An unducted fan turbine engine comprising an engine core including a first airflow, and a nacelle circumscribing at least a portion of the engine core and having an exterior surface defining a second airflow. The nacelle further comprising an internal passage between the exterior surface and the engine core, the internal passage defining a third airflow. The unducted fan turbine engine further comprising a plurality of rotatable fan blades extending radially beyond the exterior surface of the nacelle, and a cowl door located in the nacelle.