What is a key feature of duplex fuel nozzles at startup and acceleration?

A key feature of duplex fuel nozzles at startup and acceleration is that they provide a wide spray pattern. This wide spray pattern is essential for ensuring that the fuel is efficiently atomized and mixed with air as it enters the combustion chamber. During startup and acceleration, the engine requires a rich mixture to ensure smooth ignition and rapid combustion. A wider spray pattern helps achieve this by increasing the surface area of the fuel droplets, allowing for more effective mixing with air, which promotes better combustion.

In contrast, a narrow spray pattern would not provide the necessary atomization and could lead to poor combustion performance during these critical phases of engine operation. The other options, for example, suggest that the fuel nozzles could operate without fuel pressure or without using air, which is not accurate, as these components rely on proper fuel pressure and the presence of air for optimal performance.