How many stages are in the high pressure turbine?

• A. 1
• B. 2
• C. 3
• D. 4

Answer: (B)

The number of stages in the high pressure turbine is about how many blade rows extract energy from the hot gases to drive the high pressure compressor on the same shaft. In most aircraft engines used for practice questions, the high pressure turbine has two stages. The first stage provides most of the power to drive the high pressure compressor, while the second stage picks up the remaining energy and helps keep turbine inlet temperatures within material limits. Having fewer than two would not supply enough power to the HP compressor, while adding more stages typically adds weight and complexity without proportionate gains. So, two stages is the standard, making it the best answer.