What is the maximum operating air temperature from 25,000 feet to 35,000 feet?

The maximum operating air temperature from 25,000 feet to 35,000 feet is indeed ISA +31°C. This limitation is critical for the King Air 350 to ensure safe performance and operation as specified by the manufacturer.

At higher altitudes, aircraft performance can be impacted by temperature variations. The International Standard Atmosphere (ISA) provides a baseline for temperature, and the addition of degrees above this baseline allows for some flexibility in operations within safe limits. The specific number of +31°C is derived from extensive testing and operational data that indicate the thermal limits of the aircraft's systems, including performance metrics such as engine efficiency and structural integrity.

Understanding this limit is essential for pilots to ensure that they do not exceed the design temperature parameters, which could result in diminished performance or potential system failures at cruise altitude. Options suggesting lower temperature limits may not capture the maximum capability of the aircraft in terms of performance and safety, leading to a more conservative operational envelope than necessary for the King Air 350.