It’s been more than six months since MH370 vanished, and in some ways we know no more now than we did in late March: no new clues have emerged, no more data has been discovered. In a sense, though, we have come a very long way. For one thing, we now understand how many of the “breaking news” developments that occurred in the early days were actually untrue. (There were no wild altitude swings, no “fighter plane-like” maneuvering, and probably no cell-tower connection with the first officer’s phone.) What’s more, thanks no doubt to a drumbeat of public pressure, the authorities have released a tremendous amount of data and provided useful explanations of how that data is being interpreted. And finally, a spontaneous collaboration between technical experts and enthusiasts around the world has provided a trove of insight into avionics, aerodynamics, satellite communications, and a whole host of other topics that collectively shed light on what might and what might not have taken place on the night of March 7/8, 2014.
While a great deal of information has become available, it has not always been easy to find; much of it, for instance, has been exchanged via email chains and Dropbox accounts. For my part, I often find myself rummaging through emails and folders looking for information that I’m pretty sure I’ve seen, but can’t remember where. So what I’d like to do with this post is try to aggregate some of the most basic facts — a set of canonical values, if you will, of the basic data on MH370. Necessarily, some of this data comes with implicit assumptions attached, so as far as possible I’ll try to make these assumptions explicit.
Okay, on to the data. What we know now:
The bedrock data. In the wake of MH370’s data, there were numerous news reports concerning information leaked by anonymous sources from within the investigation and elsewhere that have subsequently been either disproven or inadequately verified. For the purposes of the present discussion, the following are considered the bedrock sources of information upon which our understanding of the incident can be built — the “Holy Trinity” of MH370 data:
- Up to 17:21: radio communications, ACARS, transponder, ADS-B
- 17:22-18:22: military radar track. This information is of uncertain provenance but has been endorsed by the governments of both Malaysia and Australia. Furthermore, it plausibly connects the prior and following data sets.
- 18:25-0:19: Inmarsat data, especially BFO and BTO values. There is some discussion as to how this data is best interpreted, but the numbers themselves are assumed to have been received and recorded by Inmarsat from MH370 via their 3F-1 satellite. The “ping rings” in particular are derived through relatively simple mathematics and should be regarded as established fact unless someone comes up with a specific mechanism by which some other result could be obtained.
Timeline. Courtesy of Richard Godfrey and Don Thompson, here is a basic timeline of MH370’s disappearance (all times UTC):
- 16:41:43 MH370 departs runway at KUL runway 32R
- 17:01:14 MH370 flight crew report top of climb at 35,000 feeet
- 17:07:48.907 Last acknowledged DATA-2 ACARS message sent from plane
- 17:19:29 Last radio voice transmission
- 17:21:04 Plane passes over IGARI waypoint
- 17:21:13 MH370 disappears from air traffic control (secondary) radar screens
- 18:22 Last primary radar fix
- 18:25:27 Inmarsat log-on request initiated by aircraft
- 0:19 Final transmission from aircraft to satellite
A more complete table of values, including the location of the plane at each point in time, can be found here, courtesy of the inimitable Paul Sladen. And Don Thompson has created an impressively detailed breakdown of the sequence of events, with a special focus on radio communications between the aircraft, ground, and satellite, here.
More stuff after the jump…