Conjecture on 737 crash?
 

Any pilots have any conjectures on how this can happen?
How can the pilot's O2 fail?
How fast does this happen?
They found a flight attendant in the cockpit, probably trying to wake up the co-pilot.
How many hand carry bottles of O2 are there on this plane?

thanks

Can happen any number of ways. Time of USEFUL consciousness is measured in seconds. There are factors (shorter times) for health, surprise factor, suddenness of onset. Plane was at 34000. Outside (now inside) temp could be -20C to -50C.

We always discuss these scenarios on ocean crossings. Worst case scenario is some sort of a pressurization failure. Would have to take an (otherwise) perfect airplane (engines) down low enuf for pax to breathe, AND stay warm. Fuel flows double or more.

I'll usually mention to the lead FA as I walk aboard as a passenger that I am typed and / or current in the plane type if help is needed.

Intercept pilots said FO was slumped, Captain was not in his seat.

Sad, but this business keeps teaching some people that we don't get paid for the good days.

A web site for 737 plots mentions the report from the F16 pilots scrambled to check out the plane. They saw someone "slumped over" in the cockpit and two persons in the cockpit as well. It was also noted this aircraft had experienced loss of cabin pressure in the past.
Could be a combination of poor maintenance and too many cycles.
My condolences to the families.
Les

All of Helios' 737's were NG's (Next Generation). Planes were reasonably new.

The passengers' oxygen comes from individual chemical generators. The pilot's oxygen comes from a tank, and there is a shutoff behind the copilot's seat (supposedly checked every first flight).

The Capt. could have been out of his seat for any number of reasons. I have flown with guys that could not sense a 1000 foot per minute cabin rate. I have always had sensitive ears, and can spot 100 foot per minute. Who knows, the Cockpit Voice Recorders have been recovered, but since they only record the last 30 minutes (endless loop), and the plane was holding at a fix over Athens for 90 minutes, and had not communicated since crossing the FIR at Rhodes 20 minutes prior to that, there won't be anything useful there.

Bad day, may they all RIP.

Why are the recording tapes only 30 minutes long and endless loop?

I read that the F-16s saw a person or persons in the cockpit trying to regain control of the plane, I wonder why they were not out cold(?) How could anyone still be awake and functioning if there was no oxygen and it is -50deg.?



:confused:

The SMS message "pilot is blue, freezing cold, and goodbye cousin' has been debunked. Never happened. Man arrested for sprading this rumor in Larnaca.

The CVR has always been a 30 minute duration. The technology exists to be more, but has never been implemented beyond what is required by law. In the 'old days' it was a continous loop tape. I believe nowadays, any installation after like 1995 is a chip.

Singpilot:

What is your speculation on why the pilots did not immediately do a decompression dive?

Can you miss a catastrophic decompression like this? I mean can you just not notice it until you are starved of oxygen and freeze?

We all practice the rapid decompression dive. But a not so rapid decompression (say 1000' per minute), might not have been noticed, believe it or not.

First sign of trouble to such a crew might have been the "LOW CABIN PRESSURE" EICAS message. Meaning 'high cabin altitude'. Book says 'Masks on, check 100% (oxygen), check A/C sources (packs and bleeds), use manual pressurization (usually closing the outflow valve), and check cabin rate'. If no joy, or at first sign of smoke or contamination, declare and descend.

Captain out of the seat says to me bad timing, or he was up troubleshooting. Or maybe removed by the FA or pax trying to get him revived with the walkaround bottle (if the pilots O2 valve was closed, for instance). The valve's location would not have been evident to anyone else, the FO being asleep too.

All of this is speculation (dangerous), but would explain the apparent circumstances.

Captains' body not identified yet. The cause will eventually be found. The Government of Cypress 'raided' the offices of the airline in Larnaca today. Is their way of getting maintenance records. Hopefuly they will keep them reasonably intact.

More developments today. The Cockpit Voice Recorder CASE has been found. The innards have not been found. These things are designed for like 1000g's (crash). The pictures after the crash usually show these having been pried open, even after the crash.

The captains remains have not been found / identified. Granted, there can be a common area of several remains in one spot, but seems strange as well.

