Information Pertaining to the
Search for MH370
Duncan Steel, 2014 April 06.
duncansteel.com
In this post I present various pieces of information, and in particular graphics and maps, intended to assist in the search for the path taken by MH370 and so its final resting place.
In my last post I showed the locations of the ping rings based on the back-engineering of the Google Earth graphic, and other materials, by GlobusMax. Here I present other graphics that might assist people involved or interested in the search.
Let me first summarise what is required, based on the best-available (to my knowledge) information.
(1) The final radar detection of MH370 was at 18:22 UTC on 2014/03/07, at which time the aircraft was located near the aviation waypoint MEKAR, about 200 nautical miles from Butterworth on a bearing of 295 degrees from the military radar there. I have adopted a geographical location of latitude 6.50 degrees North, longitude 96.5 degrees East for that final radar-detected point.
(2) All LOS speeds after that time as measured through Doppler shifts in the ping signals received back by the Inmarsat-3F1 satellite appear to have been characteristic of the aircraft moving away from the satellite. The decomposition of the Burst Frequency Offset graph from Inmarsat has been accomplished by Mike Exner, resulting in values for the LOS speed satellite to aircraft as shown in the table below. I have previously shown these same data, but with the times of the pings in minutes and the speeds in km/sec. For your convenience, here they are in hours and minutes (UTC) and knots.
|
Time (UTC) |
Line-of-Sight Speed (knots) |
|
18:29 |
39.77 |
|
19:40 |
39.14 |
|
20:40 |
60.80 |
|
21:40 |
79.85 |
|
22:40 |
100.64 |
|
00:11 |
125.35 |
(3) The ‘ping rings’ represent a range of possible positions for the aircraft at the times of the pings. That at 18:29 is outside of those at 19:40 and 20:40, but inside those from 21:40 onwards.
The requirement for any plausible path taken by MH370 must therefore encompass all of the following:
(a) A start at near 06.50 N, 96.5 E at 18:22 UTC
(b) The direction of motion of the aircraft at the times of all pings being away from the satellite and producing LOS speeds in accord with the above table.
(c) Movement inwards from the 18:29 ping ring and then consistent movement outwards thereafter, crossing the rings at the correct times.
Note that this means that despite MH370 apparently moving away from the satellite at 18:29, by 19:40 in had shifted rather closer to the satellite and was again moving away from it so as to cross the 19:40 ping ring from the inside.
Views from the STK 3D window
People have asked for some cities to be inserted as reference points, so here they are: 
Close-up of one possibility for the initial part of the flight (orange path). The trajectory after waypoint IGARI is not securely known. The location at 18:22 UTC (final radar detection) is labelled as ‘P_18_22’. 
A wider view showing the ping rings: 
Southerly parts of the ping rings: 
Northerly parts of the ping rings: 
Relevant parts of the globe with lines of latitude and longitude added (in ten-degree steps): 
Equal-distance rings centred on P_18_22 added in bright green, at distances from 1,000 to 3,500 nautical miles in steps of 500 nautical miles: 
Close-up of the southerly portion of the possible paths of MH370 with bright green range rings: 
Close-up of the northerly portion of the possible paths of MH370 with bright green range rings: 
Views from the STK 2D window (i.e. maps)
Detail of the initial (possible) path of MH370: 
Map of the general SE Asia region with ping rings: 
General map of the full limit of possible locations for MH370: 
Southern region of possible locations for MH370: 
Northern region of possible locations: 
Wide-area map showing range rings centred on P_18:22: 
Detailed map showing range rings, southerly part: 
Detailed map showing range rings, northerly part: 
Someone complained to me that the images were too small to see any detail. To make any image appear larger, just left-click on it. You can then right-click on it to save it.
The 2D maps I have shown here are the full spatial resolution that I produced from STK, although stored as 8-bit PNG files rather than the original bitmaps. The 3D window views were also stored as 8-bit PNG images, converted from bitmaps, although the original bitmaps had pixel scales four times larger (i.e. I reduced them from 6,000 pixels wide to 1,500 pixels wide).
Nice work… I overlaid one of your maps (the cylindrical projection) in Google Earth. This can be done with an accuracy of about 1 to 2 minutes (mostly).
Any idea what happened from 18:22 to 18:29? From (6.5N, 96.5E) to the 18:29 ping ring (20 nm thickness on the graphic) appears to be no less than 50 to 70 nm. That’s at least 430 knots, and furthermore by 18:29 the aircraft is supposed to be travelling away from the satellite… in other words, an abrupt turn must have occurred.
From another graphic you have no doubt seen (MILITARY RADAR PLOT FROM PULAU PERAK TO LAST PLOT AT 02:22H) the 18:22 position seems about (6.63N, 96.27E): 37 to 57 nm from the ping ring. This eases the speed requirement to 320 knots.
What do you make of this? Did the 18:29 ping occur because of an abrupt manoeuvre? Was the aircraft at 18:29 travelling away from the satellite?
By the way, the white ping ring labelled “0:11” on another graphic seems to be the 0:19 one. It certainly lines up with the sites of the acoustic signals recently detected.
