MH370 missing

[clarion]

TimC,

Thank you for your detailed knowledge and insight.   It has really brought this to life for me and added reallife^TM to the whole matter.

PB

You're very welcome! I hope it's all reasonably clear!

Eminently clear, thank you.  Much much clearer than the speculative, uninformed, nonsense that seems to be pouring out of all media outlets.

[TimC]

Interesting stuff, thanks tatanab. Yes, EFA was seat-of-the-pants on several levels, and very low-budget in the context of 1980s fast jets.

[TimC]

TimC,

Thank you for your detailed knowledge and insight.   It has really brought this to life for me and added reallife^TM to the whole matter.

PB

You're very welcome! I hope it's all reasonably clear!

Eminently clear, thank you.  Much much clearer than the speculative, uninformed, nonsense that seems to be pouring out of all media outlets.

Well, to be fair, it's easier to respond to specific questions, or to critique others' hypotheses, than it is to indulge in intelligent speculation in an information vacuum - and I'm not trying to sell newspapers or online columns with the concomitant need to be more sensational than the next guy!

[Asterix, the former Gaul.]

..Many years before that, I designed some parts that went on EAP which was our country's technology demonstrator for Eurofighter.  I remember talking to the test pilots who were going out to test a new piece of software - brave men!

Presumably the important software would be tested by formal methods and not just the rather dodgy programming indulged in by your average IT bod.

With regard to Chris goodfellow's hypothesis, how likely is it that aircraft components could get hot enough to set the thing alight without diagnostics detecting it and communicating the fact to the pilot and to ground support?

Fire in an aircraft must be one of the oldest and most feared disasters that could occur, predating even the Wright Brothers!  i.e. hot air balloons.

[hellymedic]

'Intelligent speculation in an information vacuum' strikes me as hollow, pointless and potentially harmful.
I can understand why it happens but really wish it did not.

[clarion]

Especially when all those passengers have loved ones who have as yet no idea of their fate.

[Asterix, the former Gaul.]

'Intelligent speculation in an information vacuum' strikes me as hollow, pointless and potentially harmful.
I can understand why it happens but really wish it did not.

We are human beings, it's what we do.  One of the problems with information vacuums is knowing in which direction to best seek information. 

[tatanab]

Presumably the important software would be tested by formal methods and not just the rather dodgy programming indulged in by your average IT bod.

There's a world of difference between an IT bod and a software writer.  And yes, even then testing was by formal methods.

how likely is it that aircraft components could get hot enough to set the thing alight without diagnostics detecting it and communicating the fact to the pilot and to ground support?

Not very.  Each piece of equipment is subject to reliability calculations which includes any stress factor (such as temperature) on every component of that equipment.  The individual components are also derated according to their intended environment.  This is why you get commercial, industrial, Mil Spec and space ratings for integrated circuits.  Each component is also subject to "consequential damage assessment" i.e what happens to the piece of equipment if that one component fails.  Yes, things do fail and stuff happens - nothing is perfect.  Look at Boeing's problems with Lithium batteries on 787.  After years of banning Lithium primary cells they thought they had it cracked.

[mrcharly-YHT]

..Many years before that, I designed some parts that went on EAP which was our country's technology demonstrator for Eurofighter.  I remember talking to the test pilots who were going out to test a new piece of software - brave men!

Presumably the important software would be tested by formal methods and not just the rather dodgy programming indulged in by your average IT bod.

Just over the partition from me is a bod who worked for BAE systems on flight control software.
Formal methods? You are far too trusting, sir. Those are very expensive.

I'd hope that aircraft have cynical old lags involved in the design, who will assume failures and design around them.

[David Martin]

One of our programmers es a hardware bod on tornado. There are various paradigms such as purely deterministic programming (ie no interrupts) and much semi formal testing

[TimC]

'Intelligent speculation in an information vacuum' strikes me as hollow, pointless and potentially harmful.
I can understand why it happens but really wish it did not.

It can be very upsetting when people indulge in such speculation, but sometimes it's actually necessary in order to give an investigation a starting point. And, of course, plenty of people are paid to do it and in doing so create snowballing crassness which serves no purpose other than to spread fear and ignorance. Hopefully, in trying to bring some light to the discussion, I can counter the more irrational fears

[TimC]

Presumably the important software would be tested by formal methods and not just the rather dodgy programming indulged in by your average IT bod.

