The Free Flight Environment

Pilot Tom de Dorlodot flying high in the Karakorum during Phase I, with oxygen and logging pulse oximeter on his right arm.

Project Summary

We hope to understand the physiological and cognitive effects of flying paragliders to improve pilot safety and performance. We are also trying to gather improved epidemiological data on accidents, incidents and near-misses and to develop protocols for managing downed pilots. Finally, we are working with comparative physiologists to draw parallels between human and animal flight.

In Phase I (2016-2017) we measured baseline physiology in pilots flying up to 7,458 m altitude, completing the first ever in-flight cardiopulmonary exercise testing during cross-country and acrobatic (SIV) manoeuvres. The work has been published in High Altitude Medicine and Biology, available here, and in Cross Country Magazine.

Phase II (2018-2019) used the data from our field studies to simulate the paragliding environment with high fidelity in the University of Portsmouth Extreme Environment Laboratory, undertaking tests of performance, including markers of cognition and safety behaviour under cold and hypoxia. The results were published in Aerospace Medicine and Human Performance, available here, and in Cross Country Magazine.

Phase III (2019) investigated the ergonomics of pilots’ reserve parachute deployment while under physical and cognitive stress. The results are under review for publication, but a video explaining some of the key findings is available here.

The next phase will be a follow up study of Phase III but with additional environmental stressors.

Researcher Matt Wilkes testing the Metamax portable metabolic system over Laragne-Monteglin, France.

What the advantages of paragliding for hypoxia research?

Unlike mountaineers, paragliders are exposed to hypoxia over acute timescales, climbing at 1-10 m.sec-1 in thermal updrafts and reaching heights above 8000 m, without days of acclimatisation and often without supplementary oxygen. Pilots do this with minimal physical input, sat suspended in a harness below the paraglider wing and able to wear instrumentation, removing the confounding effects of exercise. They are also completely exposed to ambient conditions (cold, wind, noise, G forces and hypobaric hypoxia), adding realism without the need for extreme physical fitness, and so opening the studies up to a wider range of subjects. Paragliding is cheaper and more environmentally friendly than research using hypobaric chambers or powered aircraft.

We believe that paragliding has the potential to be the most appropriate, inclusive, cost-effective and environmentally sound analogue with which to study a wide range of healthy volunteers in hypoxic environments.

What are the potential benefits of the research?

Paragliding Safety

The setting in which paraglider pilots fly and in which accidents occur, is unique among mountain and air sports: the slow and demanding climbing of mountaineering, the protected flight of an enclosed sailplane, and the explosive decompression of a failing fighter plane do not replicate the experiences, risks, and challenges of paragliding. There is almost no literature directly relating to paragliding physiology; however, there is a great deal of relevant work that may translate from allied disciplines: aviation medicine; accident investigation; altitude and temperature physiology; avalanche science, as well as human factors.

Paragliding is cognitively demanding, for example: reading the landscape for thermal triggers and calculating glide angles, while remaining sufficiently spatially aware to pilot a craft though an invisible three-dimensional air mass, often containing other gliders in close proximity; in cold, hypoxic, ever-changing and sometimes intimidating conditions. Competition and acrobatic flying are more demanding still.

Paragliding has become much safer over time but remains a high-risk pursuit. Most accidents are secondary to errors of piloting or judgement, rather than equipment failure. When accidents do occur, the consequences are often severe or fatal and we hypothesise that hypoxia and environmental exposure play their part. Understanding the physiological demands on placed on pilots is therefore key to establishing systems to prevent injury or loss of life.

Understanding Hypoxia

Oxygen has profoundly affected the distribution of life on earth. Lack of oxygen at altitude and in the deep sea has driven adaptions across the spectrum of ecology: from invertebrates living on hydrothermal vents to birds migrating across the high Himalayas. Hypobaric hypoxia, the diminishing levels of oxygen at altitude, means that one third of people who climb above 2500m for work, pilgrimages or travel (approximately 140 million people per year) may suffer symptoms of acute mountain sickness. Up to 5% will develop life-threatening high-altitude pulmonary oedema (HAPE) and high-altitude cerebral oedema (HACE).

Hypoxia underpins critical illness at sea-level: the outcomes of heart attacks, strokes, traumatic brain injury, acute asthma and pneumonia all depend on precise management of oxygen delivery. Understanding the pathophysiology of hypoxia is the key to developing novel intervention points and refining treatment pathways in critical care.

Telemetry

Our project refines the use of novel telemetry and wearable technology in austere environments, informing future studies in other spheres of human and animal free flight.

Multidisciplinary collaboration

Finally, our project brings together animal biology, altitude physiology, aviation and space medicine, biomechanics and biotelemetry researchers to conduct fundamental studies in a singularly demanding environment. We hope it will serve as a springboard for a variety exciting projects in the future.

Methodological challenges of collecting physiological data in flight

Gathering reliable physiological measurements during free flight presents a set of constraints that are rarely encountered in laboratory or clinical settings. Sensors must tolerate rapid changes in temperature, strong airflow, vibration and occasional hard landings, while remaining comfortable enough not to distract the pilot or interfere with control inputs. Power supply and data storage have to be secured against the cold, and cables must be routed so that they cannot snag on lines, harness straps or reserve handles. Throughout the project we have used purpose-built logging equipment and redundant sensors, and we cross-check field readings against laboratory calibrations before and after each flight.

