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Old 23rd Mar 2014, 10:47   #7501 (permalink)
 
Join Date: Nov 2008
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Quote:
Shortly after last radio contact with ATC the crew have taken limited, action. I believe the aircraft has been taken into manual control by the Captain and turned approx 90 degrees away from current fight route with the intent of an emergency descent. One of the pilots have recognised the need to sqwark 7700 but due to hypoxia inadvertently turned off the transponder. The effects of hypoxia have resulted in the crew not donning O2 and the aircraft altitude varying as a result of an attempted emergency descent until they became completely unconscious.
Why manual control? Decompression protocol on 777 leaves autopilot on during descent.

To tune the transponder to 7700 you never touch the on/off switch.

By the way, the altitude warning horn is very loud and reminds you to put on your oxygen mask. It is the 1st step in the checklist and the pilots would not have not tried to turn away, descend or squawk 7700 without doing this. I know this happened in the Helios accident, but we learn from other's mistakes, and they didn't have an EICAS to tell them what was happening.

Your supposition totally depends on both pilots ignoring a blaring warning horn, EICAS messages, master caution warnings, and doing more than one thing against their training, in other words being a totally incompetent crew, which I do not think they were. My two cents.
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Old 23rd Mar 2014, 10:49   #7502 (permalink)
 
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zark7 . . .

Quote:
Based on the 'facts' available through the media, a decompression event is the most plausible scenario. Whether or not this was a slow (10000' cabin alt warnings??) or rapid decompression is unclear.
Are YOU a pilot? At FL350 you wouldn't be instantly blue in the face and pass out... Do you KNOW how long it takes to don a quick-donning oxygen mask? It takes me two (2) seconds to pull the mask out of the slot with one swoop of my left hand and plant it on my face.
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Old 23rd Mar 2014, 10:55   #7503 (permalink)
 
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max nightstop

Quote:
now it is debunked 2 weeks on.
To be fair, it was debunked two weeks ago when it was discovered that ACARS doesn't send changes of waypoints in the FMC without them being executed.
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Old 23rd Mar 2014, 10:59   #7504 (permalink)
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And how many took any notice of that SOS? That's why I made that post stand out for the OP

BTW, we have a special offer on electronic death for the pinger squad until more genuine data comes out.

Rob
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Old 23rd Mar 2014, 11:03   #7505 (permalink)
 
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If the crew are suffering from hypoxia, ie poor co-ordination, erratic behaviour, memory loss, then this is possible. They may have had the intent to do the right thing (auto response from their training) but been unable to carry it out correctly. Most of us on here have seen enough hypoxia training videos to see how poorly people perform if they don't immediately go on oxygen. All I am supposing is that they have not donned oxygen masks quickly enough. Useful consciousness at 35000' is only around 5 seconds from memory.
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Old 23rd Mar 2014, 11:09   #7506 (permalink)
 
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Glue ball would love to see you do that with glasses & a head set on.
2 secs not.
Hypoxia is different for each individual (smokers etc) so maybe slow decomp is a possibility prior to cabin alt warning horn.
Anyway with facts changing by the day speculation is futile but of course interesting. But it does distress the relatives.
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Old 23rd Mar 2014, 11:17   #7507 (permalink)
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Quote:
Originally Posted by MrDK View Post
2. A lone crew member will likely not talk.
I wish. I once flew with a single-seat jock who, not used to a GIB, sang and talked to himself the whole time.

If this aircraft went to one pilot on the flight deck he may well have talked to himself.
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Old 23rd Mar 2014, 11:19   #7508 (permalink)
 
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Donning mask

Glueball is quite correct, you can don the mask very quickly, there is no requirement to remove the headset as the quick don O2 mask is designed to go over the top of the headset and if fitted with integrated smoke goggles, is designed to fit over spectacles.

Removing the headset is not a requirement and IMO is often taught incorrectly by some SFI/TRIs.

The clue here is "quick don".
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Old 23rd Mar 2014, 11:20   #7509 (permalink)
 
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I'm of the view we are down to one of two options, either an extraordinary event which has not been managed well or perhaps was not possible to manage well.

OR

A Deliberate Act, and I don't believe for a minute the flight crew had anything knowingly to do with that, I'm thinking a lone perpetrator, either an employee or a very good friend of the Captain, someone who could be trusted and invited into the flight deck, a good friendship unsuspectingly established over a period of time, a friendship which was no coincidence.
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Old 23rd Mar 2014, 11:23   #7510 (permalink)
 
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Quote:
Are YOU a pilot? At FL350 you wouldn't be instantly blue in the face and pass out... Do you KNOW how long it takes to don a quick-donning oxygen mask? It takes me two (2) seconds to pull the mask out of the slot with one swoop of my left hand and plant it on my face.
That's not my point, there was a chain of events that led to the Helios crew not donning their masks, and all I'm saying is that with the limited information at hand, depressurization is the most plausible scenario as it explains strange crew behaviour and strange flight path.