Thanks Jack.
But: Every point you make and question you ask there has been addressed in the posts and comments here; actually, all of them in my posts, I think.
Duncan, You have indeed covered the little 18:22-18:29 story in various ways.
It would be more plausible if the 18:29 ping-ring was closer to the 18:22 position. Might that be the case? (My guess is that the ping-rings are reverse-engineered.) Or better, if the direction of travel at 18:29 was still towards the satellite. Would that be contradicting a ‘more certain’ fact?
By the way (again), what about the “00:11” label I suggested should have been “00:19”?
You mentioned severe STK mess on your computer. Similarly, I have unwieldy Google Earth work!
For the record, and with reference to this above post, I wanted to present exact statements from the transcript of the JACC presser concerning the satellite data which caught my attention. What exactly was meant by the bolded statements? In my opinion these two statements lack clarity:
From the Transcript of JACC Press Conference, 6 April 2014
Angus Houston: “Today, the international investigative team has this morning advised of a correction to the satellite data that has been used to calculate the probable flight path of MH370. The correction arises from new information about the state of the satellite itself when it received transmissions from MH370 during its flight. The effects of the correction is to raise the priority for searching the southern component of the existing search area ahead of the northern component.”
¤ Was there a problem with 3F1?
Angus Houston: “No, the search area doesn’t change at all, but what we get out of the data, the satellite—this is the Inmarsat satellite, the characteristics of that were such that on reanalysing the data that has been obtained, some other conclusions have come up which slightly change the possible profile of the aeroplane. And they are based on the fact that there might be a slight difference in the air speed that has been calculated. And we’re talking programs the aircraft — perhaps the aircraft went a little bit faster than had originally been calculated on the basis of analysing the satellite data.”
¤ Which programs are being referenced?
That’s a delightful anecdote. If you happen to have easy access to a digital image of the commemorative plaque taken on your outing please post it here (if possible). When I was learning about the meaning and applications of quaternions I was recalling the illustrative work you have presented in this blog. Ah, the consummate Professor that you are! Now if I can somehow break my wiki habit I think you’ d really be pleased.
Thanks LG!
I do have a photo somewhere, although it may be from an old-style camera (i.e. a photographic print!)
Meanwhile, see here: http://en.wikipedia.org/wiki/Broom_Bridge
You can plot it with pencil and paper, but would a route up to the Andaman Sea, then south and along Indonesia, and up to Borneo be consistent with the data?
Sorry CU, I am unable to follow every suggestion by everyone. I have done my best to make all data (as I have them) available to all, such as the plotted ping rings and a set of range rings for scale.
Many thanks for your work. You did a truly amazing job. I understand you cannot analyse everthing, however. Thanks for replying to my post.
Thanks CU. I would love to be able to handle every request but… To deal with your specific suggestion in my STK scenario would take 3, 4, 5 hours of work.
BTW, I was once a student at “CU” – perhaps the origin of your handle?
See you,
Duncan
When comparing the north route options to the ones going south the symetrical model of those routes is prevailing. That might be true if we assume, that it was flown by autopilot on its own without crew input or if we assume the suicide motive.
When it was a deliberate act to fly the aircraft to a predetermined position the north route would differ considerably in terms of altitude, speeds and routing from the south route. Why do i assume it would be? There is not much threat concerning radar detection and possible weapon employment on the possible south route, but there is on the north route. Flying further north through air defence systems like lets say Myanamar would necessitate a route planing to avoid the air defense threats and visual detection by people in towns. We cannot assume that the crew went to great length in terms of maneuvering along FIR boundaries, changing altitudes after switching off coms ( not saying that they did until prove is available) to avoid radar detection heading west and then fly on autopilot some constant speed and altitude through high defense areas in the north on published airroutes without proper identification.
We would have to create a possible low threat routing to the north, derive the altitudes and the possible speeds from it and then use heading to match the inmarsat data and the available fuel load. Do some finetuning and see where it could end.
Assume a crew doing such planning, approaching and crossing the shoreline would be the highest probability of detection, therefore they’d look for a less populated area, check the radar coverage and choose a point where coverage is weak. Fly inbound at an altitude less then 5.000 feet, climb to min safe altitude after crossiing to avoid hitting any onstacles and head for less populated areas further north. Only when out of primary radar coverage start climb again to higher altitudes and fly higher speeds again. Same might apply if the next boarder to the north is approached. There would be no published waypoints used for navigation, but just coordinates, visual clues or prominent landmarks (coastline) on the weather radar. Would such a scenario be survivable? More then the high steady flight scenario, and such a planning would have to assume some cooperative behaviour of the penetrated defense forces anyway. But in the tactical flight routing it might be sufficient if one radar station stands down due to a technical ( self induced) glitch, the high fly scenario would need a whole bunch of people to look the other way.
You might get the point, the route would be shorter and therefore ending more in the north instead northwest, as the slower speeds and heading changes would make it shorter in distance while not changing the flight time.
