Abstract
In the summer of 2018 in Karakoram (Pakistan), we used a drone capable of movie recording in two rescue operations. In the first instance, a climber who had fallen from an ice cliff on Broad Peak was found alive on a snow field at an altitude of 7500 m by a drone, which had been sent from K2 Base Camp. Initially, the victim's ability to find a safe route of descent appeared to be limited. Hence, he was guided toward a path between Camp 3 and the col by a hovering drone to route him around dangerous seracs. Several days later, we used the same drone to carry drugs to Camp 3 on K2 for a climber unable to descend safely due to acute lower back strain. A small box with the relevant drugs was attached to the drone and delivered to the climber at 6900 m.
Both these operations were performed under visual control from the K2 Base Camp. The drone DJI Mavic Pro had been modified by upgrading its software to remove limitations of maximal ceiling and vertical speed. The maximal payload of this drone is about 300 g. Drones have already been used in some search and rescue operations; however, their role was limited to taking pictures and localizing victims (Van Tilburg, 2017; Karaca et al., 2018). To our knowledge, this was the first use of a quadcopter at altitudes near the summits of the Himalayas to aid victims unable to descend for various reasons.
Rescue operations in the Himalaya or Karakoram ranges require acclimatized and fit climbers when helicopter rescue cannot be undertaken due to bad weather. Reaching a victim may take several hours or even a few days on normal routes, whereas such rescue operations on technically difficult routes may be even impossible. In contrast, aerial drones can reach heights >8000 m from the base camp within a few minutes. Nowadays, drones are not able to evacuate victims. However, they can deliver gas cartridges, food, drugs, or oxygen. Such a drone was used in a delivery of blood products at low altitude weighing up to 1.9 kg (Amukele et al., 2017). The payload depends on the particular size of the drone. At high altitudes these should be calculated carefully, as the flight performance of any aircraft depends on ambient air pressure and temperature.
The tragedy on Latok (7145 m) that occurred this summer demonstrated the need for fast delivery of bivouac equipment, gas, and food to a surviving climber at very high altitude in bad weather. Fast technological progress in the field has made drone-based rescue possible (Nguyen et al., 2018). One may expect that in the very near future, when rescue helicopter operations cannot be undertaken due to limited visibility, a drone with appropriate navigation equipment might rapidly supply the victim with all the necessary items for survival to await descent when conditions permit.