air safety

Mar 26, 2014

MH370: New satellite analysis helps define flight’s end point

Ben Sandilands — Editor of Plane Talking

Ben Sandilands

Editor of Plane Talking

The map above gives the clearest indication yet as to where Malaysia Airlines flight MH370 crashed on 8 March, but shows how difficult the task of the Australia coordinated search is when it comes to establishing a starting point for seeking the jet's 'black box' flight recorders.  As explained in this summary of satellite signal analysis, the two tracks calculated for the Boeing 777-200ER's southwards course are based on an upper estimated sustained speed of 450 knots and a lower value of 400 knots. MH370 took off from Kuala Lumpur for Beijing with 239 people on board at 12.40 am local time on 8 March. It went dark, the authorities believe intentionally, at 1.22 while on its crossing of the Gulf of Thailand toward Vietnam.  Having become invisible to civil air traffic control systems, MH370 was then seen by military radars to have backtracked across the Malaysia peninsula where it performed a series of course changes off the western coast of Thailand before turning south into a long and straight path to an end point in the Indian Ocean SW of Perth. The two tracks for faster or slower cruise speeds end at 8.11 Kuala Lumpur and Perth time when an Inmarsat satellite registered the last full standby signal from the jet.  However there was some fuel remaining in the jet, which had by then been airborne for seven hours 31 minutes.  Eight minutes later a final but incomplete electronic trace from the jet's automated performance data monitoring system was received  by the satellite. While the analysis by Inmarsat and the UK Air Accident Investigation Board doesn't discuss the possible reasons for that incomplete 'handshake' between satellite and jet, it could might indicate the actual time the flight was destroyed by impact with the sea, or had entered a dive. The analysis doesn't explain what could have triggered another attempted 'handshake' so soon after a normal handshake. On the 19th day since the crash occurred, the task for the resuming AMSA (Australian Maritime Safety Authority) search, is to identify and recover floating debris from MH370, then estimate how far it might have travelled to establish a starting point for a sea floor search for the two flight recorders, one the cockpit voice recorder, which also picks up systems annunciator alerts, and an overall flight data archive, which tracks a host of control and flight management functions, including cabin pressurisation changes and the opening of the cockpit door. There will be up to 12 aircraft and at least five ships, including HMAS Success and an ice breaker from China, Snow Dragon, seeking to find or recover MH370 debris today.

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32 thoughts on “MH370: New satellite analysis helps define flight’s end point

  1. Darryl Smith

    This analysis is both good and bad for the searchers.

    It appears that this new plot is based on distance from satellite in addition to doppler analysis of the bust frequency in the uplink and downlink.

    A further analysis by TMS Associates (They have a great blog) puts the lateral error at about 1 or 2 degrees, with the uncertainty as to which based on unknown information about if certain timing constraints are for uplink or both uplink and downlink. My suspicion is that it is for uplink only, suggesting 1 degree, or 60 NM.

    One of the things that they had on their side was that the satellite is getting near end of life, so it is geostationary east/west, but moves north/south. Since it was moving north at the time, they were able to determine the plane was moving south from the doppler.

    My guess is also that this partial transmission was the terminal losing power, and attempting to log off from the Satellite network. This is just a guess. If this is correct, it would give an almost exact time when the plane ceased flying.

    With the previous analysis, this would give an area of about 60 NM radius to search for the black box. This is a relatively easy task.

    The real issue for me with this new data is that the 400 and 450 NM are based on ground speeds and not air speeds. Depending on the prevailing winds, this may not be reasonable. The variables have now become the winds and the plane/pilot. My guess is that there will be cross winds, in addition to possibly head or tail winds. All this needs to be compensated for.

    I would imagine that aircraft flying that day between Australia and South Africa, as well as from Asia and Africa will have their logs checked to build up a better model of the weather.

