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Possible
in-flight events[edit]
Power interruption[edit]
The SATCOM link functioned normally from pre-flight (beginning at 00:00
MYT) until it responded to a ground-to-air ACARS message with an
acknowledge message at 01:07. Ground-to-air ACARS messages continued to
be transmitted to Flight 370 until Inmarsat's network sent multiple
"Request for Acknowledge" messages at 02:03, without a response from the
aircraft. At some time between 01:07 and 02:03, power was lost to the
SDU. At 02:25, the aircraft's SDU sent a "log-on request".[42]:22[44]:36–39 It
is not common for a log-on request to be made in-flight, but it could
occur for multiple reasons. An
analysis of the characteristics and timing of these requests suggest a
power interruption in-flight is the most likely culprit.[42]:33[167] As
the power interruption was not due to engine flame-out, per ATSB, it may
have been the result of manually switching of the aircraft's electrical
system.[42]:33
In the Wikipedia entry for MH370 (see above and
http://tinyurl.com/j4ztdks
) it is mentioned that the flight-following InMarsat satellite stationed
above the Indian Ocean sent multiple half-hourly handshake requests to
MH370 without any response - for an extended period, before coming good.
Australian investigators have
discovered evidence of a mysterious power cut during the
early part of the missing Malaysia Airlines MH370 flight
.The findings by the Australian Transport Safety Bureau
raises questions over whether the plane's cockpit equipment
had been tampered with, possibly in an attempt to avoid
being picked up by radar.
In the report, crash
investigators reveal that the missing Boeing 777's satellite
data unit had unexpectedly tried to log on to a satellite,
around an hour and a half after the flight left from Kuala
Lumpur on March 8.
This request, known as a
'handshake', was likely to have been caused by a power
failure on board, the 55-page report says.
'A log-on request in the
middle of a flight is not common and can occur for only a
few reasons,' the report states'. These include a
power interruption to the aircraft satellite data unit (SDU),
a software failure, loss of critical systems providing input
to the SDU or a loss of the link due to aircraft
attitude.
'An analysis
was performed which determined that the characteristics and
timing of the logon requests were best matched as resulting
from power interruption to the SDU.'
Aviation safety expert David
Gleave from Loughborough University says the power
interruption could have been caused by someone in the
cockpit trying to turn off the plane's communications
systems to avoid being picked up by radar. 'It could be
a deliberate act to switch off both engines for some
time,'
'By messing about within the
cockpit you could switch off the power temporarily and
switch it on again when you need the other systems to fly
the aeroplane.'
He added: 'There are credible
mechanical failures that could cause it. But you would not
then fly along for hundreds of miles and disappear in the
Indian Ocean.'
British satellite
telecommunications company Inmarsat has confirmed there was
a power outage on the plane, but has been unable to say why
this happened. |
It's concluded that "at some time" between 0107L and 0203L, power was
temporarily lost to the SDU (Satellite communication
system Data Unit ) - and permanently to the ATC transponder. As 9M-MRO had not suffered a flame-out
and was still underway, it was easily concluded that these units had been
"manually switched off".... giving impetus to the populist "illegal
interference" theory. No-one at Boeing put their hand up with any other
alternative "systems"-based explanation. It's as if there was a
technical blackout at 777 HQ. A hushed silence prevailed as Boeing's
execs and techs pursued their own inhouse agenda for "questing"
likely explanations and any associated litigational vulnerability for
the Boeing Colossus.
So, might there be another reason for this interim and temporary (and
event-coincidental) outage? It's already been described that the
flame-front of an oxygen enrichment DDT flash-over would have many
indeterminate physical effects upon the plastics-based
switchology, keypads and touch-screens of the flight-deck - and
the much disregarded singular point of non-redundancy for many systems -
i.e. that human interface of their ON/OFF switches. In many
respects you can compare an oxygen enrichment flash-over to an
Electro-magnetic pulse (EMP). However, even
though a flash-over on a flight-deck might be micro-cosmic by
comparison, it's also a very transitory systems-crippling major upset
that can leave, in addition to the depressurisation, a chaotic
electrical disordering in its wake. 777
Electrical system operation is automatic and faults are automatically
detected and isolated. But in a designer's mind, failures aren't
daisy-chained together - so little provision is made for accommodating
them, despite the No-break power transfer technology and mutually
supportive bells and whistles. Electrically
held relays are used in the 777 because they are simpler and more
reliable than the magnetically latched type. But they are vulnerable to
large scale electrical disruption. One characteristic of a
flash-over induced arcing of a wire-bundle is that it can defeat a
circuit breaker's ability to protect downstream systems. In other words,
there's no guarantee that a thermal circuit-breaker will trip
once a wiring loom (or bundle) arcs. You can end up with a
contaminated supply flux on that circuit or buss - as far as volts amps
and frequency (i.e. cycles) are concerned. You can also end up with an
induced Flight Management computer reboot..... which could also explain
the interim SDU outage. Some systems are very power-supply frequency
sensitive, the SDU and its software load likely being one of them. I
doubt very much that even a mishandled smoke and fumes checklist could
cause an SDU outage or FMC reboot.
