One of our planes is missing.

That’s basically all we know for certain right now, but more than a week after losing contact with flight MH370, there are a lot of other suggestive bits of information. Unfortunately, a lot of it is, as usual, being reported by news readers who barely understand that you don’t want to keep the pointy end aimed at the ground for an extended time. Here’s some things we do know now.

The first indication of trouble was when the transponder stopped responding to radar. This is the point where newspeople are saying it “dropped off the radar,” so let’s get a little clarity here to start. A transponder is a device that transmits a response. In a plane, the transponder is receiving an interrogation and responding by transmitting a burst of data. The problem with “dropped off the radar” from the start is that all it indicated was that the transponder stopped transponding. Imagine for a second that you’re trying to find someone in the dark. If you have a flashlight, you can use the flashlight, and hopefully see them in the reflected light. This, in radar, is called a primary radar response. It’s a lot easier, though, if the person you’re looking for has a flashlight too, and can turn it on and wave back at you with it. This is what a transponder does, and it’s the major part of what’s called secondary surveillance radar.

When MH370 “dropped off the radar,” the transponder stopped responding. But transponders have an off switch. There are two independent transponders, so it isn’t probable just that it was just a transponder failure.

It didn’t disappear from primary radar, but primary radar is a lot harder to read. They now think that they might have tracked the plane as it turned back, did some vertical excursions, and headed off into the Indian Ocean.

Turning off the transponders didn’t stop all radio transmissions, however. There is an onboard flight telemetry system that kept transmitting for a long time, as much as seven hours. It’s very difficult to crash and have the telemetry transmissions keep going, so the combination is a pretty strong indication that the transponders turned off but the plane kept flying.

Unfortunately, Malaysia Airlines doesn’t pay for the service, so the only responses were pings saying “nothing to say.” But those pings are timestamped, and that means you can estimate the distance from the satellite to the aircraft by the time the signal arrives at the satellite. Now, PJ is ill-equipped to show a three-dimensional picture, so instead imagine a map. There’s one circle centered on the last known position, which is how far the plane could have flown in seven hours. There’s another circle centered on the satellite, which is all the places that are the estimated distance from the satellite. (Strictly, that’s the surface of a sphere, but we can discount the parts of the sphere that are underground.)

This, by the way, is how GPS works: your GPS receives very accurate time signals from several satellites and computes where all the circles intersect; that’s where you are.

The result is something that looks like this:

map-malaysia

That line is actually fuzzy, because that distance to the satellite isn’t known as accurately as say a GPS signal would be, but the last transmission does mean the plane was somewhere near that circle when it stopped sending telemetry.

So, now is the part of Malay Mystery in which we speculate.

As far as I can see, there are about four possible explanations.

First, something happened that incapacitated the pilots, and the plane flew on autopilot until it ran out of fuel. This has happened before, in the crash that killed Payne Stewart, although not on a commercial jetliner. The way it apparently happened in the Payne Stewart accident was decompression.

This is fairly unlikely just as an accident on a commercial jet because the pilots have oxygen masks immediately available — but more speculation is coming.

There is a story today that there was a “supergrass” — which is Brit for a highly-placed informant apparently — who described a plot for four or five people to take over a plane by blowing open the cabin door with a shoe bomb. So, let’s imagine that this is what happened. The door blows open, and cabin pressure is lost. The pilots, being a little bit distracted and busy, don’t get their masks on. Everyone passes out — and shortly dies at that altitude. The bodies rattling around in the cockpit cause the plane to make some uncontrolled maneuvers until the autopilot finally stabilizes. I explain the second possibility on the next page.

Second, someone who knew the plane hijacked or diverted the flight. Could be a pilot, could be someone else. (In another piece today, Rick Moran speculates about the captain. I don’t think this seems very likely — guys my age aren’t the most common suicide drivers/bombers/attackers. This guy had a flight simulator setup that he actually bragged about on YouTube, but them a lot of my pilot friends do. My dad had one after he could no longer actually fly. All it’s evidence of is that ther Malaysian captain was an airplane nut, which is what you’d expect of someone with 18,000 hours.)

Now, this hypothetical hijacker basically could have one of several motivations. So possibility 2a is that they wanted to crash the plane. It seems to me that if this is what you want, you don’t fly all day before you do it, so I think this seems unlikely.

Possibility 2b is that the hijackers want the plane itself. In this option they fly somewhere equipped to let a 777 land and take off again. To do that, you need a fairly long runway, 7000 feet or more.

Possibility 2c is that they wanted the passengers as hostages, or — putting on our fiction-writing hats — they want someone or something on the plane and don’t care about the (other) passengers. In that case, they only have to get somewhere where they can land the plane. It turns out that as long as you don’t care about taking off again, that can be done in around 3000 feet of runway.

Possibility 2b — that they wanted the plane and landed — is an unpleasant one. As several people have pointed out, a 777 and a dirty bomb or a North Korean wet-firecracker atomic bomb could make a right mess. But you can bet that there is satellite imagery being taken and analyzed with some urgency — I suspect that an intact plane would have been spotted. (But maybe not, see below.)

So that leads us to possibility 2c, which would make a good thriller sort of movie, which I’ll explain on the next page.
The story opens with the plot to take the plane, and the precipitating event — what Syd Field called “plot point 1″ — is when the hijackers take control. They’re now flying the plane, and they want to land successfully but don’t care about taking off again.

It turns out that arc includes a good bit of Xin Jiang province — which is where the Uyghurs live — as well as Kazakhstan, Kyrgyzstan and Pakistan. But to get to those places, you have to fly across a good bit of China.

So, there’s the flight, trying to tiptoe along the frontier to get to a -stan. No transponder, but they’re picked up by primary radar response from Chinese air defenses. CAPT Li, the officer on duty, calls COL Wang, the unit commander. “OMG there’s an unidentified” — transponder’s off, remember — “big plane crossing into our air space.”

In the U.S., we’d intercept and have a look. I’ve got no idea what the terms of engagement might be in the People’s Liberation Army Air Force, but I’m betting they are a little sensitive about unidentified aircraft coming in from the whole Vietnam/Myanmar/South China Sea area. It think it’s entirely possible that COL Wang on his own authority says “so shoot it down.” PLAAF intercepts it and shoots it down, leaving debris and bodies scattered over the terrain.

Then someone, maybe someone in Beijing, puts two and two together — possibly after someone has gotten to the debris field and found something that identifies the plane. Now what?

It’s going to be terribly embarrassing to admit to shooting down a hijacked passenger plane. It would cause everyone involved to “lose face” — and as horrible a cliché as that is, “losing face”, 丢脸 diu4 lian3, “humiliation,” is a very bad thing in China.

Let’s recall that not too long after the disappearance, “unauthorized” satellite pictures were released showing what was said to be debris. That sent searchers off for at least a half day on what turned out to be a wild goose chase.

In my thriller-movie plot, that time would have been spent sending a whole division of the People’s Liberation Army to the crash site, and policing up the debris field.

Now, I don’t know how probable this is. I talked to some of my friends in the intelligence community, and one of them who is more or less a China specialist suggested that if the Chinese had downed the plane, they would instead be exhibiting a lot of belligerence about it, and pointing to their exclusion zones in the South China Sea, saying “don’t mess with us.” Another friend with more of an interest in Central Asia points out that as long as you could expect or extort co-operation from airport personnel, the obvious place to hide a 777 would be an airport. Land, pull into a hangear, easy-peasy.

So this may be just the fiction-writing part of my brain putting out a plot.

It’s sure an interesting plot, however.