What is the requirement for inboard engines regarding blowers?

All inboard engines must have a built-in blower to ensure safety by removing potentially harmful fumes or vapors from the engine compartment. This requirement is crucial because inboard engines can accumulate fuel vapors, which may pose a fire hazard if not properly ventilated. The blower helps to maintain safe air quality in the engine space, especially before starting the engine.

The rationale stems from safety regulations that mandate having a blower as a standard feature, mitigating risks associated with fuel vapors. Options suggesting that only some engines or those over a certain size require blowers do not align with these essential safety standards.