A Jet Airways 737 failed to pressurize due to 'a switch' having been forgotten by the crew. I suspect that the pressurization switch was left in manual after ground testing. If so, it is a repeat of Helios 522, except for the non-fatal outcome. I have to wonder how close this came. Why is there still no alarm (like a configuration warning) to alert pilots once the aircraft exceeds 10,000 ft? Seems like a no-brainer to me.
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Originally posted by Evan View PostA Jet Airways 737 failed to pressurize due to 'a switch' having been forgotten by the crew. I suspect that the pressurization switch was left in manual after ground testing. If so, it is a repeat of Helios 522, except for the non-fatal outcome. I have to wonder how close this came. Why is there still no alarm (like a configuration warning) to alert pilots once the aircraft exceeds 10,000 ft? Seems like a no-brainer to me.
https://www.bbc.com/news/world-asia-india-45584300
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Originally posted by Evan View PostA Jet Airways 737 failed to pressurize due to 'a switch' having been forgotten by the crew. I suspect that the pressurization switch was left in manual after ground testing. If so, it is a repeat of Helios 522, except for the non-fatal outcome. I have to wonder how close this came. Why is there still no alarm (like a configuration warning) to alert pilots once the aircraft exceeds 10,000 ft? Seems like a no-brainer to me.
https://www.bbc.com/news/world-asia-india-45584300
Then there is another chime and automated PA when the pax mask drop.
It takes a lot of effort to miss all the cues (and I didn't even mention the cabin altimeter, cabin VSI and diff press gauges).
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Some contradiction here:
The DGCA is following up on reports suspecting the crew forgot to turn on a switch needed for proper cabin pressure control.
Passengers reported there had been a very sharp drop of cabin pressure causing nose and ear bleeds, the oxygen masks were released.
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--- Defend what you say with arguments, not by imposing your credentials ---
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By the way, when they say "put the mask over your mouth and nose", and means and, not or.
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Originally posted by darazarbaf View PostHow can the pilots simply forget! Isn't there a checklist?
People can miss items even when honestly trying to follow a checklist. I have. It is called skipping a line.
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--- Defend what you say with arguments, not by imposing your credentials ---
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Originally posted by Gabriel View PostChecklists are helpful and mitigate the risk, but are not bulletproof.
People can miss items even when honestly trying to follow a checklist. I have. It is called skipping a line.
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Well, if it was blue font than you also understand that not only there is a warning but it served its purpose this time since the crew immediately stopped the climb.
A Jet Airways Boeing 737-800 flight 9W-697 departed Mumbai's runway 27 when the passenger oxygen masks were released. The crew stopped the climb at FL110, descended the aircraft to FL100 and returned to Mumbai
What about an earlier warning? If the cabin vertical speed matches the aircraft vertical speed and it is greater than... I don't know... 1000 fpm, then trigger an alarm. Or if the diff press is zero with the radio-alt greater than 2000ft.
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--- Defend what you say with arguments, not by imposing your credentials ---
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Originally posted by Gabriel View PostWell, if it was blue font than you also understand that not only there is a warning but it served its purpose this time since the crew immediately stopped the climb.
So, why the return? Why not just go "oh, duh" when the alarm sounds, switch to auto, and continue the climb? And why the reported injuries?
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Originally posted by Evan View PostThat wasn't in the story that broke. The mask deployment, reports of nosebleeds and ear pain and the return didn't seem to indicate that the climb was stopped at a safe altitude.
So, why the return? Why not just go "oh, duh" when the alarm sounds, switch to auto, and continue the climb? And why the reported injuries?
The report of intense ear pain, ear bleeding and nose bleeding seems consistent with a sudden loss of pressure, not with a gradual reduction in pressure caused by climbing unpressurized as reported.
The report of the pilots leveling off at 11000 ft seems inconsistent with the O2 mask deploying.
The 2 things that seem to be factual and objective are the injuries and the O2 masks being released. That is consistent with a sudden loss of pressure above 14000 ft.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Originally posted by Gabriel View PostWe have 2 contradictions in the AvHerald and others' reports:
The report of intense ear pain, ear bleeding and nose bleeding seems consistent with a sudden loss of pressure, not with a gradual reduction in pressure caused by climbing unpressurized as reported.
The report of the pilots leveling off at 11000 ft seems inconsistent with the O2 mask deploying.
The 2 things that seem to be factual and objective are the injuries and the O2 masks being released. That is consistent with a sudden loss of pressure above 14000 ft.
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Originally posted by Gabriel View PostWe have 2 contradictions in the AvHerald and others' reports:
The report of intense ear pain, ear bleeding and nose bleeding seems consistent with a sudden loss of pressure, not with a gradual reduction in pressure caused by climbing unpressurized as reported.
The report of the pilots leveling off at 11000 ft seems inconsistent with the O2 mask deploying.
The 2 things that seem to be factual and objective are the injuries and the O2 masks being released. That is consistent with a sudden loss of pressure above 14000 ft.
And the injuries... couldn't they be caused by a sudden *increase* in pressure?
So, a possible scenario: pilots accidentally leave pressurization off. Cabin alt. rises as the a/c climbs, and for some reason they miss the altitude warning at 11K. Cabin alt. continues to increase until the masks drop upon reaching 14K. At that point the pilots realize what's going on, turn on pressurization, the a/c suddenly pressurizes and injuries happen.
At which point they decide they should return to the airport not because of a technical fault but because of the injured pax.Be alert! America needs more lerts.
Eric Law
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