What is the number of borescope ports for inspecting turbine blades and nozzles?

The correct answer is based on standard practices relating to the design and maintenance of gas turbine engines, which typically include specific requirements for inspection ports. Many turbine engine designs incorporate two borescope ports, strategically placed to facilitate thorough inspection of turbine blades and nozzles.

This dual-port setup allows technicians to gain adequate visibility into the turbine components for assessing conditions like wear, damage, and buildup of foreign materials, which is critical for maintaining engine efficiency and safety. The use of two ports balances the need for comprehensive visual access while maintaining structural integrity and minimizing the number of penetrations into the engine casing.

Having more than two ports could complicate the design and create unnecessary points of potential failure without providing significant additional benefit to inspection capability. Hence, the standard practice aligns with the correct answer, confirming the use of two ports as sufficient for effective and efficient inspections.