Only cuz seems fule consumption for stock not tweaked. Mk1 jet fuel tank have 150 fuel units on stock. And basic JE with this mod eat 1.5 unts per second without afterburner and 2-3 (mb 4) times more with afterburner. It cause that you out of fuel in average of ~2 minutes. I dunno real planes, which cant fly more than 2 minutes. Yes, i can understand that afterburner is very expensive, but loosing whole fuel in a single minute... sorry, it's ridiculous. Although, overall principels of engines work much, much better than stock.