What would happen if the pilot of a modern airliner like the boeing 747-800 or Airbus A380 left the throttle at full thrust at cruise altitude for an extended period of time e.g 4 hours if the aircraft had enough fuel to reach the next destination?
1 Answer
Full take-off thrust time is limited by the engine producer: bad things like overheating and meltdowns may happen. If you mean set the thrust to maximum allowable cruise setting: nothing much would happen other than consuming a lot more fuel than when using optimum cruise setting: fly fast enough, and the drag rises a lot without icrease in lift, due to compressibility effect. So the aircraft does not need to fly higher when going faster, it only burns more fuel.