7 July 2022
The electric ZeroAvia Piper Malibu Mirage which crashed near Cranfield Airport last year lost electrical power to both motors when the power source was changed, according to a report just released by the Air Accident Investigation Branch (AAIB).
The modified PA-46-350P was at a point in the Cranfield circuit which meant the aircraft could not safely glide to the runway and the pilot made an off-airport forced landing. The crew were unhurt but the aircraft was severely damaged.
The AAIB said a number of factors contributed to the accident including “ad hoc changes being made to the flight test plan” without the knowledge of the competent person in charge of the tests under E Conditions.
The AAIB went on to say, “The competent person’s involvement was restricted in a number of areas due to issues within the organisational relationships, the fast tempo of the project, other work commitments and restrictions from the COVID-19 pandemic.
“The operator’s chief executive and the flight test director took on the day-to-day management responsibility for much of the programme. However neither individual had the necessary safety and flight test experience for that role and their focus was primarily on meeting key project targets.”
The loss of power occurred during an interruption of the power supply when, as part of the test procedure, the battery was selected to OFF with the intention of leaving the electrical motors solely powered by the hydrogen fuel cell.
During this interruption, the windmilling propeller on the aircraft generated voltage that was high enough to operate the inverter protection system. This then locked out the power to the motors and the pilot and observer were unable to reset the system and restore electrical power.
Download the full AAIB report here
