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Old 13th Mar 2014, 20:40   #2881 (permalink)
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the helios crew did not recognize the BLARING HORN as cabin altitude warning, they thought it was the landing gear horn. same sound, different interval.
They also ignored an engineers question;

"Can you confirm that the pressurization panel is set to AUTO?"
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Old 13th Mar 2014, 20:48   #2882 (permalink)
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PPRuNe gets a favorable review in the NY Times.


The Wall Street Journal reporter who still stands by the core of his story, is one of the top, if not the top, aviation reporter at the Journal. Martha Raddatz, the defense reporter at ABC News, is very well connected with national security sources. IMO, the U.S. government is selectively leaking information.

Based on the Wall St. Journal reporter's accounts, the pinging lasted for four hours, at 30 minute intervals. So there was power and a functioning communication link during that interval. Depending on whether the U.S. can triangulate the location of each ping, that would give an approximate a location at the time of the last ping. That leaves up to a 30 minute flying distance from the point of the last ping.

According to the Journal reporter's radio interview, he mentioned several times that U.S. officials haven't ruled out the plane landing, or crash-landing on land.
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Old 13th Mar 2014, 20:55   #2883 (permalink)
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I think you badly misread your source. 8.5 _minutes_ survival time does not even pass the smell test. At -20C in room-temperature clothing and without complicating factors (e.g. wind chill or rain), survival time is going to be on the order of 12 hours.

However, if you combine -20C temperature with hypoxia, things are going to turn badly much faster.
Yes, misread M for H in the abstract. The NIH number is 8.6 hours at -20C with two layers of loose clothing. Recovery time after several hours of -20C is fairly lengthly.
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Old 13th Mar 2014, 21:01   #2884 (permalink)
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Originally Posted by Chronus
It would be reasonable to expect that (the crash) ocurred over the Malacca Narrows.
Really? Shouldn't that be the Gulf of Thailand, a much bigger body of water?
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Old 13th Mar 2014, 21:06   #2885 (permalink)
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Missing Engineers

This is what Reuters had to say about the techies. Not sure that anyone said anything specific about the technology they were working on.

Loss of employees on Malaysia flight a blow, U.S. chipmaker says | Reuters
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Old 13th Mar 2014, 21:06   #2886 (permalink)
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Originally Posted by WillowRun 6-3 View Post
Correction: Satellite, Not Engine, Data Drove Investigators’ Suspicions on Malaysia Jet Flying Time
U.S. investigators suspect that Malaysia Airlines Flight 370 stayed in the air for up to four hours past the time it reached its last confirmed location, according to two people familiar with the details, raising the possibility that the plane could have flown on for hundreds of additional miles under conditions that remain murky.

The investigators believe the plane flew for a total of up to five hours, according to these people, based on analysis of signals sent by the Boeing 777's satellite-communication link designed to automatically transmit the status of some onboard systems to the ground.

Corrections & Amplifications: An earlier version of this article incorrectly said investigators based their suspicions on signals from monitoring systems embedded in the plane’s Rolls-Royce PLC engines and described that process.
What's "Boeing 777's satellite-communication link designed to automatically transmit the status of some onboard systems to the ground"? Do they mean SATCOM? So, MH370 did have SATCOM hardware?

Also of interest:

"Throughout the roughly four hours after the jet dropped from civilian radar screens, these people said, the link operated in a kind of standby mode and sought to establish contact with a satellite or satellites. These transmissions did not include data, they said, but the periodic contacts indicate to investigators that the plane was still intact and believed to be flying."
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Old 13th Mar 2014, 21:07   #2887 (permalink)
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Originally Posted by shawk View Post
Yes, misread M for H in the abstract. The NIH number is 8.6 hours at -20C with two layers of loose clothing. Recovery time after several hours of -20C is fairly lengthly.
Just to nitpick, that's for -30C.
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Old 13th Mar 2014, 21:08   #2888 (permalink)
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Media if you belive

Boeing did state that an airworthiness directive about possible fuselage cracks issued by US authorities in November regarding 777s, which had been linked in some theories to flight MH370, did not apply as the missing plane did not have the specific antenna installed.

