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Flight MH370 Depressurization Scenarios

jaydeehess

Senior Member.
Ya know that this novel was made into a movie? (Made for TV movie, anyways).

http://www.imdb.com/title/tt0465537/

I think I recall seeing snippets of it, and well...it was cringe-worthy!! (But, at least Dean Cain some some work....) :D
It was actually written twice. The authors had updated it in the second release to reflect modern(at the time) technologies.
Yes, cringe worthy for the good reasons but did require some suspension of disbelief at times as well.
 

TWCobra

Senior Member.
It is possible to control the cabin altitude at a level where those with without oxy or with inadequate masks will be incapcitated, and still survive unharmed on the cockpit system . I wont go into details here though.
 
The QF 30 incident was a " Black Swan" event. An exploding oxy bottle was totally unprecedented in the annals of civil aviation. The captain and first officer went from thinking about getting a cup of coffee to oxy masks on, depressurisation checklist complete and aircraft commencing emergency descent in the space of 20 seconds.

(I know a lot about this one due to going through pilot training with the captain and my pilots association duties at the time)

If you are following the investigation of MH370 you can see that the known path of the aircraft includes a descent to 5000 feet and manoeuvres and actions intended to mask the aircraft from radar. They aren't the actions of an oxygen starved crew.

It hasn't even been ascertained if the aircraft was depressurised either deliberately or by a malfunction.

Could it be actions of an autopilot trying to get a damaged plane to sultan ismail petra airport?
 

TWCobra

Senior Member.
No. Autopilots are dumb. They operate entirely on human direction via a manual control panel or the manual control panel and the crews inputs into the flight management computer.
They do not operate independently of the crew.
 

jaydeehess

Senior Member.
I see. If the plane maintained an altitude of ~5000 feet and bearing that took it over sultan ismail petra airport and the small island the military radar picked it up in the strait it would have struck the mountains on the northern part of Aceh. Those mountains peak between 5000 and 9000 feet.

Or was the plane taken to central Africa?

http://metro.co.uk/2014/03/18/fligh...malaysia-airlines-planes-description-4640688/
IIRC the plane went to 45000 feet crossing that area.
 

jaydeehess

Senior Member.
So all that is certain is that IF it did travel over another part of Indonesia, that it was higher than the solid bits, I take it that the entire north part of the island(s) were searched?
 
I cannot find any indication that those mountains were searched, so cannot agree with you that it missed those mountains. They should be a pretty important area to be searching when going on confirmed radar spottings.
 
No, highly unlikely. Again, the first action is donning masks...they are a "quick don" design, can be swiftly grasped and placed on the head with one hand.

Not so fast. There is a history of cockpit electrical fires in which pilot oxygen hoses have melted resulting in oxygen fed fires, for example ABX Air B767 at SFO 2008, or Egyptair Flight 667 in 2011. Granted both were on the ground but that is an irrelevant point.

Transposed to 35,000ft the initial electrical problem was enough to make pilots turn the aircraft around and then become overtaken by a fire problem, cascading further into an oxygen fed fire.



Egyptair 667



ABX Air

...and who would cope suddenly depressurised at 35,000ft engulfed in a fireball with only 30 seconds of consciousness?



The heat would melt a hole in the fuselage in seconds and then self extinguish due to the stoichiometric conditions at 35,000ft.

Perfect scenario for a ghost flight on autopilot.
 

TWCobra

Senior Member.
Simon, wouldn't such a fire in the MEC (Main Equipment Center) of a 777 take out the ACARS satcom link as well; thereby disabling the "handshake" feature?

What about the the Flight management System Computers (FMS), the Air Data Computers (ADC's), the Autoflight Director Computers (AFDC), the Inertial reference system (IRS) boxes and the FBW Flight Control computers? They are all in that area beneath the forward deck and they all supply required inputs to the autopilots for them to function.

777 autopilot modes.JPG

The following is a list of electrical components in the MEC, most of which are required for autoflight.

MEC contents.JPG

Your fire needs to avoid all these boxes for the AP to work. That it did that and also took out the pilots and all the comms gear bar the ACARS Satcom is difficult to believe.
 

TWCobra

Senior Member.
You should also be aware that the reason these fires generally occur on the ground is because the smoke detection system in the 777 whilst in the air automatically dumps smoke overboard once it is detected by opening a valve on the underside of the aircraft and uses cabin differential pressure to force it overboard. If this system fails to do this automatically, a switch on the Flight Deck is used to do it manually.

This from a report into one such fire on a British Airways 777.

