Raw Data in Aviation

In order to properly manage the aircraft in various configurations, it is essential to know the required engine thrust settings.

At 5000 feet altitude and with a gross weight of 60 tons, please provide the corresponding N1 values (with reference sources) for operating the B738 under the following conditions:

• Level flight with flaps up

  
  

• Level flight with flaps 5

  
  

• Descent with gear down, flaps 15

  
  

• Descent with gear down, flaps 30.

Answer...

To operate our B738 aircraft weighing 60 tons at an altitude of 5000 feet, the required N1 settings under different conditions are as follows:

• Level flight, flaps up: 58% N1

  
  

• Level flight, flaps 5: 61% N1 (As you can see, increased drag requires higher thrust.)

  
  

• Descent, gear down, flaps 15: 51% N1

  
  

• Descent, gear down, flaps 30: 57% N1

Knowing these values is critical for two main reasons:

• In the event of a pitot-static system failure, they allow us to safely fly and control the aircraft without relying on speed indications.

  
  

• Under normal conditions, when the autopilot is disconnected, they help us quickly set the appropriate thrust to manually maintain the desired airspeed.

Note: These values are approximate and may need to be fine-tuned based on outside air temperature, atmospheric pressure, and engine performance variations.