Old Dog, New Trick- Transponder Use On the Airport Surface

By now, many of you have heard or read that the FAA-ATC wants us to ensure that our transponders are on and in the altitude reporting mode while operating on movement areas at all airports.  If you’re like me and sometimes slow to adapt to change, particularly when it involves ingrained flying habits and procedures, it may take some getting used to.  In the meantime, at least for most of us, non-compliance shouldn’t be an issue that leads to FAA enforcement.   

If you learned to fly more than a few years ago, you were probably taught to turn your transponder on just prior to take-off and to turn it off (or to standby) after landing and taxiing off the runway, whether at a tower controlled field or not.  For many years this was the practice as promoted in the Aeronautical Information Manual (AIM).  The language in the AIM changed in 2012, 2014, and then again in 2016.  In the current chapter 4 of the AIM, it now reads “Civil and military aircraft should operate with the transponder in the altitude reporting mode and ADS-B Out transmissions enabled (if equipped) at all airports, any time the aircraft is positioned on any portion of the airport movement area.”  It goes on to relate certain other details, but the basic take-away is that ATC now wants the transponder on for all operations in movement areas, i.e. at airports with operating control towers.  The change, of course, is associated with the transition to Next Generation Air Transportation System (Next Gen) and includes the coordination of Automatic Dependent Surveillance-Broadcast (ADS-B) and Airport Surface Surveillance Capability (ASSC).  The effectiveness of the system relies on participation.  More and more ADS-B Out equipped aircraft are coming on-line and according to the FAA website, the ASSC system is installed at 35 major airports.  Why then does the FAA want transponder on use at all tower controlled airports, even the ones without ASSC?  For enhanced safety where transponders are readable and I guess they want to re-train us in advance of the 2020 mandate.   

So will you get into trouble for non-compliance—forgetting to turn on or off your transponder?  For most of us the answer is no.  It’s not required if you’re not ADSB-Out equipped as the AIM guidance is non-regulatory.   If you have ADS-B Out equipment installed, however, FAR 91.225(f) requires that your transponder must be in transmit mode at all times.  And, if ATC asks you to turn on or off your transponder, whether ADSB equipped or not, you should comply -- compliance with ATC operational instructions is required in accordance with FAR 91.123(b).   

I am still adjusting to the change and I sometimes revert to old habits by turning the transponder off and on at the wrong times.  So far, neither the controllers at my home airport, KFDK (no radar), nor the controllers at Potomac Approach seem to notice, or care, when my transponder is in the wrong mode while on the airport movement area in my non-ADSB equipped aircraft.

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Mike Yodice
Mr. Yodice has been a pilot since 1979. He took instruction at the historic College Park (MD) airport and co-owns a Piper Cherokee and flies the family Piper J3-Cub.

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