by Lcpl Hughes » Tue May 25, 2010 7:29 am
I found this while I was looking for maximum elevation for a helicopter..
Mount Everest
On May 14th, 2005, an Ecureuil/AStar AS 350 B3 helicopter operated by Eurocopter was reported to have landed on Mount Everest (29,035 feet). The landing is in dispute. The listed service ceiling of the rotorcraft is between 17 and 18 thousand feet, which is considerably short of the summit altitude.
An unmanned high altitude helicopter is nearing completion. TGR Helicorp in New Zeland has designed the "Alpine Wasp" specifically for rescue evolutions on Everest. The machine's diesel engine will give it an operating ceiling in excess of 30,000 feet.
The CH-47 Chinook twin rotor helicopter is used by the USAF to rescue climbers on Mount Denali (McKinley) in AK. It can reach an altitude in excess of 19000 to land at an elevation of around 18000. The biggest problem at that point is restarting the engines, so a special storage device directs pure oxygen into the engine inlet to restart.