SAN JOSE, Costa Rica—A DHL cargo jet slid off the runway and broke in half while landing at San Jose’s international airport Thursday, shutting down the airport, but not injuring crew. The fire department said the Boeing 757 had taken off from Juan Santamaría Airport just west of the capital, but decided to return after detecting a failure in the hydraulic system. Héctor Chaves, director the Costa Rica Fire Department, said that upon landing the aircraft skidded, turned and broke in two, exposing its cargo. “Units mobilized to remove the pilot and co-pilot,” Chaves said. “Then they applied foam to prevent a spill and now they are working on an earthen dike to avoid any fuel from reaching the drainage system.” A spokesman for cargo carrier DHL said both pilots were unharmed but one was being undergoing a medical check as a precaution. DHL spokesman Daniel McGrath said the company …