OT - Greek 737 plane crash

I'll put this down to more casualtied in the war on terror. With the cockpit door locked the passengers were only able to freeze and wait hours for the crash.

Mechanically (metal) it may have been similiar to the one in N. Dakota where the pilot went to the bathroom and then the depressurization valve failed open. The pilot was not able to leave his oxygen hose. In the Greek case, the co-pilot may have been on oxygen but he was not first rate and maybe was waiting for the pilot to return and ran out of oxygen?

The only (slim) solution I see, IF the cockpit door is not locked, is for passengers to fill their barf bags with O2 so they have a breath or

If the copilot knew anything at all about flying, he'd have descended to about 12K feet very quickly to get oxygen for the whole plane -- that's SOP!

Norm

What are the European rules on oxygen generators?

In the US the passenger oxygen generators are chemical based, and unfortunately not really testable until you need them.

In the US, the crew oxygen is from pressurized oxygen cylinders.

One could imagine a low-budget airline not keeping good tabs on the crew emergency oxygen cylinder or the plumbing. (I can imagine looking at the cylinder gauge every flight but never checking that the plumbing is intact...)

Worst case is that the passenger oxygen systems work fine but the crew is locked up front with no oxygen. "I'd rather die peacefully in sleep like my grandfather, not screaming in terror like his passengers".

Tim.

"Tim Shoppa" wrote in message news: snipped-for-privacy@g49g2000cwa.googlegroups.com... | > the other must go on oxygen | | What are the European rules on oxygen generators? | | In the US the passenger oxygen generators are chemical based, and | unfortunately not really testable until you need them. | | In the US, the crew oxygen is from pressurized oxygen cylinders.

I need to clarify this. I only build widebody Boeing aircraft, so I'll throw this out as fact as it relates to widebodies: 747's can be bottles or generators, whatever the customer orders. 767's are only generators. 777's are either as well. The crew in the flight deck has bottles mounted nearby. Flight attendants have bottles mounted throughout the airplane that are removable and can be carried around, or if needed, provided to passengers. Some planes are equipped with medical oxygen outlets for when they need to replace a seat with a stretcher and provide the passenger with oxygen on a continuous basis throughout the flight, so can be partially pumbed. The governing aviation authority has no specifications about the source of oxygen. There are advantages and disadvantages to both. The Passenger Service Units (PSU's) are a complete module that are easily reconfigured with the airplane, but plumbed oxygen requires more hassle, obviously. Some folks don't like the plumbing all over the plane with pressurized oxygen, but it is lighter than all the generators, which are a bit hefty. Chemical generators have a shelf lift. Remember that plane that augered itself into a Florida swamp? It was carrying out of date generators on pallets in violation of FAA regulations. When one goes off, they all get set off by the heat.

| One could imagine a low-budget airline not keeping good tabs on the | crew emergency oxygen cylinder or the plumbing. (I can imagine looking | at the cylinder gauge every flight but never checking that the plumbing | is intact...)

The 737 line has put gobs and gobs of planes in the sky. There's so many of them that any accidents will show a preponderance of damage to them. The airlines that maintain them are often shabby excuses for a business that I wouldn't trust them to run a taxi fleet, but the 737 is such a well built and designed airplane that it keeps an awesome safety record despite the best efforts of idiots/

| Worst case is that the passenger oxygen systems work fine but the crew | is locked up front with no oxygen. "I'd rather die peacefully in sleep | like my grandfather, not screaming in terror like his passengers". | | Tim.

There is a system on board that when cabin pressure drops below a certain point the PSU's all open up and the masks fall down. The fact that they were all down meant that the system worked as meant to. If there were a leak in the cabin air conditioning system, oxygen deficient air can be circulated in the cabin, and unknowingly, especially if most are asleep, they will either pass out or die gently. Some stayed awake because there's always a few odd ones out there. The crew gets the same ambient air as the cabin. They are no different in that respect. With the plane on autopilot, the crew up front has little to do other than read a paper or book, take a nap (one at a time, supposedly,) or snuggle with a stewardess (or steward, for those inclined or so equipped!) so I can see both pilots dozing off as well. Eventually the system keeps cooling down and they will all freeze. Autopsies will further determine what happened, as to the oxygen levels in the blood of the passengers and other stuff.

The cabin pressurization system on the 737 is supplied from the engine compressor bleeds, as you well know. I'm having a hard time envisioning any scenario wherein a leak in the cabin air con. system could feed oxygen deficient air into the cabin. An engine fire could likely contaminate the bleed supply, but that apparently didn't happen here. A malfunction in the high stage precooler maybe, causing it to supply overheated air and light off ducting somewhere. But there's plenty of warning when that happens, and it's taken care of automatically and shut off by the duct overheat system. They wouldn't have been using high stage air at altitude anyhow. A recirc. fan overheat, but that would stink so bad that the crew would shut if off immediately. I can't see any way oxygen defiicient air could be fed to the cabin. The flt. and voice recorder playbacks should be interesting. I also think you're a little quick to throw out "idiot" with respect to the people who maintain these things for a living. I've been doing it for 35 yrs., and the level of incompetency you're describing is very seldom seen. The men I work with are dedicated to the craft and take it very seriously. Our families ride on these things.