Climbing out of Larnaca, the flight requested a delay at 16000 feet to 'address a pressurization concern'. They were there for 3 minutes, then requested the rest of the climb.

The aircraft flew the entire route with no further communication after the Greek boundary, the normal arrival, transition, approach, ILS and missed approach to the miss holding fix, and entered the missed approach hold, all at 32000 feet. All at cruise speed. The entire aircraft route would have been preprogrammed by the crew either enroute or prior to takeoff. The aircraft would not have left cruise altitude unless the altitude command knob had been set to a lower altitude by the crew (who were asleep). The aircraft was in that hold just north of Athens for 90 minutes. Until they ran out of fuel, and at least one engine flamed out. The now single engine electric situation would have disconnected the autopilot, and according to the intercept pilots, it rolled off and spiralled in.

There's an unspoken situation here. From 32000 feet the guided (under control) gliding range of a powerless 737 is over 100 miles. The hold fix was 35 miles north of Athens, 25 miles northwest of the airport. The interceptors were there not to just investigate. The plane happened to flame out on a leg of the racetrack shaped hold pointed away from the city. The interceptors did not have to execute their probable second set of orders.

^^^^Meaning that the 2nd set of orders were to 'shoot' the plane out of the sky if this was a terrorist take over?

More likely to destroy it if it was going to hit the city, terrorist or not. The initial intercept report indicating a pressurization problem (masks down, pilot slumped) is why even right after the crash terrorism was ruled out.

Sing,

I enjoy reading posts written by people who know what they are talking about (probably because they are so rare). Thanks.

So hang on, Sing, I'm not sure I'm following this. You're saying that the pilots had some pressurization problems, but continued the flight anyway. But the pressurization problems resulted in everyone passing out. The plane didn't know or care, it just kept flying and ended up in the pattern on it's own. Am I reading your posts correctly?

Thanks for the info, btw. Like Burnin' says, I like having people who know the details post useful information.

Yep, that is the stink of it. Why would a competant crew take a plane with some sort of pressurization problem up to altitude. This is the typical foreign supplemental carrier. Experienced captain (usually from USA, or Common Market Country) from Germany, low time FO from flag of airline, Cypress in this case.

There are a couple of 'innocent' explanations as well. Technical, but relatively innocent. To enhance takeoff performance, there is a procedure to allow the APU to provide cabin pressurisation as well as heating and cooling in flight at low altitudes. So you take off using the APU to unload the engines, allowing them to have all available thrust for performance when needed. This was a short flight, long takeoff runway in Larnaca, sea level airport, not much fuel required (refuel planned in Athens for the continuing flight to Prague). I would have said it wasn't required that day, but then who knows what the captain wanted.

Normally, the transition back to engines for pressurisation would be after cleanup, say 6 to 7 thousand feet. Takes throttles to low power for a sec, three buttons pressed, then shut down the APU and continue. Maybe a minute, two if your new at it, or reading the checklist while doing it.

Lets speculate again for a sec (dangerous). If you forgot to do this, the climbing APU will have to work progressively harder and harder to accomplish the requested tasks. It is rated for 15000 feet under this kind of load. If they forgot or realized late, or had a weak APU, all of this would have come to head about that altitude. Perhaps explains the requested pause in the climb. Would also explain why they requested the continued climb in spite of the obvious result (after transitioning back to engines for pressurisation). The FDR (Flight Data Recorder) will shed light on this.

Interesting note here. Regs require enough fuel to destination, alternate and 45 more minutes. Alternate was probably back to Larnaca (45 minutes), plus 45 minutes actual reserve. Hold at Athens was 90 minutes, then flameout.


Will be interesting to see how it turns out.

Takes a combination of several factors to bring a plane down.
The 737 was only 7 yrs young.

...or 7 years OLD if poorly maintained...

Theoretically yes. Practically, no.

Egad.

So you're saying that the autopilot flew the approach and executed the published miss and entered the hold, all at FL 320? Makes sense if it had some kind of INS that would update off of DME's-- no need to tune the localizer in.

I can understand that-- if they had 320 in the altitude preselect (whatever it's called on the 737) then it would have captured that and leveled off. Since you have to tell it when to start down (there's no VNAV program?) in the absence of a command to descend, it just did the whole thing at altitude. Frightening.

