The crew of a CHI Aviation helicopter replaced a damaged JEA transformer with a new one Sunday to supply electricity to the Riverwalk Townhomes at the Plaza downtown. The CHI Aviation pilot deftly maneuvered the Sikorsky S61N heavy-lift helicopter ferrying an electrical transformer weighing slightly more than 7,000 pounds at the end of steel cable attached to the aircraft's belly from its staging area at the Shipyards, then out over the St. Johns River and back to shore where he gently lowered his cargo into place without even the slightest "thud."