It's not known whether there are any self-resetting circuit-breakers
in the 777's electrical architecture, or any AFCI circuit-breakers
(arc-fault circuit interrupts), but there is a "hierarchy of needs"
embedded within the 777's highly complex electrical system's design and
construction. ETOPS aircraft need hardened systems. This sophisticated
system contains many "work-arounds" in the shape of generator
supervisory panels, bus-tie switches and a sprinkling of load-shedding
devices, each with its own tripping thresholds for electrical
load-shedding and transfer. ELMS (the Electrical Load Management System)
decides which systems get the power and which should be monitored off.
There is also the BEPS (backup electrical power system). Many of these
load-shedding pathways aren't "one-way streets" (i.e. some systems can
sample their input power supplies, test their ability to reconnect - and
in some cases will do so, once volts, amps and cycles fall within their
own sub-systems' protective parameters (much as they do on their BITE
test after initial aircraft ground power or APU power-on).
At 17:07:29, the plane sent an ACARS report via its
satcom. At 17:20:36, five seconds after passing waypoint
IGARI and a minute after the last radio transmission, the
transponder shut off (i.e. the time of the
"event").
For the next hour, MH370 was electronically dark. The next
ACARS transmission, scheduled for 17:37, did not take place
(see box below for a likely reason why).
At 18:03 Inmarsat attempted to forward an ACARS text message
and received no response, suggesting that the satcom system
was turned off or otherwise out of service. At 18:22, MH370
vanished from primary radar coverage over the northern Malacca
Strait. Three minutes later the satcom system connected with
Inmarsat satellite 3F-1 over the Indian Ocean and initiated
a logon at 18:25:27. One explanation
for the time taken to log back on could well be "the loss
of the link due to aircraft attitude". Whilst inside
cloud and being tossed around, it's quite possible that the
attitude at the relevant times (every 30 minutes) was
momentarily outside the aspect limits for the antenna [just
forward of the vertical fin]. |
Generators power busses and busses are segregated, rated and
prioritised in a pecking order dependent upon their subsystems'
criticality for flight. Critical systems such as the primary flight
controls (for instance) can be powered by alternate combinations of
busses. These are characterised as ESSENTIAL busses and are further
sub-divisible into single phase AC, three phase AC and rectified DC
power. "Essentiality" is best characterized as a "fall-back",
fault-tolerant and fail-safe system logic. This vital redundancy factor
is in stark contrast to galley power, Inflight Entertainment systems and
cabin bus lighting priorities. Those non-vital services reside upon
non-essential busses. The SDU would logically lie somewhere midway
between vital and "sheddable" in that risk-spreading hierarchy of needs.
It could reconnect if its parent bus comes back on-line or if parameters
fall within limits as other systems fail due to ongoing arcing - and are
then monitored OFF.
What might have happened to cause the SDU power outage is easily part
of the oxygen flash-over theory and its EMP effect upon volts, amps and
cycles in 9M-MRO's electrical system - as controlled by the BPCU (Bus
Power Control Unit). Therefore I personally favour the Flight Management
computer reboot as emanating from the electrical maelstrom that resulted
from that electrical systems crippling flash-over vulnerabilities and
consequential bus-switching. That reboot happened yet again some six
plus hours later when the flame-out occurred and there was a slight
hiatus until the APU started, its generator came on-line and the
InMarsat sign-on hand-shake for 9M-MRO was triggered. In flight, when no
other power source is available, the APU will self-start and power Left
and Right busses, regardless of transfer switch positions.
i.e. in Wikipedia:
" The ATSB investigators also reported that a second mysterious
"handshake" request occurred nearly six hours later. This one, they
speculated, was caused by fuel exhaustion and power loss before the
plane crashed into the Southern Indian Ocean."
And of course, if you subscribe to the theory of the Flight
Management computer reboot, you may also prefer to see that as being the
autopilot OFF initiator at flash-over and the radar-registered climb to
40Kft as being just what the airplane might do during that FMC reboot
period - until everything input/output-wise was nulled out and reset.
