Firstly, let me apologize for the lack of info and thank you for your suggestions. - I mainly use X-Plane 9 CRJ-200, but I think the same thing happens to me in XP10, I have to try it. Always starting from Cold&Dark. - I'm using fuel page on the EICAS, that displays fuel quantity to the nearest 1lb. -The taxi I did for the test is 2-3 minutes long, very short taxi. -The fuel burn in the air is normal. -That's definitely a leak, the FF and the reduction don't coincide at all. I've noticed that if i turn off gravity xflow I don't get the issue. Maybe something is interfering with CRJ's plugin, maybe another plugin? BTW, where is X-Planes MTBF option? Thanks again!