Why is it difficult to fly at altitude?
 

Magplug stated "It is difficult enough hand flying a big jet at high altitude with everything working normally"

Why is it difficult?

I have flown B-720, 707, 737, 727, 757,767,777, MD-11 and have found they all fly normally at high altitudes.

Yes there is a very public history of such devices - Abdulmutallab's underpants were meant to explode but actually just caused a fire in the cabin wall and his underwear as NW253 was on approach into Detroit.

Improvised Explosive Devices often do not function as expected. But an IED in the forward galley, possibly in a refreshment cart, that caused a minor Abdulmutallab style explosion followed by a severe fire in the area of the avionics bay/cockpit rear wall but completely contained not causing an explosive decompression would fit the 'evidence' so far.

Not sure if this has been covered previously, and I'm not inclined to wade through 500-odd posts this morning, but those contributors referring to an avionics/electronics bay may not all be aware that the A320 has two such compartments separate in the forward fuselage. (Their official names escape me at the moment.)

1) A small bay or compartment accessed just forward of the nose L/G bay (hence roughly beneath the cockpit), accessed by a small plug-type oval hatch in the bottom of the fuselage ;
2) A larger electronics bay/compartment between the nose L/G bay and the forward hold. So it is beneath the forward passenger cabin.

(1) Contains, among other things, the two main batteries, LGCIUs and SEC 3.

(2) Contains, among many other things, the remaining FCCs,

Right now I can't remember where the WHCs are located.

It would be interesting to know how long MS804 spent in Tunis before the leg to CDG and the state of the local security environment there.
The media concentration on security in Paris seems to overlook an important consideration, given the extent of the Tunisian contribution to Daish/ISIL - which exceeds that of any other country.

@aussiepax: read...think...write... in that order


@Ian W: A severe fire needs two things - an ignition source, but more importantly a volatile fuel that is able to propagate the fire in a rapid way. There is no good flammable material in the galley, especially in the food cart. The various plastics burn slowly, especially in the thin cabin athmosphere at FL370. In another life I conduct expeditions to remote areas where standard practice is to burn any combustible trash, remove all other. I know how difficult and time consuming it is to burn plastic garbage. It requires a liberal dousing of diesel for it to properly catch fire, and without wind the flames die repeatedly. As all catering and cabin materials are made of certified (relatively) fire retardant materials, I find it a bit hard to envision an accessible fire on board strong enough that it cannot be put out with the extinguishers. With SR111 the problem was that the fire was inaccessible, and the severity was not recognized until too late. Similarly with the two 74F accidents, the crew had no access to the fire location.

Scheduled timings (gate-to-gate) for SU-GCC's rotations were:

MS843 DEP CAI 08:15L 06:15Z
MS843 ARR TUN 10:35L 09:35Z

MS844 DEP TUN 11:35L 10:35Z
MS844 ARR CAI 15:40L 13:40Z

According to FlightRadar24, it spent 1 hour 20 minutes on the ground at Tunis (09:33Z to 10:53Z), which is broadly consistent with the schedule, though bear in mind that the 1:20 includes taxi in/out as FR24's timings are for landing and takeoff (though it refers to them as ATA/ATD).

Back in 1966 I was involved in a severe incident when we temporarily lost control of a large jet transport. The problem started when the whole aircraft filled with dense smoke and we thought we were on fire. The captain initiated a descent when we could not see the flight instruments and we found ourselves in a spiral dive from which we were very lucky to recover, see:-
http://www.pprune.org/accidents-clos...ml#post9069763

All I would like to say to the many people who have posted here is that things can go wrong very quickly and that smoke and fire on board an aircraft is something that can be very difficult to deal with.

There presumably was no flammable material in Abdulmutallab's underpants or the cabin of NW253 yet the IED he had there caused a fire in the cabin wall that had to be put out. The bottom trays of many meal carts are also full of plastic miniature bottles of spirits. So 'imagine' a muted explosion (i.e. more fire than explosion) that blows down and forward from the bottom of a cart into the avionics bay and rear wall of the cockpit. Now get to that area with your fire extinguisher.

Chemical and electrical fires are significantly different than burning trash.

Electronic Flight Bags With Lithium Battery Installations


These problems experienced by users of lithium batteries raise concern about the use of these batteries in commercial aviation. Accordingly, the proposed use of lithium batteries in Astronautics electronic flight bags on Airbus A318, A319, A320, and A321 series airplanes has prompted the FAA to review the adequacy of existing regulations in Title 14 Code of Federal Regulations (14 CFR) part 25. Our review indicates that the existing regulations do not adequately address several failure, operational, and maintenance characteristics of lithium batteries that could affect the safety and reliability of lithium battery installations.

https://www.federalregister.gov/arti...nic-flight#h-9

That's good. We have no such procedure for an iPad catching fire in the flight deck.
What does your procedure involve? Do you have fire resistant gloves on the flight deck?
( serious question)

Gloves yes and a specially designed fire proof bag.

