Aviation / Current

London, We Have a Problem

The British satellite company Inmarsat today released 47 pages of satellite data it received from Malaysia Airlines Flight 370 on 8 March 2014. I have suspected for months that this initial finding from Inmarsat was grossly misunderstood:

Before continuing, I must note the altitude of the Inmarsat satellite—35,800 kilometers. The circumference of the Earth is less than 5,000 km greater than that distance, why so high? Geostationary orbit:

http://www.rap.ucar.edu/~djohnson/satellite/figures/satview1.gif

This is important because the terms “Doppler Effect/Shift” are mentioned at length, but the key measurement, the distance from the Inmarsat satellite, should be predicated only on the motion of the airliner.  The satellite effectively functions as a ground station with far greater range.  Inmarsat-3 F1’s motion matches the rotation of the Earth–the satellite is traveling at more than 7,000 mph, but its ground speed is approximately 0 mph.

The last known position of MH370 based on satellite data put the Boeing 777-200 somewhere over two arcs—the northern arc includes large swaths of China and Kazakhstan. As the flight’s destination was Beijing and entering Kazakh airspace without first transiting Chinese airspace from Kuala Lumpur was practically impossible with the airliner’s fuel load, the fact that no radar track of the plane has ever been located outside of Malaysian airspace led aircraft investigators to focus on the southern arc, over the Indian Ocean.

This is not a “corridor” or a “track”—essentially Inmarsat tried to measure the mean distance MH370 was travelling from a high-flying satellite and plotted the last known position relative to the aircraft’s range:

A map showing the location of the Inmarsat satellite that received keepalive pings from MH370, and the plane's possible radius from that satellite, which led to the current search area in the Indian Ocean

Why do I say tried? Because the data is clearly wrong.

Has Anyone Else Ever Heard of Erroneous Data?

Let’s look at the uncluttered image again…

…and look at the caption included this time:

This map released by Malaysian officials shows two red lines representing the possible locations from which Flight 370 sent its last hourly transmission to a satellite at 8:11 a.m. on March 8, more than seven hours after it took off from Kuala Lumpur’s airport, and when the plane would most likely have been running low on fuel.

No, the 8:11 a.m. (00:11:59.928 Zulu to be precise) transmission wasn’t the last sent from the Malaysian 777. MH370 sent two more transmissions to Inmarsat-3 F1 at 00:19Z:

Time Channel Name OceanRegion  GES ID(octal)  ChannelUnit ID  Channel Type SU Type  BurstFrequencyOffset (Hz)

BFO

 

Burst TimingOffset(microseconds)

BTO

 

 

00:10:58 – Handshake Request, with response

 

8/03/2014 00:10:58.000  IOR-P10500-0-386B  IOR 305 10 P-Channel TX  0x14 – Log Control – Log-on Interrogation     
8/03/2014 00:10:59.928  IOR-R1200-0-36ED  IOR 305 4 R-Channel RX  0x15 – Log-on/Log-off Acknowledge  252 18040

 

 

00:19:29 – Log-On Request (reported as a Partial Handshake), initiated from the aircraft terminal

 

8/03/2014 00:19:29.416  IOR-R600-0-36F8  IOR 305 10 R-Channel RX  0x10 – Log-on Request (ISU)/Log-on Flight Information(SSU) 182 23000

 

00:19:37 – Note that the following R-Channel burst at 00:19:37.443 is the last transmission received from the aircraft terminal

8/03/2014 00:19:37.443  IOR-R1200-0-36F6  IOR 305 10 R-Channel RX  0x15 – Log-on/Log-off Acknowledge  -2 49660 

 

The BTO values determine the distance from the satellite:

Understanding the Burst Timing Offset (BTO) values:

  • The round trip time for a message is a combination of:
  1. Time from the ground station → satellite → aircraft → satellite → ground station
  2. Processing time within the ground station, satellite and aircraft terminal, which are constant
  • The BTO is a value (in microseconds) relative to a terminal at a nominal fixed location. Only R-Channel messages are used.
  • The BTO therefore allows the determination of the distance between the satellite and the aircraft. It does not provide the actual aircraft location.