Only Boeing and their inhouse "iron bird" simulator could tell you for
sure, and they're keeping "mum" on this. But I like this alternative
theory because I'm just not seeing either pilot having survived that 10
to 15 second oxygen enrichment flash-over (as witnessed by Mike McKay
the oil-rig worker) - or either pilot doing anything survivalist
pursuant to its snuffing. But you never know..... adrenaline is a real
kicker.
If you think this to be a circumlocutory argument without underlying
proof and/or one that assumes too much, you might even say: " Why
should anyone conclude that it would have been an oxygen fire on the
flight-deck that disabled MH370?" The simple unadorned answer is
that there have been similar precedents, that oxygen fires under
pressure are not fightable airborne (or on the ground) - and that
most accidents do historically have these prototypical precursor
precedents lurking in the background. A corollary to that simple
rejoinder might be: " ...and why else would the FAA punch out two
omnibus Airworthiness Directives covering the precise known (and
"suspected") cause of the two indicative prior accidents, yet make
no reference to the threat and make these two AD's applicable to the
entire Boeing line of models (from the 707 to the 787)..... and
quietly do that so soon after MH370 disappeared?" You could also
point out that the rapidity of the event that overwhelmed the pilots
would not have been a Lithium battery fire, a simple wiring short,
or weather. Nor was it conceivably a bomb or even a hijacker or
suicide. You could then factor in contingent and contemporaneous
events such as the transponder "switch off" and the cessation of ACARS reports..... and ponder their likely origins within the
theory. A general acceptance is that at some point a
depressurization occurred, to which the pilots failed to respond via
initiation of an emergency descent or declaration of an emergency to
ATC - and you arrive back at the start point of the quiz? Why not,
why didn't they? One logical answer is that both pilots were quite
soon "hors de combat" (i.e. quite out of the picture by then, after
an initial desperate turnback for the "nearest available").... so a
classic "ghost flight" resulted. " What caused the depressurization?"
you might then say. The simple production of a number of images that
clearly show what pressurized oxygen fires in flight-deck side
consoles and impinging upon airplane hulls might be the wordless
reply. It's the blowtorch effect. You may next hear: " Why didn't the
aircraft continue burning after the depressurisation?" Some people
have the whacky idea that oxygen burns. No Dorothy, it just
accumulates and supports and stimulates fire. Oxygen will oxidize
materials via combustion but the reality is that the oxygen
enrichment stems from a high inflow volumetrically overcoming the airconditioning swap-out rate on the sealed flight-deck, until the
oxygen enrichment of that enclosure's atmosphere reaches a level
where every surface was combustible only because it was "wetted" by
the oxygen's triggering enrichment level..... and that leading to a
flame-front suddenly sweeping the flight-deck. Pilots couldn't have
seen that coming. All they were aware of was a fire in the side
console that wasn't being suppressed by the F/O's efforts with the
flight-deck's hand-held Halon fire-extinguisher. Oxygen enrichment
is as insidious as carbon monoxide poisoning. You are quite unaware
of its deadly accumulations. It's a well-known cause of fiery
accidents in hospital operating theatres and in industrial accidents
- but less well-known in airborne aviation. Ramp accidents during
maint and replenishment are far more common-place. USAF and NASA
have both established specialist departments to research and educate
the issue. NASA's White Sands Facility is perhaps the best known for
their accident narratives on both GOX and LOX events. Its accident log for NASA alone is
voluminous. And you probably didn't know that Halon is also a known
cause of mental loss of faculties when discharged in quantity within
an enclosed area. It displaces oxygen, but it can't handle any
fires fed by pressurized flows of it. The FAA has published that as a cautionary
fact, but it's not widely promulgated. The enriched oxygen flare
is not explosive, moreso inflammatory - but it could be described as
a low order explosion or flare (similar to the backdraft that's
feared by firemen fighting high-rise fires). It's known as a
Deflagration to Detonation Transition (or DDT). That flare would've
been heard in the cabin as a loud thump, followed by the rubber
jungle as the pax masks dropped. That detonation's peak overpressure
imposed atop the normal pressurization differential would've been
sufficient to complete a rupture in the blowtorch weakened 0.08 inch
hull skin and allowed an explosive depressurisation (see Nefertiti
imagery). Without any oxygen enrichment at all, in fact now with
only an internal atmosphere of the very thin air at 35,000 ft, no
unestablished fire could be self-sustaining. It accords very well
with what that oil-rig worker Mike McKay saw distantly (courtesy of
the nocturnal visual acuity phenomenon known as "empty field
myopia"- a known phenomenon that can re-focus the retina at many
hundreds of kms - if the flash against a dark sky is bright enough
and ambient light levels low enough). But unlike the totally
destroyed 777 cockpit of SU-GBP seen in the Egyptair ramp burndown
of 30 minutes of unfought ramp fire, all that would be seen
residually, after around 15 seconds, is a light surface covering of
soot across the 9M-MRO flight-deck. So if it wasn't the electrically
conductive helical coil in the oxygen hose (per the prior events),
what might the fire's starter have been? Investigators in both
precursor accidents found many oxygen/wiring associated glitches in
the vicinity as well as unsecured and unclamped loops of wire under
the side consoles - and across the entire 777 fleet - flaws that had
been there since the Boeing build and that were contrary to Boeing's
own design specs. Unsupported wiring is a known cause of chafing and
shorts. The vibration of flight can erode wiring insulation over
time, unless the wiring is supported and encased or shielded or run
in a conduit. That's chafing. The destroyed ABX Air 767 at SFO sported
wiring that was tie-wrapped to stainless-steel oxygen lines. Its
entire length of oxygen piping was ungrounded due to the use
throughout of rubber-lined support clamps that are usually used for
wiring bundles. That design flaw was later found to be global across
most aircraft types.
