Q&A
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.
Q: Is the KT74 mode S approved for installation in Europe
Yes the KT 74 is approved for installation in Europe. Note the KT 74 is an Elementary Surveillance (ELS) Mode S Transponder and does not support Enhanced Surveillance (EHS).
In European Airspace aircraft with a maximum operating altitude above 25,000 feet must be equipped with and EHS capable Mode S Transponder. Also, the KT 74 does not support antenna diversity functionality (two antennas installed on aircraft) so aircraft with maximum certified take-off mass in excess of 12,500 lbs and/or maximum cruising true air speed in excess of 250 kts are not eligible for installation of the KT 74 transponder.
Q: Where do I buy the GPS module and GPS antenna for the KT-74 ?
ADS-B compliance requires a certified WAAS GPS source. The BendixKing KGX 150R is a great option. Also, 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: Is the KT74 compatible with the Garmin 650? Can it get its position from the Garmin?
Yes, per the STC the GTN 650 is an approved WAAS GPS source.
Q: If you already have a Garmin GNS530W, what more do you need to buy in addition to the KT74 transponder to make it ADS-B compliant?
The combination of a WAAS GPS source (such as the Garmin GNS 530W) and the KT74 transponder would comply with ADS-B out requirements.
Q: Does the KT-74 have extended Squitter?
The KT-74 does have a 1090 MHz Mode S extended squitter.
Q: Is the KT-74 a slide in replacement for a Kt-76?
The KT-74 is a slide in replacement for the KT-76A and KT-76C models but not the KT-76.
Q: Is the KNS 770 an approved GPS data source for the KT 74 to meet ADS-B out compliance?
Yes, the KSN 770 is an approved GPS data source for the KT 74 per the STC
Q: Does the Bendix/King KT-74 accept both gray and serial encoder data?
Per the installation manual, the KT-74 does accept both gray and serial encoder data.
Q: I see the stc has been approved for kt-74 and garmin 430w/530w.I also see my aircraft is on the approved list.How can i get the stc paperwork to complete my installation??
The FAA stipulates that a certified ADS-B Out solution must have both an STC and be installed by an authorized Part 145 facility. Peregrine owns the STC and requires installation performed at Part 145 facility for this paperwork.
Q: Could The KT 74 ADS-B Mode S Transponder use the tray/rack/wiring of an existing KT 76?
It can for the KT-76A and KT-76C but not the KT-76.
Q: Is this unit compatible with the garmin 480 WAAS as an acceptable GPS source?
Per the manufacturer: No the Garmin 480 is not compatible with the KT 74
Q: Will the KT-74 Transponder be a direct replacement for the Narco AT50 and AT150 Transponders and use the same rack and plugs?
The KT-74 is not a direct slide in replacement for the Narco AT50 and AT150 Transponders.
Q: Does the KT 74 output TIS-B traffic? When installed with a KSN770, will the traffic displayed be only TIS-A or both TIS-A and TIS-B?
The KT 74 outputs only TIS-A traffic data. At this time (April 2018) traffic cannot be displayed on the KSN 770. Note, the KSN 770 is an approved position source for ADS-B Out compliance.
Q: Will this work with a King KLN94 GPS?
Per Bendix King: No, the ADS-B function is not supported between the KT74 (11-12038) and the KLN94 GPS.
Q: Is the KT74 mode S and ADS-B approved and compliant for operation in Canada?
Per Bendix King: Yes, the KT74 (11-12038) is approved for use in Canada.
Q: Is the KT 74 both ADS-B IN and OUT?
Standalone, the KT 74 is ADS-B Out only (with a WAAS GPS source). With the optional KGX 150R UAT receiver (978 MHz) and WiFi adapter traffic/weather can be displayed on portable devices (for example, tablets with Foreflight).
Q: Is the KT 74 both ADS-B IN and OUT?
Standalone, the KT 74 is ADS-B Out only (with a WAAS GPS source). With the optional KGX 150R UAT receiver (978 MHz) and WiFi adapter traffic/weather can be displayed on portable devices (for example, tablets with Foreflight).
Q: Is the Trig TN70 WAAS GPS kit compatible with the KT-74 Transponder
Per Bendix/King: The KT-74 can not be used with the TN70 as an acceptable ADS-B out solution.
Q: I want to replace my KT78A in a Piper Cherokee 180 hp in Europe. Is this with a KT74 possible with retrofit to keep all the wiring?
The wiring is the same for all transponder functionality. You would only add a few wires for ADS-B Out capability, if needed.
Q: You say plug & play - but doesn't the KT74 and KT76A ADS-B WAAS connection involve a rack change / mod?
The KT74 is a plug and play slide-in for the KT76A but you will need additional wiring to connect to a certified GPS source to meet the ADS-B mandate. Rack change: if the secondary electrical connector is utilized, then the KT 74 mounting tray must be installed.
Q: (1) The KT-74 is Plug-N-Play replacing a KT-76A, is there a discount for just the KT-74 without Tray & Connector?
(2) What else is required to make the KT-74 ADS-B compliant?
BendixKing does offer the KT 74 without the install kit at the same price with the tray and connector. An approved WAAS GPS source is required for ADS-B compliance; per the STC, 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 all of the required STC paperwork from Peregrine come with the transponder? Need the STC to use a GNS430W as a position source in a Cessna 172N
The STC paperwork for the KT 74 is available under the documents tab for this part. With the latest software revision (v3.17 March 2018) and AML STC the differential pressure switch is no longer required in most installations. The paperwork, installation manual and STC manual can be provided after purchase.
Q: The Mode A/C transponder uses an altitude encoder to report altitude. How does the Bendix King KT74 Mode S transponder receive altitude information?
