06/23/2026
On this day in aviation history, 1972: Highest helicopter altitude record!
https://www.thisdayinaviation.com/21-june-1972/
On June 21, 1972 Aérospatiale Chief Test Pilot Jean Boulet started up his Aérospatiale SA 315 Lama. After the start up mechanics removed the battery and starter motor to decrease weight in the helicopter. Also removed were various instruments, co-pilot and passengers seats, as well as the helicopter’s synchronized horizontal stabilizer and tail rotor guard. The standard fuel tank was replaced with a very small tank holding approximately 22.7 gallons (70 kilograms) of jet fuel. Not only that but Turboméca modified the engine to increase the output shaft r.p.m. by 6%.
Boulet climbed up to 36,089 feet (11,000 meters) in 12 minutes. At this point he had to slow down to 30 knots to prevent the blade tip speed of the main rotor blades from breaking the sound barrier which would induce blade stall not to mention he was approaching the retreating blade stall speed at that altitude. He was playing the balancing act of staying above the transitional speed at which the main rotor blades are most efficient at creating lift and staying below the speed at which the retreating blade will stall.
When it got to the point at which the Lama was no longer climbing, which was 40,820.21 feet (12 442 m), Boulet reduced throttle and lowered the collective. Because of the lack of oxygen and cold temperatures at that altitude the engine flamed out. Boulet immediately entered auto rotation and because there was no battery and no starter motor he could not attempt to relight the turbine.
During the autorotative glide back down the Lama passed through several cloud layers. Boulet would lose temporary reference to the outside world and had no artificial horizon in his cockpit to stay upright. But he could still make reference to the sun to help keep himself upright.
Eventually Boulet made it back to Aérodrome d’Istres and landed close enough to his take off point to still make the record books for the Fédération Aéronautique Internationale (FAI): The Absolute Highest Altitude World Record for helicopters without a payload.
This record still stands today.
¹ FAI Record File Number 11657: Class: E (Rotorcraft): Sub-Class: E-Absolute (Absolute Record of class E)
https://www.fai.org/news/legendary-helicopter-pilot-jean-boulets-altitude-record-still-stands-50-years