More confirmatory Clues: The Boeing Colossus runs
Interference I used to be a well-known identity on
pprune.org but then I was covertly permanently banned -
like many others of my ilk. The problem was that I
started pushing my MH370 theory in that thread and it
was far too close to the bone for the new owners of
pprune.org After they bought it from Danny Fynne (Capt
Pprune), they (Boeing) engaged a quite scurrilous
group with a very dubious reputation "Internet Brands" (link)
- to run Pprune in lieu of the voluntary moderators. IB
is a digital media company that takes over, proxy
runs, controls and ruthlessly moderates web forums in
order to control criticisms of its unseen employer. They
figure hugely on many similar sites. It's an iron-fist
business model that is accelerating on the internet as
various corporations try and control their public image
and the so-called proprietary information that can
damage them in the public arena. Boeing also has a fully
dedicated group running interference via DMCA, utilising
takedown notices whenever they see information
pertaining to them that they consider should not be in
the public arena. They prevail 95% of the time via the
scare factor. The scary thing is that IB has a similar
record of willingness to go to court. It is a massive
deterrent to truth online ever surfacing. |
A hard-nosed inquisitioner might then go on to point out the
apparent anomalies of an airplane wending its way pilotlessly across
the Malay Peninsula and through the Straits of Malacca and up to the
tip of Sumatra, all without human guidance, as intermittently
painted by radar - before turning for the Southern Ocean and
bee-lining to a far distant splash-point. A simple dissertation on
the seasonal movement of the ITCZ, its positioning on 08 March, and
the exact nature of that meteorological beast, should fill in that
present blank of why MH370 tracked thusly. And that long trek South?
No more complex than 9M-MRO's exit heading from its final cloud
encounter.... more likely than not. Now above the weather and
established South of the ITCZ and then South of the Equator in
smooth air, and with only very scattered convective clouds and a
consequent low likelihood of ever hitting one now? It would've
been a smooth sailing that's quite within the capability of the
777's active flight control system with its inbuilt wing-levelling
stability and a propensity for enroute climb as fuel burnt off (and
being ably assisted by an immobilized pax-load). It may not have
flown a dead-straight course, but achieved a straight enough meander
to end up flaming out roughly where InMarsat's satellite and Doppler
theory says it did.
So where did MH370 end up? Likely a little further south of the
latest search area off a nice wings level glide to a Hudson River
class touchdown. Why?
(1) The 777's Active Flight Control system is capable of doing
that classy touchdown ditching. It sports an asymmetry compensation
mode and an adaptive pitch that will adopt a stall-avoiding 1.2 Vs
nose-up attitude once thrust is but a memory. As we speak, it's
bumping across the rocky bottom's inclines, shedding its bits and pieces.
(2) A step-climbed cruise (versus a constant altitude lower
cruise height) can give you a 3% improvement in range overall.
Because it was a constant climb (and not a step-climb) as fuel burnt
off, it was probably more like a 5% overall increase in range to
splash.
(3) The "constrained autopilot dynamics" used to determine
the various possible tracks of 9M-MRO are possibly misleading.
Consider an un-autopiloted 9M-MRO with a meander of no more than 5
degrees left and right of a mean tracking - due to its inherent
active FCS ability to correct any turbulence induced wing drop
immediately - and no significant encounters with turbulence once
clear of the ITCZ. Would there be any significant increase in track
miles flown? (yes but probably no more than 10 nms over the route
distance flown in six hours). The probable impact upon the
splashdown position would be minimal.... so the theory holds for
autopilotless flight. The only distinct variable would be the
overall range to flame-out.
