121 dead in Greek air crash

[righthand]

[center]CNN.com ...Sunday, August 14, 2005 Posted: 1417 GMT (2217 HKT
121 dead in Greek air crash[/center]
http://edition.cnn.com/2005/WORLD/eu.../greece.crash/

ATHENS, Greece (CNN) -- A Cypriot plane with "no sign of life" in the cockpit as it approached Athens has crashed into a mountain, killing all 121 people on board, Greek officials said. F-16 pilots escorting the jet after air traffic controllers lost contact with it said the pilot was not in the cockpit and the co-pilot was slumped over the controls, according to reports. The pilots of the Helios Airways Boeing 737 had reported an air conditioning problem, and Greek TV said a passenger sent a text message to his cousin saying it was freezing in the plane. "The pilot has turned blue (in the face)," the passenger said in the SMS message, Reuters quoted the television report as saying. "Cousin farewell we're freezing." The plane, Helios Flight 522 with 115 passengers and six crew en route from Larnaca, Cyprus to Athens, crashed about 12 p.m. Sunday (0900 GMT, 5 a.m. ET), officials said. The Greek government said there were no survivors. The jet entered Greek air space about 10:30 a.m., but efforts by air traffic controllers to contact the pilots were futile. After some time, two Greek F-16s were scrambled, Greek Air Force spokesman Yiannis Papageorgiou told CNN. As the F-16s approached, their pilots saw "no sign of life" in the cockpit, and the plane apparently was on autopilot, Papageorgiou said. The F-16 pilots reported the pilot was not in the cockpit, and the co-pilot was slumped over the controls, Anastasi said. They also reported they could see through the plane's windows that the oxygen masks had dropped down. The F-16s escorted the plane until it struck the mountain. The Greek Defense Ministry has denied reports that the F-16s shot down the plane.

{I'm sorry for the double posting. When I tried to post first , I got a 'No Server' message. I waited, posted and only then saw the earlier post.}

A possible explanation for the Crash. Obviously something happened the air conditioning system. Yet you would expect that lowering altitude would correct the freezing problem. My son suggests that the excellent insulation of planes would have the effect like a thermos flask. Even after they descended the plane would still be frozen.

Last night the BBC had program "The Guinea Pig Club" on the 60th anniversary of its existence. All had received horrific burn type wounds. One lost all his fingers through frostbit over Germany. Though lack of oxygen he blackout. The metal part of the plane was -40. It took 10 minutes for the pilot to get low enough for oxygen, saving his life with frostbit.

So in older type planes, descending works.

[righthand]

[center]All the signs point to a loss of cabin pressure... but why?
TELEGRAPH ...By Nic Fleming,
Science Correspondent

http://www.telegraph.co.uk/news/main.../wcrash215.xml [/center]

One of the main lines of inquiry for accident investigators scouring the wreckage of the plane was whether it suffered a loss of cabin pressure. Reports of a passenger in a mobile phone call saying that the pilots were unconscious and "we are cold" would suggest decompression was at least partly to blame for the disaster. Most airliners fly at an altitude of around 30,000ft where air pressure is substantially lower than at sea level. Air inside the cabin is "pumped up", or pressurised, because otherwise it would be so thin passengers and crew would be unable to get enough air to stay alive. So-called "creeping decompression" can be caused by leaks from faulty window seals or small breaches in the hull. However, in most commercial airliners a gradual leak would provoke decompression alarms. They would trigger oxygen masks and other emergency measures to bring the aircraft down to around 10,000ft where extra oxygen is not needed. David Kaminski Morrow, the deputy news editor of Air Transport Intelligence magazine, said: "It is a very confused situation. Ultimately, the suggestion that the cabin became very, very cold suggests that the crew may have been suffering from lack of oxygen. But it is very difficult at this point to tell what the reasons for that are. ''If the aircraft is at 30,000ft, you don't stay conscious for long, maybe 15 to 30 seconds. It is like standing on top of Mount Everest." More rapid decompression, also known as explosive decompression, causes an explosive noise. Greek state television quoted Haris Thrasou, the Cypriot transport minister, as saying the aircraft had experienced decompression problems in the past.

[monty of ll]

righthand- You quoted something interesting in that last post: ''If the aircraft is at 30,000ft, you don't stay conscious for long, maybe 15 to 30 seconds. It is like standing on top of Mount Everest."