However, the Malaysian authorities said reports that more data had been transmitted automatically by the plane after it went missing were inaccurate, adding that the final information received from its engines indicated everything was operating normally.
A report in the Wall Street Journal had claimed that US investigators believed the plane had flown for five hours, based on data allegedly transmitted to Rolls-Royce, the British engine manufacturers.
But Malaysia Airlines chief executive, Ahmad Jauhari Yahyain, told reporters: "We have contacted both the possible sources of data – Rolls-Royce and Boeing – and both have said they did not receive data beyond 1.07am. The last transmission at 1.07am stated that everything was operating normally."
A Reuters report said sources close to the investigation claimed communications satellites picked up faint electronic pulses from the plane after it went missing, but the signals gave no indication where the jet was heading nor its technical condition. They said one engine maintenance update was received during the flight.
Neither Boeing nor Rolls-Royce would comment, citing international conventions on air accident investigations.

Last edited by ZAZ; 13th Mar 2014 at 21:10. Reason: extra
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Old 13th Mar 2014, 21:08   #2889 (permalink)
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Originally Posted by V-Jet View Post
There are multiple O2 bottles aside from the a/c built in supply.

None will work if you dont know you are incapacitated.

The question I still have is how long does it take to 'wake up' once the aircraft is below about 15,000'? I would have have thought that unless it was descending very fast there would be time to regain consciousness prior to impact.

Anyone know?
I can only quote from subjective experience way back when we were put in small groups into 'the chamber' to experience and watch each other get hypoxic. The chamber was 'climbed' to (I think) about 30,000ft equivalent.

We were given a simple maths test to work out - write down 500 now start subtracting 17 - then one in each pair had their oxygen switched off.

I became woozy and not with it relatively rapidly say 45 seconds or less but subjectively within 20 - 30 seconds was back up to speed when given 100% oxygen. My 'partner' seemed to be totally unaffected when his supply was shut off neatly writing sum after sum.... it was only when we looked after about 45 seconds we noted that although the writing was neat it was gibberish... he also recovered quite rapidly 20 - 30 seconds or so.

So what we learned was onset can be fast and obvious - or fast and not obvious, imagine the FO happily punching nonsense into the FMC. Recovery - on 100% oxygen was rapid. However, we had not spent a long time at height and were young and relatively fit. I expect as with all things biological YMMV.
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Old 13th Mar 2014, 21:13   #2890 (permalink)
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It could be, it seems to me, that the WSJ reporter still does not have it right.

As noted above and before, it seems that this T7 did not have SATCOM so how could it be transmitting pings to satellites?

What if what was actually pinging was the ACARS/RR monitoring radios but these transmissions were picked up by NSA satellites?

That seems more likely and could explain the confusion of the reporter and his source(s).

Last edited by jehrler; 13th Mar 2014 at 21:14. Reason: typos/clarity
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Old 13th Mar 2014, 21:14   #2891 (permalink)
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I am neither familiar to a great extent with the FBW architecture of the Bus , nor the 777. However, from what I understand it operates ( without Autopilot engaged ) in a form vaguely similar to CWS on my "steam driven" 737, I.E. the aircraft will more or less maintain the same angle of pitch/bank, and within certain limits , return to same if disturbed.

This being the case, given that they had already attained cruise altitude, unless whatever catastrophe that occurred interrupted electrical power such that power to the FBW was disabled, any discussion involving the autopilot is without value, as the aircraft would have continued in controlled flight anyhow until fuel exhaustion.

As a footnote, I think more is known than is being released (particularly radar data) & find it difficult to believe that Satellite data etc would not be available.

Having said that, it took from 5 days to 2 years between finding surface wreckage & anything useful in the Air France accident, so don't hold your breath.
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Old 13th Mar 2014, 21:17   #2892 (permalink)
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Please read it again, you will note that it says it would be reasonable.. had it ocurred ... it is a proposition that had it, then given this narrow channel of water it would be reasonable to expect that there would be some flotsam. So as no flotsam why are they still busy dreging this narrow water way.
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Old 13th Mar 2014, 21:18   #2893 (permalink)
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Glossary for noobs.

Dear pro pilots and engineers,
This thread has over 4 million views... safe to say it's gone viral amongst non-professionals, regular folks just listening in on a fascination conversation.
So, first, thanks.

