I hope the SLF on here dont get the notion that ATC only reacts to the magic Mayday x 3 call as I can assure them that the merest mention by pilots of any sort of trouble sets their mental alarm bells ringing. As for the pilots, it is probable that 99.9% of them go through their entire careers without uttering Mayday for real, so cut them some slack when the day finally arrives. In this tragedy, on the speculation so far, its looks bad for the crew. The initial report will tell us the facts of the fuel situation. It could even have involved a fuel leak, who knows right now?