What is the maximum allowable temperature for takeoff from sea level?

The maximum allowable temperature for takeoff from sea level being ISA + 35°C is based on the aircraft's performance limitations. As temperatures increase beyond the standard temperature (ISA), the performance of the aircraft generally decreases. This means that as temperature rises, the engine's thrust, lift generated by the wings, and overall performance can diminish, which can impact safety and flight capabilities.

In the case of the CRJ 200, the limitation set to ISA + 35°C provides a buffer to ensure that the aircraft can achieve necessary performance metrics such as adequate climb rate and takeoff speed under normal operating conditions. The choice of ISA + 35°C reflects industry standards and ensures that safety margins are maintained during takeoff operations, particularly at sea level where higher temperatures can have more pronounced effects on aircraft performance.

Setting the maximum allowable temperature at ISA + 25°C, 30°C, or 40°C would not adequately account for performance degradation in higher temperatures, affecting the aircraft's operational envelope. Therefore, the value of ISA + 35°C strikes a balance for safety and performance, ensuring that the CRJ 200 can operate effectively even under warmer conditions at sea level.