There's a world of difference between an IT bod and a software writer.  And yes, even then testing was by formal methods.

how likely is it that aircraft components could get hot enough to set the thing alight without diagnostics detecting it and communicating the fact to the pilot and to ground support?

Not very.  Each piece of equipment is subject to reliability calculations which includes any stress factor (such as temperature) on every component of that equipment.  The individual components are also derated according to their intended environment.  This is why you get commercial, industrial, Mil Spec and space ratings for integrated circuits.  Each component is also subject to "consequential damage assessment" i.e what happens to the piece of equipment if that one component fails.  Yes, things do fail and stuff happens - nothing is perfect.  Look at Boeing's problems with Lithium batteries on 787.  After years of banning Lithium primary cells they thought they had it cracked.

Electrical/electronic fires are very, very rare, but they do happen from time to time. I once had an inverter catch fire in a Hercules which prompted us to get the aircraft on the ground in less than 10 minutes from the cruise at FL280. Fortunately, Manston was very close. The Swissair MD11 crash near Halifax, NS, was the result of an electrical fire.* Both of these events were caused by shorting in wiring, not failures in individual components.


* There are several features of this crash which are or will be relevant to MH370, not least the fact that in hitting the water in one piece and at relatively high speed, there was very little debris on the surface for the rescuers to find - and they knew exactly where to look.

[Hot Flatus]

'Intelligent speculation in an information vacuum' strikes me as hollow, pointless and potentially harmful.
I can understand why it happens but really wish it did not.

It can be very upsetting when people indulge in such speculation, but sometimes it's actually necessary in order to give an investigation a starting point. And, of course, plenty of people are paid to do it and in doing so create snowballing crassness which serves no purpose other than to spread fear and ignorance. Hopefully, in trying to bring some light to the discussion, I can counter the more irrational fears

A hefty dose of popular culture revolves around disasters....just look at all the aircraft disaster movies from the '70s. Add in the internet, where everyone gets a say, and that news is now primarily a form of entertainment and this is what you get.

Its nothing new, however annoying and poignant it is for you , Tim. Its just a bit harder to avoid than it used to be.

[tatanab]

The Swissair MD11 crash near Halifax, NS, was the result of an electrical fire.* Both of these events were caused by shorting in wiring, not failures in individual components.

The problem in that case was that the In Flight Entertainment had been wrongly installed and connected to an essential power bus and so could not be isolated.  Flight crew of course would have no idea of this and would shed whatever power they could expecting to isolate the source.

Wiring shorts are very rare and arguably should not happen because the circuit breaker on that power line is rated to protect the wire - any equipment connected to that line has to look after itself.  e.g 16AWG wire will carry a 15A breaker.  So a real short will pop the breaker.  Wire insulation is also not random, it is approved by the industry and some are specifically forbidden by the aircraft manufacturers.

[Hot Flatus]

Also not a particularly old aircraft, or design.

[TimC]

'Intelligent speculation in an information vacuum' strikes me as hollow, pointless and potentially harmful.
I can understand why it happens but really wish it did not.

It can be very upsetting when people indulge in such speculation, but sometimes it's actually necessary in order to give an investigation a starting point. And, of course, plenty of people are paid to do it and in doing so create snowballing crassness which serves no purpose other than to spread fear and ignorance. Hopefully, in trying to bring some light to the discussion, I can counter the more irrational fears

A hefty dose of popular culture revolves around disasters....just look at all the aircraft disaster movies from the '70s. Add in the internet, where everyone gets a say, and that news is now primarily a form of entertainment and this is what you get.

Its nothing new, however annoying and poignant it is for you , Tim. Its just a bit harder to avoid than it used to be.

Hey, I'm used to it - it happens every time there's a crash. Here, I can do something about it by providing information to educate the discussion.

[TimC]

The Swissair MD11 crash near Halifax, NS, was the result of an electrical fire.* Both of these events were caused by shorting in wiring, not failures in individual components.

The problem in that case was that the In Flight Entertainment had been wrongly installed and connected to an essential power bus and so could not be isolated.  Flight crew of course would have no idea of this and would shed whatever power they could expecting to isolate the source.

