We tend to always believe what our fuel gauges tell us.
The concept of CRM was initiated at a large US airline years ago because of a DC-8 accident in Portland, OR. The Flight Engineer was aware of questionable accuracy with their fuel gauges and expressed his concern-but the Captain seemed unconcerned....until three or four engines flamed out over the city.
Let's hope that none of us must divert to an alternate with either (maybe) reserve fuel remaining at ETA or marginal weather and/or a non-precision approach required, even in flat terrain: NDB anyone?
Certain mountain airports near lakes or rivers can easily have unforecast fog with no alternate fuel loaded. ...glaciers in the moonlight...and fresh snow covering up ALL of the runway lights at an uncontrolled airport.
So it seems silly to plan to land with more than 45 minutes fuel onboard?
