I’ve got some notes here that might be useful;
Time of useful consciousness;
Altitude (feet) Time
15,000 30+ mins
18,000 20-30 mins
22,000 5-10 mins
25,000 3-5 mins
30,000 1-3 mins
35,000 30-60 secs
40,000 15-20 secs
45,000 9-15 secs
50,000 6-9 secs
For pete’s sake: Did they get the black box?
What an odd, bizarre tragedy.
The data recorder has been sent to Paris for analysis.
Okay NO. A bullet hole will not cause an airplane to depressurize. You need to watch more Mythbusters.
The myth they busted was that a bullet hole would cause an explosive depressurisation. However, I’m pretty sure the pressurisation system would keep up with a small hole (it does, after all, continually let air out of the cabin normally anyway, it just supplies more than it releases.)
According to a new AP story, all of the passengers and crew were killed on impact.
It’s FL 250 (25,000 feet) above which one person has to be on oxygen if the other leaves the seat.
And yes I was at work but I posted in the GQ thread discussing this when I got home - I never thought to check MPSIMS for another discussion on this!
The plane had pressure issues in the past.
Those knowledgeable, please address: Is it possible that the plane could have had a pressure issue that was just severe enough that it affected people at a modest to severe rate…thus knocking out and/or killing a large percentage of people (yet leaving some the the ability to get into the flight deck)?
I’m thinking of some condition on the plane that enabled the pressurization issue to teeter in and out of a severe condition. In other words, whatever malfunctioned indeed malfunctioned long enough to take out most everyone on board (or art least render them unconcious), yet function enough so that some very able folks functioned enough to be seen by the scrambled fighter jets???
See where I am going with this, esp in light of the planes history?
Philster…I think what you’re getting at is a slow depressurization rather than a rapid one.
The answer is most likely no: once the cabin altitude exceeds 10,000 feet a very loud, very annoying warning will sound in the cockpit. If it continues to climb past 14,000 feet the oxygen masks will deploy in back.
The only way that a slow depressurization could affect people was if the flight crew did absolutely nothing from the time the cabin went above 10,000 feet until it reached ambient pressure (ie over 30,000 feet). As other people have pointed out, the cabin is pressurized by taking air from the engines (from the compressor section, before fuel is added obviously) and pumping it into the aircraft. The engines produce more air than is needed and outflow valves are used to maintain the correct differential pressure. Some sort of outflow valve problem (ie one of them getting stuck full open) would cause a the pressure differential to slowly decrease (causing the cabin altitude to increase), but once again the aircraft warning systems would alert the crew to this problem.
Sorry for so much technical stuff - this sounds like a GQ post!
Gods, that poor flight attendant. Seems he was the last one concious and continued to cry for help up until the crash.
[url="http://www.salon.com/tech/col/smith/2005/09/16/askthepilot154/index.htmlHere’s an interesting update on what happened on this flight.
I’m on a trip using my laptop, and have no Salon subscription (and I don’t want to sign up for a free day either).
Can anyone give me the gist of the article without violating any copyright rules?
In brief, it reports that the pressure malfunction was caused by a control knob faultily installed by maintenance staff. A pressurization warning alarm went off at 10k feet, but was taken to be a malfunctioning takeoff configuration horn, which apparently sounds the same in a 737. Because they thought it was a malfunctioning alarm, they continued climbing and succombed to apoxia whilst trying to find out which breaker to flip to turn off the horn. Throughout it all, the German captain and Cypriot first officer apparently had trouble communicating due to language barriers.
Salon synopsis (written by a pilot):
A mechanic left a pressurization knob out of place during the previous day’s service.
The pilots missed that in the pre-flight.
The appropriate alarm went off as the plane climbed past 10,000 feet, but the pilot and co-pilot wasted time trying to figure out why the (same sounding) alarm for mis-positioned flaps while on the ground was going off. (The pilot/author of the Slate article notes that he and a senior pilot made the same error during a training flight, but that by reviewing the control panel, realized their initial error and made the correction.) Unfortunately, according to the cockpit tape, the German pilot and his Cypriot co-pilot were having difficulty communicating in English and began suffering oxygen deprivation (interfering further with communication) until they blacked out before they recognized their error. They also apparently fixated on the idea that it was a ground-level flaps warning, rather than the pressurization warning and the pilot was actually trying to find and disable the flaps warning buzzer when he passed out. This was compounded by the fact that they were in radio contact with maintenance after the warning started, and no one on the ground had the wit to say “At 30,000 feet, that warning means pressure, not ground-level flaps problems.” It remains a mystery why the pilot continued fighting with the flaps alarm when the cabin oxygen masks deployed (along with an audible announcement) and the cabin depressurization siren went off. Early hypoxia? It is unknown and not even speculated at this point.
The rest of the article raises questions about the quality and rigor of the training in which Helios has invested (or could afford).
Flying a 737?
Pilot141, one more point I recall from the article was that the pilot writing it could easily understand getting the cabin pressure alarm and the landing equipment malfunction alarm mixed up, since he’d had that sprung on him by a sadistic trainer in a simulator.
What the writer was very critical about was that they air crew fell in love with that interpretation of the alarm horn, even to the point of trying to *pull the fuse * for the horn, since it had to be a malfunctioning alarm, instead of trying to consider what other conditions could cause the alarm. Even after the secondary indica listed by tomndebb.
Reminiscent of the 1972 Eastern Airlines Tristar crash in the Florida Everglades, when the plane flew into the ground while the crew were trying to find out why the nosewheel light wasn’t illuminated. In any emergency, the very first priority is always “Fly the plane!”. Stuff like this happens when the crew forgets the basics, usually because of the airline’s poor training practices.
Unfortunately the symtoms of hypoxia make it less and less likely, as time goes on, for the pilots to realise what’s going on.
The first symptoms are generally a blueness in the lips and fingertips, a feeling of euphoria, and a tendancy to “tunnel vision”–focussing on some task to the exclusion of all else.
So while these guys are going blue they are becomming increasingly more focussed on trying to find a circuit breaker which is not actually causing the problem, and all the while they are feeling that everything is going really well.
My point is that, unlike the Everglades crash, the failures of the crew in this case were probably ultimately caused by their hopyxia rather than a lack of airmanship.
The first action in any depressurisation incident should be to immediately go on to oxygen. You then have the luxury of being able to scan the pressurisation controls to check for any obvious causes of the problem (the airflow being turned off for example) prior to commencing a descent to 10,000’ if required.
The fact that these guys didn’t recognise the warning for what it was would point to a lack of adequate training and possibly to the manufacturer for using similar aural warnings for different problems. What happened subsequently is typical of hypoxia.
Oxygen first.
Thanks for the responses everyone.
I’ve flown several jets that have horns/bells that mean one thing on the ground and another in the air. It sounds like this crew got focused in on the supposed flap warning and ignored everything else.
I wonder if they ignored the normal checklists while dealing with this - most checklists will have you check the pressurization passing either 10,000 ft or 18,000 ft while climbing. Any check of the actual cabin pressurization gauges would have told them the real problem. Of course if hypoxia had begun to set in then their responses would be sluggish and unfocused.
It also sounds like the captain was busy trying to pull the circuit breaker (no fuses on an airplane - it’s all circuit breakers that pop with no damage to the breaker) for the flap warning. This might explain why he was out of his seat, as several older airplanes have circuit breaker panels in very inconvenient locations.
And tomndebb I fly the 727 now, but I bring my laptop with me on trips.