I had a situation yesterday at KSFO where I had two planes arriving, with one on 28R and another on 28L. I sequenced a third plane to follow the plane about 10mi out on final for 28L. There was another plane on final for 28R about 6mi out. The pilot that was just sequenced ASSUMED the plane on 28R was the one to follow and turned base too early. I had to issue extend downwind to correct the error.
It’s difficult to tell at airports where the runways are relatively close together which runway was assigned to a plane on final, so what should the pilot have done? You may know which runway a plane was assigned if you were on frequency when they were given pattern entry, but that’s not always the case. The best approach is to assume you don’t know which plane is targeting the runway you’ve been assigned, and follow the plane furthest out. You may end up being resequenced, but that’s a far less chaotic situation for the controller than jumping ahead of the sequence you’ve been given.
The moral of the story is the following… If you’re not sure of how to respond to a command, don’t make assumptions. Take the safest approach possible. It may not be what the controller intended, but more often than not, a safe approach won’t create heartburn for anyone.
That was my first ever level 2 violation was for failure to follow sequence. And it wasn’t because I trying to “cut” in line, I just couldn’t tell who to follow and I assumed it was the guy on final.
The vague-ness of the traffic to follow command has been a source of confusion for myself at times.
Perhaps a fix would be where the controller has to select the specific aircraft to follow and then the command is read out as “N123AB, traffic to follow is [ a United Airlines 737-800 ]
or [ United 123 ] cleared visual approach runway 28 left at San Francisco”
Either Airline/Aircraft Type or Callsign would work, with each having their own sets of advantages and drawbacks.