Malaysian Airlines MH370 contact lost

[rigbyrigz]

Andrew Stevens in Malaysia just reported on CNN that the police there have gone to the pilot's home and his simulator was examined by experts. No news on what was found, if anything, of interest.

(Police there are busy, now also just interviewing the friend of the 2 Iranian fake passport PAX)

[isca]

Hypothetical by Bloxin page 119 #2370
Hello.
This is my third attempt to make a post here. Maybe, as I'm new here I'm doing it wrong.
I am a licenced engineer, B747.
This post attempts to describe, with precedents, a possible single failure that would cause loss of coms, depressurisation and crew disablement due to hypoxia.

Precedent: QF30 25 July 2008 Pax oxygen bottle "explodes" tearing a hole in fuselage.

Ref: Please google "Qantas oxygen bottle explosion" and view photos of damage.
The picture taken inside the fwd cargo compartment shows one bottle missing.
there is no evidence of shrapnel damage in the photo. Therefore, no eplosion.
The bottle appears to have detached itself from its connections and propelled itself down through the fuselage skin.

777: The crew oxygen bottle is mounted horizontaly on the left aft wall of the nose wheel well structure with the fittings (propelling nozzle) facing forward. This aims the bottle, in the event of a QF30 type failure, directly into the MEC containing all boxes concerned with coms and a lot more.
Before all of its energy is spent, an huge amount of damage could be caused to equipment and the bottle could, conceivably, cause a decompression.
When the crew respond by doning oxygen mask, there is no oxygen and hypoxia is the next link in this proposed chain of events.
This link is entitled "Hypothetical" and is only that. I believe it ticks a few boxes.
Hoping this post make it and generates some discussion.
Bloxin.

This is the only hypothesis I have seen that gives a feasible single source failure that could cause all of the electronics failures and fire and/or decompression.

Assuming of course the crew bottles are aligned fore and aft not vertical

[LASJayhawk]

Just to clarify what Yancey posted. The spacing between the 2 pulses sent be the DME is fixed (12 uS in X and 30 or 36uS in Y Y I can remember the Y spacing from the aircraft...I'm old and forgetful) but the timing between the pairs being sent out is somewhat random. In general a single channel DME interrogates the ground station a little over 100 times a second till it locks on, then 23 times a second thereafter.

[awblain]

At high-altitude - above about 30,000 feet - you need to have pressure, and not just funny diaphragm things going on, or you'll die. You don't breathe by atmospheric pressure - not at sea level and not higher up. Given sea level atmospheric pressure is equivalent to a water column of 10m, even 5% of that is quite adequate to fill your lungs.

Pressure and oxygen content both need to be adequate: if the pressure drops quickly while you're full of nitrogen, you can get the bends too.

[Tim Hamilton]

A question that Malaysia Airlines should answer

In what may yet be a critical issue in the disappearance of MH370, Malaysia Airlines CEO Ahmad Jauhari Yahya could not last night (12 March) confirm that a vital airworthiness directive concerning metal fatigue cracks had been carried out on the missing Boeing 777-200.
Were it not for the airworthiness directive concerning possible fuselage failure points on older 777s, it would probably never have been given a second glance.

It could be that Ahmad Jauhari was simply unprepared for the question as to Malaysia Airlines’ compliance with the airworthiness directive, and that the checks and any necessary repairs stipulated by Boeing had in fact been carried out before the jet that operated MH370 took off.
Or, it might be that this work wasn't done, or done properly, with terrible consequences for the 239 people on the missing 777-200.
It is a question that Malaysia Airlines should answer. - Plane talking.

Full piece here Malaysia Airlines CEO unsure if vital repairs done to MH370 | Plane Talking

[VinRouge]

tell you what, anyone who thinks you can sustain 40k continously on an unpressurised emergency oxy system needs to read the books again. time of useful conciousness without pressure breathing at that level is not particularly long...

[Backseat Dane]

Re: Oxygen - there's a world of difference between what's "enough" for the PAX and what's enough for the crew. The PAX merely has to be kept alive semi conscious without the risk of brain damage until a safe altitude has been reached where the oxygen masks will work for sure, while the crew has to be in a state in which it can carry out it's duties (is the flight deck O2 supply under pressure or flowing free?) At least that's what I'd be thinking as an engineer designing the systems.

No need for the O2 partial pressure for the PAX to be high enough to keep them alive at 40.000 ft for a sustained amount of time (i.e. under pressure) - if the plane's descending at 3000 ft/m it'll reach an altitude where the partial pressure of O2 will be high enough to ensure survival for all but the the weakest relatively fast. If the crew's incapacitated at that altitude then the flight will be doomed anyway.

[Lonewolf_50]

Originally Posted by Lost in Saigon

If what you say is true, why are airliners required to have passenger oxygen?

To breath in an emergency.

[Ka6crpe]

Lost in Saigon, On any flight where depressurisation occurs an emergency descent is likely to get the aircraft down to an altitude where the passengers will be able to breathe with the aid of the masks. On large aircraft there are bound to be a few passengers who have taken an hypoxia course at some stage in their life, even if it was more than 40 years ago.


I give my wife an additional safety briefing over and above the one given bt the CC. I tell her that if the masks fall, get it on asap, breathe in normally, then immediately exhale fully. Breathe in normally, but forcibly exhale.


It should only take about 10 - 15 breaths before the aircraft is down to an altitude where normal breathing is possible.