Doing a few simple calculations using Skyvector. Very whizzy app too that I knew nothing about until a few days ago.
I think it can be demonstrated that the track to the 19.40 ping circle follows established waypoints, with a few first order approximations, using the likely aircraft speed as a constraint.
(i) Kuala Lumpur to IGARI takes about 40 minutes, hence average speed is about 412 knots. I’ve assumed that IGARI is reached a few minutes after the ATC sign-off at 17.19.30
(ii) Left turn and track back to ANDOK, VAMPI and MEKAR. Total distance 434nM. At 450 knots the 18.22 ping would have occurred just short of MEKAR
(iii) Track to SANOB, NOPEK, BEDAX, ISBIX. Total distance 505nM. Add about 30nM for the distance unaccounted for in (ii). At 450 knots that will take about 71 minutes, making the time 19.33.
(iv) Now compare the position of ISBX with Duncan’s yellow ping line at 19.40. I would say that IBEX is a little too far north, so extend the track south beyond ISBIX until the time gets to 19.40 – – – and Bingo! I think we have a match.
(iv) That would place the 19.40 ping on the equator at 93.7 degE
My inclination is that the pilot flew standard waypoints to get to this position. The times and speeds seem to match pretty well, and I think the locations and directions do not violate the constraints of LOS in Duncan’s table.
Correction, in (iv), all the references are to waypoint ISBIX
Thanks Brian, I will look into this. This is useful input.
I just posted a reply saying that I have seen little/nothing about the default mode(s) for the autopilot if the crew is incapacitated. Perhaps it heads for the nearest (or some other consideration giving the decision) waypoint, and after that skips on to other waypoints in accord with (a) The distance(s) to them; and (b) Its heading as it reaches them? That is, it would not make a 150-degree turn to go to a waypoint that is 100 nm away when it could make a 20-degree turn to go on to a waypoint that is 120 nm away. And then on it goes… If this were the case then one could definitely solve for the route of the aircraft! (In physics/maths this might be termed a Markov Chain analysis.)
To me, it would make a lot of sense if that were what defined the algorithm in the autopilot code.
Any autopilot experts out there? I do not mean pilots (users of autopilots), necessarily. I mean people who actually design autopilots and know what the software would be designed to do in the absence of any human input on the flights and a waypoint (the last one humanly-entered during the flight) being reached. On the other hand, perhaps airliner pilots get detailed instructions on what the autopilots would do under different circumstances? Me being me, if I were training to be a commercial pilot I would keep asking questions until I was satisfied that I knew what the autopilot defaults were.
Duncan
Dang internet changes whitespace. Here is the comparison again with comma separations:
Time, ∆LOS/∆t (knots), LOS speed by doppler (knots)
07:40:00 PM, -58.4, 39.14
08:40:00 PM, 24.6, 60.80
09:40:00 PM, 93.4, 79.85
10:40:00 PM, 153, 100.64
12:11:00 AM, 212, 125.35
The distance rings make it much easier to plot. I assumed that the plane travelled west for 15 minutes to 7.25E,94N (approx) and then in a great circle to 43.4E,77.6N (approx). The doppler and distance looks good (remembering the doppler at my assumed start at 18.45 looks like it was negative – the line on Inmarsat’s plot being meaningless.) The Southern route is almost the mirror image about the line joining the satellite to the start. My resolution (with pencil, paper and ruler) is insufficient to distinguish which is more likely as a result of satellite movements. Lower speeds might work if the start point is moved even further west.
Thanks Duncan.
So assuming a 500kt maximum ground speed for upper range limits then the initial arc at 18:29 which is only 7 mins after the last radar contact should be fairly small with an equal distance ring with a radius of only 58.3nm.
I think it would be useful to see the following equal distance rings plotted from the last radar contact point placing upper bounds on the ping arc segments .
Time: Radius:
18:29 58.3nm
19:40 650nm
20:40 1150nm
21:40 1650nm
22:40 2150nm
0:11 2925nm
Do you have an STK project/data file that you would be willing to share which can be loaded into STK to render the ping range rings and the equal distance rings?
I know you mentioned that it would typically take a couple of weeks to become familiar with STK, but I’m assuming it wouldn’t take much time to take a pre-setup data file for what you’ve rendered in this blog post and then to tweak the equal range rings etc.
Cheers
Your assumption in the final sentence is wrong, I am afraid.
So far I have worked up about 30 STK *scenarios* (specific meaning in STK) in connection with MH370, each in its own folder, and each contains many files that contribute. The latest contains 240 files. However, when I open a scenario in STK it accesses not only that 240 files but also many, many other files spread all over your C disk: there are several that define the satellite orbit, others for 3D models, others for GIS imagery, others for each planet involved (because the orbit ephemeris integration requires those, especially the Moon and Sun), then there’s the Earth gravitational field (v complex), next the Earth orientation data, then there’s…
Problem with a sophisticated software tool is that it’s not portable, much. There are ways to move things from one machine to another, using .vdf files which pack it all (or most of it) up, but that needs a paid version I believe.
Sorry!
Duncan