Tag Archives: Mount Everest

14 May 2005

Didier Delsalle approches the summit of Mount Everest. (Eurocopter)
Didier Delsalle approaches the summit of Mount Everest. (Eurocopter)

14 May 2005: Test pilot Didier Delsalle landed a Eurocopter AS 350 B3 Écureuil, c/n 3934, registration F-WQEX, at the summit of Mount Everest, the highest point on Earth, at 8,848 meters (29,029 feet).

The Fédération Aéronautique Internationale required that the helicopter remain on the summit for at least two 2 minutes for the landing to be considered official. Delsalle actually landed on the summit twice, staying four minutes each time. The flight set two world records for the highest take-off. ¹ At the summit, the wind was blowing 65 knots (75 miles per hour/120 kilometers per hour), and there were severe updrafts and downdrafts. The air temperature was -35 °C. (-31 °F.).

Delsalle said that on the upwind side, even with the helicopter’s collective fully down to reduce power and lift, the As 350 continued to gain altitude. On the downwind side, the winds blew him away from the summit, and at full power, he was unable to counteract that.

The most difficult problem, though, was that when over the summit, the mountain drops away in every direction. Delsalle had no visual referent to guide him to the surface.

These records broke Delsalle’s previous records for highest take-off, 7,927 meters (26,007 feet), set just two days earlier. ²

Mount Everest, looking north. (Wikipedia)

During flight tests to evaluate the practicality of the Everest flight, on 14 April 2005, Delsalle and the AS 350 set three time to climb world records over Istres, France. The Écueriel climbed to a height of 3,000 meters (9,843 feet) in 2 minutes, 21 seconds; 6,000 meters (19,685 feet) in 5 minutes, 6 seconds; and 9,000 meters (29,528 feet) in 9 minutes, 26 seconds. ³

Delsalle also rescued two Japanese climbers at 16,000 feet (4,877 meters).

Didier DelSalle with F-WQEX, 2005
Didier DelSalle with F-WQEX, at Lukla, Nepal, 2005. Elevation 2,866 meters (9,403 feet). (Magazine Aviation)

Didier Delsalle was born 6 May 1957, at Aix-en-Provence, France. He joined the Armée de l’Air (French Air Force) in 1979, and was trained as fighter pilot. In 1981 he transitioned to helicopters and was assigned to search-and-rescue operations. After twelve years military service, Delsalle became an instructor at École du personnel navigant d’essais et de réception, the French test pilot school at Istres, France. He then became the chief test pilot for light helicopters for Eurocopter, and later for the NH90 medium helicopter.

Delsalle holds seven FAI world records, five of which remain current.

FAI representatve (left) presents a World Record certificate to Eurocopter test pilot Didier Delsalle while company CEO looks on. (Aviation International News)
Fédération Aéronautique Internationale (FAI) representative Jacques Escaffe (left) presents a World Record certificate to Eurocopter test pilot Didier Delsalle while company CEO Fabrice Brégier looks on. (Aviation International News)

The Eurocopter AS 350 Écureuil is a  6–7 place, single-engine light helicopter, operated by a crew of one or two pilots. (It is known as the A-Star in the United States.) Introduced by Aérospatiale in 1975, it remains in production today and is one of the most popular civil helicopters. The manufacturer is now known as Airbus Helicopters.

Eurocopter AS 350 B3 Écureuil F-WQEX. (Airbus Helicopters)

The AS 350 B3 is a high-performance variant, widely used in law enforcement. The overall length with rotors turning is 12.94 meters (42 feet, 5.4 inches). The fuselage is 10.93 meters (35 feet, 10.3 inches) long and the cabin is 1.87 meters (6 feet, 1.6 inches) wide. The helicopter’s overall height is 3.14 meters (10 feet, 3.6 inches).

In keeping with standard French practice, the Écureuil/A-Star’s main rotor system turns clockwise as seen from above. (The advancing blade is on the helicopter’s left side.) The fully-articulated the three-blade rotor has a diameter of 10.69 meters (35 feet, 0.9 inch). The normal operating range is 385–394 r.p.m. (320–430 r.p.m. in autorotation). A two-bladed tail rotor is mounted on the right side of the tail boom in a pusher configuration. It rotates clockwise, as seen from the helicopter’s left. (The advancing blade is below the axis of rotation.) Its diameter is 1.86 meters (6 feet, 1.2 inches.)

