Flight training school is back in session. In previous classes, I said you should state your position laterally and vertically when contacting air traffic control. There are exceptions to this rule, and we will discuss them today.
In our last class, we used the example: “Piper 774 Juliet Tango, over the tank farm at 3,500, inbound for landing at Fulton County.” The lateral position was “over the tank farm,” and the vertical position was 3,500. So far, so good. This radio call works exactly as described if you are making initial contact with air traffic control. If you are already in radar contact with air traffic control there is no need to state your lateral position.
Why? Because ATC has your position identified on radar. However, radar contact does not release you from stating your altitude. Mis-calibration in your transponder’s altitude reporting feature, or accidentally setting the wrong barometric pressure into your altimeter may cause an unsafe difference between the altitude a controller sees on his radar screen versus the altitude you see on your altimeter. That is why altitude verification is required, even when under radar contact.
Let’s say you are operating under visual flight rules (VFR) and you are in radar contact with Atlanta enroute air traffic control center (ARTCC) for flight following. As you near Fulton County Airport, your intended destination, Atlanta Center tells you to switch to Atlanta Approach Control. Unless told otherwise, you can be assured you remain under radar contact. Your initial radio call to the new air traffic controller does not and should not include your lateral position. Instead, it should simply sound like this: “Atlanta Approach, Piper 774 Juliet Tango, 3,500, landing Fulton County.”
In the Traffic Pattern
Radar contact relieves you of the need to state your lateral position. There are other exceptions, such as when either your lateral or vertical position is implied. Here’s an example of what I mean:
“Cessna 585 Uniform, left downwind.” No altitude. Why? If you are on left downwind, your aircraft is either at or near the published traffic pattern altitude for that airport. No need to say what everyone knows.
Flying an Instrument Approach
Here’s another exception, and this applies to pilots flying an instrument approach procedure. Even if you are not IFR rated, it still pays to know about this exception, so when you hear a pilot make this type of call, you know where to look for his aircraft.
All instrument approaches have published altitudes for each segment of the approach. A pilot flying the approach must comply with the published altitudes for the approach. For example, look at the profile (side view) depiction of the instrument landing system (ILS or Localizer) approach to Runway 35 at Lihue Airport in Kauai, Hawaii (figure below.)
When an aircraft is on the ILS approach and crosses over AKULE intersection, 5.4 miles from the end of the runway, the procedure requires the aircraft to be at or above 1,900 feet. Although the procedure allows the pilot to fly above 1,900 feet at this point, if the aircraft is on the proper glideslope to the runway, the aircraft will be at 1,900 feet at AKULE. This is a long lead in to explain simply that when the pilot contacts Lihue Tower, all he need say is “Lihue Tower, Aircraft XXX, AKULE.” The altitude is implied in the same way it is implied when you report your position in an airport traffic pattern.
There are other exceptions to the position report, and we can discuss them in the comments section of this article if you like. For now, let’s move on to the next bit of anatomy in an aircraft radio call. I’ll have that for you in our next lesson. See you then.