Egyptair Flight MS804 Disappeared from Radar [New conclusion]

[earlyriser]

Reading the PPrune forum it sounds like there may have been a fire in the front right lavatory that may have spread? This may be wrong just doing my best to decipher the advanced discussions there.

 

[Skyring]

Reading the PPrune forum it sounds like there may have been a fire in the front right lavatory that may have spread? This may be wrong just doing my best to decipher the advanced discussions there.

It's gone a bit too technical for me to follow. ACARS reports of smoke in the avionics bay and various window errors. Apparently the reports are genuine and the fellows are discussing what it means.

EgyptAir flight data show smoke alerts - CNN.com

Fire and possibly an explosion in a wing tank. The discussion continues.

 

[jb747]

On PPPRuNe, the last radar data has been discussed. Consensus appears to be that a 90° turn left is standard procedure for a sudden depressurisation event, as the aircraft must descend quickly, and this gains immediate horizontal separation from any aircraft on the same airway at a lower flight level.

Consensus amongst the obvious non pilots perhaps. Whilst you MAY decide to turn off track, it's only about 30 degrees or so...

Anyone who mentions 'wing tank explosion' is not a pilot...

 

[Skyring]

Consensus amongst the obvious non pilots perhaps. Whilst you MAY decide to turn off track, it's only about 30 degrees or so...

Thanks. That makes sense, given what you said earlier about turns taking minutes rather than seconds.

 

[Skyring]

Anyone who mentions 'wing tank explosion' is not a pilot...

Because the wings are where they keep the fuel. Most of us here are not pilots, and it was in my mind that there might possibly be a centre tank on the A320 for transferring fuel or something. What do I know?

 

[jb747]

Because the wings are where they keep the fuel. Most of us here are not pilots, and it was in my mind that there might possibly be a centre tank on the A320 for transferring fuel or something. What do I know?

No, it's an indicator from prune that the person mentioning it isn't a pilot.

Less than half of all posters there are pilots...going by what they say.

 

[Quickstatus]

Apologies for my editing, but I couldn't resist. Why anyone thinks just about anything that comes of of Donald's mouth is factual is beyond me and in particular feel his opinions (masquerading as fact) add no value whatsoever to this particular discussion.

Whatever the opinions are about DT, his comments are no more or less speculative than some have proferred here. I suppose his carries a bit more weight/influence as he is in the spotlight during the Presidential campaign.

Back to the topic. Even his opponent HC has publicly stated that it was a terrorist attack. Speculative - perhaps. Based on substantive? information from US intelligence? Who knows? However all Presidential candidates are briefed about National security and intelligence issues and therefore should have more reliable ?? information than us who just read the news outlets and share (speculate) here.

Additionally do we really think that any of the news outlets (include PPrune and even this thread) and their "expert" (read armchair) commentary are any more accurate?

 

[JessicaTam]

I have deleted some off topic posts before the political discussion gets out of hand. Politics is a sensitive subject, so please keep to the subject of the thread.

 

[jb747]

These are the ACARS messages that were supposedly sent. I've copied this from avherald.com. For what it's worth, the editorial commentary there is normally very sensible, though the comments from the masses can be less so. One of the better sources.

On May 20th 2016 The Aviation Herald received information from three independent channels, that ACARS (Aircraft Communications Addressing and Reporting System) messages with following content were received from the aircraft:

00:26Z 3044 ANTI ICE R WINDOW
00:26Z 561200 R SLIDING WINDOW SENSOR
00:26Z 2600 SMOKE LAVATORY SMOKE
00:27Z 2600 AVIONICS SMOKE
00:28Z 561100 R FIXED WINDOW SENSOR
00:29Z 2200 AUTO FLT FCU 2 FAULT
00:29Z 2700 F/CTL SEC 3 FAULT
no further ACARS messages were received.

Early May 21st 2016 the French BEA confirmed there were ACARS messages just prior to break down of communications warning however that they are insufficient to understand the causes of the accident until flight data or coughpit voice recorders have been found. Priority as of current is to find the wreckage and the recorders.​

If these are correct, then it points away from the terrorist theories, and more towards an aircraft fault.

 

[Skyring]

These are the ACARS messages that were supposedly sent. I've copied this from avherald.com. For what it's worth, the editorial commentary there is normally very sensible, though the comments from the masses can be less so. One of the better sources.

If these are correct, then it points away from the terrorist theories, and more towards an aircraft fault.

It is probably expedient for politicians to blame terrorism or some other external source over something caused by (say) poor maintenance.

I noticed in a comment above that the three security guys aboard tend to light up in the forward galley. Would cigarette smoke cause ACARS alerts of smoke in a lavatory and avionics bay? If so, these might be regular occurrences unrelated to the actual cause.

A bit of quick googling reveals videos of A320 avionics compartments located in various places. Under the coughpit, near the tail, possibly other places. https://www.youtube.com/watch?v=rd960o1nK8M is a video showing one such bay packed with technical gear, but unlikely to be affected by cigarette smoke.

If not a spurious or inconsequential alert, then it seems to me that a fire in the avionics could have any number of possible effects, none of them likely to be good.

Leaving aside my uninformed speculation about what could go wrong amongst the electronics, what is the reaction of flight and cabin crew likely to be to such an event? Would they be able to smell fumes? Would a swift descent be a possible response?

 

[Foreigner]

BBC has interesting news article here, giving views of lithium battery-related fire risks, by a former pilot:

http://www.bbc.com/news/world-middle-east-36349096

 

[JessicaTam]

These are the ACARS messages that were supposedly sent. I've copied this from avherald.com. For what it's worth, the editorial commentary there is normally very sensible, though the comments from the masses can be less so. One of the better sources.