The AS 350 B3 has an empty weight of approximately 1,174 kilograms (2,588 pounds), depending on installed equipment, and maximum gross weight of 2,250 kilograms (4,961 pounds)

AS 350 B3 three-view illustration with dimensions. (Eurocopter)

The AS 350 B3 variant is powered by a single Turboméca Arriel 2B turboshaft engine. The Arriel 2B is a free turbine turboshaft engine which uses an electronic engine control system (EECU). The engine has a two-stage compressor section (single-stage low-pressure axial flow, single-stage high-pressure centrifugal flow); an annular combustion chamber; and two-stage turbine section (single-stage gas generator and single-stage power turbine). The compressor section turns 52,110 r.p.m. at 100% N1; The power turbine, N2, turns 39,095 r.p.m. at 100%. A gear reduction unit reduces the engine’s output shaft speed to 5,990 r.p.m.

The Arriel 2B produces 847 shaft horsepower, but is de-rated to the helicopter’s main transmission limit. Installed, the Arriel 2B is rated at 536 horsepower for cruise; 700 horsepower, Maximum Continuous Power; and 733 horsepower for take off (5 minute limit).

The Arriel 2B is 118.0 centimeters (3 feet, 10.46 inches) long, 50.0 cm (1 foot, 6.69 inches) wide, 62.0 cm (2 feet, 0.41 inches) high. It weighs 134 kilograms (295.4 pounds), dry. The Arriel series engines are now produced by Safran Helicopter Engines.

Eurocopter AS 350 B3 Écureuil c/n 3934, F-WQEX, at Mount Everest. (Eurocopter)

The AS 350 B3 has a cruise speed of 132 knots (152 miles per hour/245 kilometers per hour) and maximum speed of 155 knots (178 miles per hour/287 kilometers per hour). It carries over four hours of fuel and has a maximum range of 357 nautical miles (411 statute miles/662 kilometers). The maximum allowable altitude is 7,010 meters (23,000 feet).

AS 350 B3 c/n 3934 was originally registered F-WWPN, then F-WQEX, and was later registered as F-HMGM, in service with Hélimountains, Bourg-Saint-Maurice, France. As of 2014, F-WQEX is on display at the Musée de l’Aviation, Saint-Victoret, Provence-Alpes-Côte d’Azur, France.

Didier Delsalle with Eurocopter AS 350 B3 c/n 3934, F-WQEX. (André Bour/helicopassion.com)
Detail from The Henry Washburn Shaded Relief Map of Mount Everest. (Reddit)

¹ FAI Record File Number 11596: Highest take-off (Subclass E-1); FAI Record File Number 11596: Highest take-off (Subclass E-1c). 8,848 meters (29,029 feet).

² FAI Record File Number 11594: Highest take-off (Subclass E-1); FAI Record File Number 11595: Highest take-off (Subclass E-1c). 7,927 meters (26,007 feet).

³ FAI Record File Number 11323: 3,000 meters (9,843 feet), 2:21; FAI Record File Number 11325: 6,000 meters (19,685 feet), 5:06; and FAI Record File Number 11326: 9,000 meters (29,528 feet), 9:26.

© 2019, Bryan R. Swopes

3 April 1933

Lord Clydesdale, flying Westland WP-3 G-ACAZ, approaching the summit of Mt. Everest, 3 April 1933. (The Houston Mount Everest Flying Expedition via National Geographic)

3 April 1933: Squadron Leader Douglas Douglas-Hamilton, Marquess of Douglas and Clydesdale ¹ (Lord Clydesdale)—at the time, the youngest squadron leader in the Royal Air Force, and in command of 602 Squadron—as Chief Pilot of the Houston Mount Everest Flying Expedition, flew a modified Westland PV-3 biplane, G-ACAZ, in formation with Westland PV-6, G-ACBR, over the summit of Mount Everest, the world’s highest mountain, elevation 29,029 feet (8,848 meters). The PV-6 was piloted by Flight Lieutenant David Fowler McIntyre, also of 602 Squadron.

The two airplanes took off from Purnia, in the northeast of India, at 8:25 a.m. Aboard Lord Clydesdale’s airplane was observer Lieutenant Colonel Latham Valentine Stewart Blacker, O.B.E. (“Blacker of the Guides”), and on McIntyre’s was Sidney R. G. Bonnett, a cinematographer for Gaumont British News. During the ascent to Everest, Bonnett damaged his oxygen hose and lost consciousness due to hypoxia.

Douglas Douglas-Hamilton, Marquess of Douglas and Clydesdale, photographed 12 November 1929 by Bossano Ltd. (National Portrait Gallery, London)

The Bristol Pegasus S.3 was considered to be the only aircraft engine in the world that would be capable of powering an airplane with the necessary personnel and equipment high enough to fly over Everest. It was an air-cooled, supercharged, 1,752.79-cubic-inch-displacement (28.72 liter) nine-cylinder radial engine, with a compression ratio of 5.3:1. It had a Normal Power rating of 525 horsepower at 2,000 r.p.m. at 11,000 feet (3,353 meters), and produced a maximum of 575 horsepower at 2,300 r.p.m. at 13,000 feet (3,962 meters). It had a Takeoff Power rating of 500 horsepower at 2,000 r.p.m. at Sea Level, with a three minute limit. The engine drove a two-bladed, fixed-pitch wooden propeller manufactured by The Airscrew Company Ltd., through either a 0.5:1 or 0.655:1 gear reduction.