MEC cooling.JPG
 
Simon, wouldn't such a fire in the MEC (Main Equipment Center) of a 777 take out the ACARS satcom link as well; thereby disabling the "handshake" feature?

That is not absolutely so. We do not know the nature, exact location, or cause of any fire nor exactly what was involved. Just because you can't imagine it, does not mean it isn't so. This is clearly an exceptional event with a complex combination of factors whichever explanation you subscribe to. No simple single cause can replicate all the known features of this disappearance and the cascading effect of electrical failure, electrical fire, explosive decompression comes closest to explaining all the imponderables.

For example, the fifth prototype Boeing 787 test aircraft suffered a generator fire on approach to land at Laredo on 10 November 10, 2010 which knocked out cockpit displays and disabled the auto-throttle. However the crew isolated the fault and managed to land.

En-route to Northern Sudan, on 24 August 2010, an Airbus A321-200 operated by British Midland suffered loss of cockpit displays and un-commanded turns which vanished with de-selection of No.1 generator.

A McDonnall Douglas DC-9, AirTran flight 913, on 8th August 2000, experienced inflight arcing of relay bus cables though the flight continued after the fault was isolated.

The point is electrical faults can be isolated and aircraft continue to fly.

What about the the Flight management System Computers (FMS), the Air Data Computers (ADC's), the Autoflight Director Computers (AFDC), the Inertial reference system (IRS) boxes and the FBW Flight Control computers? They are all in that area beneath the forward deck and they all supply required inputs to the autopilots for them to function.

No that is a false assumption. In reality a fire could breach the hull in just 20 seconds and rapid explosive decompression could knock out the fire before vital electrical components were destroyed. In particular a ruptured oxygen line could cause a highly concentrated blow torch effect.

I am surprised that someone like you who seems well informed about the multiple redundancy features of the Boeing 777, for example dual ADIRUs, that you of all people would advocate the fragility of this aircraft?

In principle pilots could quite effectively manage to isolate the electrical problem, turn the aircraft around and only then discover a blaze. Insulation has been known to catch fire in airliner avionics bays from electrical arcing and as such insulation can keep burning after isolation of the electrical fault has removed the ignition source. Once depressurised the fire would snuff out.

Your fire needs to avoid all these boxes for the AP to work.

Processor units in the underfloor avionics bay of a Boeing 777 are widely spaced to ensure that a fire in one processor box does not affect others.



It is implicit in the scenario which I suggested that pilots first isolated an electrical fault and turned the aircraft about before any fire broke out. This is the state of the avionics bay in Egyptair 667 after the cockpit fire was extinguished. Whilst much of the console interface was destroyed or charred, the actual processors were not:



In the oxygen fed fire of Egyptair 667, the hose down by the right leg of the co-pilot had an anti-kink spring which acted like an induction coil and heated to over 600 degrees F. This melted and ruptured the hose.



That fire took just 20 seconds to breach the hull from when the co-pilot noticed smoke beside his leg, jumped up and discharged a fire extinguisher.

Granted that these anti kink hoses were all due to be replaced within 18 months of a Service Bulletin issued in April 2012, but then Malaysian Airlines was also required to remove Black Boxes for servicing and battery replacement by the original manufacturer and that did not happen either.

Electrically conductive Oxygen hoses are not the only possibility... just one illustration of what might have happened.


That it did that and also took out the pilots and all the comms gear bar the ACARS Satcom is difficult to believe.

No, not that it took out all the comms gear... The pilots were following training, aviate, navigate and before they got to communicate were overcome by fire and explosive decompression.

There is no inference that communications equipment was disabled, rather the possibility that pilots died fighting an emergency before they had any chance to communicate.

The ADS-C system sent information via a Mode S transponder on MH370. You cannot say just because Kuala Lumpur lost contact with that transponder at 17:21 UTC that the transponder was disabled.

IGARI is just south of Ho Chi Minh FIR, therefore the pilots had to Log In by entering a new code. The effect of entering a new code is also to log off with Kuala Lumpur.

It is also worth noting that ADS-C information continued to be fed to SITA via ground relay stations in Vietnam after 17:21 UTC which suggests MH370 did not descend or turn west.
 
You should also be aware that the reason these fires generally occur on the ground is because the smoke detection system in the 777 whilst in the air automatically dumps smoke overboard once it is detected by opening a valve on the underside of the aircraft and uses cabin differential pressure to force it overboard. If this system fails to do this automatically, a switch on the Flight Deck is used to do it manually.

This from a report into one such fire on a British Airways 777.

MEC cooling.JPG

Dumping smoke inflight is not the same as extinguishing a fire.

