If an uncontrollable N2 overspeed is detected, what does the Electronic Overspeed System (EOS) command the EEC to do?

If an uncontrollable N2 overspeed is detected, what does the Electronic Overspeed System (EOS) command the EEC to do?

• A. Reduce N1 speed
• B. Automatically shut off fuel to the affected engine
• C. Engage starter motor
• D. Notify captain only

Answer: (B)

When the Electronic Overspeed System detects an uncontrollable N2 overspeed, its primary protective action is to cut fuel to the affected engine. Removing the fuel source halts the runaway, preventing damage to the high‑pressure spool and turbine. The EEC then follows the EOS command to shut off fuel, rather than trying to adjust N1, engage a starter, or simply notify the captain. Fuel shutoff is the direct, protective response to an N2 overspeed, because it stops the energy driving the compressor and prevents further overspeed progression.

When the Electronic Overspeed System detects an uncontrollable N2 overspeed, its primary protective action is to cut fuel to the affected engine. Removing the fuel source halts the runaway, preventing damage to the high‑pressure spool and turbine. The EEC then follows the EOS command to shut off fuel, rather than trying to adjust N1, engage a starter, or simply notify the captain. Fuel shutoff is the direct, protective response to an N2 overspeed, because it stops the energy driving the compressor and prevents further overspeed progression.