17 Mar 2014

Exaustiva descrição (em inglês) de tudo o que se sabe até este momento.

First a synopsis
The ship took off normally and headed on course to Beijing
The last ACARS transmission was 01:07 local.
The last comms were "All right, good night" transmitted to Malaysia ant hand-off to Vietnam control. Vietnam was not contacted. It has been reported it was the First Officer's voice.
NOTE: Saying "good night" or "so long" or "see you" or "Go Broncos" (okay not that one) is very common for hand-offs.
The transponder stopped transmitting at 1:21 - loss of secondary radar.
There are reports of a climb to 45K, uneven descent and some changes in altitude. Since this is based on primary radar - altitude data is somewhat uncertain. The last has been reported as 29,500ft but that seems in dispute.
There are subsequent primary radar returns west over Malacca Strait and then north west. Since it is primarily radar - a reflection - it does NOT identify the a/c, however it has been correlated with SATCOM pings so confidence is high that the returns are from MH370
SATCOM system pings continued for 7+ (last ping at 08:11 local) hrs after LOS (loss of signal)
SATCOM pings do not locate the aircraft but based on correlation to signal strength there are two loci that indication aircraft distance from the Satellite.
These are not paths and I have changed my language to reflect that. They represent a distance from the satellite.
Loci one is north over Andaman Sea, Bay of Bengal as far as Kazakhstan/Turkmenistan and is consistent with primary radar.
Loci two is south over the India Ocean west of Australia. We've had no reports of radar signals in that area.
The last SATCOM ping was at 8:11 am Malaysian time. At that time it would be dark on the north radius and light over the south radius.
Best data I have is SATCOM pings are hourly - so the 8:11 ping could be up to 1 hour before the aircraft stopped 'pinging'.
We have no ELT signal detected.
While authorities (Malaysian) have not confirmed this is a hijacking or purposeful event - it is believed that is highly likely by most, however, motivation is unknown.
Debris reported by Greek oil tanker has already been reported as not relevant.
Recent reports attributed to the FBI that the plane 'could have landed' and sent a satellite signal from the ground appear to be just confirming what we already knew - that the SATCOM pings could come from an a/c in flight, or powered up on the ground..
There have been no reports that a Rolls Royce EH report was sent upon landing.

Time-line (from CNN)
1.07 am - Last ACARS transmission.
1.19 am - Last verbal communication "All right, good night" from the plane; believed to be the co-pilot
1.21 am - Transponder stopped transmitting (turned off or failed)
1.30 am - Civilian (primary) radar lost contact
1.37 am - Expected ACARS transmission; not received
2.15 am - Last military primary radar contact
8.11 am - Last (hourly) satellite handshake

ACARS is an automated aircraft communication system that transmits a/c information, primarily maintenance information, to maintenance facilities like the airline, Boeing, Engine Manf, etc.
ACARS is NOT a flight system - it is not needed for safe flight.
ACARS is a subscription service and costs money. All indications are the MH370 was subscribed only to engine health monitoring and data from that is sent to Rolls Royce.
ACARS communicates via VHF or SATCOM (and maybe Wifi at the gate). The communications channel depends on availability and is independent of the ACARS.
ACARS can be instructed not to use SATCOM or VHF from the Cockpit. This would effectively stop ACARS from sending data. Access to the EE bay is not required.
While it has been widely reported that ACARS was "disabled before the transponder", that claim seems to be incorrect. We think it is a misunderstanding based on when the last ACARS was received and the next expected.

ACARS data from MH370
The ACARS system sent 2 engine health reports to Rolls Royce, both prior to the LOS event.
The Rolls Royce page indicates that a 'snapshot' of engine data would be sent at: takeoff, climb, cruise and landing. We know 2 ACARS Engine Health reports were received, so that would be consistent with the 1st two.
The last engine health report was received at 1:07am. The next was expected at 1:37 am and was not received. This indicates that the transmission of ACARS data was disabled between 1:07 and 1:37, but not when during that period.
The Engine Health report received prior to LOS had 'interesting' altitude data/fluctuations including 40K drop in a minute. That data is suspect.
Since no "landing" report was received, then either the ACARS communication was disabled, or the a/c did not land.
We have not heard if ACARS would send a report upon fuel starvation flame-out.

