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garage mechanic re- hacking
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Satellites can be hacked, missiles can be hacked, cars can be hacked, ATMs can be hacked. ANYTHING computer based can be hacked. Not strictly true at all. I have a fairly old car. It has an engine management computer. It cannot be hacked. Why not? It has NO external interface, except for a single WIRED connector. It cannot be reprogrammed through this connector. The only way to re-program it is to replace the internal EPROM with another. Sure there are NEWER engine management computers in newer cars, that have DIFFERENT architectures, that may not be so robust... My point is it is NOT true that ANYTHING with a computer in it can be hacked. Only systems with open interfaces can. Some of the most unhackable computers are old MS-DOS machines (remember 386 CPUs. eh!), with NO Ethernet or similar network interface. Hack that. I've worked with the T7 avionics.... However we have progressed most modern ECU use an FPGA which is reprogram in situ and these have been in common use for over 10 yrs. If the aircraft system didn't have them originally you can bet it has been upgrade because program changes become quicker and cheaper than box swapping. Now that means there is an external access to them so plugging into the PC port or wireless may well make hacking possible. I subscribe to the belief if you can build it someone will hack it, look at the so say secure financial systems that have been hacked. To see IT guys believing that a system is unhackable is frightening with it's complacency. Do you remember stuxnet? |
They could just target specific components of the system (for example disable comms) and cause an accident without actually trying to fly the aircraft. But how much could they do to safety critical systems ? I suspect the numbers plummet dramatically, if not to zero. How much could they do to safety critical systems that the flight crew could not overrule by flicking a switch or pulling a CB ? I suspect the number is exactly zero. |
Lost in Saigon, Unless you have been trained in high altitude breathing then even if you are receiving oxygen, you still wont be able to breathe. At high altitude you must consciously inhale and exhale, there is insufficient air pressure for your body to exhale automatically.
Think of the acclimatisation periods required by climbers ascending Everest, they are training their bodies to breathe with reduced air pressure. |
did mil rad see SQ68
back on page 112 DYE wrote in post 2234 (now 2230)
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. Going to very embarassing if this is true |
As fr a standby list on a plane that appears not to be full- it is possible they were operating a restricted passenger load due to cargo/weight restrictions. Any T7 drivers care to comment? My lot do this regularly but it is usually on much longer routes... |
worth pointing out pax oxy pointless above about 25k. The unpressurised 25K limit was, I thought, due to issues with decompression "sickness"... |
secure financial systems that have been hacked. To see IT guys believing that a system is unhackable is frightening with it's complacency. Do you remember stuxnet? And a difference between aircraft systems and stuxnet. You only need to go read up a bit on stuxnet to realise how "special" it was for many reasons (i.e. highly likely to be a well funded, "western" government project with specific targets in mind that they had evidently done much research on before). A LOT of money and manpower went into stuxnet .... more than any tewwowist organisation could ever dream of ! I'm not saying aircraft systems are invincible, I'm just saying its utterly ludicrous to say someone can get 100% remote control over an aircraft, even more so in a manner that the flight crew can't overrule. The chance of an aircraft being hit by a meteorite is far more likely ! |
Wiggy, it definitely seems like a customer option. Every Boeing I've ever worked on (737, 767, 777) has had a fixed chemical system, another poster pointed out that some have bottled.
In my outfit they are chemically generated. I was under the impression that bottles were an add-on option for airlines who mainly fly through high terrain alts on a regular basis (i.e. QF 747s to UK) Seems I was wrong on that. But it's definitely varying between operators because mine uses individual generators. They are also one of the largest 777 operators so this may have something to do with it |
Originally Posted by Lost in Saigon
(Post 8369956)
So you are saying the B777 does not have the correct Pax O2 masks?
Go play your games with someone else. |
Hoagey74
Unless the National Reconnaissance Office or the DOD itself whose SBIRS satellites are lying to us, just not saying, there were no flashes, explosions, or bright lights in the area being discussed at the time being discussed.
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Originally Posted by Ka6crpe
(Post 8369961)
Lost in Saigon, Unless you have been trained in high altitude breathing then even if you are receiving oxygen, you still wont be able to breathe. At high altitude you must consciously inhale and exhale, there is insufficient air pressure for your body to exhale automatically.
Think of the acclimatisation periods required by climbers ascending Everest, they are training their bodies to breathe with reduced air pressure. |
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) |
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. Assuming of course the crew bottles are aligned fore and aft not vertical |
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.
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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. |
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 |
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...
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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. |
Originally Posted by Lost in Saigon
(Post 8369990)
If what you say is true, why are airliners required to have passenger oxygen?
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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. |
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