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BendixKing KT 74 ADS-B Mode S Transponder For Certified Aircraft - WAAS GPS Nav Required

Part# 11-12038
MFR Model# 89000007-002001


If a new transponder is on your "to-get" list, you might want to choose one that's both relevant now and in the future. The KT 74 transponder from Bendix/King is the easiest upgrade for the popular KT 76A/C and KT 78A models, with a 'plug and go' capacity. And it's ADS-B compliant, therefore meeting all 2020 requirements. It is low-cost, easy to install and fits into your existing panel. Suiting your needs now and in the future.

  • Retrofit - 'plug and play' installation
  • Low-cost solution that will offset future costs
  • Low power consumption
  • ETSO and TSO approved Mode S
  • Accurate readings with updates every few seconds
  • More efficient routing and better situational awareness
  • Meets ADS-B 2020 requirements when paired with Garmin 430 / 530W or GTN 650 / 750.
  • ADS-B will result in better communication between pilots and air traffic controllers for more efficient routing and resource management
  • Anyone who flies a Mode C or Mode S transponder will need to be equipped with ADS-B "Out" by 2020
  • Radar controls can be 12 seconds out of date
  • ADS-B "Out" means you're broadcasting your position information to ground stations and other aircraft
For STC information submit request at time of order

Peregrine STC no longer required per latest software revision.
California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -


  • Type Class 1 Mode S Level 2 els
  • Certification TSO C112D, C166B and ETSO C112C, C166B
  • Compliance DO-160G, DO-181E, DO-260B Class B1S, DO-178B Level B, DO-254 Level C
  • Supply Voltage (DC) 11 - 33 V
  • Typical Current Consumption (at 14V) Idle: 0.22 A, Active: 0.45 A
  • Nominal Transmitter Power 240 W at connector
  • Operating Temperature -25 to +70
  • Cooling Requirement No fan required
  • Weight 1.35 kg
  • Dimensions H 43mm (1.7") x W 160mm (6.30") x L 272mm (10.7")

In The Box

  • KT 74
  • Rack
  • Connector Kit


I did not want an add-on to my old transponder, as it could die at any time. I already had a GNS430W as a GPS source, so the KT74 made sense as the least expensive ADSB transponder available. However, dont let the slide-in replacement idea fool you, ADSB-out capability has a significant installation effort/cost. This unit is actually designed and built by Trig, but I prefer the buttons on the King badged version for entering codes. Once installed the unit works fine.

Dan M
February 14, 2018

Great transponder, great price couple it with a new digital encoder and its even better. What they dont tell you is it needs to be coupled with the Peregrin airspeed switch and all the work needs to be done at a 145 Avionics shop that sells Bendix King to get the STC. In an age where we talk about PART 23 reform for the added safety and reduced cost to the aviation community we take a step backwards with how this STC is listed. What does a customer do when there is no facility nearby?

Odin L
September 7, 2016

If you already have a WAAS GPS, this best way to Comply. If not look at UATs.

Alan L
June 21, 2016

Works great. This is one of the more affordable ways of becoming ADS-B Out compliant if your plane already has an approved WAAS GPS (such as a GNS430W). If you have an older rotary-dial transponder then youll find this to be an especially welcome upgrade.

Jeffrey L
February 4, 2016

About four months after installing a Uavionix tail cone ADS-b out, my KingBendix KT76 died while in flight. So instead of buying a used KT76 for few hundred bucks I spent just over $2,500 for the KT74. As a slide in replacement for the KT76, it does just slide in, but dont over tighten the 3/32nd allen screw, the locking piece is plastic. I would have given this five stars for the ease of installation, it did just slide in and work, but the installation manual is near impossible to find (Needed if you do the whole install with ADS-b out with other components). At a later date if I want ADS-b in, or have this transmit ADS-b out (On 1090es for international flights like to Mexico), youll have to install a different radio rack (Which came with this radio along with a plug) and you have to add more components, such as the king KGX 150R (Receiver with ADS-B Traffic and Weather) and an integrated WAAS GPS antena. That will set you back another three grand, I think it will transmit to a tablet too after you install this. So for now, its just an expensive replacement for my broke KT76, When my Uavionix Tailcone Ads-b-out stops working Ill spend the money for a gps antena and use the KT74 ADS-b out function. Bottom line, it did just slide in and work, problem fixed! Took 30 minutes to install and I was flying again. In the box it said, Made by Trig so go figure, its probably compatible with Trig products.

