Altitude or height is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context. Although the term altitude is commonly used to mean the height above sea level of a location, in geography the term elevation is often preferred for this usage.
Decompression sickness is a medical condition caused by dissolved gases emerging from solution as bubbles inside the body tissues during decompression. DCS most commonly occurs during or soon after a decompression ascent from underwater diving, but can also result from other causes of depressurisation, such as emerging from a caisson, decompression from saturation, flying in an unpressurised aircraft at high altitude, and extravehicular activity from spacecraft. DCS and arterial gas embolism are collectively referred to as decompression illness.
The de Havilland DH.106 Comet was the world's first commercial jet airliner. Developed and manufactured by de Havilland at its Hatfield Aerodrome in Hertfordshire, United Kingdom, the Comet 1 prototype first flew in 1949. It featured an aerodynamically clean design with four de Havilland Ghost turbojet engines buried in the wing roots, a pressurised cabin, and large square windows. For the era, it offered a relatively quiet, comfortable passenger cabin and was commercially promising at its debut in 1952.
Hyperbaric medicine is medical treatment in which an ambient pressure greater than sea level atmospheric pressure is a necessary component. The treatment comprises hyperbaric oxygen therapy (HBOT), the medical use of oxygen at an ambient pressure higher than atmospheric pressure, and therapeutic recompression for decompression illness, intended to reduce the injurious effects of systemic gas bubbles by physically reducing their size and providing improved conditions for elimination of bubbles and excess dissolved gas.
Barotrauma is physical damage to body tissues caused by a difference in pressure between a gas space inside, or in contact with, the body, and the surrounding gas or fluid. The initial damage is usually due to over-stretching the tissues in tension or shear, either directly by expansion of the gas in the closed space or by pressure difference hydrostatically transmitted through the tissue. Tissue rupture may be complicated by the introduction of gas into the local tissue or circulation through the initial trauma site, which can cause blockage of circulation at distant sites or interfere with normal function of an organ by its presence.
Decompression Illness (DCI) comprises two different conditions caused by rapid decompression of the body. These conditions present similar symptoms and require the same initial first aid. Scuba divers are trained to ascend slowly from depth to avoid DCI. Although the incidence is relatively rare, the consequences can be serious and potentially fatal, especially if untreated.
Aviation medicine, also called flight medicine or aerospace medicine, is a preventive or occupational medicine in which the patients/subjects are pilots, aircrews, or astronauts. The specialty strives to treat or prevent conditions to which aircrews are particularly susceptible, applies medical knowledge to the human factors in aviation and is thus a critical component of aviation safety. A military practitioner of aviation medicine may be called a flight surgeon and a civilian practitioner is an aviation medical examiner. One of the biggest differences between the military and civilian flight doctors is the military flight surgeon's requirement to log flight hours.
Uncontrolled decompression is an unplanned drop in the pressure of a sealed system, such as an aircraft cabin or hyperbaric chamber, and typically results from human error, material fatigue, engineering failure, or impact, causing a pressure vessel to vent into its lower-pressure surroundings or fail to pressurize at all.
Cabin pressurization is a process in which conditioned air is pumped into the cabin of an aircraft or spacecraft in order to create a safe and comfortable environment for passengers and crew flying at high altitudes. For aircraft, this air is usually bled off from the gas turbine engines at the compressor stage, and for spacecraft, it is carried in high-pressure, often cryogenic tanks. The air is cooled, humidified, and mixed with recirculated air if necessary before it is distributed to the cabin by one or more environmental control systems. The cabin pressure is regulated by the outflow valve.
RAF North Luffenham was a Royal Air Force station in Rutland, England, 1940 - 1998. It is near to the villages of Edith Weston and North Luffenham.
A pressure suit is a protective suit worn by high-altitude pilots who may fly at altitudes where the air pressure is too low for an unprotected person to survive, even breathing pure oxygen at positive pressure. Such suits may be either full-pressure or partial-pressure. Partial-pressure suits work by providing mechanical counter-pressure to assist breathing at altitude.
A diving chamber is a vessel for human occupation, which may have an entrance that can be sealed to hold an internal pressure significantly higher than ambient pressure, a pressurised gas system to control the internal pressure, and a supply of breathing gas for the occupants.
A hypobaric chamber, or altitude chamber, is a chamber used during aerospace or high terrestrial altitude research or training to simulate the effects of high altitude on the human body, especially hypoxia and hypobaria. Some chambers also control for temperature and relative humidity.
The term military medicine has a number of potential connotations. It may mean:
The Royal Air Force Institute of Aviation Medicine was a Royal Air Force aviation medicine research unit active between 1945 and 1994.
The RAF Centre of Aviation Medicine is a medical organisation run by the Royal Air Force and based at RAF Henlow in Bedfordshire. It is the main organisation conducting aviation medicine research in the UK.
The decompression of a diver is the reduction in ambient pressure experienced during ascent from depth. It is also the process of elimination of dissolved inert gases from the diver's body, which occurs during the ascent, largely during pauses in the ascent known as decompression stops, and after surfacing, until the gas concentrations reach equilibrium. Divers breathing gas at ambient pressure need to ascend at a rate determined by their exposure to pressure and the breathing gas in use. A diver who only breathes gas at atmospheric pressure when free-diving or snorkelling will not usually need to decompress, Divers using an atmospheric diving suit do not need to decompress as they are never exposed to high ambient pressure.
Altitude decompression or hypobaric decompression is the reduction in ambient pressure below the normal range of sea level atmospheric pressure. Altitude decompression is the natural consequence of unprotected elevation to altitude, while hypobaric decompression is due to intentional or unintentional release of pressurisation of a pressure suit or pressurised compartment, vehicle or habitat, and may be controlled or uncontrolled, or the reduction of pressure in a hypobaric chamber.
Decompression theory is the study and modelling of the transfer of the inert gas component of breathing gases from the gas in the lungs to the tissues and back during exposure to variations in ambient pressure. In the case of underwater diving and compressed air work, this mostly involves ambient pressures greater than the local surface pressure, but astronauts, high altitude mountaineers, and travellers in aircraft which are not pressurised to sea level pressure, are generally exposed to ambient pressures less than standard sea level atmospheric pressure. In all cases, the symptoms caused by decompression occur during or within a relatively short period of hours, or occasionally days, after a significant pressure reduction.
The United States Air Force School of Aerospace Medicine (USAFSAM) is the United States Air Force (USAF) organization focused on education, research, and operational consultation in aerospace and operational medicine. USAFSAM was founded in 1918 to conduct research into the medical and physiologic domains related to human flight, and as a school for medical officers trained to support military aviation operations, later coined as flight surgeons. The school supported early military aviation from World War I through the evolution of aviation and into the modern era. USAFSAM conducted medical research and provided medical support for the initial US space operations beginning in 1947 through the establishment of NASA in 1958. After the creation of NASA, USAFSAM continued to actively support civilian and military manned space missions through clinical and physiologic research. USAFSAM is one of the oldest continually operating school for flight surgeons and other operational medical personnel of its kind in the world. USAFSAM is located in Dayton, Ohio at Wright-Patterson Air Force Base, and is part of the 711th Human Performance Wing and the Air Force Research Laboratory (AFRL).
