A Shenzhen Airlines Airbus A330-300 today suffered a sudden loss of cabin pressure at 9100 meters (FL300). The aircraft was performing a routine flight from Shenzhen to Xian under the flight number ZH-9209. Almost 25 minutes into the flight, after climbing out of Shenzhen’s Bao’an International Airport, the crew initiated an emergency descent to 3600 meters (FL118). Five minutes later, pilots tried to climb again; however, aborted at 6000 meters (FL197). The aircraft then turned back and landed safely back in Shenzhen about 100 minutes after departure.
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Details
As of now, there is not a lot of available information on the incident. It is known that all the passengers and crew onboard the aircraft are safe and no one was injured seriously. An alternate Airbus A330-300 with registration B-1036 completed the flight with a delay of about 4.5 hours. The involved aircraft is still on the ground about 10 hours after landing back.
At the time of cabin pressure drop, the crew was quick to respond by setting transponder to the emergency code of 7700 (squawking 7700). This helped the aircraft get special consideration and priority landing at Shenzhen. The descent is said to be rather dangerous, with the aircraft falling 6000m in nearly two minutes.
Possible reasons
Although the loss of cabin pressure is not a frequent phenomenon, there have been many such instances in the past. Frequent fliers will relate to pre-departure announcements, which advise passengers to use the oxygen masks if a loss in pressure occurs. Though it might sound scary, having a knowledge of such a situation can prove to be very vital.
Aircraft cabins are pressurized using cooled, and filtered air bled from the engines, keeping the air pressure inside the cabin at the equivalent of an altitude of around 8000 feet. This is done in order to create a safe and comfortable environment for passengers and crew flying at high altitudes. Significantly lowering cabin pressure can have fatal consequences on passengers onboard.
Cabin pressure loss can be either slow or sudden. Technical problems, for example, failure of pressurization systems are one of the most common causes. However, very dangerous situations, for example, cracks in windows or the fuselage, incorrectly sealed doors, and explosion on an aircraft, can cause a sudden pressure drop.
Past incidents
In most cases, loss of cabin pressure is known to be a handleable situation. Immediate response is very significant as far as the safety of those onboard is concerned. Any delay can prove to be fatal as passengers or crew can have hypoxia or a lack of sufficient oxygen.
In 2005, a Helios Airways plane en route from Cyprus to Athens crashed into a mountain after a loss of cabin pressure, killing all 115 passengers and six crew onboard. It was later found that pilots fell unconscious as they suffered hypoxia. In 2018, more than 30 Ryanair passengers, some bleeding from their ears, received injuries after their plane lost cabin pressure at 36,000 feet.
Have you ever been in a stressful situation like this? Let us know.