At 35,000ft with an electrical fire if you pump bleed air into a closed compartment you are merely feeding the fire with more oxygen. You also rob engines of thrust.

It sounds to me that you are grossly underestimating the speed with which a fire may take hold. Granted there are QRH procedures and crew train for emergencies, but in reality if there was a cascading effect of one problem developing into another unforseen emergency compounded on top of that with a third problem explosive decompression, then these guys were not merely fighting to keep control of the aircraft, they were each fighting just to stay alive themselves personally.

In a matter of seconds they would go from fire fighting mode to a hurricane through their cockpit, probably no oxygen feed into their masks, temperature dropping to -50 and the utter fear and confusion.
 
Indeed yes. That speculation seems to be based on what is (likely) an inaccurate radar "hit".

I gather the take off weight for MH370 has been published somewhere yet I have not seen that personally. I gather it took off with about 4 tons of cargo, 239 POB and 31,000 US Gallons therefore I imagine a take off weight around 266,000kg.

No way on earth could a Boeing 777 less than an hour into flight climb to 45,000ft. Service ceiling is 43,100ft which is the altitude where an aircraft can only climb at 100 feet per minute, so by inference it would take another 20-30 minutes to reach 45,000ft from 43,100ft even were that possible. I read someone on PPruNe saying they took a B777 simulator to 43,000ft and it was not even possible at a weight over 167,000kg.
 

Andy

Member
Flight MH370 Depressurization Scenarios

It would need to be a "Decompression Event" - which would NOT result in an ACARS fault transmission. Right ?
Wow, so that should really make it a much shorter list.
Help me understand.

So this discounts : Hull tear at SAT antenna mount, no tire well fire, no cargo fire etc right ? All these 'events' should all trigger an ACARS fault transmission - Right ?

1. This "Decompression Event" happens either before or after the turn.
2. And this "Decompression Event" would either need to happen after or coincide with some sort of electrical 'failure'
3. It cant be a component failure that results in an instant full short circuit, because that should instantly blow a circuit breaker.
- however it may be possible in 'that moment' to result in ignition, still likely to only take out the 'one breaker' though at the initial short..
Enough other residual circuits to allow comms ? Or are all comms a single breaker ?
4. Maybe an over current draw, but within breaker amperage tolerance, which slowly allows heat build up, so very likely first smoke, then flame
- but this 'heat build up' requires continued current through circuit, with everything probably still powered, hmmm seems like this would trigger an ACARS fault transmission from smoke detection ?

Am I right so far, is no fault transmission via ACARS a big clue to the type of event ?

The event isn't great enough to take the plane straight down, it isn't great enough to prevent a turn.
Ok so a plane has a hole in it's skin which results in sudden pressure loss, so what happens at that point in the hull, does it tear rapidly ? (like in movies):D

And then all just after a hand over ? huh ?
Is the hand over instant ?
Say bye to one (KL), switch freq., say hello to HMC ? or is it delayed ?
 

WeedWhacker

Senior Member
Is the hand over instant ?
Say bye to one (KL), switch freq., say hello to HMC ? or is it delayed ?

A typical frequency change (handing-off between ATC facilities) is like tuning your TV set to another channel. You are told the next frequency, you enter it on the "inactive" side of a dual-head VHF Comm radio panel. You acknowledge, then flip the switch to make the new frequency "active".
 

Mick West

Administrator
Staff member
A typical frequency change (handing-off between ATC facilities) is like tuning your TV set to another channel. You are told the next frequency, you enter it on the "inactive" side of a dual-head VHF Comm radio panel. You acknowledge, then flip the switch to make the new frequency "active".

A handover goes like this, initially MH370 is talking to Malaysian ATC (Lumpur Approach) on one frequency

12:42:52 ATC "Malaysian Three Seven Zero contact Lumpur Radar One Three Two Six good night" [ATC tells MH370 to contact Lumpur Radar on 132.6, and hands off with "good night"]
MAS 370
"Night One Three Two Six Malaysian Three Seven Zero" [370 acknowledges the hand off with "'night", and reads back the 132.6 frequency.]

At this point MH370 will enter 132.6 into the "other side" of the radio


MH370 now tells Lumpur Radar he is with them:
12:46:51 MAS 370 "Lumpur Control Malaysian Three Seven Zero"
(He really should have said "Lumpur Radar" there)

And they acknowledge him.
12:46:51 ATC "Malaysian Three Seven Zero Lumpur radar Good Morning climb flight level two five zero" [They say hi, and tell him to climb to FL250, 25,000 feet]

So the hand-over is essentially a manual process. Flipping frequencies on the radio happens when you push the button to toggle them, however nothing actually happens, you are not transmitting until you press the push-to-talk button. It's generally instant from the pilots POV, as he will stop hearing one ATC and start hearing the next. But ATC will not know if the frequency has been switched until the pilot talks to them.
 
