Primary finding
Probable cause
The operator’s failure to maintain separation between two drones during dual simulated engine out recoveries, which resulted in a midair collision.
Investigator assessment
Analysis narrative
The operator of the unmanned aircraft system (UAS) reported that during a test flight, N213PA was intentionally faulted by the UAS operator to simulate a “motor out recovery” and diverted to an alternate landing pad as the system was designed to do. The same fault was applied to N282PA as it was departing, which then diverted the UAS to the same alternate landing pad and into the flight path of N213PA, resulting in a mid-air collision. Both UAS sustained substantial damage throughout. The operator reported that there were no preaccident mechanical failures or malfunctions with either UAS that would have precluded normal operation.