SATCOM is a communications channel - Satellite Communications. It is a radio system that uses satellites to communicate various information.
SATCOM is not ACARS - it is one of the channels ACARS can use.
The SATCOM system on MH370 was connecting to Inmarsat 3 satellites. In the area covered, the only satellite with coverage is IOR.
Big version: Width: 720 Height: 516 File size: 199kb
Since only 1 satellite has coverage, no triangulation is possible. All that can be determined is distance from the satellite. This has been used to define 2 potential loci were the a/c could have been.
North Corridor
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South Corridor
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We do not know if these corridors are defined by the last SATCOM ping, or multiple pings.
We cannot distinguish if the a/c was flying or parked on the ground (powered up) when these pings were sent.
We have not been told how the distance from IOR was estimated - it could be signal strength or time of flight (signal propagation time).Opinion: as an EE I think signal strength is unlikely - it would depend on things such as a/c orientation. Time of flight - which is how GPS works - seems more likely.
NOTE: While these may appear as paths - they are not. They are simply a set of potential locations based upon ping data. The aircraft could have been in a constant standard turn circle somewhere along one of the loci (red lines) and the satellite could not tell. We only know it was somewhere along those lines.

The SATCOM system sends (or responds to) periodic 'pings' to/from the satellites (hourly). These 'pings' are a network communication that says "I am here."
SATCOM pings are not communicating a/c status, they are part of the communications channel. They are akin to registration pings on a cell system.
The last pings were detected at 8:11am Malaysia time. This does not mean the aircraft went down or landed at this time, only that the last ping was 8:11. Source I've seen indicate the pings are hourly - but that is not confirmed.
SATCOM pings provide no aircraft heading, speed or altitude information, however, distance from the Satellite can be estimated, and ONLY distance.
Based on analysis of the SATCOM pings by Inmarsat, two possible corridors have been predicted based upon a radius from the satellite picking up the pings.
SATCOM pings would be sent as long as the system (aircraft) was power up and withing coverage area. So, on the ground, if powered up (thanks to mandala499).
People have asked if SATCOM pings could come from a crashed plane if the right parts survived.
Very unlikely. The system is not self contained, the equipment, power and antennas are separate.
Recent news about the fact that the plane could have landed really appears to be just a restatement of known data.
Specifically - the SATCOM pings could have been sent from an aircraft powered, but landed - or from an aircraft in flight.
Clarification: The key is the system is powered, whether by engines, apu or shore line (on the ground).
Again: These pings to not contain ANY data about the aircraft position, speed, altitude, etc.
The 'location' data inferred from the SATCOM pings is based analysis of those signals which gives an approximate distance from the satellite to the a/c.
Since the satellite is in geosynchronous orbit (~22,000 miles), the difference in distance between a flying aircraft and one on the ground is probably not measurable.

The CVR (cockpit voice recorder) and FDR (flight data recorder) do not transmit data in flight.
They do emit sonic pings if immersed. These will last a minimum of 30 days. We can expect sonar is being used to listen for them.
The pinger operates at 37.5KHz 106.5dp re 1μPa. (thanks k83713)
Maximum depth of beacon detection in Normal Conditions: 1-2km
Maximum depth of beacon detection in Good Conditions: 4-5km
Localising a pinger from the surface in shallow water is relatively easy, as described above. In deep water, the detection equipment should be installed on a self-propelled underwater vehicle, presupposing that the position is already known to within the maximum 2-3km detection range.
More Info:http://www.hydro-international.com/i...Deepwater_Black_Box_Retrieval.html
The CVR reportedly is a 120 minute CVR so it would contain only the last 120 minutes of flight (presuming it did not fail or was turned off prior to that).
I don't have data form the recording time of the FDR, but it is typically much longer.

The ELT, or emergency locater transmitter is mounted in the rear of the aircraft - difficult to access in flight.
The ELT is battery powered - independent built in power source. It is this source that is suspect in causing the 787 fire at Heathrow.
The ELT will be trigged by G forces in a crash. It will not operate under water.
The ELT can be triggered from the cockpit - it is a hardwired switch not dependent on computer systems.
The ELT transmits on the guard frequency (VHF) and on 406MHz to satellites. If it had been triggered, satellites would have heard it and been able to locate the a/c. That is isn't purpose in live.