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WeedWhacker

Senior Member
Except the photo above is more for a GA airplane.

Here's a common modern example on a Boeing:


(The thing is in "Lights Test" mode, hence all the numerical displays are illuminated).

Also, this particular control panel allows for tuning of the HF and AM (NDB) as well.
Every installation in an airplane might vary slightly in the specific arrangement, depending on the airline's choice of avionics equipment.

Here's another example (simulation graphic):


The Comm control panel on top. Next below, the Audio Control panel (mic selector switches, volumes, etc.)

Then next is the transponder (again, there are many different 'looks', depending on manufacturer). Finally, just some center pedestal controls, for aileron and rudder trim.
 
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TWCobra

Senior Member.
Simon, I am not advocating the "fragility" of the 777, far from it. It is one of the safest aircraft ever built.

Some errors you have made.

43100 is not the service ceiling of the 777. It is the altitude to which it was certified, that is, the upper limit of its flight envelope that was tested to all certification limits.

I don't believe it went to 45000' either but depending on the weight it could get there if required, just not with certified stall margins and reduced cabin pressurisation.

The MEC is not a closed compartment. It is ventilated. The override function changes where the ventilated air goes to, from inside the aircraft to outside, and requires no extra bleed air from the engines. The pressurisation system would cope by reducing the amount of air leaving the aircraft via the outflow valves to maintain cabin altitude.

Dumping the smoke overboard does not supply more oxygen. It changes the direction of the airflow in the compartment which changes the path of any fire towards the valve on the floor of the compartment.

ADS is independent of the squawk code. The Ho Chi Minh controller would have seen the aircraft on his radar screen showing the transponder code assigned by KL. The aircraft controllers sometimes assign a new code when entering a new FIR but MH370 never got that instruction. Otherwise the new FIR simply uses the current squawk.
ADS works on a discrete aircraft ID number and is not generally able to be changed from the flight deck. Turning off the transponder however turns both the SSR response and the ADSB.

You state that ADS-C info was received by Vietnamese stations? Info please?

You state that your scenario had an electrical fault which was isolated by the crew followed by a turn south, followed by an uncontrollable fire, followed by a depressurisation.

The division of responsibilities on a flight deck during an emergency has the PF, pilot flying, handling navigation and communications whilst the PM, pilot monitoring, carries out checklist items under the supervision of the PF.

Turning back off an airway in busy airspace is a big deal for obvious reasons. ATC has to be told immediately. No call was made and no emergency code was selected on the transponder. Those omissions themselves are highly non-SOP.

There were no maintenance messages regarding a major electrical failure were sent via the ACARS. No record of an aircraft transiting through Singapores ADIZ. Even Mike McKays sighting does not have the aircraft turning south. Major electrical failures/fires will render autopilots inoperative.

Sorry, but I can't see any corroborating evidence for this scenario at all.
 

Andy

Member
the push-to-talk button. It's generally instant from the pilots POV, as he will stop hearing one ATC and start hearing the next.

Thanks Mick,
Ok, so microphone is in hand, you have just said "Good Night & Have a Nice Life" to KL.
Is safe to assume, you don't stop fighting a fire to say "Good Night"..
You are now listening to Vietnam's ATC...

So then:
Do you then announce yourselves to Vietnam's ATC..?
Wait till spoken too ?
What's the etiquette here ?

If a delay, how long ?

There were no maintenance messages regarding a major electrical failure were sent via the ACARS
That's what I refer to, no message, why ?
 

TWCobra

Senior Member.
Thanks Mick,
Ok, so microphone is in hand, you have just said "Good Night & Have a Nice Life" to KL.
Is safe to assume, you don't stop fighting a fire to say "Good Night"..
You are now listening to Vietnam's ATC...

So then:
Do you then announce yourselves to Vietnam's ATC..?
Wait till spoken too ?
What's the etiquette here ?

If a delay, how long ?


That's what I refer to, no message, why ?


As others have said, ATC will give you the next frequency. Most pilots will be putting it into the standby window as it is being read to you, followed by a readback of the frequency and your callsign. the frequency then gets changed by a button push, you wait a second to make sure there already isn't a conversation already happening and check in with your callsign and altitude. It takes 10 seconds.

You can hear it all happening on ATC.com
 

WeedWhacker

Senior Member
Ok, so microphone is in hand, you have just said "Good Night & Have a Nice Life" to KL.
Is safe to assume, you don't stop fighting a fire to say "Good Night"..

