US investigators are saying that lost Malaysia Air Flight 370 may have flown an additional four hours after its last confirmed location, according to a story in the Wall Street Journal.

The information is based on data sent to Boeing by the plane’s engines.

UPDATE: CNN reported at 3:06PM Eastern on 3/13/14 that the Malaysians may in fact have additional data points suggesting the plane WAS in the air 4 to 5 hours (this may or may not confirm the earlier report from the WSJ – it’s not clear if this is the same data, or something different). CNN got this information from the Obama administration. If the plane turned around, and headed towards the Indian Ocean, if you flew four to five hours you’d reach the huge US naval base at Diego Garcia once you traveled a little over 2,000 miles. Diego Garcia is a rich target.

And let me just add, I’ve been asking for days why everyone just assumed the plane went down and didn’t continue flying.

Now, the plane is a Boeing 777-200ER. According to Boeing, that plane has a cruising speed of .84 Mach at 35,000 feet.

At 35,000 feet, Mach 1 is 660.7mph.

Assuming that’s the definition of Mach 1 they’re using, that’s a cruising speed of around 554mph. Wikipedia seems to back that up, they say 560mph is the cruising speed at 35,000 feet of the 777.

But, Wikipedia notes the *maximum* speed is 590mph. So that means it may have traveled an additional 2,240 miles at cruising speed, or an additional 2,360 miles at maximum speed.

(Of course, that’s assuming the plane was at 35,000 feet. At lower elevations, Mach 1 is faster. At ground level, for example, .84 Mach would be 639mph – making the cruising speed distance 2,557 miles.)

But let’s assume around 2,250 miles traveled from the last location plotted, which is the x in the center of the map below.

That means the red circle on the map below is the distance the plane could have traveled if it traveled 2,250 miles. If it traveled more like 2,500 miles, it would extend the circle out a bit – if you look at India, for example, the circle would extend out to New Delhi. It’s not a great difference.

But that’s a heck of a lot of area to search. And it again raises the question of whether the plane was hijacked and landed somewhere. Why else would it stay aloft for four hours, not contacting anyone, and not trying to land. Unless the equipment was so damaged, the plane just flew on and on trying to identity some landmarks in an effort to land. And failed.

In fact, that map matches closely to the map I made the other day, showing the distance to Beijing, the original destination of the plane, and then drawing a circle based on it.

And here’s the map of Diego Garcia’s location side-by-side with the maximum range of the plane at cruising altitude (assuming the usual cruising speed):