Which statement is true about the warm-up N1 limit?

Which statement is true about the warm-up N1 limit?

• A. Do not exceed 75% N1 for 2 minutes until gauges are normal
• B. Maintain N1 at 50% for 5 minutes
• C. Keep N1 above 85% until engines stabilize
• D. There is no N1 limit during warm-up

Answer: (A)

During warm-up after start, the engine needs to come up to normal operation gradually without stressing cold components. The correct practice is to keep N1 below a ceiling—75%—for about two minutes, or until the engine gauges indicate normal ranges (oil pressure, EGT, etc.). This window protects the engine during start-up, helps establish proper lubrication, and confirms the engine is stabilizing before you advance toward normal operating speeds. Once those gauges are in the normal range, you can continue warming up and move toward normal N1 settings. The other statements don’t match standard warm-up procedures: holding at 50% for five minutes isn’t the prescribed limit, keeping N1 above 85% during warm-up is excessive, and there is indeed a defined limit during warm-up.

During warm-up after start, the engine needs to come up to normal operation gradually without stressing cold components. The correct practice is to keep N1 below a ceiling—75%—for about two minutes, or until the engine gauges indicate normal ranges (oil pressure, EGT, etc.). This window protects the engine during start-up, helps establish proper lubrication, and confirms the engine is stabilizing before you advance toward normal operating speeds. Once those gauges are in the normal range, you can continue warming up and move toward normal N1 settings. The other statements don’t match standard warm-up procedures: holding at 50% for five minutes isn’t the prescribed limit, keeping N1 above 85% during warm-up is excessive, and there is indeed a defined limit during warm-up.