Garrett Fulton

I'd feel even happier if all maintenance workers had to fly to work each day on the planes they maintain.

That's the solution they found for sloppy parachute packers during WW2.

At the end of every day, they gave each packer a chute at random from the day's lot, "here, we're gonna go take a quick jump...."

Jim

Guess you never went deep skin diving have you. I used to dive to 35 to 40 some odd feet breathing out as I went down to have less to buoy me up. Grab the lobster or sea shell or miss altogether - look around and begin the drive home.

As a teenager, I used to spend pre. low tide to post next low tide hunting and eating lunch on a tube carrier in the deep lagoon - mid Pacific.

The risk would be O2 or air once there. If the control was in a funny place it might be there but not available.

I see this issue as a serious condition of a solid locked door. There should be a NO JOY or Dead man switch that must be disabled or an alarm and then call home... It then should put an alarm on the whole plane and unlock the door.

E.g save our souls by a piper cub pilot...

Martin

Since the plane crashed & still had fuel, maybe the co-pilot set the autopilot to a lower altitude and it took too long to get there?

Yeah, I was around an old 4 engine turboprop Tupolev something at a place I worked overseas. The Russians didn't seem to build airplanes with a lot of finesse, in my opinion. Wasn't a flush head rivet on the thing. Had to lose several hundred horsepower to drag and the African carrier didn't maintain it worth a damn. It's a small thing, but the air cycle machines in the packs never pull in outside air. Air from the ram air doors flows across the the air to air heat exhangers to cool the engine bleed air before it enters the air cycle machine, and then again between the compressor and turbine of the A.C.M. But every molecule of air in the cabin at altitude has passed through the engine's compressors. The recirc. system was added years ago as a fuel saving measure. I keep thinking that maybe something in the aft. baggage bin, (pressurized with cabin air for the dogs), was releasing some kind of agent. We've been puzzling over this thing at work. Of course, if it was a terrorist thing, those wailing shitheads would have long since claimed responsibility.

Garrett Fulton

Interesting. I would've suspected that pressurized oxygen would be heavier.

In any event, when I'm on an airplane I'm nervous enough that it's a hurtling kerosene tank. Pressurized oxygen and plumbing, or chemical oxygen generators, give me the heebie-jeebies. I would've thought that the pressurized oxygen was heavier due to tankage but maybe the O2 cylinders I see in hospitals/shops are way overdesigned compared to aircraft weight standards.

Now, smoking while on a hurtling kerosene tank that also has chemical oxygen generators and/or pressurized O2, that does not strike me as the right thing to do at all! It's not that I'm afraid of flying, it's just all those risk factors being put in the same place. In the shops I work (related to public transportation but generally not exposed to the public) having any two of those four things in the same place would have you shut down so quick by the safety people, and we aren't even hurtling through the air!

Tim.

Not likely. The average airliner has so little in common with the average lightplane that the pilot would just change the scene of the crash. Airliner navigation systems are so complex that he wouldn't be able to figure out where he was, much less get the thing configured and lined up for a workable approach and landing, and things like gear and flaps slats and spoilers and reverse thrust can keep two experienced pilots plenty busy. Just figuring out how to disable the autopilot might take time. An airliner responds very slowly to control inputs compared to a lightplane and is travelling much faster, so requires a lot of advance thinking. We have commercial students who have trouble keeping up with an advanced lightplane while breathing good air at low altitude, unlike our mythical Cub pilot in a depressurized and freezing-cold airliner.

Dan

Remember, 19 guys who had never flown a real heavy (just light craft and simulators) managed to line up on some pretty tight targets 4 years ago.

Bringing that plane into the pentagon at exactly ground level was quite a feat. (Of course they had practiced this hundreds of times on the simulator I'm sure.)

Tim.

There are more problems with landing (at lower speed, needing to brake, dealing with air flows from the ground) than in hitting big buildings. You have a great point, but it can only go so far. The 9/11 terrorists were rather well trained, for what they were trying to do.

Oh, for gosh sakes! There's a button right on the control yoke that says "A/P Disengage". It is almost identical on all commercial aircraft. An airliner responds very slowly to control inputs

Yes, so it might be a lot better to NOT disengage the autopilot, and let the computers fly the plane. You just set the desired heading and altitude. We have commercial students who have trouble

Well, if deprived of (normal) oxygen for 5 minutes or more, even experienced mountain climbers get pretty groggy. I've read so many reports by people who were experienced pilots in a low cabin pressure situation, and its amazing how badly they performed. A number of them were in the situation of flying their plane and wondering "Why the hell am I having trouble thinking through this task? Oh, better check the cabin altitude!"

Jon

It's my understanding that the newest airliners can land themselves without pilot input. Is that true?

While it depends on the infrastructure on the ground, they can and do. In fact, it is the preferred method at airports like LAX depending of course on the airline and equipment.