context: -LRB- CNN -RRB- -- Three members of a U.S. Navy helicopter crew were killed after their helicopter went down in the waters off San Diego , California , a Navy spokeswoman said Wednesday . Rescuers are still searching for the two remaining crew members from the helicopter , which went down late Tuesday night , U.S. Navy spokeswoman Karin Burzynski said . No further details concerning the deaths were immediately available . Burzynski said the helicopter was operating from the USS Nimitz . The Navy received word that the helicopter went down around 11:30 p.m. Tuesday , she said . It crashed about 20 miles off the Mexican coast , the Navy said . Coast Guard spokesman Henry Dunphy told CNN earlier that Coast Guard helicopters and boats , as well as vessels from other agencies , were helping in the search .
question: Who is using helicopters ?
answers: U.S. Navy
content_span_normalized_text: three members of a u.s. navy helicopter crew were killed after their helicopter went down in the waters off san diego , california , a navy spokeswoman said wednesday .
question_normalized_text: who is using helicopters ?
context_asr: THREE MEMBERS OF A ES NAVY HELECOPTOR CREW WERE KILLED AFTER THE HELECOPTER WENT DOWN IN THE WATERS OF SANTIAGO CALIFORNIA A NAVY SPOKE OMEN SAID WEDNESDAY RESCUERS ARE STILL SEARCHING FOR THE TWO REMAINING CREW MEMBERS FROM THE HELICOPTER WHICH WENT DOWN LATE TUESDAY NIGHT ES NAVY SPOKESWOMMAN CRAN BERSINKY SAID NO FURTHER DETAILS CONCERNING THE DEATHS WERE IMMEDIATELY AVALABLE BERINKY SAID THE HELECOPTER WAS OPERATING FROM THE ESES LIMIT THE NAVY RECEIVED WORD THAT THE HELICOPTER WENT DOWN AROUND ELEVEN THIRTY PM TUESDAY SHE SAID IT CRASHED ABOUT TWENTY MILES OFF THE MEXICAN COAST THE NAVY SAID COAST GUARD SPOKEMEN HENRY DUNFE TOLD SANN EARLER THAT COST GARD HELICAPERS AND BOATS AS WELL AS VESSELS FROM OTHER AGENCIES WERE HELPING IN THE SEARCH 
question_asr: WHO IS USING HALLPOPTERS 