http://www.airliners.net/aviation-forums/general_aviation/read.main/6025843/ - Post 66 (rcair1)

Sanity Check

• Doing this as much to keep my brain aligned as to provide a data source.
• The facts have not changed much, however the is more data about track and time-line
• I've tried to be as factually accurate as I can - but I'm not an expert in each system - so if there factual errors please advise.
• I'm going to try to list what we know, not what we think - we being the public. And sadly it is very short.

First a synopsis

• The ship took off normally and headed on course to Beijing
• The last ACARS transmission was about 01:07 local. Confusion continues about if and when ACARS was turned off(See ACARS below)
• The last comms were a normal hand-off from Malaysia to Vietnam control at about 1:30 local. It was a normal 'good night' on the Malaysian side, but Vietnam was not contacted.
• The aircraft dropped off secondary radar with no communication from the cockpit.
• 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 Straight and then north west Since it is primarily radar - a reflection - it does 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+ hrs after LOS (loss of signal)
• SATCOM pings do not locate the aircraft but based on correlation to signal strength there are 2 paths the aircraft could have taken
• Path one is north over Andaman Sea, Bay of Bengal as far as Kazakhstan/Turkmenistan and is consistent with primary radar.
• Path 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 path and light over the south path.
• 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.

ACARS

• 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 data from MH370

• The ACARS system sent 2 engine health reports to Rolls Royce, both prior to the LOS event.
• There seems to be disagreement on if the ACARS was switched off, or if it was not expected to send more data.
• The Malaysian PM stated they had high confidence ACARS was turned off.
• But, Rolls Royce has not commented on if more ACARS reports would have been expected prior to landing.
• Turning off ACARS reportedly requires entering the EE bay which is not simple in flight.
• UPDATE per TriStarSteve,26, 186:Pilots can deselect ACARS transmission by VHF and SATCOM. This does not turn off the VHF and SATCOM, just stops ACARS from using them.
• The ACARS report received prior to LOS had 'interesting' altitude data/fluctuations including 40K drop in a minute. That data is suspect.
• UPDATE: Per the RR webpage a snapshot would be expected at takeoff, climb, cruise and summary post landing.
• Since no "landing" report was received, then either the ACARS was turned off, or the a/c did not land. It is not clear to me if the last report was climb or cruise.
• We have not heard if ACARS would send a report upon fuel starvation flame-out.

SATCOM

• 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 satellites.

SATCOM Pings

• The SATCOM system sends (or responds to) periodic 'pings' to/from the satellites. 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.
• The last pings were detected at 8:11am Malaysia time
• SATCOM pings provide no aircraft heading, speed or altitude information, however, distance from the Satellite can be estimated.
• Based on analysis of the SATCOM pings by Inmarsat, two possible routes have been predicted based upon a radius from the satellite picking up the pings.
• People have asked if SATCOM pings would occur if the aircraft was landed, but operating.
• We have not seen data on this, but I would presume it would.
• 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.

CRV/FDR Data

• 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 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.

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 along the path.

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

Lithium Battery Fires

• There are reports of a shipment of lithium batteries on the a/c and that perhaps they caused a fire.
• It seems very unlikely a fire could be intense enough to disable the crew, but then the a/c would survive and fly for 7+ hours.
• Opinion: as a firefighter, I doubt this. The fire would destroy the a/c.

Search Areas

• 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 straight
• North west of Malacca straight
• Along the two tracks 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 route 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.

Conspiracy Theories

• There are lots of conspiracy theories out there - from the Malaysian government hiding something to pilot suicide, to hijacking to whatever.
• The breadth of the countries searching alone makes me discount many of the government is hiding it aspects
• It is likely there are covert (secret) resources in the area that are trying to provide the info without revealing themselves.
• 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.
• Investigations of crew have begun in earnest.
• Despite the belief this is incident required human actions - we have no evidence of that. Rather - no other theory seems credible.

Mobile phones

• We know that if any mobile phones were connected to the tower - we would have a location and would search there.
• We don't have any reports or evidence of that - so I conclude that it is not viable to consider.

I've deleted the sections on incompetence and false sitings - for brevity.

In summary what we know is.

• 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.
• 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.

What seems likely.

• 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 unobserved.

That is all.
Respectfully Submitted - rcair1