Bell’s prototype for an autonomous pod transport cargo drone suffered a failure during a recent test flight at Fort Benning, Georgia. No one was injured, although the aircraft sustained substantial damage. According to the NTSB report, a cracked ceramic capacitor in the circuitry of one of the motor controllers caused one of the four electric lift motors to fail, leading to the crash. All flight test programs have failures, but multi-motor, multirotor drone designs have different failure modes and reliability problems compared to conventional helicopters. It’s a tough challenge. Jim Anderton comments.

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