1. Identify that the PHX is ready for a battery swap.

The PHX can perform a battery swap whenever the user feels it is an appropriate time. 

The recommended time for a battery swap is when the battery remaining is between 30% and 25%. This gives the PHX time to land and have enough power in reserve incase the landing needs to be aborted or adjusted. 

Figure 1: Fly PHX Battery Display

If the aircraft falls below 20% battery remaining it will automatically return to land. 

2. Note which waypoint the aircraft is at or tracking towards.

Best practice for multi-battery PHX flights is to maintain awareness of flight progress. Specifically, which waypoint or transect the drone is at when it departs from the flight plan to land for the battery swap. This allows the pilot to know where the drone should be returning to after the battery has been changed. This helps ensure that all the data for the field is collected and no images are missed. 

Transect 

Flight progress (red flight path lines) are not persistent. They will disappear once the aircraft is powered off. They will not reappear when the aircraft is powered back on.

Figure 2: Transect Lines

Waypoint

Enable the Mission Item Index parameter in the telemetry values box to show the current active waypoint. 

Figure 3: Waypoint Indicator

Use the RTL button on the left-hand side of the Fly screen to command the aircraft to land.

Figure 4: Return Button

Once the aircraft has detected that it has landed it will automatically disarm.

If either of the wings has come off during the landing the aircraft may not disarm itself. Use the drop-down menu at the top of the Fly screen to disarm the motor. The slider at the bottom of the screen may read EMEMERGENCY STOP. This is normal and is the same as disarming the motor. 

Figure 5: Disarm Drop Down Menu and Slider

5. Use the post flight menu to select how you want to proceed.

WARNING: If the aircraft is powered down after flight, this menu will disappear and will not reappear. Ensure these menu options are used or reviewed before removing the battery from the aircraft.  

After the aircraft is disarmed the post flight menu will appear on the right-hand side of the screen. 

Figure 6: Post Flight Menu

3. Resume mission from waypoint X.

This will update the flight plan that is currently on the aircraft so that it starts one waypoint before the last waypoint the aircraft was headed towards. It will also remove any of the previously completed waypoints and shorten the total flight plan size.

 

Figure 7: Post Flight Menu

Go to the aircrafts location and remove the discharged battery. Then recover the aircraft.

7. Disassemble the aircraft and inspect structural components.

The best practice between each PHX flight is to disassemble the aircraft and inspect for damage to the structural components and connectors.

1. Remove the wings and spar joiner from the powered down aircraft.
   
2. Perform a mechanical inspection of the spar joint to ensure there are no cracks or other damage.
   
3. Inspect the fuselage, wings, connectors, and Pitot tube for damage or debris.
   

8. Reassemble, Insert fully charged battery, and connect.

1. Reassemble the aircraft as normal and insert the fully charged battery. 
   
2. Wait for the aircraft to connect to to fly PHX.           
   

9. Verify mission. 

4. Ensure the flight plan is correct. Make any necessary adjustments as needed.
   
5. Ensure the flight plan is uploaded to the vehicle.
   
6. Ensure that the takeoff waypoint is the active waypoint. If another waypoint is the active waypoint the aircraft will not launch properly.

Figure 8: Incorrect Active Launch Waypoint

Figure 9: Correct Active Launch Waypoint