Question: Is it that the helicopters truly can't fly as in not enough lift? That seems strange because hot air in Death Valley is still thicker than cooler air in the mountains.
Or is this an FAA problem? Aircraft are not allowed to operate outside their published performance tables. Phoenix has been hit by that more than once--lots of tables top out at 120F and it becomes illegal to operate the aircraft if it reaches 121F.
It gets so hot in Death Valley, that helicopters can’t fly on some summer days.
“Helicopters cannot get enough lift to take off at extreme temperatures,” said Death Valley National Park ranger Elyscia Letterman. “The local air ambulance service determines if they can safely respond on a case-by-case basis, depending on temperature and the capabilities of each helicopter. However, they typically deem it unsafe to fly to Death Valley in temperatures above 120°F (49°C).”
Yeah, I read that--doesn't mean the ranger is right.
Look at the next comment--the tables for the helicopters don't go above 120F. That *will* ground them for legal reasons at 121F no matter what the actual aerodynamic situation is.
Cold air is more dense than hot air which counteracts the effects somewhat. 130 degree heat is roughly the equivalent of being at 5000’ at 60 degrees if I’m using the air density calculator right.
It's most likely the FAA problem: the official Pilot Operating Handbook for their helicopters top out at 120F and they cannot legally operate them. As tstrimple points out in a sister comment, Death Valley (elevation below sea level) at 130F is like 5,000' ASL at 60F, well within most ambulance helicopters operating range.
Or is this an FAA problem? Aircraft are not allowed to operate outside their published performance tables. Phoenix has been hit by that more than once--lots of tables top out at 120F and it becomes illegal to operate the aircraft if it reaches 121F.