In 2005, a helicopter finally landed on Mount Everest. But the pilot couldn't cut the engine—if his two-ton aircraft fully rested on the fragile snow, it would tumble down the mountain.
At 29,029 feet above sea level, the air density is only about a third of what it is at sea level. Helicopters rely on the rotors biting into the air to generate lift. Above 20,000 feet, standard helicopters usually lack the aerodynamic power to remain airborne, let alone execute a precision landing.
To break the altitude barrier, Eurocopter (now Airbus Helicopters) test pilot Didier Delsalle took a standard AS350 B3 "Squirrel" helicopter and aggressively reduced its weight. He stripped out the passenger seats, non-essential equipment, and standard weights, cutting 120 kilograms from the aircraft.
On May 14, 2005, Delsalle ascended toward the summit. The conditions were brutal, with updrafts reaching nearly 300 km/h. Delsalle located the small snow cornice at the very top of the mountain and brought the helicopter down.
To set an official Fédération Aéronautique Internationale (FAI) record, the aircraft had to remain touching down for at least two minutes. Because he could not rest the helicopter's full weight on the peak, Delsalle maintained 100% rotor power while touching the skids to the snow. He essentially balanced the aircraft in a high-powered hover that kept contact with the ground, holding this precarious position for 3 minutes and 50 seconds before safely descending to base camp.
When skepticism arose about whether the landing was simply a lucky fluke, Delsalle silenced critics the very next day. On May 15, he flew back up to 29,029 feet, navigated the same treacherous updrafts, and landed on the summit of Mount Everest a second time.