Author Topic: Jet Airways flight in India forced to return due to low cabin pressure  (Read 250 times)

Offline kb4tez

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https://www.palmbeachpost.com/news/jet-airways-flight-india-forced-return-due-low-cabin-pressure/cjYWxYdP21ROt0lbQfPk4N/

A Jet Airways flight from Mumbai to Jaipur in India was forced to turn back Thursday when 30 passengers complained of nose and ear bleeds because of low pressure in the cabin, CNN reported Thursday.
An official with the Directorate General of Civil Aviation told News 18 that the crew allegedly forgot to press a button to pressurize the cabin.

"During (the) climb, crew forgot to select bleed switch due to which cabin pressurization could not be maintained, and oxygen masks got deployed," the official said.



Offline wiedehopf

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Re: Jet Airways flight in India forced to return due to low cabin pressure
« Reply #1 on: September 24, 2018, 08:05:54 AM »
Forgetting to turn the bleeds back on is a somewhat common occurence on the 737.

One report of a South Korean 737:
https://aviation-safety.net/reports/2015/20151223_B738_HL8049.pdf
EDIT: avherald article: http://avherald.com/h?article=49158d84&opt=0

Basically they forgot the bleeds, the excessive cabin altitude warning horn sounds and they run the checklist for excessive cabin pressure.
The checklist is basically an emergency procedure and not a good idea when you just forgot the bleeds.

They fully close the outflow valve manually (as the checklist calls for it). Then they decide to continue the climb.
Passengers complain of ear pain as while they were climbing the cabin has fully pressurized to sea level (they were at 10000 ft before).

Now they descend increasing cabin pressure further. Some time they overpressure relief valve opens because the outflow valve is manually closed.
They talk to maintenance at 8000 ft with maximum differential pressure. Because of the differential the cabin is actually below sea level and the needle therefore shows a cabin altitude of 25000 ft (while it is actually -5000 ft or something but the scale can't handle that)

The maintenance engineer advises them to slowly open the outflow valve and they land more or less uneventfully.


So going back to this occurence: When you are at 14000 ft and then fully pressurize the cabin and even descend you can cause quite some hurt because the cabin pressure is increasing quite quickly.


Anyway can't find the second report right now but it seems they should change the checklist to leave it in automatic mode if you just forgot to switch on the bleeds after taking off :(
« Last Edit: September 24, 2018, 01:17:31 PM by wiedehopf »