The EEC provides N1 and N2 redline overspeed protection in which modes?

The EEC provides N1 and N2 redline overspeed protection in which modes?

• A. N1 and N2 in normal mode only
• B. N1 and N2 in alternate mode only
• C. N1 in normal and N2 in alternate
• D. N1 and N2 in both normal and alternate

Answer: (D)

N1 and N2 overspeed protection are built into the Electronic Engine Control for both normal operation and the alternate (degraded) mode. The EEC continuously monitors the speeds of both spools—N1 (low-pressure) and N2 (high-pressure)—and, if either approaches its redline, it steps in to limit fuel delivery or alter the control to keep the speeds from exceeding safe limits. This dual-mode protection is essential because even when the primary control path is unavailable or operating in alternate law, you still need safeguards to prevent mechanical damage from overspeed. Since each spool has its own redline limit, the EEC protects both N1 and N2 across normal and alternate modes.

N1 and N2 overspeed protection are built into the Electronic Engine Control for both normal operation and the alternate (degraded) mode. The EEC continuously monitors the speeds of both spools—N1 (low-pressure) and N2 (high-pressure)—and, if either approaches its redline, it steps in to limit fuel delivery or alter the control to keep the speeds from exceeding safe limits. This dual-mode protection is essential because even when the primary control path is unavailable or operating in alternate law, you still need safeguards to prevent mechanical damage from overspeed. Since each spool has its own redline limit, the EEC protects both N1 and N2 across normal and alternate modes.