It seems there is a question remaining on the flight controls Gust Lock.
The Gust Lock Handle was in the OFF position. Normal.
The throttles could be advanced and that indicates the Gust Lock was not engaged. Normal.
I’m uncertain what the FDR is recording; where it was getting its info that the Gust Lock was indicated ON? Abnormal.
Many pilots go forward – aft - left – right on the yoke as a matter of habit somewhere before T/O. This report says the FDR did not record a control check. What was it looking at?
If the controls were locked they would not have felt right on the TO roll, would not have “lightened up” as Vr approached. That would have alerted the pilot flying.
It had been a long day, but my conversations with corporate pilots indicate that was not unusual.
It was a night VFR takeoff on a dry runway.
No reason to expect anything unusual. The airplane worked fine on the inbound legs.
They apparently hit the brakes and reversed at about 165 kts, possibly around the 5500’ point on the 7100’ runway and stopped when they hit the ditch about 1850’ beyond the end of the runway.
Pretty skinny looking tires so braking would not appear to be really significant; but they were hard on the binders because the nose and one landing gear sheared off in the overrun. The wheels were probably not turning much due antiskid.
It takes a couple or three seconds at least for the thrust reversers to work.
They did everything they could but something appears to have been broken between the yoke and elevator.
This was a very expensive, sophisticated airplane, with primary and backup systems that had a lengthy and normal history. What went wrong?