# FlightPhaseEstimation (UORB message) [source file](https://github.com/PX4/PX4-Autopilot/blob/main/msg/FlightPhaseEstimation.msg) ```c uint64 timestamp # time since system start (microseconds) uint8 flight_phase # Estimate of current flight phase uint8 FLIGHT_PHASE_UNKNOWN = 0 # vehicle flight phase is unknown uint8 FLIGHT_PHASE_LEVEL = 1 # Vehicle is in level flight uint8 FLIGHT_PHASE_DESCEND = 2 # vehicle is in descend uint8 FLIGHT_PHASE_CLIMB = 3 # vehicle is climbing ```