A B757-200 IS MANDATED TO RETURN LAND AT ORD WHEN THE TWO OUTER LAYERS OF A PAX WINDOW WERE NOTED TO BE DEFORMED AND POSSIBLY PEELING AWAY FROM THE ACFT. THE DAMAGE WAS ALLEGED TO HAVE BEEN CAUSED BY THE POSITIONING AND USE OF A NEW TYPE GND PWR UNIT THAT HAS BEEN EMPLOYED BY THE AIRLINE.

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FA CALLED APPROX 8-10 MINS AFTER TKOF ON FLT FROM ORD- CLE. HE INFORMED US THAT COCKPIT JUMPSEATER (AIRLINE PLT) SITTING ON ACFT'S R SIDE RPTED OUTER WINDOW PANE HAD COME LOOSE AND WAS PEELING AWAY. I WENT TO CABIN TO INSPECT AND VERIFIED 2 OUTER WINDOW PANES WERE PULLING AWAY. FEARING INNER PANE FAILURE; HAD FA'S MOVE PAX SEVERAL ROWS AWAY AND ADVISED CAPT TO DESCEND; REDUCE SPD AND RETURN TO ORD. IT SHOULD BE MENTIONED THAT APU FAILURE AT GATE BEFORE DEP NECESSITATED USE OF GND AIRCART FOR ENG START. THIS WAS A NEW TYPE WHICH IS TURBINE PWRED; IE; HIGH EXHAUST TEMP. IT WAS POSITIONED ON R SIDE OF ACFT BELOW THE TWO WINDOWS WHICH DEFORMED. IT OPERATED THERE FOR 15-20 MINS; AND IT SHOULD BE NOTED ACFT WAS DOWNWIND FROM EXHAUST. WHEN I FIRST SAW THE WINDOWS MY FIRST IMPRESSION WAS THAT THEY WERE MELTING AS THEY WERE DEFORMED AND CURLED AT THE EDGES. IT IS MY THEORY THE HOT EXHAUST FROM THE GND AIR CART HEATED THE WINDOWS AND AIRFRAME CAUSING THE WINDOWS TO DEFORM AND ALMOST PEEL OFF AIRFRAME. THESE NEW AIR CARTS WITH THEIR HIGH EXHAUST TEMPERATURES NEED TO BE POSITIONED FURTHER AWAY FROM THE ACFT AND IF POSSIBLE; DOWNWIND. THIS MAY NECESSITATE A LONGER HOSE FOR AIRPLANE CONNECTION. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR RECEIVED A CALL FROM THE SAFETY DEPARTMENT AND RPTED THAT THERE WERE MEETINGS AND A TELEPHONE CONFERENCE BETWEEN OPERATIONS; MAINT AND QUALITY ASSURANCE PERSONNEL. RPTR STATED THAT THE 'COMPANY IS ON TOP OF THIS.' THE UNITS WERE MADE IN GERMANY; MANUFACTURER'S NAME AND TYPE UNKNOWN TO RPTR; HAVE BEEN TAKEN OUT SERVICE UNTIL A FIX CAN BE MADE. THE 'FIX' WOULD BE GND CREW TRAINING ON PLACEMENT; LONGER HOSES AND DEFLECTORS ADDED TO PREVENT THE EXHAUST FROM HITTING THE ACFT. THE AIRLINE IS COORDINATING WITH THE MANUFACTURER REGARDING CHANGES REQUIRED. THESE UNITS; THREE OF THEM; ARE AT DEN AND ORD AND ARE USED FOR ANY TYPE ACFT. RPTR HASN'T HEARD OF ANY OTHER INCIDENTS SUCH AS THIS ONE. THE AIRLINE IS GOING TO PUBLISH A RPT ON THIS INCIDENT IN THEIR SAFETY MAGAZINE.