Which statement describes the low-pressure turbine in the JT15D engine?

Which statement describes the low-pressure turbine in the JT15D engine?

• A. It has four stages
• B. It has two stages
• C. It has one stage
• D. It has three stages

Answer: (B)

Two stages on the low‑pressure turbine. In the JT15D, the low‑pressure turbine is designed to extract the right amount of energy to drive the low‑pressure compressor and any associated spool loads across the full operating range. A two‑stage arrangement provides enough energy extraction for the LP spool while keeping the engine compact and efficient; fewer stages wouldn’t supply enough power at high throttle, and more stages would add unnecessary weight and complexity. This two‑stage configuration is typical for a small two‑spool turbofan like the JT15D.

Two stages on the low‑pressure turbine. In the JT15D, the low‑pressure turbine is designed to extract the right amount of energy to drive the low‑pressure compressor and any associated spool loads across the full operating range. A two‑stage arrangement provides enough energy extraction for the LP spool while keeping the engine compact and efficient; fewer stages wouldn’t supply enough power at high throttle, and more stages would add unnecessary weight and complexity. This two‑stage configuration is typical for a small two‑spool turbofan like the JT15D.