Wiring shorts are very rare and arguably should not happen because the circuit breaker on that power line is rated to protect the wire - any equipment connected to that line has to look after itself.  e.g 16AWG wire will carry a 15A breaker.  So a real short will pop the breaker.  Wire insulation is also not random, it is approved by the industry and some are specifically forbidden by the aircraft manufacturers.

Indeed. While that was the cause of the fire, it's likely that had the crew spent less time diagnosing and more time getting the thing on the ground, they might have lived. That accident changed a lot of thinking about emergency handling. There was lots of other fallout about post-manufacture installations, but I expect you know more about that than me!

Edit, and an aside, wasn't it Kapton wiring? We had the same stuff in that Herc...

[Kim]

'Intelligent speculation in an information vacuum' strikes me as hollow, pointless and potentially harmful.
I can understand why it happens but really wish it did not.

It can be very upsetting when people indulge in such speculation, but sometimes it's actually necessary in order to give an investigation a starting point. And, of course, plenty of people are paid to do it and in doing so create snowballing crassness which serves no purpose other than to spread fear and ignorance. Hopefully, in trying to bring some light to the discussion, I can counter the more irrational fears

A hefty dose of popular culture revolves around disasters....just look at all the aircraft disaster movies from the '70s. Add in the internet, where everyone gets a say, and that news is now primarily a form of entertainment and this is what you get.

Its nothing new, however annoying and poignant it is for you , Tim. Its just a bit harder to avoid than it used to be.

Hey, I'm used to it - it happens every time there's a crash. Here, I can do something about it by providing information to educate the discussion.

Well it's not like any of the tens of thousands of fatal road accidents that have happened since MH370 disappeared are actually *interesting*...

[tatanab]

Edit, and an aside, wasn't it Kapton wiring? We had the same stuff in that Herc...

I do not know if it was Kapton in that case, but you are right that Kapton is a no-no.

As I recall, this incident was a feature in the demise of Swissair in that form in 2002.

[TimC]

I'm sure it didn't help, but they were in financial doo-doo anyway.

[Jacomus]

Something that I haven't seen brought up yet is, 'why are pilots able to turn off the aircraft's reporting systems?'.

[TimC]

Pilots have control over all aircraft systems, to a greater or lesser degree. It is the pilots who are responsible for all communications with ATC and others, and there are several equipment failure situations (as intimated in the conversation about Swissair 111 above) where control over electrical loads is crucial. Many areas of the world are incompatible with some more modern datalink communication systems, and require it to be switched off to eliminate frequencies being saturated with automated aircraft systems trying to find a compatible receiver. These systems do fail, also, and in order to use the alternate system, the first must be able to be switched off. All that said, the next generation of transponders are likely to be automated, and will carry a totally unique identifier for the aircraft (like an IPv4 or 6 address) that will, if all the supporting systems work, identify the aeroplane and the flight it's operating at all times, including in areas where VHF communications and radars are not available. But there will still be times when it fails!

[andyoxon]

Sorry if this have been covered already; but I still find it strange that the 'black boxes' don't have some high gain 'pinger' that really works, rather than a seemingly less than satifactory ultrasonic device that stops after a few weeks.

[TimC]

I don't think anyone envisaged a scenario where no-one had any idea where a plane went down. Though it has happened a few times, and I'm quite sure that the next generation of flight recorders will incorporate better batteries, and stronger transmitters that work on more wavebands. The 7000m underwater scenario is still going to be pretty tough to deal with, however. Eventually, we'll have real-time data download of the thousands of parameters the flight recorder covers, but we'll need a better broadband deal than we have now!

[Wombat]

I recall my uncle spending many happy* hours bumbling about various oceans, but most typically the north sea, listening/looking for flight recorders of a variety of aircraft (but most commonly oilrig super pumas)  He hated it, but as his job (with AAIB) was mostly about flight recorders and their analysis, finding them was the first step! And rather a tricky one...

He's got an American Aeronautical Society lifetime achievement award for his work on the Lockerbie bombing - proper proud of him, I am! (shame its a huge tasteless monstrosity, but you can't win them all)

* may contain traces of lies - he considered helicopters to be un-natural, and I'm inclined to take his word for it.