Dual Loss of Navigation Systems and Link
INDICATIONS
Warning Message: “Failsafe Enabled: No Global Position” (AMC), or
Warning Message: “Failsafe Enabled: No Local Position” (AMC)
Warning Message: “PRISMSKYXXX: Total Loss of GPS” (Uncrew)
Simultaneously occurring with GCS Message “Loss of Comms” or aircraft generally unable to be commanded.
Stale Telemetry, aircraft position no longer updating on GCS display
POSSIBLE CAUSES
Electromagnetic interference
Cell tower failure
Hardware failure
Signal degradation
FAILSAFE BEHAVIOR
When there is Loss of GPS and Loss of Link simultaneously, the aircraft autopilot will command the aircraft to immediately land. The aircraft, due to the Loss of GPS condition, will be unable to maintain its current lateral position and will drift while landing. The lateral velocity of the aircraft will increase as windspeed increases. Upon landing, the aircraft will disarm.
In the event that the aircraft collides with an obstacle or obstacles during its descent, the parachute recovery system will activate if the parachute maneuvering limitations are exceeded.
PROCEDURE
EMERGENCY GPS AND LINK LOSS ANNOUNCE
The RPIC is to announce the voice comms “GPS and Link Loss” once emergency conditions are identified using the indications information above.
If Uncrew Link Not Re-established After 15 Seconds:
Record last known location — NOTE B.A.T.H.S.
The RPIC shall note the last known battery percentage, altitude, current time, heading, and speed of the aircraft using the RPIC Control Station. This shall help with the recovery of the aircraft.
AIRCRAFT — SEARCH, RECOVER
The RPIC and/or available crew member(s) will search and recover the aircraft.
If Uncrew Link Re-established:
GPS Status Indicator INSPECT
Inspect the GPS Status Indicator within the Uncrew Mission Console on the RPIC Control Station. A full GPS lock is achieved when the system is connected to 20 or more satellites.
If GPS Indicator Displays Full Connection:
Uncrew: Return to Home SELECT
Select the Return to Home Button on the Uncrew Mission Console on the RPIC Control Station.
Once the button is selected, a popup window appears requiring RPIC confirmation. This window will remain displayed until “CONFIRM” is selected or exit (“x”) is pressed.
Once the command is confirmed, the aircraft will stop performing the mission and begin navigating to the takeoff location. The aircraft will maintain its altitude at the defined desired altitude. Uncrew will navigate the aircraft so that all NFAs and perimeters are avoided. The Aircraft Status shall be Contingency.
At the takeoff location, the aircraft will land. Precision landing mode shall be automatically attempted during the landing sequence.