    Regardless, a spiral search pattern for the black box starting at the 400 kts and 450 kts points on the arc and moving out to search for the black box has to be the best starting point

  2. Frequent Traveller

    The plot of ‘impact’ might correspond to a point of low-speed controlled ditching (in the early morning daylight of March 8th) of the aircraft at some pre-agreed co-ordinates followed by recovery of the crew (whomever those were at that time ?) into some sub-marine waiting at the point of RDV … if yes, then the odds are that if/when the wreck of the 772 ever is located by NTSB/BEA/AAIB, unfortunately they will discover the DCVR and DFDR are missing (were removed) ?

  3. wendal

    Excellent link Darryl. Thanks for that!

  4. Rocket Rocket

    FT – I’m not a pilot but I understand that water ditching a wide bodied jet with engines hanging off the wings would be pretty difficult.

  5. Matt Dalton

    Just an idea.

    The analysis so far is focussed on the end point, but there seems to be uncertainty about the airspeed.

    If the SATCOM is sending a ping every hour, what are the plots for each of those? Wouldn’t plotting each of these points show the air speed?

  6. Confirmed Sceptic

    The plots do not provide a coordinate, just an angle, hence the arcs of equal angle. So no progress points along the track from which to derive groundspeed.

    This blog is almost the sole source of sober discussion on the internet. FT, no disrespect, but really.

  7. wendal

    Matt, points can only be placed on the arcs of equal angle by making an assumption of:

    1. Track
    2. Airspeed

    These cannot be derived from the satellite data.

  8. RiskMan

    If each plot was precise on the map, the search would not take days. Each ping should provide an estimation of distance and the time between pings should provide an estimation of position depending on the airspeed. For the amount of time taken to search and not find debris, someone should autopilot the route and head south for a few hours by estimating airspeed and calibrating the pings. Re-enactment is the closest to conditions on 8 March and locating the aircraft.

  9. Amateur Sleuth

    Interesting article on the pilot.

    These stories keep swirling around in the media, with no confirmation or rebuttal…

  10. greg frost

    What is the behavior of the autopilot under cross/head/tail winds? Does it maintain a constant air speed? Does it fly into a cross wind to maintain the ptogrammed ground track? If you made the assumption that most of the journey southwards was flown on a single autopilot setting, and did the analysis to take varying wind conditions into account, you should be able to come up with a path that best fits both the sat ping arcs, and the Doppler measurements.

  11. RiskMan

    Just a thought. Looking at the arc based on estimated distance for the satellite, why doesn’t AMSA follow the arc? Similar to cutting a wedge of onion, and peeling a layer at a time? Or some can use Tomnod to conduct a virtual search in “arcs”? The current search zones are in rectangles, yet the only reliable data is in arcs.

  12. redtrigger

    Updated map:

    Todays search are highlighted purple. Apologies for the objects drawing underneath the search areas.

    I have added two possible flightpaths both ending to 90° South and 90° East. Whilst everyone is trying to work out where it flew, I was wondering if it had a destination and what it would be. Given the assumed route, the South Pole seems a likely place to be heading. Assuming the original idea of going around the top of Indonesia it works out at 426 knots via BEDAX crossing the 40° Inmarsat intercept. At 450 knots it has to go a bit further and then I noticed that the route from GIVAL towards IGREX via 200 nm of Penang could actually go via LEKIR and from there follow airway P627 until waypoint NIXUL, which is pretty close to 90° East.

    How certain is any of this? Well, we may of course never know, but Inmarsat seems to be pretty close and they have a lot more info that I do. If the aircraft did track to -90, 90 then the search area needs to move futher east as any debris will have moved about 160 nm by now.

  13. Ben Sandilands


    You look to be right on the money when it comes to drift looking at the search maps for today, one of which has only just been posted.

    Having been to the south pole by ski-Hercules, and also making a few very long trans Antarctica flights in the same equipment ex McMurdo, the incredible distances involved are burned into the back of my eyeballs.