Really? I know next to nothing about this topic but I assumed that one could survive for quite a long time on the top of Everest without an outside source of oxygen. I could have sworn that I had seen pictures of climbers on top of Everest without their masks for at least a few minutes. Is there a difference? What am I missing here? Is a rapid decompression in an airplane at 30,000 feet not survivable? Is this somehow a different situation? I was under the impression that this had happened several times in the past. Wouldn't an aircraft descend to at least 20,000 feet very rapidly where I know for a fact that a person can do quite nicely for an extended period of time?

[Matt W]

I'd imagine if you're acclimatised to high altitude & low oxygen (like the climbers & sherpas in the Himalyas), you could manage to breath for quite a while. However, if you're not wearing cold weather gear and an oxygen mask (like the passengers & crew of the plane), for the air to be literally sucked out of your lungs by decompression and then hit with immediate frostbite as well....not pleasant. :(

[PatrickHenry]

I bet explosive decompression can result in "the bends" or nitrogen bubbles in the bloodstream which can cause loss of consciousness within seconds. That's apparently what happened to Payne Stewart's jet and also to this airliner. The bodies were found frozen solid, despite that some were charred by the fire of the crash.

[Trotsky]

The offices of Helios-air have been raided by the authorites and arrest warrants have been issued for senior directors apparently.

[Wonderland]

Quote by: Matt W I'd imagine if you're acclimatised to high altitude & low oxygen (like the climbers & sherpas in the Himalyas), you could manage to breath for quite a while. :(

Yes, people who are accustomed to living at high altitudes, like some peoples that live and farm at high altitudes on some mountain ranges, build up physical atributes that allow them to function a these oxygen levels. For example, their blood thickens quite dramatically which allows them to survive, but also leads to complications in later life as thick blood often leads to a heart attack.

These pilots were obviously unaccustomed to these heights, and the rapid decompression can lead to symptoms alikened to the bends and it would take seconds to pass out.

They believe that all of the pasengers were passed out or dead before the plane struck ground.

[monty of ll]

Actually Patrick and Wonderland, I was wondering if you knew for sure if a person could get the bends (nitrogen narcosis) from rapid decompression. When a diver gets the bends it's from breathing compressed air at 2, 3, or 4 atmospheres. When a plane is pressurized I believe it is only pressurized to 1 atmosphere to equal sea level pressure. This would make sense considering that the plane would be pressurized to about 15 psi if the outsie was at complete vacuum.

I'm certainly not an expert on the subject but I am a scuba diver and I know what causes the bends and what happens to divers who don't take the necessary precautions. I also know that breathing air at 1 atmosphere over sea level pressure (33 feet down) is considered safe for almost any amount of time. And as a point of interest, 100 feet down gives you about 25 minutes breathing compressed air safely within the limits.

Now that we are into the subject maybe someone who really knows about the subject could comment on the possibility of getting the bends in an aircraft which descends too rapidly.

Oh and btw wonderland, the bends doesn't make you pass out. Rapid decompression might.

[PatrickHenry]

Bends can kill you. I don't know if explosive decompression can cause it. Nono should know. He's a pilot.

I dive, too. The instructors told us not to go to high altitude after diving because of the possibility of getting bent...

I think that airliners are pressurized to simulate 8,000 ft.

[monty of ll]

Patrick- No doubt bends can kill you. Yes, we are told not to fly or if we do fly after diving then stay away from your diving limits.

You said: "I think that airliners are pressurized to simulate 8,000 ft"

As we dive in the ocean the pressure increases and as we go above sea level the atmospheric pressure decreases. As we ascend from a dive it's the decrease in pressure that causes the bends. Knowing that, your comment above has lost me altogether. Maybe Nono will be able to help out?

[Zeebadee]

Quote by: monty of ll Patrick- No doubt bends can kill you. Yes, we are told not to fly or if we do fly after diving then stay away from your diving limits. You said: "I think that airliners are pressurized to simulate 8,000 ft" As we dive in the ocean the pressure increases and as we go above sea level the atmospheric pressure decreases. As we ascend from a dive it's the decrease in pressure that causes the bends. Knowing that, your comment above has lost me altogether. Maybe Nono will be able to help out?

I don't believe that even explosive decompression would cause the bends in this case, as going from a pressurized cabin to an altitude of 34,000 feet isn't even a one atmosphere change. This sounds more like a slow pressure leak that wouldn't be recognized before causing oxygen deprivation and loss of consciousness. The air conditioning and the cabin pressure controls are two different systems. The A/C could keep up with the extreme cold at 34,000 feet for a bit, but eventually would not be able to compensate for such low temps at that altitude. By then, however, most of the people aboard would be unconscious from lack of oxygen. If the flight crew didn't recognize the slowly declining cabin pressure, they could have been incapacitated before they realized what was happening.

