ETOPS
I was down at EOG in '96 so didn't partake in that trial, but was on the B737-436 from introduction until 1995 and remember using the RTA function for DANDI timings over the North Sea to/from Scandinavia. Worked well, but screwed other aircraft on the same routes who suddenly found a B737 flying anywhere between M0.68 and M0.76!
RTA's are a crude tool, at best.