Capt Pit Bull,
Honeywell. See AD at;
http://www.airweb.faa.gov/Regulatory...pandSection=-3
In summary;
This AD results from the transponder erroneously going into standby mode if the flightcrew takes longer than five seconds when using the rotary knob of the radio management unit to change the air traffic control code. We are issuing this AD to prevent the transponder of the COM unit from going into standby mode, which could increase the workload on the flightcrew and result in improper functioning of the traffic alert and collision avoidance system.