KT 74 for ADS-B Out

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DwayneSmithUSMC

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DwayneSmithUSMC
i have a KT 74 installed in my aircraft. I am having a Garmin GPS-500W installed. I need some clarification if these two devices together will allow the KT 74 to be used for ADS-B out or do I need something else? Thanks in advance for your help
 
If you don't have a squat switch with a spare pair of contacts on the gear, then you will need an air pressure switch plumbed into the pitot line to provide air/ground sensing per the KT-74 STC. You can purchase the kit from the STC holder (Peregrine) for about $150. Maybe others, but it's been years since I looked. The switch itself is only about $25 if you can source it.
 
bkspero said:
If you don't have a squat switch with a spare pair of contacts on the gear, then you will need an air pressure switch plumbed into the pitot line to provide air/ground sensing per the KT-74 STC. You can purchase the kit from the STC holder (Peregrine) for about $150. Maybe others, but it's been years since I looked. The switch itself is only about $25 if you can source it.
Click to expand...

Aircraft Spruce sells the Peregrine switch for the KT-74 and the Trig TT31 transponders. If I was OP I would check the King STC and installation guide as it may require the Peregrine as part of the approved installation, despite the fact the plane may have a squat switch.
 
GRG55 said:
Aircraft Spruce sells the Peregrine switch for the KT-74 and the Trig TT31 transponders. If I was OP I would check the King STC and installation guide as it may require the Peregrine as part of the approved installation, despite the fact the plane may have a squat switch.
Click to expand...

The STC at the time I had my KT-74 installed a few years ago allowed for either a squat switch or the air pressure switch. The squat switch did need to have a set of unused contacts, though. It did not allow for connecting two sets of wires to the same contacts. Pasted below is the introduction from section 3.5 of the STC installation manual.

3.5. Airborne Status Determination
The transponder will receive an input from an aircraft source that indicates when the
aircraft is airborne. This source will be one of the following:
 An airspeed switch interfaced with the aircraft pitot-static system
Note: Installation of the airspeed switch for airborne status determination
is restricted to aircraft on the AML that have a maximum weight of under
6,000 pounds. For aircraft that have a maximum weight of equal to or over
6,000 pounds, a weight on wheels switch must act as the airborne status
source.
 A weight on wheels switch that indicates when the aircraft is on the ground. This
switch is integrated with the aircraft landing gear. The weight on wheels switch
activates when weight is detected on the extended wheels.
 
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