Daniel M
March 1, 2020

Display difficult to read in sunlight even on brightest setting, also screen to reflective needs to be matt finish not gloss.

Rod H
June 21, 2017


Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Can the KT-74 be operated in mode C if desired?

Although the KT 74 transponder cannot be operated in individual modes, it responds to both legacy Mode A/C interrogations and to Mode S interrogations from both ground radar and airborne collision avoidance systems.

Q: Is the KT 74 a plug and play replacement for the KT 79?

No it is not as the KT 74 is only a slide in replacement for the KT 76A/C and KT 78A model transponders. However, it is very similar and a good choice when upgrading because it minimizes the installation effort.

Q: Will the KT 74 display TIS-B traffic on a Garmin 430W. As the Garmin GTX 330 does?

TIS-B reception requires an ADS-B In device, also referred to as a UAT receiver (978 MHz). Neither the KT 74 nor GTX 330 receives ADS-B In. With the optional BendixKing KGX 130/150 TIS-B can be displayed on a Garmin 430W (Intruder only).

Q: What are the traffic display options and requirements for the KT-74 in the cockpit?

Traffic information associated with ADS-B In known as TIS-B requires a UAT receiver (978 MHz) like BendixKing’s KGX 150R. Traffic and weather can be displayed on portable devices (for example, tablets with Foreflight) with the KGX Wi-Fi adapter. Note, light aircraft has no requirement to display traffic.

Q: How does the altitude alert work on the Bendix King KT-74 ADS-B Mode S Transponder? Is it an audio alert?

The KT74 includes an altitude monitor function that can alert the pilot to altitude deviations in cruise flight. It will alert when the pressure altitude differs from the selected altitude by more than 200 feet. The altitude alerter output, on the 12 way secondary connector, is switched to ground when the altitude deviation is detected and can be connected to a warning light or sounder to warn the pilot.

Q: Is the Bendix/King KT 74 unit 1090ES compliant?

Yes, the KT 74 is 1090ES compliant (note it will still require a certified WAAS GPS source). Further, the KT 74 Mode S transponder is an ED-73E and DO-181E, Class 1 compliant, Mode S Level 2es datalink transponder, with support for extended squitter, elementary surveillance and surveillance identifier codes. The KT 74 is also a DO-260B Class B1S compliant ADS-B out participant.

Q: Will the TIS-B traffic display on the Garmin Aera 796 Portable?

No, it will not. The optional BendixKing KGX with Wi-Fi adapter will display traffic and weather on portable tablets, however, it is not compatible with the Aera 796 portable.

Q: The KT 74 requires a certified WAAS GPS antenna. The unit must therefore contain a GPS receiver. Is this correct?

The KT 74 does not require a GPS antenna for standard installations. For ADS-B Out compliance it requires an input from an approved position source (WAAS GPS) in the RS 232 format. Per the STC, approved GPS sources include BendixKing KSN 765 & KSN 770, BendixKing KGX 150, Garmin GTN 6XX/7XX & GNS 400W/500W series (including GPS 400W & GNC 420(A)W), NexNav Mini 21000, and FreeFlight 1201.

Q: Does the KT 74 transponder have a STC for a C172E?

Yes, the C172E is included on the AML STC along with hundreds of the most popular general aviation airframes.

Q: What frequencies does the BENDIX KING KT 74 ADS-B MODE S TRANSPONDER operate at and does it operate at both 978 MHz and 1090MHZ?

Per the KT74 manual, the transponder is only capable of the 1090MHZ frequency.

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