The hand-mic can be used, or the headset boom mic.


You are now listening to Vietnam's ATC...
So then:
Do you then announce yourselves to Vietnam's ATC..?
Wait till spoken too ?
What's the etiquette here ?

Yes, once on the newly assigned frequency, you wait for a break (as not to interrupt others), and "check in". Call-sign and altitude (if level), or altitude leaving and climbing/descending to (if that is the case). This is in a radar environment, of course.

( EDIT: Ooops, got beat to it, above! :) )
 

Andy

Member
( EDIT: Ooops, got beat to it, above! :) )
Nah, that's great, between you both I get the idea.
In fact I thank you all for the insight you have provided.

I know with Australian taxi radios your ID (Cab number) is sent with each transmission.
A click of PPT, you are queued, wait and you will be called, in turn by ID.

So it really is, Bye to one, wait till channel is clear, then say Hello to next.
I got it.
This did not happen, no "Good Morning Vietnam" ever happened.
Ok, so let's say BY 1250 The Ho Chi Minh controller should have heard from MH370

0107 hours a full ACARS transmission takes place which indicates everything is normal.
0121 hours transponder is off and plane has not turned.

So what ? LOL
A fire / electrical fault starts @1247 firstly takes out the radio - never trips a safety/fault/maintenance transmission
1248 Pilot knows radio is gone, has time to change squawk of transponder & does nothing.
0107 full (no fault) ACARS takes place, ACARS never heard from again.
0120 Plane on course.
0121 transponder now off - THEN a turn takes place ?


Too many 'beyond belief' coincidences !
No way this looks to be 'a fault', it looks very calculated.
 
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derwoodii

Senior Member.
I had put forward this idea some weeks back, it seems to be getting some traction but still not on top of likely list.
we may never know if they dont find that wreckage.

http://www.pprune.org/8441805-post10106.html

Sudden climb may cause loss of windscreen
I have speculated that the ADIRU failure experienced by 9M-MRG, which led to a sudden climb, was experienced by 9M-MRO (on route MH370) on March 8, 2014. The sudden increase in the pressure differential across the hull may have led to another problem recently experienced by two other B777-200s.

On April 13, 2012, an Alitalia B777-200 (EI-ISB on route AZ-8320) flying from Rome to Dubai at FL370 declared an emergency near Athens. The first officer's windscreen had cracked. The crew descended rapidly to 6000 feet and diverted to Athens.

On July 3, 2012, an Air France B777-200 (F-GSPL on route AF-85) flying from San Francisco to Paris at FL370 declared an emergency over Hudson's Bay. The windscreen had cracked and the crew reported problems maintaining pressurization in the cabin. The crew descended to 10,000 feet and diverted to Montreal.

All three aircraft are of pretty much the same vintage:
Alitalia EI-ISB first flight December 18, 2002
Air France F-GPSL first flight June 12, 2000

Malaysian 9M-MRO first flight on May 14, 2002

One would need to know the number of cycles, rather than simply the calendar age, to determine if windscreen problems are fatigue-related, and possibly represent a systemic problem which is just now coming to light in the B777 fleet.
Content from External Source
and more

http://www.pprune.org/8442340-post10116.html


Just on the issue of windshield failure, there is an interesting digression on the manufacture of the above, in the TSB report pertaining to


AIR FRANCE
BOEING 777-228ER F-GSPZ
CHURCHILL, MANITOBA 290 nm NE
17 OCTOBER 2002


where an arc resulting from overheating in the J5 terminal caused a small fire and the windshield to crack.


I won't link as I can't get it through moderation,

but anyway comms were not affected (obviously)

so if this were a contributing factor in the present case we would need to find a reason for lack of comms.


ETA (from the report)


'Boeing has undertaken a program to redesign the window terminal block to eliminate the screw connection. The new window blocks were scheduled to be incorporated into Boeing 777 aircraft, Line Number 471 (delivery date February 2004). The new design incorporates a locking pin/socket, which will address issues concerning loose or cross-threaded screws and inset ferrules. All Boeing 747, 757, 767 and 777 windows delivered thereafter, either on new aeroplanes or as spares, will have the new terminals installed. Boeing intends to deliver spares in kit form with the new wire end terminals included. The operator will have to remove the existing wire end terminal and splice in the new one when replacing windows on existing aircraft. The intent is to eliminate concerns with arcing at the window power terminals.


Boeing released a Fleet Team Digest article to B757 operators in May 2003, discussing terminal arcing and overheating. The article detailed actions to incorporate re-designed terminals into the affected cockpit windows.'




