Flameouts have occurred in gravity-fed fuel systems as low as which altitude?

Flameouts have occurred in gravity-fed fuel systems as low as which altitude?

• A. 7,000 feet
• B. 5,000 feet
• C. 9,000 feet
• D. 11,000 feet

Answer: (A)

Gravity-fed fuel systems move fuel to the engine primarily by gravity, often without an electric pump. Because they rely on ambient pressure to keep fuel flowing, conditions that promote fuel vapor formation can interrupt that flow. At altitude, lower ambient pressure and sometimes higher fuel temperatures can cause the fuel to vaporize in the lines or tank, creating vapor pockets that block the liquid fuel from reaching the engine. When this happens, the engine loses its fuel supply and can flame out. This vulnerability can appear even at relatively low elevations; flameouts have been observed as low as seven thousand feet in gravity-fed systems, especially with long fuel lines, warm fuel, or leaks that let air enter the line. The take-away is that without an active pump to boost pressure, the system is more susceptible to vapor formation and flow interruption as altitude and conditions vary.

Gravity-fed fuel systems move fuel to the engine primarily by gravity, often without an electric pump. Because they rely on ambient pressure to keep fuel flowing, conditions that promote fuel vapor formation can interrupt that flow. At altitude, lower ambient pressure and sometimes higher fuel temperatures can cause the fuel to vaporize in the lines or tank, creating vapor pockets that block the liquid fuel from reaching the engine. When this happens, the engine loses its fuel supply and can flame out. This vulnerability can appear even at relatively low elevations; flameouts have been observed as low as seven thousand feet in gravity-fed systems, especially with long fuel lines, warm fuel, or leaks that let air enter the line. The take-away is that without an active pump to boost pressure, the system is more susceptible to vapor formation and flow interruption as altitude and conditions vary.