After using the fire ext to stop the fire the offending lithium runaway is put in to a specially made sealable fire proof bag that can be filled with up to 5 litres of water to keep the lithium battery cooled, then the bag would stowed in a safe area usually a metal container in the galley.

Egyptair is actually a dry airline. However I'm not contesting what you say is possible, I just think its improbable.

Except that normal strength spirits are not flammable.

Apologies if it's already been mentioned, but what about a crew oxygen fed fire?

How about? How about? How about? How about waiting until the recorders have been found and analysed by trained experts in the field of accident investigation?

Example of IPads w lithium batteres used as EFB's
 

I haven't heard anything about pings from the flight recorders being detected yet. Always wondered whether marine seismic vessels would be of any help. They tow very long arrays of geophones (lengths of kilometers typically). Of course the sensors are tuned to normal sound frequencies, but I don't think it would be too difficult to swap out a geophone for a sensor tuned to the ping frequency of the black boxes. There are marine seismic vessels all over the world (and, these days, probably quite a few which are idle).

Sorry wageslave, but normal strength spirits such as whisky, gin, vodka, brandy etc at around 40% alcohol are very flammable indeed

'Windshield Fire Exposes Airbus Faults

European safety regulators may require European operators of Airbus A330s and A320s to replace aircraft windshields following an investigation into a June 2009 Jetstar flight from Japan that was diverted to Guam after a fire ensued at the base of the right main windshield.

The Australian Transport Safety Bureau (ATSB) on Friday concluded the right windshield experienced an overheating failure, which was related to the use of a polysulfide sealant (PR1829) within the body of the electrical connector terminal block. The sealant caused unintended heating effects when the windshield was being heated subsequently causing the thermal breakdown of the sealant, which ignited the fire.

Airbus initiated a safety program in early 2010 to identify and replace all windshields that had been produced using the sealant within the electrical connector. The manufacturer replaced some 1,500 units within the fleet.

The ATSB has been advised that due to limited fleet-wide completion of Airbus' replacement program, the European Aviation Safety Agency is considering implementing an Airworthiness Directive, which will require all European operators flying the specified aircraft to have all windshields replaced.'

AFAIK no Directive was issued, was this aircraft included in the windshield replacement program?

Once heated, they very much are!

Thanks andrasz,
Good info.

@ Lurker40752: The fault identified in the Jetstar incident affects aircraft fitted with windows manufactured between January 2007 and October 2008. SU-GCC was manufactured in 2003 so not affected (unless a window replacement occurred from that batch).

Exactly ...

I was thinking of posting regarding an anti-terrorism theory but why bother ... I can outsmart people but I'm damned if I'll outstupid them!

The current pumped into the screens seems to be astonishingly high. In the 70's I had an incandescent lump metal hit me from a poor side window connector. It came from the opposite DV window as it was closed.

One night, despite being pretty quick with getting the windshield heat off, fragments of hot glass were spitting onto our clothes.

Cheers Above the Clouds, exactly the answer I was looking for as well. I understand it would have to be a class D extinguisher, may I ask what the composition is, for example is it a Copper or Graphite based extinguisher?

Thanks for that (I apologise for not having dug up the info myself). A fairly rapid turn around so not a lot of opportunity for access - and in daylight. I suppose that the next question that occurs to me, if nobody else, is did the flight take on any catering supplies when in Tunis? One assumes there was time for a routine internal cleaning.
Clearly there's a trend amongst those who are able to interpret the available information, which is pretty meagre, to discount malicious action but I don't see how or why it can be discounted completely. Tunisia itself, whilst currently "quiet" is actually in a very precarious state.

First post here, and not a pilot for anything with a wingspan beyond 2m.
However, I work _a lot_ with LiPo batteries (the kind in the iPad for example), and I would seriously recommend that you talk to someone about those procedures.
A fire-extinguisher will only pause a lithium fire. Once oxygen reaches the battery, it will flame up again.
Also, putting a lithium based battery into water is questionable at best, as water has plenty of oxygen in it. It might contain the flames, but it might not.

The industry standard (for us that makes the devices, not the end-users obviously) is to have a two buckets half-full of sand. When on fire, toss the battery into one, and pour the sand from the other bucket on top of it.

There are also "LiPo sacks" that are made of fire-resistant materials, designed specifically to contain LiPo fires. Some users that push the batteries a lot (more risk), charge in these sacks. I don't know how you use your iPads, but I'm guessing that this will be inconvenient and/or not allowed.

