Why is it important for bleed air temperature not to exceed design limits?

The importance of keeping bleed air temperature within design limits primarily revolves around preventing damage to aircraft components. Excessively high temperatures can lead to thermal stresses that can compromise the integrity of materials used in various systems. For instance, components such as valves, ducts, and other parts that rely on bleed air for their operation may be made from materials that have specific thermal tolerance levels. If the bleed air temperature exceeds these limits, it can result in warping, melting, or other catastrophic failures that could affect the aircraft's performance and safety.

While factors like engine overheating, safe cabin conditions, and system efficiency are relevant in the broader context of aircraft operation, they do not address the immediate risk of component damage that can occur due to excessive temperatures in the bleed air system. Maintaining temperature within design limits is thus crucial for ensuring the long-term stability and reliability of aircraft systems.