4 ms·

I see that does making exceeding 60k pretty scary. I was from London to Denmark and we had cabin pressure loss I think we were maybe at 30k and dropped pretty

by taf2 7y ago

I see that does making exceeding 60k pretty scary. I was from London to Denmark and we had cabin pressure loss I think we were maybe at 30k and dropped pretty fast to 20 if I recall correctly. The sensation that I remember was slow motion and shock from the flight attendant as the masks did not deploy. Later after landing the captain told us during preflight they set the cabin pressure incorrectly such that as we went too high an emergency system kicked in the prevent the cabin from exploding... I was maybe 12 so the details are fuzzy but definitely the take away is cabin pressure loss is no joke

sokoloff 7y ago
Hard to puzzle the details there without knowing the aircraft type, but in the pressurized piston plane I fly, there is a main outflow valve used to regulate pressure that's under my (indirect) control and a safety outflow valve that's set just over the rigged max pressure differential (such that it partly dumps the cabin if that pressure is exceeded). Given that your flight didn't get the "rubber jungle" of deployed masks, the cabin pressure probably never dropped precipitously low, but rather started to oscillate as the safety valve dumped and closed, but never dumped enough to deploy the masks and the crew declared and descended in order to sort things out. A small number aircraft (non-airliners) are lost each year due to pressurization issues. It's a serious business, even in the high 20s and 30s (of 1000' MSL). Single pilots are required to continuously wear O2 mask at/above FL350 (35000') and one pilot of a two pilot crew must continuously wear O2 over FL410. Between FL350 and FL410, two pilot crews may rely on quick-donning masks. This is believed to be a commonly violated regulation (in that air crews regularly do not wear the required mask when things are operating smoothly).
- VBprogrammer 7y ago
  > This is believed to be a commonly violated regulation I believe that is an understatement. I've heard it described as the most commonly violated rule in aviation. There are a number of youtube pilots who commonly violate this rule seemingly without too much worry.

by taf2 7y ago

sokoloff 7y ago

Hard to puzzle the details there without knowing the aircraft type, but in the pressurized piston plane I fly, there is a main outflow valve used to regulate pressure that's under my (indirect) control and a safety outflow valve that's set just over the rigged max pressure differential (such that it partly dumps the cabin if that pressure is exceeded). Given that your flight didn't get the "rubber jungle" of deployed masks, the cabin pressure probably never dropped precipitously low, but rather started to oscillate as the safety valve dumped and closed, but never dumped enough to deploy the masks and the crew declared and descended in order to sort things out. A small number aircraft (non-airliners) are lost each year due to pressurization issues. It's a serious business, even in the high 20s and 30s (of 1000' MSL). Single pilots are required to continuously wear O2 mask at/above FL350 (35000') and one pilot of a two pilot crew must continuously wear O2 over FL410. Between FL350 and FL410, two pilot crews may rely on quick-donning masks. This is believed to be a commonly violated regulation (in that air crews regularly do not wear the required mask when things are operating smoothly).

VBprogrammer 7y ago
> This is believed to be a commonly violated regulation I believe that is an understatement. I've heard it described as the most commonly violated rule in aviation. There are a number of youtube pilots who commonly violate this rule seemingly without too much worry.