Flying Safety

[xoxoxoBruce]

I’ve flown on commercial airliners a zillion times and at the beginning of each flight carefully checked out the stewardesses boobs while she gave us the safety drill.
Maybe that’s why I was surprised today when I was reading this article in the Wall Street Journal about the Cypriot Airliner crash in Greece.

snip~~ At cruising altitudes of more than 30,000 feet, the occupants of an aircraft are heavily dependent on cabin pressurization and climate control to stay alive. Normally, cabins are pressurized to the equivalent of 8,000 feet above sea level. If there is some sort of failure, which appears to be the case in the crash of the Helios Airways Boeing 737, the crew and passengers must react within seconds to don their emergency oxygen masks before losing consciousness.

For passengers, the importance of donning masks quickly is underscored subtly in every U.S. airline's preflight briefing, when travelers are told to put on their own mask before helping children or others. According to the FAA, the time of "useful consciousness" after a rapid depressurization can range from under a second to about 30 seconds, depending on the individual and the circumstances.

When decompressions do occur, they can be drastic and uncomfortable. A sudden loss of pressurization can result in piercingly painful ear blockage, loss of consciousness -- even exploding dental work as pressures within the human body try to come back into balance with external air pressure.

On passenger airliners, there are two separate emergency oxygen systems. Pilots have one that consists of so-called quick-don face masks attached to oxygen bottles. They are located within reach of both pilots are designed to be put on in five seconds or less. Emergency procedures, which are trained until they become rote, call for the pilots to immediately begin a rapid descent of about 3,000 feet a minute, much more noticeable than the 300 feet to 500 feet a minute of a routine descent.

Passengers have a less-sophisticated system that relies on oxygen-generating canisters that are attached to yellow plastic cups that drop from overhead. These canisters are activated by pulling sharply on the mask, starting a chemical process that generates oxygen for about 15 minutes.

"Neither one of these systems is designed to provide oxygen for continued flight at higher altitudes," says Rogers V. Shaw II, a team leader at the Federal Aviation Administration's Civil Aero Medical Institute in Oklahoma City. "They are designed to get you down to a safe altitude." ~~snip

1 to 30 seconds! Holy cow...I thought I'd be good for as long as I can hold my breath.

[mricytoast]

That really just depends on your age and weight and other bodily circumstances. If your body isn't able to adjust to stressors, then yea, maybe you'll black out, but probably as long as you can hold your breath for a healthy, fit, in shape human.

I imagine the exploding dental work might interfere with your breath holding ability.

[plthijinx]

the higher you fly, the more chance you have of falling unconscious more quickly. This may help. this web page has good explanations and graphs on the physical reactions to the body at altitude.

[Hobbs]

Me thinks that next time the flight attendant is explaining how to place the face mask over my face before the flight, I...I'll just have mine already on. With my hand on the cord ready to pull at the slightest hint of danger.

[mricytoast]

It seems now that I don't want to hold my breath. But this sounds strangely like it belongs in "Culture of Fear". What are the actual statistics of a plane decompressing? What are the actual chances? I would listen to them more than I would listen to the media and the fact that there have been two recent plane crashes.

And it also reminds me of Fight Club with the Air Plane manuals and the people screaming and killing each other for the oxygen mask.

[plthijinx]

i came across a figure of the number of explosive decompressions but i can't find it now. it was something like 1 in 50,000 flight hours. what happens is this. there is an air bladder seal around the door and when you turn on the compressor the bladder inflates and seals the door. now, there are valves that regulate the cabin altitude, typically to hold the pressure in the cabin to 8,000 feet but you can adjust that. if your at altitude and the seal pops or a window breaks somehow then you have your explosive decompression. usually though you'll get a sticking or leaking valve that would be the cause and that would just cause discomfort and the pilot would execute a decent to below 12,000. ah, HERE is the site i found earlier....

[Mr.Anon.E.Mouse]

Grunt breathing can help force oxygen back into the blood system.

[xoxoxoBruce]

That first link suggests the gas in my intestinal will likely cause me to shit myself in the event of cabin pressure loss.
In the event of cabin pressure loss, I'd say shitting myself is a given.

[plthijinx]

from avweb

Helios 737 Speculation, Evidence…
Student Pilot Was At Controls, Says Magazine
A Helios Airways Boeing 737-300 full of unconscious or semiconscious crew and passengers ran out of fuel with a student pilot / flight attendant at the controls before crashing in Greece last week, according to a report in Flight International. The flight's cockpit voice recorder has been recovered (in pieces), but its contents have not been publicly disclosed. The magazine said it obtained an exclusive interview with Capt. Akrivos Tsolakis, the head of the Air Accident Investigation and Aviation Safety Board, who confirmed earlier reports that a male flight attendant, identified by a Macedonian news agency as Andreas Prodromou, who had a few hours of private pilot instruction, managed to take the plane off autopilot and begin a descent. If true, that might help explain the plane's final maneuvers, which included "a descent from 37,000 feet to 2,000 feet and then an ascent to 7,000 feet," according to a report from The Associated Press. Meanwhile, the coroner has reported carbon monoxide was not responsible for rendering the aircraft's occupants unconscious -- decompression still ranks high in suspected causes. Late reports state that the plane ran out of fuel as it passed through 7,000 feet (and after about three hours in the air, on a scheduled 80-minute flight). It crashed about 25 miles northeast of Athens. According to Flight International, Tsolakis said Prodromou and another flight attendant were able to stay conscious by using portable oxygen tanks after the rest of the crew and passengers passed out when the air conditioning and pressurization system malfunctioned. The magazine said Tsolakis noted that the plane's air conditioning had been fixed five times in the previous two months. On the crash flight, the captain reported air conditioning problems a few minutes into the flight but the plane continued to climb, likely on autopilot, to 34,000 feet. The last radio communication with the plane was 11 minutes into the flight.