What feature is specifically required in a Class B baggage compartment?

In a Class B baggage compartment, the specific requirement is the inclusion of a fire warning system. The need for this feature arises from the potential fire hazards associated with the storage of baggage, which may contain flammable materials. The presence of a fire warning system is crucial as it enhances safety measures by providing an early warning in the event of a fire, allowing for prompt action to mitigate risks.

While other features may be beneficial or standard in different contexts, they are not mandated for a Class B baggage compartment. A separate access door is not a specific requirement, as compartments can be accessed via other means. An external cooling system may be useful but is not explicitly necessary for safety regulations concerning baggage compartments. Increased baggage capacity is not a safety feature and does not address the risks associated with fire, making it irrelevant in this context. Thus, the fire warning system is critical for ensuring the safety of the aircraft and its occupants.