🔍 Key Concepts

• How gas turbine compressor stages are arranged around the casing • The legend in the lower left that explains symbols for borescope inspection ports, thermocouple ports, and pressure probe ports • Where fuel nozzles and thermocouples are normally located in a gas turbine (combustor vs turbine discharge)

💭 Think About

• Look closely at the circular diagram labeled Typical Compression Stage (14–29) and note which symbol is repeated around that circle • Compare the symbols used at locations 10 and 13 with those used at 14–29; what type of port is common to all of them? • Think about whether fuel nozzles or bell mouth strut cones would typically be spaced evenly around each compressor stage casing

✅ Before You Answer

• Verify which symbol in the legend (open circle, solid square, triangle) appears at positions 14–29 • Confirm from the legend what kind of port that repeated symbol represents • Make sure your choice matches a feature that would logically appear at each compressor stage around the casing, not just at one or two special locations