I'm not sure how relevant this might be, but it looks like there was no retro-fitting of the new system so as far as I can figure out, 9M-MRO will have had the original sort.
Content from External Source
 

WeedWhacker

Senior Member
Well....I personally experienced a case of windshield heat circuits that were arcing, due to short circuiting...and per the procedure, the Windshield Heat for the affected side (MY side!!) was turned off. This though, was on a DC-10. (Some years ago...).
Over the Atlantic Ocean...at night. Eastbound, KEWR - LFPO. (Newark - Orly)

This at cruise altitude, 37,000 feet. The thermal shock after the heat was turned off caused the outer pane to shatter. Yeah, it was disturbing.

The "book" said that as long as the other panes were intact, it was 'OK'. In the middle of the ocean, there was no place to divert...so, we pressed on. To destination. And, looks like I lived to tell about it.......
 

WeedWhacker

Senior Member
And..... had you been under an hour from take off, with 5 hours to go...
Would that have changed anything, you still would have pressed on ?

For the windshield issue? There is, when overwater, an 'ETP' or "Equal Time Point" (applies more importantly for two-engine operation, but even with three or four, it still is calculated, and used in decision making).

For my scenario (the DC-10) we were destined to continue on to Europe, regardless.

Since there was no dire emergency, was no need to divert to our ETP airport, so carried on normally.
 

Andy

Member
Yeah, it was disturbing.
Disturbing - Sure I got that impression from your post overall, you make it sound rather 'spooky' in your word choice - (MY side!!)etc
So shattered is like what can happen with a car windshield, a million cracks, but in fact still intact ?

I guess the last thing any airline wants to do is 'turn back' - it's all about 'getting to the destination'
Glad you made it OK, I suppose as you say 'no dire emergency', pax knew nothing and everyone ultimately was fine.
Would you say this is you 'hairiest' event in your history of flying ?
 

TWCobra

Senior Member.
I guess the last thing any airline wants to do is 'turn back' - it's all about 'getting to the destination

Not so Andy. Getting on the ground in one piece is the goal. Being at the intended destination is a bonus. "Press-on-itis" is an aviation disease that has killed many.

Having said that, the reliability and systems redundancy of modern airliners makes it rare that you dont get where you were supposed to.
 

WeedWhacker

Senior Member
Disturbing - Sure I got that impression from your post overall, you make it sound rather 'spooky' in your word choice - (MY side!!)etc
So shattered is like what can happen with a car windshield, a million cracks, but in fact still intact ?
I guess the last thing any airline wants to do is 'turn back' - it's all about 'getting to the destination'


Again.....yeah it was "disturbing" in the sense that it was one of the forward windshields....and my seat was directly behind it!!

BUT again.....we looked at the AFM and the procedure, and it assured us that....for the DC-10 anyway, in this situation....the Forward Windscreens were designed to be safe, in this circumstance. THIS is what we do....as pilots.

And to re-iterate....we were past the 'ETP' Usually for the Atlantic Ocean crossing, your 'ETP' diversion airports vary...Shannon (in Ireland) is one...also, Reykjavick (but it depends on the OTA, or Oceanic Track that you happen to be on, for any particular trip)
 
Flight MH370 Depressurization Scenarios

....And then all just after a hand over ? huh ?

No, not just after a handover.... That's your distorted interpretation

JAL750 spoke to co-pilot Fariq Abdul Hamid just after 17:30 UTC over Vietnam on short-range VHF and all appeared normal at that stage according to the Japanese captain.


It would need to be a "Decompression Event" - which would NOT result in an ACARS fault transmission. Right ?
Wow, so that should really make it a much shorter list.
Help me understand.

Malaysian Airlines was NOT prepared to pay for ACARS via satellite, only via SITA ground VHF link. There is no secret why they had no ACARS. It was only subscribed for Rolls Royce to monitor engines at take off and during climb out as part of the engine lease agreement.

Perhaps you are trying to refer to Mode-S transponder transmissions?
We know the transponder transmissions continued after 17:21 UTC because SITA recorded ADS-C transmissions with Vietnam after 17:21 UTC, but picked up through a VHF ground relay station at Kuala Terengganu. That is why the preliminary accident report now acknowledges that MH370 turned east from IGARI and reached BITOD.

So this discounts : Hull tear at SAT antenna mount, no tire well fire, no cargo fire etc right ? All these 'events' should all trigger an ACARS fault transmission - Right ?

As I have said ACARS was not subscribed for this purpose or coverage. You are confusing Malaysian Airlines for Air France AF447. Vietnam does not operate a FANS 1/A class airspace therefore there is no ability in Vietnam to process such data unless the airline subscribes to a satellite service. Malaysian Airlines did not.


