AeroTrain Corp.
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Aircraft Navigation Systems Trainer Model AT-09

The Model AT-09 Aircraft Navigation Systems Trainer consists of fully functional aircraft navigational equipment used in a typical general aviation aircraft. The trainer includes secondary radar equipment (Distance Measuring Equipment (DME) and Transponder), and radio navigation equipment (VOR, LOC,GS, MB, and ADF). The Model AT-09 may be upgraded with the optional feature to include satellite navigation(GPS). The trainer is a realistic mock-up of aircraft navigational systems with functions and capabilities that facilitate the following aspects of hands-on training:

  • Conduct practical training for flight line tasks like physical removal, installation, operation, and maintenance testing by using ramp tester.
  • Perform diagnostic testing as done in an avionics maintenance shop, using real time navigation transmission and reception with a DME/Transponder bench test set.
  • Test the equipment using simulated navigation/flight data in compliance with standard technical procedures.

The emphasis in Model AT-09 design is to allow the students gain hands-on experience.

Secondary Radar Training:

The DME and Transponder are the secondary radars used for navigation and identification. The Model AT-09 contains both equipment.

Distance Measuring Equipment (DME):

The panel-mounted DME has digital readout which displays aircraft’s distance to the selected ground station, groundspeed, and time-to-station. The 200-channel receiver can be either digitally channeled through NAV receiver or can be tuned directly with frequency control knobs. The DME uses a single crystal digital frequency synthesizer.

Mode A and C Transponder:

A panel-mounted mode A and C transponder is installed in the trainer. Also included is a Digital Encoder. The transponder has digital display which shows the Mode A codes and Mode C altitude. The transponder operates on 28V DC power, and has backlit bezel for easy reading of the panel nomenclature and knobs. The digital encoder can convert simulated static pressure input representing altitudes from -1,000 feet to 35,000 feet with the accuracy within +/-20 feet. The encoder is a generic encoder that will work with all aircraft transponders.

Students’ Lab-sheet for DME:

The Model AT-09 is supplied with a comprehensive lab-sheet for the students to perform tasks typical to DME testing and maintenance in real aircraft.

Students’ Lab-sheet for Transponder:

The Model AT-09 is supplied with a comprehensive lab-sheet for the students to perform tasks typical to Transponder testing and maintenance in real aircraft.

DME Testing:

The panel-mounted test set is capable of testing and calibrating DME, Transponder, and ARINC568 Digital DME Indicators. The test set can perform several tasks, such as:

  • Measuring DME Transmitter Frequency and Power
  • Measuring Transmitter Pulse Characteristics
  • Measuring Receiver Memory Time
  • Measuring Receiver Bandwidth and Sensitivity
  • Measuring Pulse Position Decoder Accuracy
  • Adjacent Channel Test
  • Measuring Accuracy and Tracking
  • Measuring Acquisition Time
  • Measuring Echo and Co-Channel Performance
  • Testing ARINC 568 Digital DME Indicators
  • Provision of a -1 nm Range delay, if selected
  • Generating DME serial data stream

Transponder Testing:

The test set can be used to perform several testing and maintenance tasks, such as:

  • Measuring Receiver Bandwidth and Minimum Threshold Level (MTL)
  • Measuring Side Lobe Suppression (SLS)
  • Measuring Pulse Deviation
  • Verification of Interrogator Recovery Time
  • Pulse Width Decoder Operation
  • Measuring Frequency and Power Output
  • Measuring Pulse Shape and Width, Transmitter Droop and Frequency Pulling
  • Measuring Transmitter Power (digital display)
  • Measuring Identification and Altitude Codes
  • Measuring Identification and Altitude Codes
  • Testing ARINC 572 Transponder (local or remote mode)
  • Selecting variable or calibrated pulse spacing for P2 and P3 pulses in the plus or minus directions
  • Selecting variable or calibrated pulse width from 0.2 μs to 1.85 μs in 0.05 μs steps
  • Selecting side lobe suppression (SLS)
  • Suppression Recovery through Interference and DBL Interrogation function

Aircraft Radio Navigation System:

The Model AT-09 is equipped with radio navigation receivers comprising:

  • VHF Omnidirectional Range (VOR)
  • Instruments Landing System (ILS), that includes Localizer (LOC), and Glide-slope (GS)
  • Marker Beacon (MB)
  • Automatic Direction Finder (ADF)

The Aircraft Radio Navigational System is installed on a mobile test stand with a work bench-top, moveable lockable caster wheels. A ramp tester is used for the simulation of radio navigation signals. An ADF simulator is used to provide a radio bearing. The system requires mains voltage (either 110V/60 Hz or 230V at 50/60Hz; all other voltages required for equipment operation are internally generated. The radio navigation system is equipped with standard general aviation, panel-mounted receivers, antennas, and indicators which include:

  • One navigation receiver with GS
  • One NAV indicator for VOR/LOC, and GS display
  • One MB receiver with outer, middle, and inner marker indicators
  • One ADF receiver
  • One ADF indicator
  • One splitter for VOR/LOC and GS signals
  • One NAV antenna
  • One ADF antenna
  • One MB antenna

Radio Navigation System Testing:

The radio navigation system testing is accomplished by using a ramp tester and an ADF simulator to perform testing and maintenance tasks which are realistic representation of the real aircraft experience. The tasks include:

  • Testing of navigation receiver for various simulated VOR bearings
  • Testing of VOR indicator
  • Testing of TO/FROM flags
  • Testing of NAV/GS warning flags
  • Testing of navigation receiver for various simulated LOC deviations
  • Testing of LOC deviation indicator
  • Testing of navigation receiver for various simulated GS deviations
  • Testing of GS deviation indicator
  • Testing of MB receiver for outer, middle, and inner marker reception and indication
  • Testing of ADF receiver
  • Testing of ADF indicator

Troubleshooting Training:

The model AT-09 is equipped with fault simulation panel that can be used by instructors to induce one or multiple faults, to train students in troubleshooting methodology. The fault panel includes 15 fault insertion switches that cover:

  • DME channeling, antenna, and power failure faults (4 faults)
  • Transponder altitude, antenna, and power failure faults (4 faults)
  • Radio navigation faults (7 faults)

Upgrade with GPS
The Model AT-09 is upgradeable with the inclusion of a GPS navigation display.

Computer Based Training (CBT):

The model AT-09 is supplied with a CBT package. The CBT package allows up to 30 perpetual licenses without any license renewal fees. The following CBT titles are provided and installed on the computer:

  • Primary and Secondary Radar Systems
  • Distance Measuring Equipment (DME)
  • Aircraft Transponder System
  • VHF Omnidirectional Range (VOR)
  • Instruments Landing System (ILS)
  • Automatic Direction Finder (ADF)


The Model AT-09 is supplied with:

  • Student lab-sheets for DME, Transponder, and Navigation System
  • Instructor’s Manual (describing learning objectives for each simulated fault and its description)
  • Training Manual (describing theory, system block diagrams, and operating instructions)
  • Wiring Diagrams (soft and hard copies)


The Model AT-09 has been designed with students’ safety in mind. The wiring and warning signage is in accordance with standard practices prevalent in the aerospace industry.