So, if you accept all the provisos and dissections - and
rule out the UFO's, there's no mystery, just the misery of a nasty
tech failure.
It's every breath you take.
Master document: tinyurl.com/or9bzf2
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Forty minutes after the plane took off from Kuala Lumpur, MH370 went
electronically dark, just after signing off with KL ATC. For about an
hour after that, the aircraft was tracked on primary radar via its
"skin-paint". ... after its reversal of course, some mystery zigzags and
while still traveling quite fast. Then it suddenly disappeared from
military radar..... probably due to terrain masking of the radar head.
Three minutes later, now somewhere SW of the tip of Sumatra and unmasked
by terrain but outside radar range, 9M-MRO settled down onto a final
(and terminally steady) southerly course, the communications system
logged back onto the satellite. This was a major revelation. This
event corresponded with the first successful half-hourly satellite ping
interrogation ... since the turnback event. Over the
course of the next six hours, 9M-MRO remained on that steady southerly
course and generated six more satellite handshakes.
Why hadn't the aircraft logged on during
the prior half-hourly attempts by the satellite to seek a log-on by
MH370 (i.e. at the 30 minute satellite interrogative ping after the turnback)?" The answer may well be quite simple.
Many such mysteries are. During its time over
the Malay Peninsula, later on in the Straits of Malacca, and until
west-bound around the tip of Sumatra, MH370 was embroiled in regular classic ITCZ
severe weather encounters and after each one, was being spat out on a
new heading - and obviously took some time (after each encounter) to
regain its stable composure. In other words, at the exact time of each
half-hourly solicitous ping from the satellite, MH370 was likely in
cloud, pitching and rolling and having a "tangle with the angle". The satcom (aka Satellite Data Unit or SDU) cannot remain locked on
(or be receptive and compliantly responsive to satellite ping
initiation routines) when in any sort of unusual attitude for any finite period
- i.e. due to being inside (or just exited/spat out from) a cumuloNimbus
- and those nasty clouds are typically massive and dense in that ITCZ
band. Successful handshaking sequences require a period of stable non-manoeuvring
flight within the line-of-sight limits of the SDU's antenna (located
atop the fuselage and just forward of the vertical fin). A bank angle of
greater than 30 degrees will mask that antenna's required electronic view of the heavens.
Until 9M-MRO escaped that 300km wide band of activity on its southerly
track, it was destined to blunder into heavy weather inside convective
cloud build-ups - CumulNimus clouds that can extend up to 55,000 ft.
But many hours later, the final handshake at the 7th arc wasn’t completed. The interchange of
data was OK until it suddenly stopped short of logging on the IFE (Inflight
Entertainment System) and completing a BITE exchange of validation data.
This led to speculation (later endorsed by trials and SDU manufacturer
input), that MH370 had run out of fuel and lost power, causing MH370 to
abruptly and
finally lose its connection to the satellite. The APU had previously
started after both engine-driven IDG generators had shut down, taking 60 seconds to start and bring its
own generator online to
provide power for the satcom unit to initialize its own internal reconnection
routine, just before the plane crashed. However only around 30lbs
maximum of fuel were trapped in the feed-lines between the (now empty)
LH main tank and the APU. However this fuel is being sucked through by
the APU and that feed continuity being vulnerable to aircraft attitude
change, the APU flamed out
also - after less than 3 minutes
of glide (see the graphic).
Ditching considerations
(from the ATSB Conspectus)
A controlled ditching scenario requires engine
thrust to be available to properly control the direction and
vertical speed at touchdown and to provide hydraulic power for
the flight controls including the flaps.
The final SATCOM transmission was considered by
the satellite working group to be due to a power interruption to
the SDU. Given the performance analysis by Boeing, it is
entirely reasonable to assume that engine flame-outs triggered
the APU auto-start that restored power to the SDU and enabled an
almost completed aircraft-initiated log-on.
This evidence is therefore inconsistent with any controlled
ditching scenario. |
The only source of power was then the battery BUS and the
Ram Air Turbine (the RAT), dangling from its compartment below the
fuselage.
Where exactly MH370 would have gone down was then dependent
upon its flight path subsequent to the second (LH or port) engine's
flame-out. This indeterminate variable has played a large part in a
scholarly determination (and some ongoing revisions) of the sea-bed search area
astride the 7th Inmarsat arc.
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