It may have been a hi-jacking or suicide but very unlikely IMO.
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Old 23rd Mar 2014, 11:31   #7511 (permalink)
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Time of useful consciousness at 35,000ft is not in seconds. For a start you have a lung full of air, CO2 and water vapour and that will see you OK for quite a time. I can't remember off the top on my head but we used to fly with cabin altitude at 39,000ftand you could certainly drop your mask to blow your nose. The rule changed above 40k and you were down to seconds. IIRC it was something like 20-30 seconds at 45k and you had to initiate a 5k/m descent with a minute. Higher still with considerable overpressure (and you would have had a mask on) you had 30 seconds to initiate the descent.
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Old 23rd Mar 2014, 11:36   #7512 (permalink)

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Anyone remember this?

New plastic garbage patch discovered in Indian Ocean | Coastal Care

Instead of running around like a bunch of schoolboys at a footbal match all wanting to have a kick of the ball, heading off for every bit of something a poor satellite photograph coughs up, why don't they fine search the programmed flight path and any viable diversion routes from the point of last contact?

When there's a problem with this size of ac, do the airline pilots disengage the autopilot and fly the ac manually !!! Or is the ap reprogrammed allowing the pilots to deal with the immediate problem?
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Old 23rd Mar 2014, 11:42   #7513 (permalink)
 
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Quick-donning mask

https://www.youtube.com/watch?v=4HMiF5YlWyk&ap=%2526fmt%3D18&fs=1"> https://www.youtube.com/watch?v=4HMiF5YlWyk&ap=%2526fmt%3D18&fs=1" type="application/x-shockwave-flash" allowfullscreen="true" width="425" height="350" wmode="transparent">
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Old 23rd Mar 2014, 11:42   #7514 (permalink)
 
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Quote:
Originally Posted by Pontius Navigator
Time of useful consciousness at 35,000ft is not in seconds.
Hmmmm.....

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Old 23rd Mar 2014, 11:46   #7515 (permalink)
 
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Quote:
Time of useful consciousness at 35,000ft is not in seconds. For a start you have a lung full of air,
A lung full of very thin air - after you've forcibly exhaled most of what was in there during depressurisation - leaving you with oxygen rich blood (relative to what is now in your lungs). O2 will start to flow the wrong way out of your blood stream. Every breath you take will blow more O2 out of your body until you lose consciousness.

Its not like holding your breath under water.

That said - you will still get more than just a couple of seconds @35K, 30 secs, 45??
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Old 23rd Mar 2014, 11:59   #7516 (permalink)
 
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Quote:
The aircraft flew on in LNAV or HDG SEL and at the MCP/VNAV altitude. If in LNAV and passing over the last waypoint the mode changed to HDG HOLD
A perfectly valid scenario, and one that puzzled me hasn't been elucidated upon more.. rather than all of this obtuse deliberate zig zag stuff.
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Old 23rd Mar 2014, 12:01   #7517 (permalink)

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Quote:
All of the reports of the route change having been deliberately pre-programmed into the flight computer.............DEBUNKED.
All of the reports of the change being made at least 12 minutes prior to the 1:19 "alright goodnight" last communication with ATC............DEBUNKED.
Anyone heard of RTE 2 or don't they have it on the T7? I wouldn't have thought that ACARS would show a route change until it has been executed.
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Old 23rd Mar 2014, 12:02   #7518 (permalink)
 
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Do we 'know' that the a/c zig-zagged along the FIR boundary (apart from the previous claim that those waypoints had been entered into the FMS?)
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Old 23rd Mar 2014, 12:04   #7519 (permalink)
 
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Quote:
Whatever went wrong, went wrong quickly between 1:19 and 1:22.
And to those who dismiss the various hypoxia theories simply because the cabin altitude warning could not be ignored, there may have been a whole heap of other alerts and warnings going off at the same time.
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Old 23rd Mar 2014, 12:08   #7520 (permalink)
 
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Quote:
Anyone heard of RTE 2 or don't they have it on the T7? I wouldn't have thought that ACARS would show a route change until it has been executed.
All Smiths (737 Classic and I assume later 737's) and Honeywell (757/767/777/744) FMC's have RTE 2.
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