In a shocking case of negligence, a Jet Airways Mumbai-Jaipur flight had to be redirected to Mumbai today. During the climb, the crew of Boeing 737 forgot to turn on a switch to maintain cabin pressure inside the aircraft. Soon enough, the passengers started complaining of headaches and as many as 30 of them started bleeding from their ears and nose. According to sources, the crew had forgotten to switch on what is known as the “bleed switch,” which led to low cabin pressure, triggering the bleeding episodes.
What is Cabin Pressure?
The insides of aircraft are pressurised in a process known as cabin pressurisation to maintain a comfortable environment inside for humans. Through this process, cool filtered air is pumped into the cabin from gas turbines to keep the oxygen at a safe level. Even if the aeroplane scales 40,000ft, the air pressure inside will be at tolerable levels, that of 5,000ft- 8,000ft. Jet Airways Issues Statement After Passengers Face Harrowing Time Mid-Air in 9W 0697 Mumbai-Jaipur Flight.
To understand cabin pressure, one should know what Armstrong’s limit is. It is a measure of altitude above which humans cannot survive in an unpressurised environment. Usually, this limit starts at 18-19 km above sea level.
Above this limit, humans can experience a host of physiological problems due to the reduction in air pressure and breathable oxygen.
How Does Cabin Pressure Impact the Human Body?
The higher one goes, the lower the air pressure gets. Once the aircraft starts climbing, the air pressure decreases inside the cabin, causing the gases to expand. Similarly, when the aircraft descends before landing, the air pressure increases, causing the gases to contract.
When the aircraft descends, the air flows back into the middle ear and the sinuses and equalises the pressure. But if this doesn’t happen, we feel a blockage-like sensation in the ears.
These changes in the pressure also affects the air that is trapped inside the human body. That’s why, we feel a funny sensation inside the ears when the plane takes off. The popping sensation in the ears is caused by the air escaping from the middle ear and the sinuses when the aircraft starts climbing.
What Happens When Air Pressure is Not Maintained Inside The Aircraft?
The Boeing 737 incident happened because the air pressure inside the cabin wasn’t maintained. When the plane went higher, the air escaped outside where the pressure was lower, further lowering the pressure inside. The air inside the ear and the sinus cavity, which was at a higher pressure, also escapes, creating a pressure on the tissues. Here’s how it affects the human body. Jet Airways 9W 0697 Mumbai-Jaipur Flight: Passenger Recounts Mid-Air Horror as Cabin Pressure Falls.
Barotrauma –The nose and ear bleed experienced by the passengers in the aircraft is a result of low cabin pressure and its impact on tissues. When the aircraft climbed, the gases trapped in the body expanded inside the middle ear and the sinuses, putting pressure on the tissues.
Tears in tissues can cause gas to enter the body and cause a blockage in circulation or interference with organ function.
Common repercussions of barotrauma is sinus injury, ear injury, facial injury, tooth injury, gastrointestinal cramping, skin bruising and bleeding inside the lungs.
Hypoxia – Hypoxia is a condition where the human body experiences a shortage in oxygen (hypo means low and oxia refers to oxygen). When the cabin is pressurised, the air inside contains enough oxygen for the passengers. But as the air pressure decreases, the oxygen in the blood reduces.
Altitude Sickness – When the air pressure drops and there is less oxygen available, one can experience breathlessness, fatigue, nausea, headaches, sleeplessness and in some cases swelling in the lungs. That’s because hypoxia makes the person hyperventilate, helping increase oxygen levels. But it can cause carbon dioxide levels to fall in the body, raising the pH level of blood and causing alkalosis.
Usually, airlines are careful about safety protocol and such instances, where the crew forgets to turn on the bleed switch, are rare. Environmental and physiological changes that occur due to low cabin pressure can worsen underlying medical conditions such as sickle cell anaemia, cardiac problems, lung diseases, middle-ear and sinus problems, deep vein thrombosis, etc.