FAA Powerplant Written Practice Test

To what altitude does a turbocharged engine maintain sea level pressure?

1. Critical altitude

2. 50,000 feet

3. 15,000 feet

4. 30,000 feet

The correct answer is: Critical altitude

The critical altitude of a turbocharged engine refers to the maximum altitude at which the engine can produce sea level manifold pressure. At this altitude, the turbocharger is capable of compensating for the decrease in atmospheric pressure due to the increase in altitude, effectively maintaining the engine's performance as if it were operating at sea level. This concept is crucial for pilots and engineers because it helps in understanding the capabilities of turbocharged engines during flight. Turbocharged engines are equipped with a mechanism that forces more air into the engine, which counteracts the effects of thinning air at higher altitudes. The critical altitude varies based on the specific engine design and the efficiency of its turbocharging system, meaning that different engines may have different critical altitudes. The alternative choices reflect various altitudes, but they do not correspond to the characteristic of turbocharged engines maintaining sea level pressure. Only the critical altitude directly addresses the performance standard of keeping sea level pressure in the context of a turbocharged engine's operation. Understanding this altitude is essential for pilots operating at high elevations to ensure proper performance and engine efficiency.