    It’s interesting that with full fuel the 777-200ER might just have made it to 90 degrees S had to it headed for it immediately after leaving KL and not hit the usual ferocious cross winds between 50-65 degrees S. But on the statements made in Malaysia it only had enough fuel for a flight little longer than the one it made. I don’t think it could have made it to the Wilkins Blue Ice runway either with that fuel, even though it is in the order of 3400 kms closer to KL than the South Pole.

  14. Glen

    Finally a technical explanation. I withdraw “secretive”. Seems I was wrong about ping timing.

    I’m not fully understanding this graphic. What would “D1-aircraft” be? There’s no doppler shift inside the aircraft. Presumably it represents aircraft transmitter signal drift (e.g. from temperature), which they exclude by comparing pings from multiple similar installations.

  15. caf

    redtrigger: What do you mean by 90S90E? Longitude is meaningless at 90S, do you mean that it tracked to the 90E meridian and from there due south?

  16. Glen

    90E is just a number in his map model (which, being clever computer code, it doubtless insists on). He means that the final track (direct or via NIXUL) may have been due south (geographic). That would be a nice round number. You can see it if you zoom right out.

  17. BugSmasher

    Ben, it may have been the hope of whoever was in control to reach the northern extent of the winter sea ice (highly optimistic). At this time of year a ditching aircraft would sink, but with winter approaching there would be no locating or retrieving any part of the aircraft until at least next summer. And what a mission that would be.

  18. Confirmed Sceptic

    Answer for Greg Frost re autopilot tracking:

    Modern autopilots will follow a variety of tracks:
    1. Long Range Nav, called LNAV in the trade. The crew can build a route from a series of sequential waypoints in the flight management computer, or they can try to go direct to a waypoint half a world away. Typically programmed as per a flight plan or ATC clearance. Corrects for wind. It is typically accurate to within a few metres* it does not care how much fuel is onboard.

    2. Heading (HDG) which follows a constant compass heading in degrees magnetic. In polar regions (much farther south than today’s topic) the option exists to select degrees true to avoid a furball close to the magnetic poles.
    The salient point here is that there is no wind correction…and drift at high altitude in the strongest crosswinds can easily be 15° (That means that at a ground speed of 420 kts, for example, in a very fast crosswind, the aircraft can drift off track 105 nautical miles in an hour.

    3. Some aircraft have the option to follow a specific magnetic track, ie, they will correct for wind. Unknown if MH 777s have that option.

    4. A variety of approach selections can be made to enable using various airport approach aids. Not relevant to this discussion, but included to show off.

    Vertical performance, ie speed, can be as programmed in the flight management computer to the most economical, the minimum drag, the longest range, or any random number up to the maximum Mach number, which I believe is .86 on the triple. Best range would likely be Mach 0.82, around 470-480 kts true airspeed.

    * on navigational accuracy: in the old days of inertial navigation we thought ourselves pretty fancy to pass an opposite direction airliner (differnt altitudes, obviously) within about 300 metres. These days, we pass opposite direction aircraft on an exact collision course. In fact, on my plane, we can hear them go by. It is the spookiest thing in the world, and still gives me goosebumps.

    Sorry for the long winded explanation: none of your new insights will help you to know which mode, and hence, which track MH370 flew.

  19. Glen

    Scep, if a disturbed aviator wanted to say, just head south, what do you think they would be most likely to do?

    1. Select a waypoint near the south pole (which?)
    2. Select heading 180° magnetic (uncorrected for wind)
    3. Select 180° true (uncorrected)
    4. 2. with wind correction
    5. 4. with wind correction?

    Second guessing that might be the best search targeting strategy available. Is it already being applied?

    Note that the local magnetic variation west of Sumatera is currently small, about -2°. But a magnetic track would deviate rapidly eastwards the further south you went, see: Wind deviation ought to be readily calculable (given altitude), e.g. from global weather model analyses. Has been by now, surely.

