What is the minimum distance required between a fuel tank and the firewall separating it from the engine?

The minimum distance required between a fuel tank and the firewall separating it from the engine is one-half inch. This specification is crucial for safety and compliance with aviation regulations. The firewall serves as a barrier to prevent the spread of fire from the engine to the fuel tank in the event of an engine failure or fire, thereby reducing the risk of ignition of the fuel. The one-half inch distance allows for some insulation between the tank and the heat generated by the engine while also ensuring that structural integrity is maintained during normal operation and in adverse conditions.

While varying distances could seem adequate, one-half inch is specifically established to balance safety and practical engineering requirements. Distances shorter than this could increase the risk of heat transfer, while larger distances may not be necessary and could add unnecessary weight or complexity to the installation.