FAA Powerplant Written Practice Test

What is generally considered ground boosted engine manifold pressure?

1. 10" Hg

2. 20" Hg

3. 30" Hg

4. 40" Hg

The correct answer is: 30" Hg

Ground boosted engine manifold pressure is generally considered to be around 30 inches of mercury (Hg). This measurement refers to the pressure relative to atmospheric pressure that the engine's intake manifold can achieve when the engine is at full power on the ground, usually during takeoff or when tested in a static condition. At this pressure level, it indicates that the engine is providing maximum performance due to the increased air density and pressure from the throttle being fully open. This is significant for turbocharged or supercharged engines that can create higher manifold pressures than naturally aspirated engines, allowing for greater power output. Understanding this concept is essential for pilots and mechanics alike, as it impacts performance calculations and engine tuning. The other values listed do not align with the typical parameters for ground boosted manifold pressure for most engines, particularly those designed for high performance in aviation applications.