What may cause engine flameout above 20,000 feet due to loss of fuel pressure?

The correct answer is that engine flameout above 20,000 feet may be caused by dumping fuel. Fuel dumping is an action performed to reduce aircraft weight, often necessary for landing or due to emergency situations, and involves releasing fuel from the aircraft's tanks. This can lead to a sudden decrease in fuel pressure if the fuel is removed rapidly or if the system experiences a malfunction.

At higher altitudes, such as above 20,000 feet, the engines require a consistent and adequate fuel supply to maintain combustion and performance. If fuel pressure drops too low due to sudden dumping, this can lead to the possibility of flameout, which is when the engine loses its flame and can no longer sustain operation.

In contrast, transfer and crossfeed options typically focus on directing fuel from one tank to another or allowing engines to draw fuel from multiple tanks, which are designed to ensure consistent fuel supply and do not inherently cause pressure loss. Venting relates to the release of pressure from the fuel tanks and does not typically lead to loss of fuel pressure sufficient to cause flameout. Thus, dumping, when done rapidly or without careful management, presents a significant risk for flameout under high altitude conditions.