  20. Confirmed Sceptic

    Glen, for the last two weeks I have been queasy with considering the actions of a man presumed to be insane. I do not understand how health care professionals perform their jobs.

    To answer: someone here posited the idea that he programmed in the coordinates of the Diamantia Deep, with a holding pattern. The aircraft would have obeyed until it couldn’t anymore, then plunged in.

    Or, he could have left it in heading mode, say 185° without looking at the plots. That likely would have ended up on the arc, give or take. Or he could have gone direct 90S, knowing that everything south of Indonesia was removing the possibility of being found*

    *I emphasise again: no airline pilot that I have pinged lately was aware that their satcom calls home periodically. I expect that if he knew we would all still be looking in Berzerkistan..

  21. Glen

    300 hPa (30,000 ft) winds were light for much of the track. There was a moderate (westerly!) jet stream near the southern limit:

    That’s enough for maybe 150 km of easterly deviation. Add maybe 350 km of easterly deviation if flying a magnetic heading (average ~10° x 2000 km) and you could be 500 km east of redtrigger’s “straight south” courses.

    Most of that deviation happens after passing the “last ping” circle.

  22. Confirmed Sceptic

    Agree to all of that, but there’s nothing to convince me that a seasoned, and selectively reasoning, aviator would not apply some rule of thumb to account for what he knew to be typical. So, for example, he could have selected a heading that would, on aggregate, yield the resultant track, or he could have just programmed in an end point beyond all possible endurance and sent the aircraft, drone-like, along that track.

    Once again, the intermediate ping data may reveal more info pertinent to the eventual impact point than is widely suspected. For example, knowing the winds, and the approximate longitude of the pings it should be possible to ascertain if the aircraft was on HDG or LNAV. Knowing that, you could then refine the last hour track significantly. Which would refine the location of the circle that would define the impact point.

    I imagine that, as an experiment, all 777 operators could be asked for a :15 minute window at the end of all scheduled simulator sessions to model the end phase behaviour, given a few constraints. I expect that most impact points happen within 50 miles of fuel exhaustion, but it would be useful to plot a distribution of, say, a hundred results. That would then give dimension to the end impact CEP*, which should help narrow the possibilities somewhat.

    *CEP= circular error probable, a ballistic weapon targeting metric used for everything from aiming to weapons systems appropriations. The uncertainty in CEP is what gave us the six-pack MIRV, the arc-light raids, the Tsar Bomba, overkill, Robert McNamara, etc.

    But it is useful in plotting a contour map of equal probable locations of the remains on the sea floor, such as it is.

  23. Glen

    I gather AF447 searchers used a Bayesian inference approach, to much the same effect, probably.

  24. [email protected]

    Confirmed Sceptic,
    LNAV means lateral navigation mode of the autopilot/flight management system, nothing to do with range.
    HDG, heading mode, can be magnetic or true heading, depending on pilot selection.
    A more commonly used expression for navigation is MPP, most probable position, which is not quite the same as CEP.

  25. Grant Sutherland

    The most likely scenario is that of the aircraft being navigated due south (True south towards the South Pole). This is what is known as a great circle track and it involves no course correction (as would be the case had it been going say SW). Looking at the search area and running a line from the north of the Andaman Islands (west of Thailand and Malaysia – and where Military radar observers / or Inmarsat scientists consider the aircraft turned south)…through to the south pole the actual search area is very close to this line of Longitude….Furthermore assuming an Inmarsat scientist puts forward the hypothetical scenario that this type of navigation is so simple for a pilot to enter (the South Pole waypoint) ..then they can supposedly back-calculate the derived doppler data to see if there is any correlation. If it’s not well known what the waypoint at the north end actually is, an iterative process can be undertaken to obtain the best fit from incremetally changing the line of longitude…

    For those of you who don’t understand modern aeronautical navigation, a combination of gyro (true north seeking compass) and multi unit GPS are used (including inertial systems too), and once set the auto-pilot will track the route exactly. So if there is a 50 knot westerly cross wind for example and the aircraft is doing 500 knots, the aircraft will adjust the heading by +5.74 degrees to ensure the course made good is along the navigation route.

