From Big Medical Encyclopedia

EJECTION - 1. The way of the forced automated escape of a cabin of the aircraft applied to rescue of crew members in emergencies. 2. A way of dispersal of deck airplanes at their start from the ship-samoletonostsa by means of special deck catapults.

Forced To. most often occurs in case of emergency at a speed of flight of St. 500 km/h when at the majority pilots are not enough physical. forces on overcoming pressure of a counterflow of air and ejection from a cabin. Besides, at these speeds force of an air flow is so big that, having been thrown out, the pilot inevitably hits against tail plumage.

The aircraft catapulted installation consists of a special chair, the shooting mechanism and guides of rails. Besides, To. it can be carried out in the individual capsule or the separated part of the aircraft together with a cabin. For ensuring rescue of crew in various situations of flight, including on take off and landing, the universal automated catapult installations representing difficult technical devices are created. Are their part: the catapulted chair with a zagolovnik; system of the fastened-suspended belts providing communication of the person with a chair and parachute system; the shooting mechanism and the reactive accelerator; system of computer-controlled parachutes; mechanisms of restriction of dispersion and protection of extremities; devices for protection against an air flow; system of oxygen food etc. For rescue of astronauts on start a cabin, in a cut they are placed, is discarded (catapults) from the spaceship and the carrier rocket on safe distance by means of the emergency rocket engine. All catapulted devices (chairs, cabins, capsules) after separation from the aircraft go down on parachutes (parachute or parachute and reactive systems).

Distinguish experimental, educational and forced To. In the course of experimental To. safe conditions of action on an organism of shock loads and a high-speed air flow are studied, means of protection of the pilot from action of adverse factors are fulfilled.

Educational To. carries out sya, as a rule, on special exercise machines — land catapults on which skills of preparatory and executive actions are developed necessary at forced To., i.e. real escape of the aircraft in an emergency.

The main stages of escape of the aircraft are: assessment of an emergency situation and decision-making; preparation in a cabin to To. and turning on of the shooting mechanism (at this moment the unblocking of systems, fixing of a body by fastened belts, dumping of a lamp of the hatch of a cabin and other operations is automatically carried out); ejection from a cabin or actually process To.; separation from a catapult chair (in case of big height the stabilized descent together with a chair is made previously); disclosure of the main parachute and descent on it; landing (landing on water).

At To. the organism of the pilot is affected by shock loads (see. Acceleration ) — at ejection from a cabin, braking in an air flow, disclosure of a parachute and a landing and a high-speed counter air flow (at the time of an exit of a chair from a cabin and at the subsequent stages of flight after separation from the airplane). Besides, at To. the pilot tests strong psychological tension.

The overloads arising at To., cause changes fiziol, functions and in certain conditions can lead to damage of the ossa, soft tissues and internals. Shock character of overloads at To. is defined by a high gradient of their increase (within 200 — 400 g/sec.). The maximum size of an overload in the direction the head — a basin shall not exceed 18 — 20 units (g), and time of its action 0,2 — 0,4 sec. (it is established experimentally).

Portability the person of shock loads depends on the following factors: sizes, time of action and speed of increase of an overload; directions of a vector of an overload of rather longitudinal axis of a body of the person; poses, conditions of muscles, initial level of the main fiziol, functions by the time of influence of an overload; the areas of a support of a body and conditions of its fixing in the catapulted chair.

Action of a shock load belongs to the extraordinary irritants having generally exciting effect (nonspecific defense reaction). At the same time pulse rate and breath increases for 100 — 150%, lung ventilation increases, oxygen consumption increases, the ABP raises, vasomotor, miotonichesky and sensomotor reactions change, shifts of uniform elements and enzymatic activity of blood are observed. Also the apnoea, an asystolia, falling of the ABP, reduction of minute volume of blood, etc. are observed.

A short-term result of impact on an organism of a shock load is tension and deformation of all its fabrics and bodies. The main loading is perceived by the bone and copular and joint device, frame elements of fabrics and bodies.

Increase in portability by the person of shock loads is reached by use of protective agents and devices, special training and a training of aircrew.

To specific damages at To. spinal fractures in cervical, nizhnegrudny or lumbar departments, and also so-called asymptomatic compressions of vertebrae belong that obliges to carry out a X-ray analysis of a backbone at all catapulting pilots. The structure of traumatism is not characteristic since it constantly changes depending on conditions and the district of flight (To. over the sea, at the small height, the mountain area etc.), development of the aircraft equipment, degree of readiness of aircrew (including psychological) to escape of the aircraft etc.

Medical control for To. it is carried out in several stages. At the first stage the aviation doctor participates in studying of the model of the airplane in design office. All parameters of escaping of a cabin are studied at To., tilt angles of a back of a chair, seats, convenience of a pose that at an exit of a chair after shooting from a cabin of the airplane there were no injuries of extremities and that the pilot was not tired in flight of an inconvenient pose. The second stage of medical control is usual medical examination and poll of aircrew before flight. Later To. and landings carry out a survey of crew members, and for detection of possible injuries — a X-ray analysis of a chest and lumbar part of a backbone.

See also Flights .

Bibliography Alekseev S. M. and d river. Modern means of emergency escape of the airplane, M., 1961, bibliogr.; And with and to about in P. K. and d river. Theory and practice of an air medicine, M., 1975, bibliogr.; Bioastronautics and medicine» under the editorship of V. I. Yazdovsky, page 138, M.» 1966, bibliogr.; Lavnikov A. A. Fundamentals of air and space medicine, M., 1975; Fundamentals of bioastronautics and medicine, under the editorship of O. G. Ga-zenko and M. Calvin, t. 1 — 3, M., 1975.

S. A. Gozulov.