Operating Procedure | Flying and Monitoring the Tethered ALTA X
How to Fly and Monitor the EON800 powered Alta X
Last updated
How to Fly and Monitor the EON800 powered Alta X
Last updated
The EON800 Tether System is designed to supply continuous power and communication to the ALTA X. The LCD Screen on the Tether Ground Station (TGS) monitors ALTA X MAVLink data, identifies in-flight errors, and warnings, and provides actionable guidance to the user.
Autoland Battery Failsafe is not automatically setup on the ALTA X. Please refer to the Autoland Battery Failsafe and Geofence section of this manual and the Procedures section of the Freefly Systems ALTA X Manual for more information on setting up this Freefly Systems feature.
Toggling ON the TGS High Voltage (HV) Missile-Switch will automatically trigger the Tether System Data Page on the LCD screen. At the top of the Tether System Data Page, a timer is included to display the duration of high voltage activity (flight time). Four quadrants, known as Data Cells, divide the Tether System Data Page.
Each Data Cell highlights the cell name, the data value, a bar graph, and a continuously updated exception value. The top corner of the Data Cell displays the exception value, indicating the most critical value recorded during the last 3 minutes of operation. Alternatively, the exception value in the Altitude Data Cell indicates the real-time m/s velocity change.
For Example, the Data Cells on the Tether System Data Page above (Fig.1) displays the following parameters:
Current: The APU is drawing 61.3 Amps, with the highest draw in the last 3 minutes reaching 62.9 Amps.
Voltage: The APU output voltage is 48.6V, with the lowest output voltage in the last 3 minutes being 48.0V.
Temp: The APU's current temperature is 45°C, with the highest recorded temperature in the last three minutes also at 45°C.
Altitude: The aircraft is at a height of 80m, maintaining a constant velocity of 0.0 m/s as the ALTA X hovers in place.
The Exception Value is displayed in the bar graph, with its visualisation and marking reflecting its severity. Most data shown on the Tether System Data Page is sourced from the Air Power Unit (APU).
Colour coding is used to signify the status:
GREEN denotes a value well within the system's operating range.
ORANGE indicates the value is nearing the system's operating limits.
RED signifies a value outside the operating range of the system.
The Current Data Cell displays the APU current draw in Amps. Ensure the EON800 Tether System never exceeds 100 Amps, with XM2 recommending current draw remains below 90 Amps. The APU consistently supplies the final power to the ALTA X from the tether system, also integrating the Backup Battery Function. The most critical data point is the current draw. An LCD Warning Message will alert the operator if the tether system continuously draws over 95 Amps for 3 seconds. The bar graph presents the current draw as a percentage of the maximum output (100 Amps), while the exception value shows the highest instantaneous current draw in the last 3 minutes of operation.
The Voltage Data Cell shows the APU current low-side output voltage to the aircraft. This voltage also represents the backup battery voltage. Typically, the voltage output ranges between 47.0V and 50.0V, and an LCD Warning Message is triggered if voltage drops below 46.5V for over 5 seconds. The bar graph illustrates voltage as a percentage from 40.0V to 52.0V, while the exception value displays the lowest recorded voltage over the last 3 minutes.
Excessive current draw is the primary cause for low output voltage. The TGS automatically reduces output voltage to prevent system failure.
The Temp (temperature) Data Cell reads the temperature of critical APU components. XM2 recommends maintaining an APU temperature of 10-20°C (50-68°F) above the ambient air temperature. An LCD Warning Message is triggered if the APU temperature exceeds 90°C (194°F). If the temperature goes beyond 110°C (230 °F), the APU will shut down and the EON800 Tether System will no longer be powering the aircraft.
Operating near maximum power, high outdoor temperature, and positioning against strong winds can elevate APU temperature, reducing internal heat sink airflow. If a temperature Warning Message appears on the LCD, follow the instructions on the screen. An example prompt to lower the APU temperature would be to yaw the aircraft and direct the nose of the ALTA X into the wind. The bar graph illustrates the current temperature as a percentage of the maximum advised temperature of 90°C (194°F), with the exception value indicating the highest temperature within the last 3 minutes.
The Altitude Data Cell displays the current aircraft altitude, measured from the takeoff point to the aircraft's height. Altitude value must not exceed the maximum permitted altitude based on the operator's configured tether length. The bar graph represents the current flight altitude as a percentage of the maximum allowed height for the tether system. The exception value in the Altitude Data Cell displays the real-time meters per second of velocity change.
The Simplified In-Flight Data Page displays the current flight time (HV is switched ON) and the current altitude of the Aircraft. The LCD will automatically display any Warning Messages or Critical Error Messages.
During tethered flight, the Battery Cell Data Page shows individual cell voltages, indicating backup battery health monitored by the APU's Battery Management System (BMS). The APU is equipped with a built-in BMS to monitor and manage the backup batteries. The BMS aims to control the battery's environment, balances the battery cells, and protect them from operating outside of their specifications.
The graphs on the Battery Cell Data Page illustrate the voltage of each individual cell as a percentage, ranging between 3.2V and 4.3V. If any cell falls below 3.4V or exhibits a significant voltage imbalance of 150mV, the operator will receive a Warning Message to land the aircraft. This warning indicates a potential battery cell issue. In the event of a critical error with the tether system, a significant issue with the battery cells may affect your ability to emergency and using Backup Batteries. If you receive a Warning Message about the battery cells, it's crucial to check battery health and replace them if necessary.
The Logging Data Page displays onboard log data on the SD card (FAT32 format) including: file name, current log size, available space, and total capacity. The tether system will automatically remove any old telemetry log files and make space for new ones. This eliminates the need for the user to delete files on the SD card as it fills up.
If a Warning Message appears on the LCD, follow the instructions provided. After addressing the issue, such as lowering the aircraft to reduce the load, press the middle button below the LCD for three seconds and clear the Warning Message to resume operation.
If you experience a Critical Error Message during operation, the TGS will alert you with a beeper, the LCD beacon will flash red and green, and the LCD will provide guidance on the necessary steps to take.
Autoland Battery Failsafe is not automatically setup on the ALTA X. Please refer to the Autoland Battery Failsafe and Geofence section of this manual and the Procedures section of the Freefly Systems ALTA X Manual for more information on setting up this Freefly Systems feature.
