Why are pneumatic starters preferred for most large turbine engines?

Pneumatic starters are favored for large turbine engines primarily due to their ability to provide high power output while being efficient in terms of weight and size. Using compressed air allows these starters to deliver the necessary torque needed to crank an engine effectively, and they are often lighter than electric or hydraulic starters, making them particularly advantageous in aviation where weight is a critical factor.

In terms of performance, pneumatic starters can initiate engine operation without the necessity of complex electricity supply systems, which can add extra weight and complicate the design. This simplicity and efficiency contribute to their preferred status in the context of large turbine engines. Additionally, the capability to use the aircraft's pneumatic systems means they can effectively leverage existing infrastructure without heavy modifications.

While the other options touch upon aspects like reliability, cost, and maintenance, the balance of weight and the effective application of pneumatic power play a more significant role in their preference for large turbine engines. This understanding is crucial for flight engineers in optimizing engine start procedures and ensuring operational efficiency.