The KT-74 also requires an encoder to receive altitude information.
Q: Is the Bendix King KT74 plug and play with the Bendix King KT73?
No, a new wiring harness and rack will need to be installed.
Q: I recently had my KT76A transponder inspected as is required bi-annually, so will I have to conduct this testing again when I swap it out for the new KT74, or will it be all set to operate as is?
The KT 74 installation will need to be signed off by a mechanic. After the installation is signed off, you will not be required to perform another inspection until your next bi-annual.
Q: If the KT-74 is installed into an experimental aircraft, can the KT-74 be wired to the Garmin 796 WAAS GPS to be ADS-B out compliant?
No, the 796 is not an ADS-B approved GPS source. Per the STC approved WAAS 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: Is the KT74 NVIS compliant or can it be supplied by the factory as an option?
No, King does not offer a NVIS version at this time.
Q: Would a Garmin GA 35 WAAS GPS antennae suffice for the WAAS input for the KT-74? Intend to use a G-5 EFIS.
The KT 74 does not have a direct input for a WAAS GPS antenna. It requires an input from a WAAS GPS source. Per the STC, approved WAAS 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: The STC for the KT74 lists all the Garmin GPS/GNS 4xx through GTN 6xx/7xx devices with a WAAS option as compatible sources The 412 page Garmin GTN installation manual says nothing about the connection to a KT74. There is no public KT74 installation manual. So WHAT interface is required. I have a Garmin G-5 with a WAAS Antenna, can it be a source?
No, the G5 is not an ADS-B approved GPS source. GPS sources are RS-232 connections. Per the STC, approved WAAS 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.
The KT 74 installation manual and STC manual are available by contacting the Avionics team.
Q: Can I use this Bendix King HT 74 as an ADS-B out and use Foreflight and a kit for ADS-B in?
Yes. The KT 74 meets the requirements for the FAA ADS-B mandate, you will also require a WAAS GPS position source and an altitude encoder for full compliance. ADS-B In weather and traffic is available with the remote mounted BendixKing KGX + Wi-Fi adapter. ADS-B In can also be received via in-cockpit kits/devices.
Q: Does the KT-74 STC cover the Garmin GNS 400 Series WAAS GPS?
Yes, the STC covers both the GNS and GTN WAAS systems.
Q: Will the KT74 work with just a WAAS antenna and not a WAAS GPS?
The KT74 requires a WAAS GPS source to fully function. It will not take a WAAS GPS antenna.
Q: Can a Garmin 496 be used with this unit to provide the WAAS capability?
No, the Garmin 496 is not an approved WAAS GPS source for ADS-B purposes.
Q: I have a 69 172k with an old BendixKing AT50A. What do I need to make the plane ADS-B compliant, every piece of equipment?
You will need a Mode S 1090 transponder with a built-in extended squitter. The transponder will need to be paired with an FAA-Approved WAAS GPS position source. The KT 74 is a qualifying transponder when paired with an approved waas gps source and the peregine stc airspeed switch.
Q: Does the Bendix King KT 74 unit come with installation manual?
It is not included as paperwork, but rather a PDF download is made available after the unit is purchased.
Q: Where are the buttons for 8 and 9 numbers?
Transponder codes only have numerical values 0-7 per position. There is no need for the 8 and 9.
Q: Is the KT-74 a replacement for the KT-78 (not the KT-78A)?
Yes, this is a good replacement for the KT-78, you will need additional wiring, however.
Q: Is the new Garmin GPS 175 an approved GPS source for the KT 74?
Yes. The Garmin GPS 175 (11-12038) is an approved WAAS GPS for the KT 74 ADS-B mode S transponder
Q: Does BK offer software updates and if so, how would one get access to the latest software versions?
They do not offer software updates over web. You will need to go to a Bendix King installer to update the transponder.
Q: My helicopter is currently using the Bendix King KT71 transponder. May I know if it is possible for me to replace it with the KT74 transponder unit directly without changing any other components?
No, this in not a direct slide in replacement for the KT71. It would be a new install.
Q: If the KT-74 is installed into an Cessna 182Q aircraft, can the KT-74 be wired to the Garmin 695?
The Garmin 695 is not acceptable GPS unit for the KT74.
Q: Does the KT 74 transponder have a STC for a C182Q?
Yes, this aircraft is on the AML/STC paperwork.
Q: Do any transponders slide into the Cessna transponder tray?
Most new certified transponder kits will require a complete new installation for the install to be considered legal for certified aircraft. This means removal of the old tray and install of the new tray.
Q: Will this BendixKing KT-74 work with a Uavionix Tail Beacon?
Yes, the uAvionix tailBeacon decodes mode A, mode C, and mode S. Since this is mode S it will work.
Q: Is there a remote version of the kt 74?
No there is not
Q: I have KT76A installed now and a Garmin GDL82 with gps for ADS-b. Will the KT74 be a direct slide in replacement and still be ADS-b compliant?
No, the GDL82 does not function with MODE S transponders. You would need to find a compatible WAAS GPS unit.
Q: Will the KT-74 work with Diversity in Canada or can I upgrade it to work in Canada ?
No, the KT-74 is not a diversity unit and there are no options available to retrofit it for a diversity ADS-B mandate.
Q: I currently have a KT76/A with a FreeFlight Ranger FDL-978-XVR UAT for ADS-B Out/In. This has been working fine, but I have been thinking of getting the KT74. If the KT74 is just slid into the existing KT76/A tray, will it work compatibly and transmit ADSB-Out with the FreeFlight system with no further modifications?
The KT74 will work as a slide in replacement for the KT76A it will work with the freeflight ranger. Part # 10-05913 peregrine switch will be required for STC installation.
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