Sent chief engineer for the product line to inspect unit in field, found that the accident site condition had been compromised since the original accident condition.Discovery showed that the safety system had been bypassed allowing the lift to run.Backup failure caused the unit to drop.Based on discussions at site with dealer, suspect this bypass of safety system occurred when dealer serviced the unit in april 2017 (10 months before the accident).After locking out the equipment, access to the safety circuit is only gained by using tools to remove large tower access panels.Then the drive nut safety circuitry was bypassed with a harness.Maintenance of the equipment and the circuitry is gone over in detail during required dealer training.The ability to bypass the drive safety circuitry is required in the event of failure to allow first responders to use the safety nut for a one way trip safely lower the platform to lower landing and then "lock out" system until parts can be replaced.
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