What is the transient engine oil temperature limit when N1 is at 61 +/- 1%?

• A. 120 °C
• B. 125 °C
• C. 127 °C
• D. 130 °C

Answer: (C)

The transient engine oil temperature limit when N1 is at 61 +/- 1% is established to ensure the safe operation of the engine and to help prevent damage caused by excessive temperatures. According to the NATOPS guidelines, the limit specifically allows a transient maximum temperature of 127 °C during this specific engine condition.

When an engine operates within the transient range, it is permissible for certain parameters, like oil temperature, to exceed normal operating limits for a brief period. This transient tolerance is designed to accommodate normal variations encountered during operation, such as changes in power settings or engine response to different flight maneuvers.

For N1 speeds at 61 +/- 1%, it is critical to adhere to the 127 °C limit to ensure the engine remains within a safe temperature threshold that protects its components and maintains performance integrity during transitory phases. Exceeding this limit could lead to severe engine wear or failure if sustained, making the understanding of these parameters crucial for the safety and efficacy of operations.