Dispatcher was thinking of PHX as a hub, the he/she wouldn’t be tracking the inbound plane thus not realizing it had lost time.
Having said that, I can’t believe neither AA nor FAA’s system wew able to catch this scenario developing.
Bottom line
Two American Airlines regional jets with the exact same callsign ended up passing one another in the sky. The flight number is used for both directions of travel between Philadelphia and Providence, but in this case, the outbound flight was delayed, while the return flight operated on time, obviously with a different aircraft.
The reason for the duplicate use of flight numbers is the limitation of flight numbers being at most four digits, and the big US carriers having many thousands of flights per day, and also needing flight numbers for codeshares, etc. That’s not an issue in and of itself, but instead, the problem is that the dispatchers seemingly didn’t update flight plans with air traffic control in light of this. The fact that this happened twice in two days isn’t good.
I imagine we’ll see American make some sort of change in its system to prevent this in the future.
What do you make of this duplicate flight number situation?
since PSA runs its own operations and presumably has its own flight tracking systems, this likely says that they don't have the safeguards to prevent a flight from departing while another under the same flight number is still in the air.
This feels like another example of where the pursuit of corporate efficiency leads to inefficiency.
I think we all know on which airline this would not happen