ADS-B Package Overview

The L3 ACSS ADS-B package includes the NXT-600 Mode S ADS-B compliant transponders, along with an NXG-900 WAAS GPS (as required), with installation supported by an Approved Model List Supplemental Type Certificate (AML-STC). This will collectively satisfy the DO-260B mandate for Automatic Dependent Surveillance – Broadcast (ADS–B) for multiple legacy aircraft models.

ACSS transponders are installed on thousands of aircraft worldwide. The NXT-600 is a form factor replacement to the highly successful RCZ-852 for business jets, regionals and helicopters. The ACSS NXT-600 is also designed to be alternative replacement for the Rockwell Collins TDR-94/94D.

NXT-600 Mode S Transponder

The NXT-600 is designed as a plug-n-play retrofit replacement for the ACSS RCZ-852 transponder and an alternative replacement for the Rockwell Collins TDR-94/94D. The NXT-600 is DO-260B and DO-181E compliant and meets the global Automatic Dependent Surveillance – Broadcast (ADS–B) mandates for aircraft that are required to have ADS-B Out capability. The lightweight NXT-600 transmits ADS–B Out data from your aircraft to other nearby aircraft and to Air Traffic Control (ATC). The higher level of ADS–B Out (DO-260B) transmission includes precise flight data, including position, speed and intent of the aircraft.

The NXT-600 is an ICAO Level III transponder, delivering the latest functionality required for ICAO ACAS II mandate compliance; European Elementary Surveillance (ELS) and Enhanced Mode S Surveillance (EHS), Downlink of Aircraft Parameters (DAPs) and ADS-B 1090ES extended squitter. The NXT-600 is based on the previously certified RCZ-852, and retrofit installations are plug-n-play. The NXT-600, an ADS-B compliant next-generation transponder, provides additional functionality, and the newly redesigned configuration card is easier and more functional than the previous RCZ-852 card.

Software upgrades to the NXT-600 are performed through on-board software loads, providing operators with cost savings and scheduling flexibility.

Model NXT-600 Features

  • Form Fit replacement for the RCZ-852
  • Alternative replacement solution for Rockwell Collins TDR-94/94D Transponder
  • DO-181E/DO-260B compliant to meet FAA/EASA NextGen mandates, transmitting more precise position, speed and intent data
  • Elementary & Enhanced Mode S surveillance compliant
  • Maximum reliability with built-in test and self-test capabilities
  • Improved Freescale MPC8308 Processor
  • Legacy Configuration Strap Card replaced with industry accepted program pin
  • On-board maintenance operations using COTS interfaces
  • Front panel LED support
  • Designed to be compatible with ARINC 735/A/B TCAS II systems
  1. ACSS TCAS 3000SP™, TCAS 2000™, and T²CAS®
  2. Rockwell Collins TTR-920/921 and TTR-2100
  3. Honeywell TPU-67A & B, and TPA-100
  • 2 Year Warranty

Flight ID

The NXT-600 transponder part number ending with (002) includes the capability to automatically generate a fixed flight ID (also known as Call Sign or Aircraft Identification) from the Mode S address for U.S. registered aircraft. In many examples, this feature removes the need to upgrade legacy control panels or flight management systems in order to provide Flight ID to the transponder. To support operators with compliance to the FAA and EU’s ADS-B Out mandates, ACSS will be amending their existing approved model list supplemental type certificate (AML STC), covering installation of the latest NXT-600 Transponder and optional NXG-900 GPS position source on a comprehensive list of Part 25 aircraft models.

Note: For aircraft currently complaint with the EU’s Elementary Surveillance (ELS) requirement, means to provide flight ID to the transponder are already present and compliant with the ADS-B Out requirement.

Control Panel

The NXT-600 transponder part number ending with (002) includes interoperability with the Rockwell Collins CTL-92E & CTL-92T control panels. In many examples, this compatibility removes the need to upgrade these legacy TCAS/Transponder control panels when upgrading to the ACSS NXT-600 ADS-B Out compliant transponders in place of the legacy TDR-94/94D transponders.


The NXT-600 transponder part number ending with (002) includes enhancements to support interoperability with additional GPS systems which provide navigation accuracy category for velocity (NACv) better than 3m/s but are unable to substantiate this level of accuracy. This may remove the need to update the GPS system when upgrading to ADS-B Out compliance.


NXG-900 GPS WAAS/S-BAS Compliant GPS Source

The NXG-900 is a GPS Solution designed exclusively for the NXT family of transponders. This unit utilizes signals from Global Positioning System (GPS) satellite constellation and Satellite-Based Augmentation Systems (S-BAS) such as the USA Wide Area Augmentation System (WAAS), European EGNOS, Indian GAGAN, and the Japanese MSAS. Currently the NXG-900 supports WAAS and WAAS compatible S-BAS systems to produce an ARINC 734A based output for the NXT series transponders.

This GPS function provides position, velocity, time, and integrity and is ADS–B rule compliant and meets the position source requirements of AC 20-138D and AC 20-165B. The NXG-900 is certified for TSO-C145c, TSO-C154c and TSO-C157a.

If the customer does not select the NXG-900, the installing facility would be responsible to insure the GPS source selected meets ADS–B and Advisory Circular standards.

Model NXG-900 Features

  • Rule Compliant Position Source
  • 978 MHz UAT, ADS-B In providing Weather (FIS-B)
  • 2 Year Warranty


NXT-600 & NXG-900: AML STC

An Approved Model List Supplemental Type Certificate (AML STC) with the Federal Aviation Administration (FAA), Transport Canada Civil Aviation (TCCA) and European Aviation Safety Agency (EASA) will be offered as a certification path for the NXT-700 transponder and the NXG-900 on the following aircraft:

  • Beechcraft Hawker 800/800XP, 700/700B, 400
  • Bombardier -7 Series, CL-600 Series
  • Dassault Falcon 10/20/50/200/900, and Fanjet
  • Gulfstream I, II, III, IV
  • IAI 1124
  • Lear 20/30 Series, 55
  • Sabreliner 265 Series
  • Textron 550/560/650
  • Embraer Phenom 100, 300

The Architecture will be as follows: NXT 600 Transponder interfaced to a Blind WAAS GPS receiver (NXG900, GDL88, and UNS1-xW) while use existing TXP controller when possible, or a replacement controller if required.

Should you be interested in an obligation free quote for your aircraft, please do not hesitate to contact Clinton Carroll on 011 659 1033 or at [email protected].



  1. Steve Anderson on December 12, 2019 at 8:18 pm

    Thanks for this Clinton, will
    Chat to you then about MGS and a Challenger 600 next week.

  2. Juan Shields on May 31, 2022 at 10:27 pm

    hello clinton,, did you get this done for a falcon 900

    • Clinton Carroll on June 2, 2022 at 9:08 am

      Hi Juan. We do have solutions for the Falcon 900. please contact us on [email protected] and we can assist you further.

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