Final answer:
The wing anti-ice controller in NORM mode keeps the wing at a temperature above freezing, likely around but not necessarily exactly 0°C. The precise temperature is dependent on aircraft specifications and the system's aim is to prevent ice formation. Design considerations account for likely operating conditions and worst-case scenarios.
Step-by-step explanation:
In NORM mode, the wing anti-ice controller maintains the wing at a temperature to prevent the formation of ice. The specific temperature at which the system maintains the wing is not given in the options provided (a) -30°C, b) 0°C, c) +30°C, d) +88°C), as the actual operation temperature could vary depending on the aircraft design and specifications. Generally, the goal of the wing anti-ice system is to keep the surface above the freezing point to prevent ice accumulation, which would likely be close to, but not necessarily exactly, 0°C.
Aircraft designers often need to consider the worst-case scenarios for temperature ranges when integrating systems like anti-ice controllers, ensuring that the systems operate effectively in the coldest conditions that the aircraft is likely to encounter. For instance, if the outside temperature is -10°C, they might design the system to handle even colder temperatures to ensure consistent performance. The system's performance and design limitations, such as the coefficient of performance of refrigeration systems used in hypothetical scenarios like producing liquid nitrogen at -200°C, also influence the temperature ranges for which these systems are designed.