Behind the Scenes with Oshkosh Air Traffic Control

As you may know, EAA Air Adventure is fully underway at Oshkosh. Here’s some information about the portion that I find the most interesting, the controlling. By Megan Esau, EAA Assitant Editor:

With more than 10,000 airplanes in attendance, the 65 air traffic controllers who sign up to work at EAA AirVenture Oshkosh every year are instrumental in making the World’s Greatest Aviation Celebration a safe and successful event.

The controllers are divided into 16 teams of four people each, and every team has one veteran team lead who has worked AirVenture for three years or more, one AirVenture rookie, and two limited members, with one to two years of AirVenture experience.

Air traffic staff from across the FAA’s 17-state Central Terminal Service Area and from the Eastern Service Area, including controllers, supervisors, and managers, compete in an application process to work at AirVenture. Veterans bid against other veterans, limited bid against other limited, and rookies bid against other rookies for a spot at what they call the “Super Bowl” of air traffic control.

The 16 teams rotate in shifts through the Oshkosh control tower, the Fond du Lac tower, the Fisk approach control site, and the mobile departure platforms scattered around the grounds called MOOCOWs, or mobile operating and communications workstations.

The controllers’ job is an important one, not just because they are relied on to make sure AirVenture is a safe and efficient operation, but because they are also the first voice to welcome incoming pilots to Oshkosh.

I listened to the Fisk VFR Approach and Tower frequencies, yesterday, and will continue to turn in for the rest of the week. It really is an amazing site to see and one I’d like to learn more about. Tune in and listen on LiveATC.

1. “Behind the Scenes With Oshkosh Air Traffic Control” by Megan Esau on July 25, 2018, from the original.

Expect progressive taxi instructions

What does that mean? In Infinite Flight’s latest update, progressive taxi instructions were introduced for the first time into the controllers’ lexicon. From 5.2.2 of the ATC Manual:

‘Taxi to RWYXX, contact tower when ready’ and ‘Taxi to Parking’ are the default commands that must be used by controllers for the purposes of departing/arriving aircraft. In addition to this, controllers have Progressive Taxi Instructions to assist with ground movement including one way systems, potential conflicts and intersection departures. Controllers should take note that VERY CLOSE MONITORING is required when using this tool and therefore should only use it when absolutely necessary. Before it’s used, controllers should send ‘Expect Progressive Taxi Instructions’ to the aircraft in question (although this
may not always be possible), once this is done the following commands are available:
– Cross runway XX
– Turn left/right next taxiway
– Continue straight ahead
– Make 180 (controllers must ensure that the aircraft has the space required to make a 180 degree turn on the taxiway)
– Already cleared to cross

Progressive taxi will become super useful at airports that require these specific instructions, to create a good flow of traffic.

Once the Progressive Taxi Instructions are no longer required, the controller must send ‘Continue Taxi at your discretion’.

Airport in sight, wait

When an aircraft is on a visual approach, you do not need to immediately clear for the visual if you want them to maintain the heading and altitude you previously assigned. The pilot must be visual before the controller can clear the aircraft for the visual approach, but once you clear them for the visual you give them the ability to turn. If you don’t clear them, even if they report the airport in sight, they can’t turn, so just keep that in mind as keeping them can prove to be helpful in certain situations.

1. 10.10.1 of the Infinite Flight ATC Manual, pulled from the original.

How do you calculate TOD?

That is the age old question. It’s never a fun experience for the controller or pilot to miss when a pilot misses their TOD (Top of Decent).

The goal is to contact approach when you are at or below 18,000ft AGL, 50nm away from the airport, at or below 260knts IAS. Here’s an example I’ll use from a flight I did a week ago, from NZWN to NZAA, cruise at FL240.

  1. First step is to open up a precision descent profile calculator. Google “descent calculator” and you’ll get a bunch of results.
  2. I’d like to do a gentle descent of 1500ft VS (f/m) to 18,000ft AGL from my cruising altitude of 24,000ft MSL, at 280knts IAS.
  3. So open up the descent calculator. To achieve that 1500ft VS descent, I’d need to start my descent 76nm out (50nm + 26nm = 76nm). So that’s my TOD, 76nm.
  4. As I get closer to the 50nm mark, I’ll continue to decrease my IAS to 260knts or below, change my VS if I’m too high or too low, then contact Approach when I’m below 18,000ft AGL, 50nm out.


You can’t learn anything if you never do anything wrong, and no one will ever be perfect.

Go around or missed approach?

A missed approach procedure tells you how to get from climb out into a holding pattern or to another point from where you commence a new approach. A go around takes an aircraft from short final to climb out directly, not touching the runway. A go around can be pilot or controller initiated and is a procedure used to cancel the approach and/or landing. If you can in to Tower on either a missed approach or go around, on Infinite Flight, you will told to go around, left or right traffic. The aircraft then will be handed over to the radar controller unless they are VFR traffic or a prior arrangement has been made between controllers.

1. 6.4.4 of the Infinite Flight ATC Manual.

I have a fuel emergency, now what

There’s three choices we have as ATC in a fuel emergency, on Infinite Flight. “Expect no delay”, “Expect delay” or in some cases we’ll tell you to divert to the nearest airport. If we tell you to “Expect no delay”, expect no delay, you’ll be brought in on the fastest route possible. Sometimes we even use the opposite end of active runways to get you down as quickly as possible.

“But what if I’m on a long haul?” The length of your flight has no meaning to us, we may not have time to check where you came from exactly so we apply equal treatment to anyone with a fuel emergency.

How do spoilers work?


When the pilot activates the spoilers, the plates flip up into the air stream. The flow over the wing is disturbed by the spoiler, the drag of the wing is increased, and the lift is decreased. Spoilers can be used to “dump” lift and make the airplane descend; or they can be used to slow the airplane down as it prepares to land. When the airplane lands on the runway, the pilot usually brings up the spoilers to kill the lift, keep the plane on the ground, and make the brakes work more efficiently. The friction force between the tires and the runway depends on the “normal” force, which is the weight minus the lift. The lower the lift, the better the brakes work. The additional drag of the spoilers also slows the plane down.

If you’re unsure on how spoilers will effect certain parts of flight on Infinite Flight, then go on Solo mode and test it out.

Inverted wedding cake

The exact shape of the airspace varies from one class B area to another, but in most cases it has the shape of an inverted wedding cake, with a series of circular “shelves” of airspace of several thousand feet in thickness centered on a specific airport. Here’s an example, you can find more examples on