Tag: ATC communications

ADS-B and Call Sign Confusion

The ADS-B mandate has arrived, and with it comes the potential for another source of confusion. Most pilots flying with ADS-B systems have a display of traffic in the cockpit, either on a moving map that’s part of a GNSS navigation system or on a tablet like an iPad running an app such as ForeFlight, Garmin Pilot, or FlyQ. These traffic systems usually show the identification of other aircraft, either the registration number or the airline flight number.

ADS-B traffic (TIS-B) as shown in ForeFlight

When ATC issues traffic advisories–for example, “Cessna 1234A, traffic 2 o’clock, 4 miles, a Southwest 737”–it might be tempting to include the target identification in your acknowledgement. For example, “Cessna 1234A, we have Southwest 2345 in sight,” or “Southwest 2345 in sight, Cessna 1234A.”

If that sounds odd, watch some aviation videos on YouTube. At least one pilot flying an airplane with a new glass panel has made a habit of such replies.

For obvious reasons, it’s a bad idea to include another aircraft’s identification or call sign when you respond to ATC. In fact, the FAA’s December 2019 update to AC 90-114 Automatic Dependent Surveillance-Broadcast Operations anticipates this issue:

2.4.3.4 Unless initiated by the controller, pilots should typically not use the call sign or Aircraft Identification (ACID) of observed traffic in radio communications, as this could create confusion for both ATC and pilots monitoring the frequency.

AC 90-114B

So even if you’re equipped with the latest technology, stick to the standard replies when ATC points out traffic:

“Cessna 1234A, traffic 2 o’clock, 4 miles, a Southwest 737.”

“Cessna 1234A, we have the Southwest 737 in sight,” or “Traffic in sight, Cessna 1234A.”

“To” & “For” Confusion in Aviation Communications

FAA recently released an update to AC 90-66 Non-Towered Airport Flight Operations (more information here at BruceAir).

That update specifically address several contentious issues, such as straight-in approaches, “the active,” and the perenially annoying and counterproductive request “any traffic in the area, please advise.”

But one section of the updated AC 90-66B also discusses the common tendency of pilots to include the words “to” and “for” in transmissions–even when not at a non-towered airport. For example:

  • Cessna 1234A: Podunk traffic, Cessna 1234A, right base for runway two.
  • Cessna 1234A: Podunk traffic, Cessna 1234A, ten miles to the south to enter downwind for runway two seven.
  • Cessna 1234: Podunk traffic, Cessna 1234, taking the active for takeoff to the south. Podunk.
  • Approach: Cessna 34A, turn right heading two five zero. Cessna 34A: Two fifty for 34A.
  • Approach: Cessna 34A, descend and maintain two thousand two hundred. Cessna 34A: Two point two for 34A.
  • Cessna 1234A: Metro departure, Cessna 1234A, one point two for two.
  • Departure: Cessna 34A, climb and maintain four thousand. Cessna 34A: Up to four for 34A. Or: Out of two for four for 34A.

You can hear many similar examples on the CTAF at any busy non-towered airport and while working with ATC. The use of “to” and “for” and abbreviated readbacks is also common in popular aviation videos on YouTube.

The use of “to” and “for” is natural in everyday communication, and perhaps it seems cool if you’re an experienced pilot who graduated from remedial ATC-speak thousands of hours ago.

But mixing words and numbers is potentially confusing in aviation, especially when the frequency is busy and workload is high. It’s also unnecessary. AC 90-66B devotes a paragraph specifically to the matter.

10.4 Confusing Language. To avoid misunderstandings, pilots should avoid using the words “to” and “for” whenever possible. These words might be confused with runway numbers or altitudes. The use of “inbound for landing” should also be avoided. For example, instead of saying, “MIDWEST TRAFFIC, EIGHT ONE TANGO FOXTROT TEN MILES TO THE NORTHEAST, INBOUND FOR LANDING RUNWAY TWO TWO MIDWEST,” it is more advisable to say, “MIDWEST TRAFFIC, EIGHT ONE TANGO FOXTROT TEN MILES NORTHEAST OF THE AIRPORT, LANDING STRAIGHT IN RUNWAY TWO TWO, MIDWEST,” so it does not confuse runway 4, runway 22, or the use of an IAP on arrival.

Rephrasing the above examples removes the unnecessary homophones:

  • Cessna 1234A: Podunk traffic, Cessna 1234A, right base runway zero two. Podunk
  • Cessna 1234A: Podunk traffic, Cessna 1234A, one-zero miles south, planning left downwind runway two-seven. Podunk.
  • Cessna 1234: Podunk traffic, Cessna 1234, departing runway two-seven, will be southbound. Podunk.
  • Approach: Cessna 34A, turn right heading two five zero. Cessna 34A: Right turn heading two five zero, Cessna 34A.
  • Approach: Cessna 34A, descend and maintain two thousand two hundred. Cessna 34A: Maintain two thousand two hundred, Cessna 34A.
  • Cessna1234A: Metro departure, Cessna 1234A, one thousand two hundred, climbing two thousand.
  • Departure: Cessna 34A, climb and maintain four thousand. Cessna 34A: Maintain four thousand, Cessna 34A.

You can find additional detailed examples in AIM Chapter 4 Air Traffic Control, Section 2 Radio Communications Phraseology and Techniques.

Of course, sometimes there’s no subtitute for using plain language. The aviation phrasebook doesn’t include standard dialog for every situation. And we all make slips of the tongue on the radio, just as in normal conversation. But remaining vigilant about the use of potentially confusing and unnecessary words and phrases is one way to reduce the potential for conflicts.