Six British tourists and a pilot were on board the Papillon sightseeing helicopter which went down in the Grand Canyon’s West Rim, killing three.
A spokesman for the Hualapai Nation Police Department said the three who lost their lives are Becky Dobson, 27, Jason Hill, 32, and Stuart Hill, 30.
Three others, named as Ellie Milward, 29, Jonathan Udall, 32, and Jennifer Barnham, 39, as well as the pilot, Scott Booth, 42, are all in a critical condition in hospital.
The UK Foreign Office said it is providing support to the families of the six.
Hualapai Police chief Francis Bradley said search and rescue teams were hampered over the weekend by severe weather conditions and rugged terrain.
He said first responders had to hike for 20 minutes to get to the scene.
National Transportation Safety Board inspectors were due at the scene on Sunday but so far the likely cause of the fiery crash has not been determined.
Officials from the Federal Aviation Administration also will be investigating the crash.
The tour company is cooperating fully with the investigation.
"It is with extreme sadness we extend our heartfelt sympathy to the families involved in this accident. Our top priority is the care and needs of our passengers and our staff," Papillon Group CEO Brenda Halvorson said in a statement.
The company flies about 600,000 passengers a year on Grand Canyon trips and on other tours.
In 2001 a Papillon tour helicopter crashed killing the pilot and five passengers.