If these are correct, then it points away from the terrorist theories, and more towards an aircraft fault.

Could someone smoking in the toilet and discarding a lit cigarette have caused the 'avionics smoke'? I.e. immediately after the 'lavatory smoke'?

 

[Quickstatus]

Because the wings are where they keep the fuel. Most of us here are not pilots, and it was in my mind that there might possibly be a centre tank on the A320 for transferring fuel or something. What do I know?

Inflight smoke--fire-- causing fuel tanks to ignite?.

Jet fuel is actually quite difficult to ignite. Like diesel. No information re temperature of wing tanks at FL370 after several hours in cruise

OZ214 Asiana crashlanding at SFO. Cartwheeling down the runway, the fuselage burned due to hot leaking engine oil which took 15 minutes to burn the fuselage. The wing and center tanks never erupted.
QF32 Qantas uncontained engine failure - extremely hot turbine fragment tore through one of the wing tanks - fuel did not ignite
B777 BA2276 uncontained engine failure engine fire, winds blew fire onto fuselage. No wing tank explosion


Fuel tank related accidents in the past:
B737-400 TG114 - faulty wiring in centre tank and airconditioning packs below centre tank caused nearly empty tank to heat up and explode on a hot day while aircraft on the ground.
B747-100 TWA800 - wiring sparks causing explosion in centre tank which was heated by aircon packs under the tank. Aircraft delayed departure (causing longer heating of centre tank by aircon packs while on ground) and was climbing when explosion occured.
B737-300 PR143 - damaged wiring in centre tank, aircon packs under centre tank causing heating of centre tank which was empty, explosion while on ground. Hot day
Concorde AF4590. FOB ruptured tyre causing rubber fragments to indirectly rupture wing tank. Fuel ignited by hot engine

Lithium battery:
UPS6 Uncontained cargo pallet fire causing disablement of pilots through smoke. No fuel tank ignition.

A380 does not have centre tank

Not to say it did not happen but just providing a different perspective.

Most commentary are now walking back from inflight explosion as a cause and raisin onboard fire as a possibility however uncertainty and lack of information clouds every theory. one commentator said - "a bit fast for a fire but a bit slow for a bomb"

 

[jb747]

Could someone smoking in the toilet and discarding a lit cigarette have caused the 'avionics smoke'? I.e. immediately after the 'lavatory smoke'?

No. Smoking in the toilet should only set off the detector in the toilet. Toilet air is generally dumped overboard.

 

[jb747]

Fuel, whilst still contained within the tanks is generally benign. Some forms of it (there are five or six variants of jet fuel in use around the world) are so hard to ignite that you could reasonably safely stand in the middle of a pool of it, and light matches.

But, when converted to an aerosol...then it will burn. As suggested above, very much like diesel.

Those fuel tank fires that have happened, mostly involved almost empty tanks, and some form of heating. Fuel vapour is a different animal. Normally fuel tanks are extremely cold. Concorde had afterburner flame to help the ignition.

This is somewhat heavy reading, but worth the effort http://aerosociety.com/Assets/Docs/...apers/SAFITA Part 1_Reference_3rd Edition.pdf

 

[Skyring]

Inflight smoke--fire-- causing fuel tanks to ignite?.

Hardly. What looked interesting was the final ACARS notification: "F/CTL SEC 3 FAULT"

Apparently this is the circuit breaker for spoilers 1 and 2, out on the wings. How do you spark faults out there? And how would they tie into a crash a few minutes later?

I really have no idea.

My guess, and that's all it is, is that a fire in an avionics bay could have any number of catastrophic effects, and generating spurious or random error messages might well be part of the process.

 

[jb747]

Assuming the abbreviations are the same on a 320 as the 380, it's not really referring to a circuit breaker. It's saying that there is a fault in the flight control system, involving SEC 3, which is one of the backup flight control computers. Most likely it's become unpowered, but it doesn't explicitly say that.

 

[Quickstatus]

Hardly. What looked interesting was the final ACARS notification: "F/CTL SEC 3 FAULT"

Apparently this is the circuit breaker for spoilers 1 and 2, out on the wings. How do you spark faults out there?

There are several flight control computers:
3 SEC (spoiler elevator computers)
2 ELAC (elevator aileron computer)
2 FAC (flight augmentation computer - rudder)

Pilot inputs from joystick (side stick), pedals and rudder trim knob feed into these computers

The fault is a computer not circuit breaker fault AKA avionics problem - fire as some have suggested

...From a JQ right seat pilot friend...

 

[jb747]

There are several flight control computers:
3 SEC (spoiler elevator computers)
2 ELAC (elevator aileron computer)
2 FAC (flight augmentation computer - rudder)

Pilot inputs from joystick (side stick), pedals and rudder trim knob feed into these computers

The fault is a computer not circuit breaker fault AKA avionics problem - fire as some have suggested

...From a JQ right seat pilot friend...

That's very interesting. It means that the flight control structure is totally different to the 380. By way of comparison, the 380 has 6 identical computers, called PRIM 1-3, and SEC 1-3. Only one of them is doing the flying at any given time, but any of them can take over the complete load. A PRIM change will involve no loss or change of flight control law, though going to the SECs will degrade the laws.

 

[Quickstatus]

From Pilot friend:

http://www.smartcockpit.com/docs/A320-Flight_Controls.pdf

Too gobbledegook for me