1. This "Decompression Event" happens either before or after the turn.

That is such a silly question I can't be bothered to answer if you can't work that one out.

2. And this "Decompression Event" would either need to happen after or coincide with some sort of electrical 'failure'

You would not be wasting our time so much if you had actually bothered to read what I have already said. - Following an electrical failure.

3. It cant be a component failure that results in an instant full short circuit, because that should instantly blow a circuit breaker.
- however it may be possible in 'that moment' to result in ignition, still likely to only take out the 'one breaker' though at the initial short..
Enough other residual circuits to allow comms ? Or are all comms a single breaker ?

Since we lack sufficient information nobody including myself can speculate the exact nature or cause of an electrical fault, except to say these can take many forms from different causes. There are however several known examples

  • A321, en-route, Northern Sudan, 24 August 2010, an Airbus A321-200 operated by British Midland, loss of cockpit displays and un-commanded turns which vanished with de-selection of No.1 generator.
  • A319, London Heathrow, 15 March 2009, an Airbus A319-100 on pushback lost all cockpit displays and developed smoke.
  • Boeing 757-200, Chicago O’Hare IL USA, 22 September 2008, a Boeing 757-200 operated by American Airlines electrical fire
  • Tupelov Tu-154 at Surgut on Jan 1st 2011, arcing caused by overload of generator bus relays.
  • McDonnall Douglas DC-9 operated by Air Canada, 2 June 1983, inflight fire actual electrical cause never identified. Knocked out cockpit instruments.
  • Boeing 787 fifth prototype test aircraft generator fire on approach to land at Laredo Texas 10 November 10, 2010 10:01am, knocked out cockpit displays and disabled autothrottle.
  • McDonnall Douglas DC-9 AirTran flight 913, 8 August 2000, inflight arcing of relay bus cables caused fire.
  • 28 June 2008 oxygen fed fire destroyed flight deck of a 767 awaiting departure at San Francisco.


4. Maybe an over current draw, but within breaker amperage tolerance, which slowly allows heat build up, so very likely first smoke, then flame
- but this 'heat build up' requires continued current through circuit, with everything probably still powered, hmmm seems like this would trigger an ACARS fault transmission from smoke detection ?

Actually each airline configures their ACARS differently according to their own needs, frequency of transmission which the airline requires, coverage subscribed to etc. In the case of MAS they did not use ACARS this way.

Am I right so far, is no fault transmission via ACARS a big clue to the type of event ?

No you are wrong, ACARS played no role. There were several other clues.

  • Distress call picked up by USN listening station VTBU-Rayong, Thailand advising the cabin faced disintegration
  • Loss of altitude data in ADS-C transmissions after the turn east at IGARI

http://www.chinatimes.com/realtimenews/20140308003502-260401


越發現油污碎片美軍稱收到SOS信號

2014年03月08日 20:25


另外,美國駐華大使館稱,淩晨2點43分美軍駐紮在泰國烏塔堡軍事基地曾監聽到一段馬來西亞航空公司MH370航班緊急呼叫的SOS信號,客機駕駛員呼叫稱機艙面臨解體,他們要迫降。目前駐泰美軍已向馬來西亞方面提供這段信號。
Content from External Source

The event isn't great enough to take the plane straight down, it isn't great enough to prevent a turn.

Sounds like you've never been a pilot. When you fly a plane the priority in any emergency is always
  1. Aviate
  2. Navigate
  3. Communicate
First of all in the Egyptair Flight 667 electrical cockpit fire it took just 20 seconds to melt a hole in the cockpit skin. melting a hole through the skin would extinguish the fire through lack of oxygen, yet not necessarily destroy the entire aircraft. If pilot's lacked oxygen then they would have just seconds of consciousness.

It is you who assumes the aircraft was not turned before decompression. That is your plot line, not mine.

What I am saying is that an electrical problem may have persuaded the crew to turn around and then a fire developed.


Ok so a plane has a hole in it's skin which results in sudden pressure loss, so what happens at that point in the hull, does it tear rapidly ? (like in movies):D

You shouldn't rely on movies as your main source of information.

Aircraft skin structures are specifically designed not to tear by their matrix of bonding/rivets.
 
Last edited:

Andy

Member
Well @Simon Gunson
The way you structure your responses makes it extremely difficult to reply.
So for the sake of clarity, I am required to break my response up into smaller parts.