 

Question: why disregard the two messages received at 00:19Z? Because the BTO times show an incredible increase in distance from the satellite, especially the last message where the distance more than doubles over the course of eight seconds. Considering that distance is measured in thousands of kilometers, the data clearly cannot be correct. But how is that possible? Processing time is constant supposedly, so how could the times change so radically?

Answer: the terminals. The condition of the ground station and satellite terminals can be ascertained by inspecting the ones on the surface and running a diagnostic on the geostationary satellite. The 777’s terminals, however, were destroyed on 8 March 2014. How functional were the linkups prior to their destruction? The link was lost between 17:07:48 and 18:03:41; why assume that the system was functioning as advertised after the nearly one hour blackout? The last two transmissions show that the BTO values could change radically due to some confluence of factors; why only throw out the 00:19Z transmissions as erroneous?

These questions have serious ramifications. The Chinese are expected to spend the next three months mapping the ocean floor in the 60,000 square kilometer search area before the underwater search for MH370’s wreckage resumes, at a cost of approximately $60 million. The waters in question can exceed 4,500 meters in depth. What if the search comes up empty?

Reconsiderations

After today’s data release, I have new fears that the distance plotted from the Inmarsat satellite is way off from the actual aircraft position.  The BTO values prior to the two transmissions at 00:19Z are showing a fairly uniform distance from the satellite–the equivalent of MH370 flying a DME arc.  No investigator appears to have been asked under what circumstances would anyone do that?  That makes no sense at all.  But if the range values are wrong in the first place, what then?

Immediately upon hearing MH370 had disappeared, I suspected an onboard fire. This week, my suspicions again (pardon the pun) were enflamed:

Questions continue to circle around a mystery shipment that was on board Malaysia Airlines Flight MH370 when it disappeared more than two months ago.

NNR Global Logistics, a Penang-based company that handled some of the cargo, has refused to reveal its contents.

The company admitted that 200kg of lithium-ion batteries formed part of the shipment. But a senior official, speaking on condition of anonymity, told the Engineering and Technology (E&T) Magazine this formed only part of the consignment, which weighed a total 2,453kg.

He said that NNR Global has been told by its solicitors not to disclose details of the cargo because of the ongoing investigations into the missing aircraft.

Oh, I bet. This has nothing to do with protecting the battery manufacturer, perhaps?

E&T says that “what is even more surprising” is that the company that produced the batteries has also not been named.

Neither NNR Global Logistics nor Malaysia Airlines have been willing to identify the manufacturer, saying that it was “highly confidential”.

Surprise!

When questioned, the airline said that the remaining weight was “radio accessories and charges” but this was not documented in the cargo manifest.

The manifest stated only that NNR shipped 133 pieces of one item, weighing a total of 1990kg, and 67 pieces of another item, weighing a total of 463kg.

There were also strict instructions on the manifest that the batteries should be handled with care and that there was a flammability hazard. However, several experts have ruled out the theory that the plane might have caught fire, as it would have struggled to fly on for several hours afterwards.

This is quite possibly the most arrogant statement I’ve ever read. The atmospheric pressure at 35,000 feet is 23.6% of that at sea level, a highly inhospitable environment that will knock pilots and passengers unconscious in less than 15 seconds due to lack of sufficient oxygen. What else needs oxygen to flourish? That’s right, fire. This…

…would kill the pilots, decompress the aircraft, and put out the fire (while knocking out 239 people in less than a minute).  Based on today’s satellite data release, the only information that seems reasonably accurate is that MH370 was still flying at 00:19Z; where the 777-200ER was at that time, however,  is anyone’s guess.

 

 

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One thought on “London, We Have a Problem

  1. Pingback: What Part of “Lost at Sea” Don’t Investigators Understand? | In The Corner, Mumbling and Drooling

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