Flight line test sets are also referred to as avionics testers. Flight line test sets are designed to support the ADS-B (Automatic Dependent Surveillance-Broadcast) performance testing, utilizing air traffic technology and minimizing reliance on ground-based radar. These avionics test equipment can improve the overall safety of air traffic control.
What is ADS-B for Flight Line Testing?
The purpose of flight line test set's are for testing protocols, such as ADS-B transponders, to verify their capability of receiving, decoding and displaying messages from the flight line, in accordance to DO-260A/B. The ADS-B standard is required by the FAA for aircraft flying within controlled airspace in the U.S. since 2020. The ADS-B requires aircraft operating in airspace to include a positioning source as part of ther aircrafts avionics. The definition of controlled airspace is characterized by altitude and airport proximity/location, which are separated as class A, B, and C airspace or Class E airspace above 10,000 ft. ADS-B standard is applicable for airliners, private jets, helicopters, turboprops, and ADS-B transponders.
Flight Line Test Sets Functions
Conducting flight line testing can achieve greater efficiency and improvement in optimizing aircraft spacing, direct routing, and situational awareness for air traffic controllers and pilots. General procedures of flight line testing identifies the controls, connectors, indicators, and display screens used in individual test modes.

Flight Line Tester Modes
- Transponder Modes
- TCAS I, II, TAS, TIS (Traffic Information Service), and, TIS-B (Traffic Information Service Broadcast)
- ADS-B (DO-260/A/B) and GICB extracted DAP's (Downlinked Aircraft Parameters)
- UAT (ADS-B monitor; FIS-B, TIS-B, and ADS-B generator)
- XPDR Mode (for ATCRBS and Mode S transponders using an Auto Test)
- DME Mode (for distance measuring equipment interrogators)
- UAT Mode (monitor ADS-B messages and generate FIS-B, TIS-B, and ADS-B messages)
- Setup Mode
Flight Line Avionics Test Equipment
Avionics test equipment has a wide range of applications, including supporting the development, manufacturing, testing, and maintenance of commercial, private, and military airborne electronic systems.
Flight Line Test Set Applications
- Transponder/DME/TCAS
- Flight line and AOG support
- 717 analysis, test, and simulation
- Avionics validation/testing
- Data recording
Key Features of Flight Line Test Sets
- Signal generation and monitoring of COMM AM/FM/SSB
- Speed and position status
- Troubleshooting and fault location
- Testing in and around the aircraft
- Over-the-air, direct, or coupled testing
- Measurement of VHF/UHF/HF transmitter, frequency, output power, and modulation
- Swept localizer DDM for coupled autopilot testing
- DME ground station simulation
- UUT parametric tests
- User programmable TCAS scenarios