Primary versus Secondary Radar (brief tutorial)
Primary radar is based on the original military usage. It sends out a strong (KW to MW) signal and looks for a reflection from something.
Primary radar provides distance and location. Comparing returns speed can be determined. Strength of return can indicate size.
Stealth a/c and ships are designed to absorb or miss-direct the reflection so primary radar cannot see them.
Primary radar does not depend on the transponder, so turning off a transponder will not make an a/c disappear from primary.
Primary radar is less prevalent than secondary - and more typically military tho ATC's do use it.
Secondary Radar is really not Radar in the defined sense. It is directional communication.
In secondary radar a directional signal is sent out (much less powerful than primary). Any a/c with a transponder that receives it will respond (the transponder responds) with information about the aircraft.
Combined with the direction of the outgoing beam, the time of flight information and returned information, the a/c location and identity (and other info depending on the mode) is returned.
Secondary radar is the primary method used by ATC.
If the transponder fails or is turned off - secondary radar will not see the a/c.
In the case of MH370
The transponder was turned off - so the a/c disappeared from secondary (ATC) radar.
A target was tracked west, then northwest using primary radar. That target was correlated with SATCOM pings help determine it was MH370.

Way-point Tracks
The use of way-points to the navigate are conjecture. They happen to line up with the direction indicated by the primary radar returns and Inmarsat data to the north.
While many believe the aircraft was under control - we cannot conclude if these way-point were used, or just coincidentally along the path.
A 777 can be programed to follow a series of way-point automatically - this is normal operating procedure and a 777 pilot would need no extra practice/training to do it. (Relevant to pilot flight simulator ownership)

Airworthiness Directive
The airworthiness directive about corrosion near the SATCOM antenna does not apply to this ship.
The ship DOES have SATCOM - but uses a different antenna

Cargo and Lithium Battery Fires.
There are reports that the cargo in MH370 did not receive normal X-ray screening.
There are also statements that the shipment held nothing hazardous or remarkable.
There are reports of a shipment of lithium batteries on the a/c and that perhaps they caused a fire.
The hold of a passenger a/c like the 777 is protected with Halon and detectors - so a fire in the hold would be detected.
The EE bay is not so protected.
Therefore some think a fire could have occurred and been suppressed. This does not directly explain loss of comms.
Opinion: as a firefighter, I doubt this. The fire would destroy the a/c. However, those on the forum with more knowledge of these systems disagree

Aircraft Type and Fuel State
The aircraft was a Boeing 777-200ER. MTOW 656,000 lbs, 301 3 class passengers (standard Boeing Config - does not reflect MH specific config.)
The aircraft could land in 6000 ft, or much less at high risk. As little as 3000ft has been stated, but it could not take off from there.
The aircraft would need a hard surface to land - this is heavier that has been done on steel matts.
It is reported the aircraft 45 to 60 minutes extra fuel. This would amount to about 7-7.5 hrs of fuel. This is a normal amount for this route.
The aircraft should have been able to fly about 30 minutes after the last SATCOM ping at 8:11.
The figure at this link show max range for the 777-200ER. NOTE: MH370 was not fueled for this range. http://www.boeing.com/assets/pdf/com.../777_range_singapore.pdf

Hypoxia and Pressurization
There has been lots of speculation about loss of pressurization in the aircraft and what that would do to passengers and crew.
IMPORTANT NOTE: all of this applies to cabin pressure - not the pressure outside. Just climbing to 45K would not exposed the passengers to that altitude.
In the case of loss of cabin pressure - O2 mask would deploy automatically.
The pilots cannot disable this above 13,500 feet - they can release the masks.
Passengers masks would last 12-20 minutes. Portable crew (FA) bottles ~30minutes. Cockpit crew longer.
Time of useful consciousness (not to loss of consciousness) will range from 1-3 minutes at 30K to 9-15 seconds at 43K. (http://en.wikipedia.org/wiki/Time_of_useful_consciousness)
Because of this the a/c must be certified able to descend and pilots demonstrate an emergency descent to ~10,000 ft in 2 minutes.
The actual regulation is that passengers cannot be exposed to a cabin altitude of more than 25K for more than 2 minutes, or more than 40K for any time.
Question: Can the pilots 'depressurize' the plane?
I believe not to a dangerous level. Per the FAA regulations the 777 is certified under it "must be designed so that occupants will not be exposed to cabin pressure altitudes in excess of 15,000 feet (4,600 m) after any probable failure condition in the pressurization system"
This is consistent with statements that, as long as bleed air is operating, the outflow valves of the 777 will not allow the cabin altitude to exceed 14,000 ft.
This, of course, excludes a major structural failure - it applies to pilot actions only.
Above 40,000 ft cabin altitude - positive pressure oxygen is required - passenger masks do not do this and would not be effective.
The discussions of climbing to 45K to "disable" the passengers really is not relevant unless you assume the a/c has had a major breech in the hull that full depressurizes it.

