Low level geo survey so max height normally 250ft, max speed is 150Kts allowed so normally around 130-140 Kts is good.
A repowered FU-24 with a PT6-11 or -21 would be OK but costs to convert??.
Can you run these Turbines on a 150-300Hr maintanence program like the PAC750?.
Vans in the USA at the mo around $800-Mil so not bad really and better resale and versatility if survey goes quiet.
Anyway Im thinkin the C210T is maybe a no go?.