After deciding on the engine, the Expedition had to select an airplane. The Westland PV-3 was chosen because it had the highest rate of climb of any airplane ever tested by the Royal Air Force.

Westland WP-3 G-ACAZ, after modifications for the Houston Everest Expedition.

The Westland Aircraft Works PV-3 was a private venture prototype torpedo bomber, based on the earlier Westland Wapiti. It had an all-metal structure and folding wings. Only one was built, and no orders for the airplane were placed. The airplane was modified for the Houston Everest Expedition. The gunner’s open position behind the pilot’s cockpit was replaced with an enclosed cabin for an observer and cameras. The original Bristol Jupiter X.FA engine was replaced by the more powerful Bristol Pegasus S.3 and a large-diameter propeller.

The Houston-Westland was 34 feet, 2 inches (10.414 meters) long with a wingspan of 46 feet, 6 inches (14.173 meters) and overall height of 11 feet, 8 inches (3.556 meters). The airplane had an empty weight of 3,420 pounds (1,551.3 kilograms) and loaded weight of 5,100 pounds (2,313.3 kilograms).

The PV-3 had a maximum speed of 163 miles per hour (262.3 kilometers per hour) and a service ceiling of 35,000 feet (10,668 meters). Burmah-Shell provided a special fuel for operations at very high altitude.

Westland PV-6 G-ACBR

The Westland PV-6 was also a private venture prototype. It was later converted to the Wallace I configuration.

The airplanes carried Williamson Automatic Eagle III survey cameras that would take photographs of the surface at specific intervals as the airplanes flew over known survey locations. It was planned that a photographic mosaic of the terrain and an accurate map could be drawn.

Dame Fanny Lucy Houston, D.B.E. (then, Baroness Byron), by Bassano, Ltd, circa 1910. (National Portrait Gallery, London)

The expedition was financed by Lucy, Lady Houston, D.B.E., who offered to provide up to £15,000 to finance the project. The flight helped to demonstrate the need for specialized equipment for high altitude flight.

For his accomplishment, Lord Clydesdale—later, Air Commodore His Grace The Duke of Hamilton KT GCVO AFC PC DL FRCSE FRGS—was awarded the Air Force Cross.

Flight Lieutenant David Fowler McIntyre, Royal Air Force. (602 Squadrom Museum)
Flight Lieutenant David Fowler McIntyre, A.F.C., Royal Air Force. (602 Squadron Museum)

Mount Everest, known in Nepal as सगरमाथा (Sagarmāthā), is a mountain in the Mahalangur Range of the the Himalayas. Its peak is believed to be the highest point on Earth. The mountain was “discovered” by the Western world in 1856, during the decades-long Great Trigonometrical Survey of India. Identified as Peak XV, the height of the mountain was measured at 29,002 feet ² (8,839.8 meters) above Sea Level. The Royal Geographical Society named the mountain Everest after Colonel Sir George Everest, FRS, FRAS, the Surveyor General of India from 1830 to 1843. At present, the agreed height of Everest is 8,848 meters (29,029 feet). The upper portion of the mountain is primarily marble and is covered by several meters of ice and snow.

Everest as seen from the south. Compare this photograph to the one above.

¹ In 1940, Lord Hamilton succeeded his father, Lieutenant Alfred Douglas Douglas-Hamilton, 13th Duke of Hamilton and 10th Duke of Brandon, as 14th Duke of Hamilton and 11th Duke of Brandon.

² Interestingly, in The Map Makers (John Noble Wilford, Alfred A. Knopf, New York, 1981), it was reported that the Great Survey actually calculated the height of the mountain at 29,000 feet (8,839.2 meters), but it was felt that this value would be taken as an approximation rather than an exact value, so 2 feet were added, resulting in the generally known height of 29,002 feet (8,839.8 meters).

The elevation of the summit may have changed due to a Magnitude 7.8 earthquake that occurred 25 April 2015, and a M 7.3 aftershock on 12 May 2015. Nepal and China both conducted an elaborate survey in 2020. Nepal used the Bay of Bengal as Sea Level, while China used the Yellow Sea. They agreed that the height of the summit of Mount Everest is now 29,032 feet (8,848.86 meters).

© 2019, Bryan R. Swopes