Search Areas (including those that have be halted)
Along the planed route. I believe searching in this area is ending or decreasing based on new data indicating the a/c is not there
West over the Malacca strait
North west of Malacca strait
Along the two loci predicted by the SATCOM pings which continue north to Kazakhstan/Turkmenistan and south to the India Ocean.
These are huge search areas - I do not have a good handle on what assets are deployed where
It appears the north loci is considered more likely because of primary radar signals that roughly correlate.
I would expect review of primary radar west of Australia is in process if not done.

Mobile phones
We continue to have lots of discussion on "mobile phones" - can the connect in flight, etc.
We don't have any reports or evidence of that any passenger or crew mobile phone has registered with any network.
Until we have that data or reports - I believe the mobile phone discussions are not useful.
UPDATE: This subject continues to be discussed. But, we have had no reports of cell phones registering with towers - we are in a loop here.

Theories and Conspiracy Theories
Currently, it seems most believe there is some positive action here - hijacker or crew based.
Opinion: Mostly, I believe this is because a mechanical failure that selectively terminates communication, incapacitates the crew/passengers, but then allows the a/c to fly on uncontrolled for 7 hours seems unlikely.
There are lots of theories out there - some clearly "conspiracy based" some just factual. Often it is hard to distinguish.
Here are a few.
A fire broke out that incapacitated passengers and crew - but allowed to aircraft to fly on it's own till starvation.
Corollary to this - the fire would have to disable comms, or cause the crew to disable comms in an attempt to fight it.
Corollary to this - the fire drove the pilots out of the cockpit.
Corollary to this - the fire disabled comms, nav and systems, and the crew - still alive - got lost trying to return.
The a/c was hijacked and flown to a remote strip to be used in a future terrorist act.
Corollary to this - The breadth of the countries searching alone makes this problematic, but it is not impossible.
The aircraft "shadowed" either a KLM or SIA aircraft to hide from radar then turned off the track and landed.
Questions raised - lot of discussion about if this was possible.
A mechanical failure depressurized the a/c and disabled the crew/passengers either rapidly or without their knowledge.
Corollary to this - What disabled comms?
One of the pilots hijacked the plane to commit suicide. (See Pilot Conspiracy below).
The plane was hijacked, either with or without crew involvement.
Despite the belief this is incident required human actions - we have no evidence of that. Rather - no other theory seems credible.
Freescale engineers have been hijacked for sensitive US data. Opinion: As an engineer who has worked with Freescale - I find that unsupportable. Companies send groups of employees around all the time. While many companies have policies about the # of executives on a flight - that typically is not enforced on regular employees.
There was something in the Cargo worth stealing - which is why it was not screened. This would require involvement of lots of people on the ground. Why not steal it on the ground.
The plane was full of undeclared gold.Gold is very heavy - what would you declare the cargo as?
The US hijacked the 777 using on board FBW technology to fly it like a drone to Diego Garcia (this one wins the insanity case).
Related: There has been a claim by counter terrorist expert that this could be a "cyber hijack" - a malicious attack of a FBW a/c. I don't know where to go with this - only reporting it because I'm trying to stay ahead of the next craze. Opinion: (speaking as an EE) this is the stuff dreams are made of (bad dreams).

Pilot Related Conspiracy Theories (some of this is my opinion).
The crew and passengers are a focus of investigation. Particularly the crew, because of the difficulty of managing an external cockpit intrusion.
The pilot has received a lot of attention because: 1) He supports opposition politics, 2) He has a mongo flight simulator, 3) There are rumors of family problems (debunked).
To address the data on a few of these:
1) The pilot supports opposition politics and may have been at a trial of the opposition leader (confirmed 'ordinary' member of opposition party). Opinion: What is the motive for suicide in this case?
2) The pilot has a very fancy flight simulator. People claim he used it to for this. Opinion: A 777 pilot does not need to train for the flying done - he knows how to do that stuff already. What he needs it planning for violent action/takeover. A flight simulator is no help.
Note - there has been some discussion that the pilot used this for training of accomplices.
3) There are rumors of family problems reported from China. This has been reported as untrue.

IN summary what we know is. (This has NOT changed)
The a/c disappeared from secondary radar and stopped communicating. We do not know why or what happened to it.
There is evidence from SATCOM and Radar that the a/c traveled west - then most likely north west.
Hourly SATCOM signals show the a/c was operating till at least 8:11am Malaysia time, over 7 hrs total flight time
We have not found it despite multiple governmental agencies from multiple countries searching hard.

Additional thoughts.
A hijacking or positive intervention by human agency seems likely.
The erratic altitude and course may indicate a struggle on board.
While we would like to believe the a/c landed safely somewhere, that seems unlikely to have happened

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