Why is overheat protection necessary for anti-ice systems that utilize turbine engine bleed air?

Overheat protection is crucial for anti-ice systems that utilize turbine engine bleed air primarily because the high-temperature air can potentially cause structural damage to the aircraft. Engine bleed air is typically very hot, and if it is not properly regulated, it can lead to overheating of the anti-ice components, which include ducts, valves, and the surfaces that require protection. Excessive temperatures can weaken materials, cause deformations, or even result in failures, which could compromise the aircraft's safety and performance.

Maintaining the integrity of the aircraft's structure is vital, especially in critical systems like anti-ice. Thus, implementing overheat protection mechanisms ensures that the temperature stays within safe limits, preventing damage and ensuring reliable operation of the anti-icing function. This protection is an essential part of the design of these systems, as it safeguards both the components involved and the overall safety of the flight.