The downside is that any wayward ty-wrap, lost split pin or lock wire that is misplaced on the XMSN deck will go through the engine.
Not quite correct. There is still a screen in front of the engine inlet, to prevent objects being ingested . On the otherhand, the airstream often changes direction, so that heavier objects will bypass the engine. They will leave the duct through the opening at the aft end of the dog house
skadi