Does this mean that the suspect control rods are exempt from failure if the VSCS system is turned back on due to a NOTAR emergency?
The chances of having a NOTAR emergency are remote. The chances of having a NOTAR emergency together with a VSCS emergency at the same time are extremely unlikely, even with the current quality problems with the adapter tubes. By the way, they are adapter tubes not control rods.
If you want 100% safety, don't go flying, or cross the road, or get out of bed!
And at what exact point of the final approach with a NOTAR emergency are you supposed to select the VSCS off?
The VSCS have only a limited effect below 80 knots, with their authority dramatically reducing below that. Coanda effect is very good below 20 knots so I would split the difference and switch the VSCS off at 50 knots.
Any comments from other MD900/902 pilots would be welcome.