oxygen mask needs to be maintained

They are all pilots. Have you found that fighter pilots need to wear masks, but the civil aircraft we are on doesn't? Why?

01 anti motor overload

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The cruise speed of civil aircraft is generally 900 km / h, and the common flight speed of civil aircraft is Boeing 737: 785 km / h; Boeing 747: 940 km / h; Boeing 777: 870 km / h; Airbus A320: 900 km / h; Airbus A340: 1050 km / h; A380: 920 km / h. And civil aircraft will not complete high maneuver.

The average speed of a fighter is more than 2500 km / h. When a fighter pilot makes a high maneuver, it will cause a fighter maneuver overload.

The maneuvering overload of aircraft refers to the maximum acceleration that the structure of aircraft can bear when flying at high speed, especially when doing various high-speed and violent maneuvers. Its unit is generally expressed by the acceleration of gravity G.

Modern fighters can generally withstand up to 9 g overload, but the pilot can not withstand such a large overload. The pilot can only bear 4.25g maneuver overload for about 10 seconds without any auxiliary equipment.

In the process of maneuvering overload, the blood of fighter pilots will move to the legs under the action of gravity, and the blood supply of eyes and brain may be insufficient. Pilots will suffer from hypoxia of brain and eyes, vision loss or even unconsciousness, which will cause serious consequences.

Fighter pilots have to use a series of technical measures such as anti overload cockpit, new anti-G suit, compensatory vest, etc. to carry out overload flight for a long time. Wearing a mask is one of the measures. By forcing a large flow of oxygen into the lungs through the breathing mask, the oxygen content in the pilot's blood is greatly increased, which can provide 1.5g or even higher anti overload effect.

02 oxygen supply

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There is a pressurization system inside the civil aircraft, which can pump the air with adjusted humidity and temperature into the cabin to achieve the pressurization process, providing a comfortable boarding environment for passengers and crew.

After pressurization, the oxygen pressure level in the cabin is similar to that at 2400 meters above sea level. In this state, people can breathe normally without oxygen mask.

oxygen mask needs to be maintained

The fighter cabin is also equipped with pressurization device, and the residual pressure of the fighter cabin is generally maintained at about 34kpa. When the flight altitude is too high, even if there is pressurization inside, the oxygen content will not be very high, so the oxygen mask needs to be maintained.

The US Defense Weekly reported that the f-35a fighter of 56 fighter wing at Luke Air Force Base in Arizona had five consecutive pilots' hypoxia incidents during flight training, and 55 F35 fighters were grounded in the world. It can be seen that the importance of oxygen demand for fighter pilots in high altitude hypoxia environment.

The oxygen supply of mask can change the air in the engine room. During the take-off and landing stage of fighter, a large amount of harmful engine exhaust gas accumulated at low altitude on the runway of the airport can be reduced to cause injury to the pilot.

03 high tech equipment

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The noise of a fighter plane is much higher than that of a civil aircraft in flight. Fighter pilots wearing masks have good sound insulation effect, and wearing masks can reduce noise interference.

Modern fighter masks also contain many high technologies. There is a pair of glasses in front of the mask, which is actually a sight. There is a radio transmitter in the mask. The communication between pilots (front and rear seats) and between pilots and the tower is carried out through the radio transmitter.

Generally speaking, the flight environment of fighter planes is more difficult than that of civil aircraft, which is why after the retirement of fighter pilots, as long as they obtain a civil aviation pilot certificate, they can open civil aircraft.