  26. Grant Sutherland

    To follow on the LNAV that is talked about above is great circle navigation gerally (shortest path between two points on surface of the earth), and as such unless running a true north / south line, will increment the heading along the track to navigate to this great circle path. Place a piece of string between Capetown SA and Perth (AUS) and you will see a great circle path

  27. Grant Sutherland

    I meant to say on a globe if you have one!!

  28. M B

    Any merit in investigating the flight path possibilities to a Lat Long that corresponds to Beijing but with a negative equiv latitude?

  29. Alfonso Rodriguez Hourcadette

    If in the southern Indian Ocean a point was plotted that was the same distance and bearing to Kuala Lumpur as Kuala Lumpur is to Beijing, it would be very near the end of the path of MH370 flying at 450 knots as pictured in your March 26 blog. The following 3 geographical points are on the same great circle, the path being 8842 kilometers long with Kuala Lumpur exactly in the middle.

    Beijing airport is located at 40°04’N, 116°36’E; Kuala Lumpur airport is located at 2°45’N, 101°42’E; thus the possible end of flight would be at 34°44’S, 87°51’E.

    If there are no more promising leads, this geographical point is specific enough to find the plane if it is there. I know this idea is crazy but we might be looking for someone crazy enough to have done this deed.

    Alfonso Rodriguez Hourcadette
    Merida, Venezuela

  30. Keith Seston

    Who says the plane turned south?
    If it went straight out from the military radar point into The Indian Ocean it would be on a course to waypoint EGPOP.
    This would seem to be Johannesburg, RSA.
    Check the Singapore Airlines Jo’burg flightpath from Singapore.
    EGPOP would also be near the last ping’s arc.

    Since the kite is not down at Jo’burg then it must have come down beforehand.

    Just a thought.

  31. Alan Munn

    I’m wondering if some cargo onboard this flight could have become activated (perhaps unintentionally) and generated an extremely strong electromagnetic field. If so, this could have interfered with the communications and navigation systems on the plane. Perhaps the pilots tried repeatedly but were unable to make radio contact with Ho Chi Minh City ATC or even other aircraft in the vicinity on emergency frequency. Realising their dilema the pilots attempted to send out an emergency distress call but that was also unable to be transmitted effectively. The pilots may then have turned back towards Malaysia in the hope of re-establishing radio communication with Kuala Lumpur ATC but found they were also unable to make radio contact with Kuala Lumpur ATC. At night and having lost all radio contact with ground the pilots would have been able to keep flying, but would be unable to land or even to communicate their difficulties to the ground. Perhaps the climb of MH370 to above the recommended cruising altitute was on purpose to avoid potential collision between MH370 and other aircraft at night when flying back unannounced over busy airspace (no other planes except military would be at that altitude). Perhaps with the loss of radio communication also came loss of satellite navigation data and the pilots ended up flying blind and became completely disoriented and lost. Other nagivational instruments like compass would also not work in the presence of a strong external electromagnetic field. The fact that radio communication between MH370 and ATC suffered from interference even prior to takeoff (garbled messages in transcript) plus the interference mentioned by the other Malaysia Airlines flight that tried to communicate with MH370 on emergency frequency are supportive of this possibility (plus lack of mobile phone communications by passengers).

  32. Alan Munn

    P.S. In this scenario ACARS and the transponders would all have stopped transmitting about the time voice contact was lost (and just before the plane turned back), but this would have been due to interference from the strong electro-magnetic field on board and not to any deliberate switching off or disabling of transponders or ACARS by the pilots. As far as the pilots would know the transponders and ACARS would still be fully operational. This would of course also explain the failure of multiple fully independent backup systems for transponders and ACARS (as they all presumably rely on radio transmission).

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