Intermittently, one of our passenger elevators continues to bypass the bottom floor and goes straight into the pit when passengers are coming down from upper floors. It only happens about once a week and always entraps the passenger. Has any one had this problem before?

I found the issue with this one if anyone is interested. There was a bad contact on the #4 drive contactor. I assume when the car was decelerating the high current across the contactor #4 (contacts 3 & 4) would fail causing the car to lose control and end up in the pit. Also, if you have later model Superdynes those contactors are obsolete and the replacement contact kits are not available. I would recommend to anyone that has these controllers on service to pop the cover off of contactors 1, 2, 3, & 4 to check the status of the contacts. You may be close to a failure and not even know it.

Sounds about like what an old Westinghouse would do.