Ok, these are very interesting facts. Last check-in with ARTCC was level at FL 160. They reported the "pressuriziation concern" then requested, and were presumably cleared, for the climb to 320. So they set 320 on the altitude capture and then somewhere after that they experienced the decompression.

Don't the masks automatically drop at 9500 +/- 600 feet?

Would the lack of ice on the windows indicate that the depressurization was not rapid, but progressive? Or would the ice sublimate off after half an hour or so at altitude?

I've never had any formal flight training but my gut instinct tells me, any issue with pressurization during a flight is a red flag. Land the plane immediately and have it checked out. The people on board whose lives are in your hands might just thank you later.

btw, isn't this standard op. procedure to land a plane with any signs of pressure problems? it just seems like the "better safe than sorry" approach. Problems at 34,000 feet don't usually fix themselves, they get worse, so why risk it? that's common sense. could it be overconfidence...

Wow, this is a thread of which I understand not a single word.

Michael,

Interesting idea here and I believe that you may have hit the nail on the head here. If there was a fresh copilot in the plane and he forgot to transfer the pressurization system over to engine bleed when he should have, then it would continue to work on the APU until it flamed out due to altitude. This would have left the plane with no heating and more important, no pressurization which keeps everyone alive in the plane. The masks would have come out at 10,000 or so and thats a good question why they did not descent at that time but who knows what happened inside the bird.

The APU normally does not have any "mixture control" and as the plane gets higher in altitude the APU will finally flame out (die) as there is too much fuel for the little oxygen available in the atmosphere. Some of the newer models will keep going up to 30,000 feet but ours is good only until 20,000.

Why the Captain was out of the cockpit is a good question but we may never know that with the short loop on the CVR. Our CVR is a newer version and is a 45 minute loop, but hear that they are working on newer models that are a 2 hour version.

Makes sense if we forget that the crew should have seen it. I am with you and can feel it when the climb or descent is off by as much as 100-200 fpm in the cabin. Got this way from too many years flying Learjets and forgetting once or twice to put the cabin air switch on!

JoeA

Yes!

John;

Sorry, am trying to keep this as 'civilian' as possible, but the technical keeps getting in the way.

Michael.

This flight had all the makings of a simple easy day. A 45 minute leg from Larnaca to Athens. Larnaca is a great airport, long sea level runway, beautiful island setting. Is home base for the airline. Athens' new airport has long sea level runways, great service, quick turns, easy stop. Then a longer leg to Prague. Weather usually stacks up over Yugoslavian border with Europe, east side of the Alps. That leg will be the challenge today. The pilots might have been lulled by the easy first leg. Overconfidence? Who knows, I sure don't. Only the guys there know, and they cannot speak for themselves. Doubtful the Cockpit Voice Recorder will either.

Hopefully the Flight Data Recorder will shed some light on the cause of the decompress. I think the second most important part of the wreck will be that oxygen valve behind the FO's seat. Was it open or closed.

It was said earlier that it is never just one thing that causes crashes. So true...thank God. That the checklists we use are written in someone else's blood. So true.

Someone asked me in a PM why would Larnaca (the origination point) be the alternate for Athens? Funny reason again. An airline is responsible (with certain limitations listed in a Geneva Convention) for it's passengers from the moment of departure until the moment of arrival at the intended airport. Any diversion (especially to an airport that they don't normally serve) is a financial disaster. If they deliver the pax back to Larnaca for a divert, no prob, pax are on their own.

Read that fine print on the back of your ticket someday.

All the -737's that I flew did not have an O2 valve in the cockpit, only a QB fitting where you unplugged the mask. Were some of them equipped with a valve?

Regarding the alternate... Other thing is that the airline delivers the pax back to home base and many of them live there, so no hotel rooms to pay for. The transit pax who do not live there would stay in hotel rooms that the airline gets "brother in law" pricing for, and if they did this at any other city at the last minute, pricing would be a lot more expensive.

Lots of things working in the background here, and you are correct that reading the back of any ticket will have a lot of info.

JoeA

The FMS on our bird will do exactly the same thing as well. All we have to do is to plug into the route the expected runway at the destination point and when we get within 30 miles it brings up "blue needles" that shows that the ILS is within range and will be tuned.

