The nš 1 tank, in all previous Boeing airplanes,
- I take it from that you don't have an answer? I cannot find one, but normally 'historic' decisions have some reasoning behind them.
Aside from which, I believe that with the increased range and altitudes nowadays, Flight Detent's system should be mandatory on all applicable new aircraft. Yes, even the 737 NG - 7 hours at 410 is enough!