Altitude, in particular, affects both the pilot and the instrumentation. Pulse oximeters can become unreliable when peripheral perfusion drops in cold hands, so we position sensors on the forehead or earlobe where possible and use heated mitts during high flights. Gas-exchange analysers used for cardiopulmonary exercise testing are sensitive to pressure changes, and we apply barometric corrections derived from the flight log and local weather data. The team also records video and audio notes during cross-country tasks, because memory for events at altitude is often degraded; these records help us match physiological traces to specific manoeuvres and decisions.

Logistics in remote mountain regions add another layer of complexity. Retrieval of data often depends on the pilot landing safely with the equipment intact, and we maintain duplicate storage cards and wireless backups where terrain allows. On several expeditions the research kit has been flown over glaciers and high passes, so impact-resistant cases and waterproof membranes are standard. These field methods have been refined across Phases I to III, and the resulting protocols are shared with other high-altitude research groups to improve comparability of future studies.

Cognitive performance and decision-making under environmental stress

Hypoxia and cold do not simply reduce physical capacity; they also alter the way pilots perceive risk, process information and choose between options. In Phase II we simulated paragliding-relevant conditions in the University of Portsmouth Extreme Environment Laboratory, exposing participants to controlled oxygen levels and cold while they completed tasks drawn from aviation human factors research. The battery included tests of reaction time, working memory, spatial orientation, divided attention and risk propensity, each administered before, during and after exposure to allow separation of acute and recovery effects.

Our results showed that performance on complex tasks deteriorated earlier than simple reaction speed, and that some participants were poor at recognising their own impairment. This has direct implications for cross-country flying, where a pilot may need to integrate weather changes, airspace restrictions, terrain clearance and escape options while already physically loaded. A pilot who feels “fine” may still show measurable slowing in the executive functions required for safe route amendments or the decision to deploy a reserve.

• Sustained attention and vigilance during long glides
• Working memory for airspace and radio information
• Risk assessment under time pressure and uncertainty
• Response inhibition when a planned line becomes unsafe

We are now translating these laboratory findings into simple field cues that pilots can use, such as self-check routines for hypoxia, structured decision points before entering complex terrain and pre-agreed personal minimums for altitude and weather. By linking cognitive test scores with in-flight behaviour, the project aims to identify which training interventions are most likely to reduce accident and near-miss rates.

Epidemiology of paragliding accidents, incidents and near-misses

Accident statistics in free flight are often incomplete, inconsistent and difficult to compare across countries or disciplines. Many events are never reported unless they involve serious injury or third-party damage, and near-misses are almost entirely absent from official records. This limits the ability of pilots, instructors and manufacturers to learn from patterns of failure. As part of the project we have developed a structured reporting framework that classifies events by phase of flight, weather conditions, pilot experience, equipment type and contributing human factors, while protecting the anonymity of those who submit reports.

Initial data from pilot surveys and voluntary incident reports suggest that a substantial proportion of serious accidents occur during launch and landing, but that the most severe high-altitude or cross-country incidents often involve a combination of deteriorating weather, dehydration, fatigue and delayed decision-making. Near-miss analysis is particularly valuable because it captures recoverable errors that may never appear in injury statistics. By comparing near-misses with accidents, we can identify the decision points at which a flight becomes unsafe and design specific countermeasures.

The epidemiological strand also informs the development of downed-pilot management protocols. We collect information on how quickly injured pilots are located, what first aid is available in remote terrain and how communication and rescue coordination could be improved. These data are shared with national associations and rescue organisations to support evidence-based changes in training and equipment recommendations.

Comparative physiology of human and animal flight

Many birds and bats routinely perform sustained exercise at altitudes that would incapacitate an unacclimatised human, and the physiological solutions they use offer a useful reference point for understanding paraglider pilots. Bar-headed geese, for example, migrate over the Himalaya at altitudes where the partial pressure of oxygen is less than half that at sea level, yet they maintain high metabolic rates without the progressive loss of muscle function seen in hypoxia-exposed humans. We are working with comparative physiologists to examine how oxygen transport, haemoglobin affinity, ventilation and muscle metabolism differ between species, and whether any of these mechanisms can inform training or acclimatisation strategies for pilots.

Although a paraglider pilot does not produce the same mechanical power as a flying bird, the combination of cold, low oxygen and sustained cognitive load creates comparable demands on oxygen delivery to the brain and working muscles. Our in-flight measurements of heart rate, oxygen saturation and ventilation during cross-country and acrobatic manoeuvres provide a rare human dataset that can be aligned with existing animal flight data. This cross-species perspective helps separate the effects of altitude from those of exercise intensity and may clarify why some pilots tolerate hypoxia well while others deteriorate rapidly at the same altitude.

We are also exploring whether the flight behaviour of soaring birds can offer insights into energy management and route selection in paragliding. Thermal selection, glide polar optimisation and decisions about when to climb or move on are problems faced by both pilots and large soaring species. Comparative modelling of these behaviours may ultimately inform training tools and flight instruments that help pilots make more efficient and safer cross-country decisions.