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FAA Regulations

Good Morning;

I am not able to find information about the FAA now requiring the Transponder set to Alt + Sqwk Code even when on the ground.  Historically, it has been set to Standby when on the ground.  Do you know when this took effect of will take effect?   (I do have the ADS-B information and understand that it is not required until 2020.)


Thank You,

Rich Lang
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2 Answers

  1. Ash on Jun 02, 2014

    See AIM 4-1-20 for the details on this new policy. I’ve copied the relevant text below:

    “3. Civil and military transponders should be turned to the “on” or normal altitude reporting position prior to moving on the airport surface to ensure the aircraft is visible to ATC surveillance systems.”

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  2. John D Collins on Jun 02, 2014

    Read the AIM, section 4-1-20 which describes the operation of transponders. Ever since the installation of ADSE-X radar systems that are used to monitor ground movement of aircraft was put into effect, the guidance has been changed to recommend that the transponder be turned on prior to aircraft movement on the ground.

    I never followed the older advice to leave it in standby, because it is too easy to forget on departure. It isn’t a formal rule requiring that the transponder be on when on the ground, but if you wish to taxi at an airport with ASDE-X, you won’t be given a taxi clearance until it is turned on.

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