[Trotsky]

Guys it wasn't the bends that killed them, it was oxygen deprivation caused by the extreme altitude which will lead to a condition called hypoxic hypoxia. This coupled with the extreme cold and they were screwed.

Also a drop from approx 1020 mbar to 250mbar (the average pressure at 35,000ft) is enough to give rise to the bends, the bends arises from sudden changes in pressure on the body, they do not need to be massive just very sudden.

[PatrickHenry]

It's all about the partial pressure of the nitrogen dissolved in the blood. Formula here: http://dwb.unl.edu/Calculators/pdf/Bends.pdf

More about scuba than decompression in airliners, but the formula works both at higher and lower atmospheric pressures.

Hypoxic hypoxia: http://www.findarticles.com/p/articl...47/ai_94931785

[monty of ll]

Thanks Trotsky, I didn't realize that a sudden drop of 1 atmosphere could cause the bends. Or at least the 'bends' to the point it would be debilitating. However I wasn't under the impression that it was the bends that gave them their problem, rather more likely a lack of oxygen. The question still remains though, why didn't either the co-pilot or the pilot use their oxygen masks immediately and then descend to an altitude where they would have been safe? Hopefully we will find out the answers when they finish their investigation.

And thanks for the informative links Patrick. I'm still at a bit of a loss as to a change of 1 atmosphere causing the bends because we both know as divers that we can spend all day at 30 feet and then rise to the surface rapidly. We also both know that nitrogen needs to be breathed off and that surely doesn't happen when we come up from 30 feet rapidly. Whatever. It gets a little technical to delve into it completely and therefore I will just accept it as is. Unless you have more to say on the subject?

[PatrickHenry]

It's too technical for me to really get it without some tutoring from an expert. But there is evidence that some people survived until impact while others were frozen solid, indicating that they had died early enough in the flight to harden up...

[monty of ll]

Frozen solid? I would like to know how long it takes to freeze a person solid! At -60 probably at least a couple of hours. I've been in -40 for a couple of hours and I was feeling o.k. Well, actually a little uncomfortable and granted, I was dressed for it. Is anyone suggesting that this plane flew itself for a couple of hours?

[Trotsky]

It was in the air for approx 55 mins. The problem with hypoxia is that your mental faculties are almost non-existant, chances are the co-pilot was away in his own little hypoxic world. The oxygen masks should decend automatically when a drop in air-pressure is detected, in fact they probably did, but most of the passangers where probably not in a state to use them.

[PatrickHenry]

Quote by: Trotsky It was in the air for approx 55 mins.

This seems to add up to a flying time of nearly 2 1/2 hours: http://www.cnn.com/2005/WORLD/europe....ap/index.html

The Cypriot plane that crashed and killed all 121 people aboard flew on autopilot to its Athens destination -- but passed thousands of feet (meters) above the airport runway, the chief accident investigator told The Associated Press Thursday. Helios Airways Flight ZU522 then turned toward the sea, flying in a holding pattern for more than an hour before changing course again crashing into a mountain north of Athens. <snip> Investigators are examining whether the 115 passengers and six-member crew aboard the Boeing 737-300 had lost consciousness, possibly just after takeoff. The aircraft appears to have flown from Cyprus to Athens on autopilot -- a flight of about an hour and a half.

Quote by: monty of ll Frozen solid?

http://www.cnn.com/2005/WORLD/europe/08/15/greece.crash/index.html

A Greek Defense Ministry source with access to the investigation told Reuters that most of the bodies recovered were "frozen solid." "Autopsy on passengers so far shows the bodies were frozen solid, including some whose skin was charred by flames from the crash," the source said.

[PatrickHenry]

http://cnn.netscape.cnn.com/ns/news/...805greek_plane
Now a story that

A man who sounded exhausted sent two frantic Mayday calls from a Cyprus airliner just minutes before it crashed with both the pilot and co-pilot at least unconscious, Greek officials said on Monday. The crash on Aug 21 into mountains near Athens of a Helios Airway Boeing 737 killed all 115 passengers and six crew setting off one of civil aviation's most baffling searches for a reason for Greece and Cyprus' worst air disaster.