Posted on 08/15/2005 6:06:27 AM PDT by OESY
...Aviation experts were perplexed, saying it was rare for a plane to crash because of depressurization.
"Although there are precedents for both pilots losing consciousness at the controls of the aircraft in the past, for it to happen on a large airliner like a Boeing 737, with all the backup systems they have there, does seem to be really quite extraordinary," said Kieran Daly, editor of Air Transport Intelligence....
Airliners are pressurized by a system that draws air from the engines, which compress air for internal use. A valve at the back of the plane determines how fast air is let out of the fuselage.
Aviation experts say that depressurization is rare, and that when it occurs, a warning horn sounds in the cockpit, and crew members are supposed to put on oxygen masks and descend to 10,000 feet, where there is enough oxygen for humans to function even in a depressurized aircraft.
In October 1999, a Learjet carrying the golfer Payne Stewart and five others crashed in South Dakota after flying hundreds of miles on autopilot. Air Force pilots who shadowed the jet reported that the cockpit windows were iced over, a sign of depressurization.
After the investigation of that crash, a doctor with the National Transportation Safety Board said pilots' cognitive ability could fade away quickly when oxygen was limited, often faster than they realized.
Another source of incapacitation can be smoke or fumes in the cockpit. If the problem is not obvious from the wreckage, it may be discerned from tests on the blood of the victims, which will show what they were breathing before they died.
The cockpit voice recorder is likely to capture the sound of the warning horn, if it sounded, and conversation between the pilots about the problem....
(Excerpt) Read more at nytimes.com ...
That's the 1st thing I thought.
Those maint. records will be scrubbed cleaner than John Kerry's discharge.
I posted this a few minutes ago on another thread:
http://www.freerepublic.com/focus/f-news/1463039/posts?page=264#264
All aboard the Payne Stewart plane were frozen solid also.
Because the cockpit and pax oxygen systems are separate, to me it seems very possible that there was a failure of the pressurization system (which also provides heat for the airplane). The pax masks dropped down and worked. For some reason the cockpit oxygen system didn't work. The pilots had only a few seconds to get oxygen before they lost consciousness. They didn't make it. This would explain the pax being alive a bit longer than the pilots. Ambient temps at FL 350 were probably way below 0 celius. But, really, I don't know.
LOL! You really meant "Did anyone blame Clinton yet?", didn't you?
"Maybe they don't supply enough O2 flow if the cabin pressure is above 30,000 feet?"
Open a bottle of seltzer? you get bubbles. I recall from my AF Aircrew training at 30,000 ft one needs pressurized oxygen forced in the lungs otherwise the oxygen "boils" out of the blood. Passenger oxygen is not under such positive pressure. In fact the oxygen masks are designed to dilute the oxygen (plastic bag).
Amen
Maybe at 300,000 feet.
IIRC The heat and pressure systems are inter-related - heat of compression - if the pressure system fails - no heat.
I'm not entirely sure, but I believe the temperature is maintained by heat from either the APU or one of the engines. The pressurization and the temperature control are part of the same system, but have some failure modes that are different.
If you want on or off my aerospace ping list, please contact me by Freep mail not by posting to this thread.
Is that Alexander's mug peering out from the tail section?
With all the sophisticated systems on board aircraft these days, why can't the avionics detect whether or not the pilots are conscious? The plane could then descend to 10,000 feet and possibly even be programmed to land itself at an airport.
I'd be most interested in the blood tests...and the unit that sent the text message. The message was sent minutes before the crash. There were no other messages or phone calls? The F-16's were with the plane for 45 minutes. Lotsa questions!!
"Nothing to see here...move along.."
Aft Pressure Bulkhead failure???? The older 737's were retrofited because of known cracking in the pressure domes. That could explain the rapid decompression when no visible signs of skin failure were seen. But still- the audio alarms should of alerted the crew in time to put on their O2 mask and follow procedures they have practiced countless times.
Very strange.
The cockpit oxygen system is supplied by a small liquid oxygen tank mounted in the aircraft that is serviced by the ground crew. If this was not properly serviced, then there would be no oxygen for the pilots.
The passenger oxygen system consists of small canisters in the overhead bin that actually burn a chemical to produce oxygen (it was the improper storage of such canisters in the cargo hold of a ValuJet that caused it to burn and crash into the everglades in 1996.)
The Flight Attendants have portable oxygen bottles that they can wear while walking up and down the isles. This is separate from the Pilot and the Passenger oxygen sources.
Cabin pressurization and heating are both derrived from bypass air from the engine's compressor stage. You lose the compressed air, you lose the heat source.
My question is was this aircraft equipped with a reinforced cockpit door, such that the flight attendants could not get into the cockpit quickly enough to provide the aircrew with an alternate oxygen source?
It is Helios, Greek god of the Sun.
Thanks for posting that piece of info. I didn't realize it was that long.
So it is. Tnx.
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