[cpdiii]

As an Instrument pilot on an IFR flight plan, you’re mandated by FAR 91.167 to take off with enough fuel to fly to your destination, fly to an alternate airport, and then fly for an additional 45 minutes at cruising speed. The FAA is quite specific in its requirement.

91.151 Fuel requirements for flight in VFR conditions. (a) No person may begin a flight in an airplane under VFR conditions unless (considering wind and forecast weather conditions) there is enough fuel to fly to the first point of intended landing and, assuming normal cruising speed - (1) During the day, to fly after that for at least 30 minutes; or

(2) At night, to fly after that for at least 45 minutes.

Commercial Aircraft fly IFR (Instrument Flight Rules) they do not fly VFR (Visual Flight Rules)

I assure before I die my last commercial flight will be burning Jet-A

[SkyDancer]

They’ll simply change the rules; it’s what they do. Your electrical meter showing how much amperage or whatever must be enough to take you to your alternate and then be able to mumble about for an additional 45 mins.