Forgive my ignorance but may I ask if the engine flamed out on departure, in the absence of visual indications of a fuel leak from adjacent windows in the cabin or perhaps smelling the vapour then how does one diagnose this as the cause of the failure? I imagine after departure the crew follows the OEI profile then when they look at the fuel distribution after cleaning up it would probably be greater on the side of the failed engine since the good one has probably consumed c250kg in 5 mins taken to complete this, assuming a minimal imbalance prior to departure. Are you then looking for a decreasing quantity or a positive fuel flow indication on the failed side to show there is a "demand" for fuel with the engine failed but the valves still open due to the start lever being in the idle detent?