How can I locate my snake in an air vent?

My baby ball python Mufasa (about 15in long, 5 weeks old) escaped from his cage yesterday, and I later located him using a mirror and a flashlight coiled in the air duct. Out of desperation, my roommate tried to use a bent hanger to get him out, but only succeeded in pushing him in further. The duct drops off, and I'm very worried about his safety especially now that I can no longer see him. Does anyone know ANY way short of ripping up the floor that I could locate him, somehow see down the duct, or draw him out? Also, could turning the AC on harm him in any way? Thank you.