What was found
APPROXIMATELY 8 SECONDS AFTER DROID RESTOWING AND SHORTLY AFTER CLIMBING FROM DELIVERY ALTITUDE, ONE PROPELLER CONTACTED AN OBJECT AND BRIEFLY SLOWED BEFORE RECOVERING. ABOUT 1.25 SECONDS LATER, THE SAME PROPELLER EXPERIENCED A SECOND IMPACT AND STOPPED COMPLETELY, LIKELY CAUSING THE BOOM ARM (FWD RIGHT) TO FRACTURE AND THE MOTOR ASSEMBLY TO SEPARATE FROM THE AIRCRAFT. FOLLOWING THE FAILURE, THE AIRCRAFT EXPERIENCED SIGNIFICANT PITCH AND YAW MOVEMENT DUE TO THE LOSS OF PROPULSION AND IMBALANCE FROM THE DAMAGED ROTOR SYSTEM. DATA ALSO SHOWED SUSTAINED VIBRATION AFTER THE INITIAL IMPACT, INDICATING PROPELLER DAMAGE OCCURRED BEFORE THE BOOM SEPARATED. THE AIRCRAFT CONTINUED FLIGHT WITH DEGRADED PERFORMANCE AND LATER RECOVERED SAFELY. AIRCRAFT: ZIPLINE, P2ZIP