Which statement about pressure-type carburetors is true?

Which statement about pressure-type carburetors is true?

• A. The fuel chambers remain filled under all operating conditions
• B. They require a heater to prevent icing
• C. They are unaffected by environmental conditions
• D. They rely on gravity feed to move fuel

Answer: (C)

In a pressure-type carburetor, fuel is kept at a controlled pressure by the fuel pump, and the amount that flows into the airstream is driven by the air flow through the venturi and the fixed pressure difference across the metering jets. Because the fuel supply is pressurized and the metering responds primarily to the air flow, the device behaves in a way that’s largely independent of changing ambient conditions within normal operating ranges. This makes the fuel delivery reliably match the engine’s air demand even as altitude or temperature changes, which is why it’s described as being unaffected by environmental conditions. The other statements don’t fit this concept: gravity feed is not how pressure-type carburetors operate, since fuel delivery isn’t dependent on aircraft attitude; icing can still be a concern in carbureted systems and typically requires proper engine-induction management rather than a blanket statement about needing a heater; and the idea that fuel chambers remain filled under all operating conditions isn’t a guaranteed rule for these systems.

In a pressure-type carburetor, fuel is kept at a controlled pressure by the fuel pump, and the amount that flows into the airstream is driven by the air flow through the venturi and the fixed pressure difference across the metering jets. Because the fuel supply is pressurized and the metering responds primarily to the air flow, the device behaves in a way that’s largely independent of changing ambient conditions within normal operating ranges. This makes the fuel delivery reliably match the engine’s air demand even as altitude or temperature changes, which is why it’s described as being unaffected by environmental conditions.

The other statements don’t fit this concept: gravity feed is not how pressure-type carburetors operate, since fuel delivery isn’t dependent on aircraft attitude; icing can still be a concern in carbureted systems and typically requires proper engine-induction management rather than a blanket statement about needing a heater; and the idea that fuel chambers remain filled under all operating conditions isn’t a guaranteed rule for these systems.