Originally Posted by
scavenger
If the gauges are not reliable, the aircraft is unairworthy. Write them up and get them fixed, whether or not the aircraft is 'light'.
While I applaud the sentiment it's not necessarily correct. The MEL for many aircraft may not include operating gauges, particularly if alternative methods of calculating the fuel quantities are available.
One of the more well known is Air Canada 143, aka the Gimli Glider. As I recall this new 767 had a fault with all of the fuel gauges but was still able to operate if the fuel quantities were calculated as sufficient for the proposed flight. While in this instance the ensuing miscalculations resulted in a major incident the point first of all is that 'light' or not, gauges are not necessarily required, nor are they infallible.
This is why I return to my earlier comment - dipping the tanks prior to a flight, particularly of any duration, is a no-brainer. It costs a couple of minutes of time perhaps, but could save an awful lot of grief. And if there's
any lingering question, do it
en route if/when you land - something else that could be taken from this report if you'd care to, the data is there...
FP.