Key Points:
Point 1:
Sounds like you've never been a pilot.
Well, I have never claimed to be a pilot. Let me clarify, I am not a pilot.
However I did explain some of my background and I asked you directly in this post. Simon, are you a pilot ?
You responded to that post here, in which I directly asked you, but never answered me. Simon, are you a pilot ?

Point 2:
The post of mine you are belatedly responding to, has 12 question marks, they look like this ?
It also has statements & questions like this: Help me understand. - Am I right so far ?
Points 1,2,3,4 are not questions, they are observations based on my experience, in my effort for me to understand cause & effect.
They can not be broken up, that effects my context. I could call those points 'thinking out loud'.
The 'initial event' - not so much the possible cascading effect event/s.
The gist of my post was an effort for me to understand, how / what / why / type of - an 'initial event' taking place which does not result in an ACARS transmission.
You seem to break those statements/points up into questions and respond to each, but your responses are actually off track to the statements.
All that without actually answering 'anything' !

Point 3:
Perhaps you are trying to refer to Mode-S transponder transmissions?
What ? There are no fault/maintenance ACARS reports sent this way, only aircraft ID.

Point 4:
An important one !
The post you are responding to today was made on the Apr 19, 2014 !
Check today's date Simon, if you can not respond to anything in a timely manner please STFU.
My knowledge, perception and understanding shifts with time, just like sources of information can also change and even be clarified, such as the Official Initial MAS report

I was/am not purposing to have all the answers. I am not claiming to be a know-it-all on this topic, seems this topic already has one of 'those types'.

Next post ACARS: ( a reply which requires detail - references/quotes/sources )
Then, other random points/statements/quotes/sources - you have made that I feel the need to respond to.
I have something drafted, still that could take a while, 'real life' calls.
 

TWCobra

Senior Member.
Simon, the problem with your analysis to my mind is that you seem to be taking a lot of unconfirmed reports as confirmed.

Where is the official report of the distress call picked up by the USN base at Rayong? I can find no reputable references to either a call or even a USN base.

The report of the conversation between JAL and Malaysian 370.... Where is that confirmed?

Ho Chi Minh ATC has a FANS/CDPLC capability. I logged on to it the day MH 370 disappeared.
 

Andy

Member
http://www.chinatimes.com
It is written in traditional Chinese, it is Taiwanese. It is not affiliated with China.
They seem to be the original source of this supposed "Distress Call" article dated the evening of May 8th.
They claim the distress call took place at 2.43 AM Malaysia time.
They claim their source was the US Embassy in Beijing. (Strangely not the US Embassy in Bangkok, Thailand)
The article has a voting score of 2/10. Guess everyone that reads it disputes it's credibility.

Obvious questions:
Why no-one else in the area received the signal ? (Oh one other source reports signal @121.5MHz)
Why wait till 2.43 AM to make distress call ?
Why Chinatimes are so privy to such information ?
What does knowing pilot/s were 'active/alive' to at least 2.43 AM do to everyone's theories ?
Back to work, I go..
 

Jason

Senior Member
Simon, the problem with your analysis to my mind is that you seem to be taking a lot of unconfirmed reports as confirmed.

Where is the official report of the distress call picked up by the USN base at Rayong? I can find no reputable references to either a call or even a USN base.

The report of the conversation between JAL and Malaysian 370.... Where is that confirmed?

Ho Chi Minh ATC has a FANS/CDPLC capability. I logged on to it the day MH 370 disappeared.
In fact there were several news agencies and sources reporting "oil slicks" off the coast of Vietnam on March 8th. Were all these agencies getting their information from China Times, I don't know
http://www.npr.org/blogs/thetwo-way...says-its-lost-contact-with-plane-carrying-239
Search For Malaysian Jet Spots Oil Slicks In Waters Off Vietnam
by BILL CHAPPELL, EYDER PERALTA and MARK MEMMOTT

March 08, 2014 2:39 PM ET
Content from External Source
http://www.theguardian.com/world/2014/mar/08/malaysian-airlines-plane-live
Oil slicks spotted in search for missing Malaysia Airlines plane – live


  • This blog has ended. Read our latest news story
  • Vietnam air force spots oil slicks consistent with crash at sea
  • Plane en route from Kuala Lumpur to Beijing
  • Boeing 777 was carrying 227 passengers and 12 crew
  • Passengers are from 14 nationalities, mostly Chinese


Content from External Source

View of oil spills seen from a Vietnamese air force plane on Saturday in the search area for a missing Malaysia Airlines jetliner carrying 227 passengers and 12 crew members.

Read more: http://www.nydailynews.com/news/wor...ite-terrorism-article-1.1715004#ixzz32AgNIRN2
 
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