Sorry for the OT. Couldn't figure out the if there's a PM function on here.
Now, back to watching quietly

Thanks @Andrasz there seems to have been multiple reports of windshield overheating in A320/330 spanning many years, an AD was issued back in '03 for the same concern.

@ skirdlov

The chances for any malicious device to have been planted at any previous stopover decreases exponentially as one goes back (Paris being the most likely). Paris, Cairo & Tunis all have their fair share of loonies, in this respect I would not single out any. Also not mentioned here previously, the role of those three security personnel on board is not limited to in-flight, they also maintain ramp security during turn-arounds, and they are the ones who actually open/close the cargo doors. Anyone trying to gain access to the avionics bay would have to dodge them. Not saying it cannot be done, but rather unlikely during a short turnaround.

For those suspecting the catering trolleys, they undergo a security screening prior to loading (lust like checked luggage) at most airports I'm aware of, Cairo certainly included. Again, things have been missed by screeners before, but still...

Last, Egyptair is not an obvious target. Inside Egypt it is a National institution, and while there are several groups opposed to the government, their main targets are the armed forces or tourism infrastructure. It could be expected that an Egyptair flight would mainly be full with Egyptians, not foreigners (as was the case), it would be a very atypical target for any local group. For foreign groups, targeting a western carrier with the same effort creates much more impact. The terrorism theory does not really add up, especially as there have been no claims in the past 3 days. One may always argue about the lone perpetrator, but getting a device on board an aircraft these days requires considerable skill and organization beyond the means of a single untrained fanatic.

Despite the replies above normal strength spirits are NOT flammable. Spirit will only sustain combustion (the definition for flammable, no?) at a strength of about 100' proof or over.

Sure, under special circumstances, heated or chucked them on a heated surface the alcohol may flash off and burn - briefly - but then so would wine to a lesser degree. On an aeroplane the far, far more serious problem would be the heat source required to achieve this brief flame.

The bottom line is that spirits are not what is conventionally considered flammable and do not constitute a fire hazard under any normal circumstance.

You probably do not do much cooking. You would know that just a couple of soup spoons of any cheap brandy (40°) make flames high enough to singe nicely your hair if not careful. ;)

Describe the Smoke configuration of the avionics A320 ventilation system.
http://fce-study.netdna-ssl.com/2/im...10907522_m.png
-- Used in response to the Avionics Equipment Ventilation Computer (AEVC) sensing smoke in the avionics compartment.
-- The BLOWER and EXTRACTpbs are placed to the OVRD (override) position inaccordance with ECAM procedure.
-- This closes the inlet valve, stops the blower fan, and isolates the cargo under floor and aircraft skin heat exchanger.
-- Conditioned air is provided by the air conditioning system through an air conditioning inlet valve.
-- The extract fan draws the conditioned air through the avionics compartment, and expels it through the small internal flap within the closed extract valve.

Source:Airbus 320 Part-1 (of 3) Flashcards - Cram.com

Wouldn't feeding the fire with fresh air make it more intense? I also read that the flight deck has a halon portable fire extinguisher, any reason why inaccessible areas of aircraft don't have inbuilt halon extinguishers?

Typical distilled spirits with an alcohol content of around 40% are GHS Category 3 ("Flammable liquid or vapor").

But anyone is, of course, free to come up with their own definition.

Flash points of ethanol/water (lowest temperature of solution when you can ignite vapours above surface):
5% (strong beer) 62 °C
10% (wine) 49 °C
40% (whisky) 26 °C
100% (pure spirit) 13 °C

Whisky is not ignitable at temperature when it is drinkable :-)

Question:
From a strict "Configuration Management" point of view.
Assuming that the airline provides Ipads/laptops to the pilots.

Are these Ipads/laptops considered to be part of:
a. the Configuration of the airplane,
b. the 'configuration' of the pilot (dont know a better 'word' to described this),
c. part of the 'configuration' of the pilot when entering the cockpit, but becoming part of the Configuration of the airplane by either c1.connecting the ipad/laptop to airplane power and/or airplane network, or c2. inserting part and/or serial number in an airplane database or airplane carried document/log.

Given the close location of the avionics bay to the cockpit, the obvious critical paths of data transfer between the two and that it appears the cockpit floor is not sealed from immunity to smoke eminating from the bay; it is concerning to learn that there is no supression in the avionics bay.

They must have their reasons and done the necessary risk analysis and effects etc and certification clearly is not required. Surprising nontheless.

@Local Variation
I am not sure (like so many on here) but fire suppression in an avionics bay is surely liable to do an awful lot of damage, if triggered, as these things often are, falsely.
I stand to be corrected by someone more current.

[QUOTE=andrasz;9384639]@aussiepax: read...think...write... in that order


@Ian W: A severe fire needs two things - etc.............


The Fire Triangle.
Fire (not just on a an aircraft) needs 3 things - heat, fuel and oxygen.