I realized I was missing half the conversation, not knowing what the many abbreviations and acronyms that are commonly referred to in these posts (SAR, NIH, PAX, UTC, ACARS etc.) So I thought I would provide a link to a wiki page which could help us amateurs follow along and possibly prevent us from asking dumb questions.

List of aviation abbreviations - Wikipedia

Again, many thanks.
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Old 13th Mar 2014, 21:19   #2894 (permalink)
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Interesting thing with hypoxia, and in pass this on to all who haven't done a chamber run, YOU FEEL MUCH WORSE POST HYPOXIC WHEN YOU GO BACK ON OXYGEN!

Effectively, your blood flushes the crud that has built up, meaning you get this god awful head rush, dizziness and nausea. Have done the training fairly recently experiencing rapid onset (easy to diagnose) and slow onset (difficult, even when my blood oxygen level dipped below 60%, and I was expecting it). The hazard is people have been known to rip off the mask trying to get rid of the sensation.

By far the worst most dangerous hypoxia was the slow onset, which is very subtle and why good CRM is essential.

Problem is, at 02:00, many of the signs and symptoms are very similar to heavy tiredness, meaning they can be missed.

With the advent of hypoxia simulators as opposed to old school chamber runs, there is NO REASON why airline pilots should not have to undergo this training on a 5 yearly basis, similar to the military requirement.

Did the jet have any form of sat based data comms, ie in flight entertainment or passenger telephone?

Last edited by VinRouge; 13th Mar 2014 at 22:35.
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Old 13th Mar 2014, 21:25   #2895 (permalink)
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I'd suspect, perhaps incorrectly, that a 777-200ER with an airline like MAS would more than likely be kitted with SATCOM.

Just because the airframe in question did not have a particular SATCOM antenna subject to an AD does not mean it didn't have one period.

I would also think the comm system would have to be "logged on" to ensure it was operational on demand.

How would an international airline maintain 'operational control' without SATCOM? VHF/HF voice-data only? Unlikely.
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Old 13th Mar 2014, 21:26   #2896 (permalink)
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A successful ditching, with no distress beacons, on a moonless night? In an aircraft not able to continue on its way or head for an airfield?

Doesn't sound very likely.

While you'd want to aviate first, if you were going into the sea, having a word with someone might help, at least to let them know what time you were going into the sea, so they could use a piece of string and a ruler to come and find the debris afterwards.
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Old 13th Mar 2014, 21:31   #2897 (permalink)
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Rather than why the aircraft went down, I believe the real interest at present must be WHERE IS IT.

Given the total futility demonstrated by electronic means to locate any wreckage, it must follow that the search methods will have to be based on the hydrodynamics of the Andeman Sea and the Malacca Straight.

Those interested in the subject may refer to the American Journal of Environmental Science, 2012,8 (5), 479-488, General Circulation in the Malacca Straight and the Andaman Sea.

Here is a link to it.

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Old 13th Mar 2014, 21:31   #2898 (permalink)
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capn p

I.E. the aircraft will more or less maintain the same angle of pitch/bank, and within certain limits , return to same if disturbed.
As an end user I reckon the T7 handles much the same as most other "normal" non FBW aircraft I've ever flown but with the addition of one or two knobs and whistles (like pitch/power couple taken out). If the aircraft is trimmed properly for the IAS at an attitude then disturbed from that datum attitude it'll eventually return to that datum (blimey, memories of CFS S&L 2) just like a Cessna or a JP - it doesn't do anything magic like pop straight back to the datum attitude if the stick is released with the aircraft close to datum ( if that's what CWS does?) - Interesting point and I guess we need someone with both 737 and 777 time to referee.

Last edited by wiggy; 13th Mar 2014 at 21:51.
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Old 13th Mar 2014, 21:41   #2899 (permalink)
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jehrler: Re SATCOM

I believe that this particular T7 DID HAVE Satcom, just not the Satcom antenna per the recent Boeing AD. Not the same thing at all.
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Old 13th Mar 2014, 21:47   #2900 (permalink)
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Originally Posted by VinRouge View Post
If you were seeking asylum, why would you use a stolen passport?
Because the airline will not let you onboard without a visa otherwise.
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acars, crash, elt, hf links, malaysian, mh370, missing, pingers, plane, vhf

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