Rescue 1, Engine 1-1, Fire Police @ AREMS alerted for the MVC w/entrapment at the intersection of Chambersburg Rd & Knoxlyn Road. Upon response of Rescue 1 (5 personnel) & the Asst. Chief (Blocher), Communications reported a 2 vehicle collision involving a pick up truck pulling a trailer and a passenger car, with at least 1 injury and callers reporting an elderly male trapped. Cumberland Twp PD & a Co.4 (Cashtown) Chief Officer arrived and confirmed one trapped in the passenger car. AC-1 arrived and assumed the Chambersburg Rd Command w/R1 initiating stabilization and extrication. E1-2 arrived shortly after and provided manpower, E4-1 established a LZ nearby and Fire Police assisted with traffic control. The patient was extricated and turned over to AREMS medical care and then transferred to the awaiting Aeromedical for transport to a local trauma center. Route 30 (Chambersburg Rd) remained closed while CTPD investigated.