Dear KMAG: 20190920 Open Thread

HEADLINE:
Delta Flight Makes Emergency Landing in Tampa After Plummeting 30,000 Feet
I hate the press, and this headline is a perfect example of why. Everything after the word “Tampa” is completely unnecessary…it’s there for the clickbait.
Lemme explain what happened so you don’t freak out if this ever happens to you.
The term “death zone” is the term used by mountain climbers for high altitude (26,000 feet +) where there is not enough available oxygen for the human body to maintain adequate O2 saturation in blood. Bad chit starts to happen, and if that condition persists….such as when climbers get trapped in the “death zone” on high mountains like Mt. Everes (usually because of bad weather)t…they can die from a lack of O2.
At FL300 (30,000 ft; 9,150 m) the avg. person with become unconscious between 60 seconds to 2 minutes without supplemental O2.
@ FL350 (35,000 ft; 10,650 ) it is 30 secs to 1 minute
@ FL400 (40,000 ft; 12,200 m) it is 15 to 20 seconds
Commercial aircraft typically fly between 30,000 and 40,000 feet. For the normal, avg. person to breath normally requires an altitude at or below 10,000 feet where the air is dense enough to maintain normal blood saturation.
Now, in order for people to travel comfortably at altitude in any given airplane the cabin must be pressurized for the time the airplane is above 10,000’. This is why your ears pop when you land. The plane is DEPRESSURIZED and the cabin pressure is equalized to the outside air pressure.
Now let’s do some math.
Assuming for the sake of this tutorial let’s say our plane Is in cruise at 40,000 when it experiences a cabin pressure failure for whatever reason. Normal rate of descent in a commercial airliner is approx. 2,000 to 3,500 feet per minute.
So, in the event of a cabin pressure failure for an airliner flying at 40,000, the crew needs to get the airplane to 10,000 as quickly as possible. But you can’t just point the plane straight (nose) down or it would very rapidly exceed it’s designed airspeed limits and the wings would/WILL SHEER OFF.
So….normally….
40,000. – 10,000. = 30,000 feet to lose
30,000/2,000 fpm = 15 minutes
But we don’t have 15 minutes to get down to 10,000 feet without people going unconscious. We only have 15- 30 seconds before people start passing out without using supplemental O2.
Even descending @ approx. 1 mile per minute (5,000 ft/min), it will still take (30,000/5,000) 6 minutes.
So…..
All airlines have an “emergency descent” plan for a loss of cabin pressure for whatever reason.
STEP 1
The airplane with automatically deploy the “plastic jungle” if it detects a cabin pressure altitude of 13,500 or greater. This is when the cabin 02 masks deploy. It looks like this…
STEP 2
The flight crew will immediately initiate an emergency descent to 10,000 feet.
But it needs to get there BEFORE the passenger O2 mask’s chemical O2 tablets run out of air.
Soooo….
What is required is a rapid, CONTROLLED descent to an altitude that even unhealthy people can breath without an O2 mask (10,000).
In the event of a cabin depressurization event (assuming nothing else, as is the case 99% of the time in all such recorded depress events) everything else on the plane is working FINE. It just needs to get lower QUICKLY, so the “deck angle” is very pronounced (nose down) and the 02 masks deploy so everyone can breath in the 4-6 minutes it takes to get down to 10,000 feet.
The plane is not plummeting…as in “plummeting out of control”….it is simply descending rapidly because of physiological considerations.
People will naturally think this is very scary because very few have actually experienced this and, since it’s something most have not experienced, they find it scary. Needless to say, Hollywood movies don’t help the situation either.
So, if this ever happens on a flight you happen to be on, now you know what is happening, and why. You do NOT need to be wondering if you’re about to die. You’re not. You’re simply being inconvenienced because you are going to divert to land at the nearest suitable airport instead of making it to your destination.
https://www.breitbart.com/economy/2019/09/19/delta-flight-makes-emergency-landing-in-tampa-after-plummeting-30000-feet/
Btw, I guarantee I’ve flown more than any 5 people here combined, and I have had my share of emergencies. This one is way, WAY down on my list of “scary”, ESPECIALLY with the systems that are now standard on all commercial jet aircraft in use today.
The article headline might just as well have read, “Delta Jet Diverts From Destination”, but that’s not going to generate as many “clicks” as the one they ran with.
Ces la vie!