Rare photos of the first flight expedition to Everest, 1933.

Both planes fly towards Lotse and Everest at an altitude of 32,000 feet. 1933.

The idea for a flight expedition on Mount Everest was originally proposed in 1918 by a British mountaineer physiologist, Alexander Callus, in his journal "The possibility of aerial possibility in the Himalayas".

As a skilled climber and expert in physiology, Callus believed that with the right precautions and the right equipment, given the time, he established the means to enable aircraft to fly efficiently, not just at such extreme altitudes. But also take useful reconnaissance photos.

However, it will take another 15 years for the technique to take hold. The effort could not be made without significant funds and in September 1932 Lord Clydesdale visited Lady Houston at Kinnera, his Scottish shooting estate, asking her to finance the expedition. He impressed her by putting on her clothes for dinner.

The emphatic nationalist Lady Houston was pleased with the idea that Clydesdale put forward that conquering Everest by air would strengthen British rule in India. She agreed to fund the campaign and would be closely involved in all phases from England.

In November 1932, the team selected two modified Westland Wallace aircraft for the expedition. The two-seater aircraft had open cockpits and were equipped with a Bristol Pegasus S3 engine. Lord Clydesdale flew a modified Westland PV-3 with Colonel Blacker, while the PV-6 model prototype was followed by Lieutenant McIntyre and photographer Bonnet. Both received modifications, including hearing and oxygen equipment. Both aircraft will become the first to fly on Everest.

Planners had to deal with significant problems in supplying oxygen and keeping them warm above 30,000 feet. An important factor with weight, it was fortunate that Vickers Armstrong was able to supply a lightweight oxygen cylinder made of a new type of alloy steel. The film and still cameras were another heavy addition to the cargo, with each film spool weighing in at 5 pounds.

For protection from extreme cold, atmospheres were designed with cumbersome double-layered, electrically heated flying suits, as well as warm gloves and goggles. The small apertures in each airman's oxygen regulation valve, which were susceptible to being blocked by ice or small insect particles, represented a worrying vulnerability.

By the end of March, the expedition was set up at Lallebu Airfield, Purnia in the north Indian state of Bihar, about 50 miles south of Everest and awaiting a favorable weather report. The April 3 forecast was 67 mph at 28,000 feet, exceeding the 40 mph limit.

Shortly after takeoff, he encountered a heavy dust mist that rose to a great height that completely obscured the ground leading to the high mountain ranges. Some 30 minutes later at 30,000 feet, battling the dreaded headwind, he gained his first sight of Everest.

At one point of the flight, Bonnet felt unconscious and experienced shooting pains in his stomach. He stopped filming and sat inside the cabin, where he discovered a gapping fracture in his oxygen line. He quickly tied a handkerchief around the breech, and was able to resume his duties without losing consciousness.

The first expeditions could not get clear pictures because of dust. He made another attempt on April 19, 1933, with photographs of Edmund Hillary and Tenzing Norgay at the top of Mount Everest.

The camera used was a Williamson Automatic Eagle III that took surface photographs at specific intervals as airplanes flew to known survey locations with the aim of obtaining photographic mosaics of the terrain and an accurate map. Photographs of the campaign were made public in 1951.

His successful flight over Everest made men a hero. Lord Clydesdale was awarded the Air Force Cross and Bonnet's footage was cut in the Academy Award-winning documentary Wings Over Everest.