When we intercept the inbound course it "goes green" (switches to the ILS for data) and shoots the approach. If we do not do anything it will then enter the hold, again totally auto and then continue in the holding pattern. It will not manage the altitude and thats why the -737 did all of the above but at altitude.

The automatic systems in todays airplanes are very nice to work with IF, and only if you know how to "massage" them into doing what you want when there is a glitch.

JoeA

So the plane 'flew' the normal flight pattern, but at 30 some thousand feet?

...and it crashed because it ran out of fuel? What would have caused the huge fire?

or maybe whoever was in the cockpit trying to fly the plane switched off the autopilot and it came down out of control?

The fire that was seen in the post crash videos was a brush fire, no fuel was evident in the crash. Is why all the rescue and fire trucks were parked so close. This was scrub brush burning, could have been started by the crash impact itself.

It appeared that the efforts to 'regain control' were after the engine flameout and roll. That whoever it was in the cockpit was not even experienced enough to be able to talk on the radio.

Hey, go easy, killer. I've heard the way you pilots talk on the radio, and that's not the same language normal people use. It seems to me that the mechanics of recovering a rolled or spinning plane would be a lot simpler than learning all that ratchet-jaw you folks use on-air.

I issued a memo to the pilots and flight attendants at my company a couple of days ago. I wanted the flight attendants to be shown how the pilot's oxygen masks work (in detail), how they are stored, and deployed. To assume the pilots was unconscious, and how to get the mask to flow 100% pressure breathing to get the pilot awake again hopefully.

Not that surprised that none of the FA's had ever been shown this.

I am a big fan of "pinch-hitter" courses and videos for every nonpilot who might ever have the occasion to take the controls. Heaven forbid a big hunk of Peter Luger's steak breaks off and goes to my brain, I would want the passenger to know how to navigate to the nearest airport and land AND call for help on guard.

Certainly the technology exists for a "panic button" to be installed somewhere in the cockpit-- upon actuation, it could;

1) Check the nav database and locate the nearest suitable airport;
2) Check the fuel status and determine whether fuel remaining would be sufficient to make it to that airport and land; or whether the aircraft would be overweight;
3) Navigate to the final approach fix and land, applying auto-reverse and the brakes, coming to a stop on the runway centerline;
4) All the while squawking a special emergency code, broadcasting on 121.5 and sending ACARS messages to everybody and their dog that things had gone horribly awry and that the airplane was in "limp-home mode."

Now obviously, there's no guarantee that the weather would allow this to happen, but it would be a decent shot.

Seems to me that the cost of such a programming change and a minimal amount of hardware wouldn't be that great, although certification could be tough. If it saves one flight every few years, might it be worth it?

John, along the lines of your post.....

More news from the German press (Der Spiegel) today. The captain was German, and the press there has taken a special interest in this crash.

The intercept pilots report of 'someone trying to regain control' has been amplified.

It now appears that someone (presumed to be one of the FA's who had a Private Pilot's License), had taken the captains' seat, and was flying the plane. The intercept pilots reported that the plane left the hold fix, descended out over the sea down to 800 meters, then turned back towards the airport. As it approached the coast, it had to climb to clear a low set of hills between them and the airport. The flight ran out of fuel as the engines spooled up to cross the ridgeline.

Wouldn't that pi$$ you off...

Wow, Michael. That's very interesting data.

I was initially very incredulous about the intercept pilots' report. The combination of thin air and cold temps would seem to preclude the idea that anyone would be able to take control. But if she had her mask on, and was able to enter the cockpit. . .

Our FA is ex-Kiwi and Eastern and we practiced it a few months ago. Also did the AED and actually did our medical training on OUR airplane. Went so far as to practice using the AED on the pilots, after getting them out of the cockpit.

Better safe and trained now than needing it in a time of crisis.

JoeA

Even more info now. The FA that sat in the pilot's seat was a male, and his significant other, a woman was also a FA, was working aboard.

Michael,

The more info that comes out, the worse it sounds. No one wants to see a bird go down but this strikes home... a lot.

Will say another prayer for them tonight. Hope that they had a good and safe flight West...

JoeA

Amen to that.

"To fly west is a flight we all must take for a final check."

How would the FA get through the locked cockpit door?