What is the approximate derate value for CLB1 climb thrust on the N1 LIMIT page?

• A. 5%
• B. 10%
• C. 15%
• D. 20%

Answer: (B)

Derate value on the N1 LIMIT page shows how much the engine’s maximum N1 is reduced when CLB1 climb thrust is active. This derate is about 10%, which provides a balance between having enough climb performance and protecting the engine from operating too close to its limits. If the derate were only 5%, CLB1 would feel almost like full takeoff thrust and wouldn’t show a meaningful CLB1 limit; if it were much larger, like 15% or 20%, climb performance would be noticeably slower and wouldn’t match typical CLB1 behavior. So, the approximate derate value for CLB1 climb thrust is around 10%.