What type of circuit breakers must aircraft circuit breakers be?

Aircraft circuit breakers must be of the trip-free type to ensure the utmost safety and reliability in flight operations. A trip-free circuit breaker is designed to automatically disconnect the electrical circuit if an overload or short circuit occurs, without the need for pilot intervention. This feature is crucial in aviation, as it helps to prevent further damage to the electrical system and potential fire hazards due to persistent overload conditions. Additionally, the trip-free design allows current to continue passing through the circuit if the breaker is manually reset while still under fault conditions, which could lead to dangerous situations.

In contrast, other types of circuit breakers may not provide the same level of safety and protection. For example, manual-reset types require deliberate action from personnel to reset after a trip, which could lead to delay or oversight in critical situations. Auto-reset types can potentially restart electrical flow automatically, which is undesirable in scenarios where faults could be present. Push-to-reset types also necessitate manual intervention but do not offer the quick protection against persistent faults as trip-free circuit breakers do. Hence, the trip-free mechanism greatly contributes to aircraft operational safety and reliability.