[MPN11]

Could it be helpful to focus on what might have happened to the aircraft somewhere NE of KL, instead if endless debate on SAR issues,or diversions on pax breathing advice? That expertise is not necessarily located in R&N, although there are some here who can contribute.

IMHO, the former might possibly lead to the latter. In other words, start at the beginning, instead of charging off in all directions and making this thread almost incomprehensible?

I believe we should be covering all bases, but please avoid a high-sprited chase down random alleys. If PPRuNe can be helpful, it's proclaimed professional focus would be a strength. Random chat isn't doing that.

[Chronus]

In our hitech world of today, where military sats in their geo stationary orbits around the planet and sophisticated radar heads covering every avaiable square foot of terrain can spot even a mozzie on the loose, with the seas patrolled with nuke subs and sewn with sonoboys that can hear a flatus of a mariner at a distance of 50 miles, how can it be possible for your every day , run of the mill variety type airliner to go into stealth mode for so long. That is what puzzles me most.

[Ida down]

Tim Hamilton, it would be handy to know, when that aircraft last had a D check. And at 14 years, she would have had a couple, and what were the results of her last D check.

[Weary]

VinRouge wrote;

What if they were already on the flight deck?

Still very iffy methinks. As soon as the flight crew reached for their quick-donning masks, so would the hijacker - for every flight deck jump seat there is a corresponding mask, and the pilots would not be able to disable them in-flight.
Plus, to depressurise the aircraft, you would either have to turn off the aircon packs or engine bleed valves (slow decompression), or deselect the automated system and manually drive the outflow valve open (depressurise as fast as you like).
Whilst I fly 767s and not 777s, so the details are likely a little different, but the basic system architecture would be pretty much the same. Playing with the aircon/pressurisation system on the overhead panel is not going to go unnoticed by the highjacker who would be watching the pilots like a hawk.
Any triple 7 chaps reading please do confirm or correct.

[NamelessWonder]

Isca

back on page 112 DYE wrote in post 2234 (now 2230)

Quote:
Checked FR24 at 07 MAR 2014 - 18:10 UTC (08 MAR 2014 02:10 local time)

FR24 shows SQ68 FL300 SIN - BCN B777W approx 200 miles north-west of Penang.
I have tried to reproduce this using flt SQ68 and MH370 and can't anyone else tried

Going to very embarassing if this is true

Yes, it is possible, though it appears on FR24 as "SIA68"

There are, however anomalies with the data as presented - for an example, set the time to 17.00 on March 7 and watch what KAL672 (and the neighbouring CCA970) do whilst MAS370 is heading for the Malaysian coast. Perhaps anomalies are to be expected, given that this is unofficial data, but to see 2 reciprocal tracks in the surrounding area of the event under question, AND within a few minutes of the disappearance seems somewhat . . . . odd!

Bear in mind you will not see MAS370 heading NW of Penang as (allegedly) it's transponder is off and therefore there is no ADS-B data to superimpose on this image.

[Edmund Spencer]

The hand over on this route is usually KL to Singapore on VHF followed by a short period on Singapore HF/CPDLC followed by a hand off to Saigon on VHF. The communications and ATC are, in my experience (25 years) usually excellent.
Singapore Radio on HF 8942 is one of the better in the region.
Of course, we don't usually keep a listening watch on HF as mostly we use HF Selcal. However, any distress call on VHF 121.5 would have been heard by any aircraft in the area.
Even at that time of night there are dozens of aircraft on that airway. If an emergency transmission was made it must have been heard by someone!
An absolutely catastrophic flight deck event IMHO.

[dsc810]

FYI the UK glider altitude record is just under 39000ft.
Whether this was done with a constant flow O2 system or a diluter-demand system I've no idea - but is was not using any form of pressure breathing O2 equipment or suit.

My own system says that it is rated up to 40000ft

[severidian]

ADS-C and CPDLC used in this region ???

[SLFgeek]

Originally Posted by michael0658

The radio horizon at 35,000 ft is about 230 nm for a ground ATC. At its last reported position, this plane was beyond the Line of Sight (LOS) radio horizon for all ATC systems and ground radio.

For VHF/UHF I agree. For HF comms, there should have been much longer range/coverage. Question is, was there any guard channel on HF, in that part of the globe, that would been monitored.

[isca]

Ok Mixture, now the statement is clearly qualified I am happy.

I was not suggesting aircraft hackers could use stuxnet, merely pointing out with determination (and resources) anything is possible.

I would not think it beyond the ability of a well financed terrorist group to invent a hack that allows them to disable an aircraft comms/electronics, maybe even screw autopilot and fly by wire (you can't pull every breaker or you can't fly it manually.

I agree a bit far to fly it from your seat or the toilets.

[threemiles]

The hand over on this route is usually KL to Singapore on VHF followed by a short period on Singapore HF/CPDLC followed by a hand off to Saigon on VHF. The communications and ATC are, in my experience (25 years) usually excellent.
Singapore Radio on HF 8942 is one of the better in the region.
Of course, we don't usually keep a listening watch on HF as mostly we use HF Selcal. However, any distress call on VHF 121.5 would have been heard by any aircraft in the area.
Even at that time of night there are dozens of aircraft on that airway. If an emergency transmission was made it must have been heard by someone!
An absolutely catastrophic flight deck event IMHO.

You fly elsewhere. The airspace of that route in SIN FIR is delegated to Lumpur and the handover is directly from Lumpur to HCM on VHF.