Large UAS; Fixed Wing
Flight Crew Remote Pilot (UAS); Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Commercial; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days (UAS) 90; Flight Crew Total 3975; Flight Crew Total (UAS) 400; Flight Crew Type (UAS) 150
Human-Machine Interface; Confusion; Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Overrode Automation
Aircraft; Human Factors; Software and Automation
While operating on a preprogramed mission mode at FL 220 and 136 IAS; I uploaded a new mission to adjust our profile for clouds ahead. The new mission was a new altitude of FL 200 and an airspeed of 105 IAS. After the mission was updated; the UAS pitched up to slow down before commencing a descent to the new altitude. Normally at this speed; altitude has priority over airspeed. I was expecting the UAS to descend first while slowing down. I took control of the UAS and quickly initiated a decent to FL 200. Later in the flight; We tried to duplicate the issue. However; we were unsuccessful. The discrepancy was noted and is currently being reviewed by engineering. In the future; I will verify the autopilot preference mode first before initiating a descent or climb regardless of the current IAS. I will also upload one change to the mission at a time and upload the other after the completion of the first.
UAS pilot reported that while the UAS was in cruise flight being flown by the autopilot the flight crew made changes to the flight profile; resulting in an undesirable aircraft state. The pilot saw the error and made a manual correction before there was a loss of aircraft control.