Three persons died when a tour helicopter crashed in the Grand Canyon, one of the most famous national parks of the US.The helicopter from Papillion Airways carrying a pilot and six passengers crashed in the Quartermaster Canyon in Arizona around 5.20 p.m. on Saturday, ABC 15 news channel reported, citing Hualapai Nation Police Chief Francis Bradley.According to Xinhua, multiple agencies took part in the rescue and investigation.Gerard Ramalho, a reporter with the NBC, posted pictures on his Twitter account on Saturday night, showing that rescue crews had found the wreckage of the helicopter, a Eurocopter EC130."Four survivors being treated at the scene, all Level 1 'critical' ... can't be airlifted because conditions too windy," he tweeted.The helicopter tour in the Grand Canyon which provides stunning aerial views of the magnificent vista is very popular in the national park and the tickets are always sold out several weeks in advance.According to the Papillion Airways' website, the Las Vegas-based company flies roughly 600,000 passengers a year on the Grand Canyon and other tours.