Hi all, long time lurker, first time poster. I've been looking closely at the two Inmarsat possible flight tracks, the 400 knot and 450 knot versions. IMO, the 450 knot track is not a great circle track; it is evidently a constant (true) heading flight track of about 187°. This is consistent with MH370 passing it's last way point, and continuing on autopilot on constant true heading. It requires active navigation, and is consistent with someone setting the controls for the heart of the Indian Ocean.
Note that neither track is consistent with a magnetic heading. As stated, the 450 knot track is a constant true heading. The 400 knot track is curved, but evidently, it is not following a magnetic heading: it crosses the equator at 93.5°E with a true heading of about 180°. There, the magnetic declination is 1.6°W; since west is best, you add the variation to get the magnetic heading, that is 181.6° in this case. However, at 30°S, 100°E, the declination is 9.5°W, with a true heading of 163°, giving a magnetic heading of 172.5°. This is a 9 degree difference from the magnetic heading at the equator. Therefore, the 400 knot flight path most likely does not represent a constant magnetic heading course.
Which leads to my theory that the aircraft might have been under no active navigational control at all....
Here is my evidence: the final heading of the 400 knot flight track at 30°S, 100°E, with a true heading of 163° is just about what you would expect if the plane was under the influence of the Coriolis effect. I did a simulation of an object heading due south at the equator until it reached 30°S. The heading I calculated is 163° (See attached chart).
I overlayed the Inmarsat flight tracks on my Google Earth to show the difference. The orange track doesn't take into account any crosswinds, and as you can see, it ends up at the 30th parallel about 3° east of the 400 knot Inmarsat flight track. However, an aircraft proceeding south from the equator in the Indian ocean can expect to encounter stiff westerly winds that would tend to push the aircraft to the east. So I reran the simulation, adding a stiff crosswind of 110 km/hr from 10°S to 35°S. As you can see, it covers the 400 knot flight track just about perfectly.
The theory is that the pilots were trying to turn the a/c around but became incapacitated somehow while the a/c was still under manual control. In that case, the autopilot would be off, but the autotrim
system would still be operational, and would keep the airplane flying straight. The main reason for the autotrim is to reduce the stick loads felt by the pilots when the a/c is under manual control. Thus, if a pilot takes his hands off the controls, the aircraft will merely continue to fly straight and level. With no other control beyond the autotrim, the only forces that would affect the airplane's trajectory would be the wind and the Coriolis effect, both of which would have the effect of pushing the a/c to the east.
Yes, I said the autotrim would keep the aircraft flying straight if the pilots released the controls. But, as you can see, the flight track appears to be curved. That's what the Coriolis effect does. It's like if you launched a ballistic missile due south from the equator. It would describe a ground track that curved to the left. Thus, the 400 knot Inmarsat track perfectly describes what a "zombie" plane flight path would look like.
Assuming, the above scenario is possible, the question then becomes whether it is plausible that a radical democrat and a guy about to get married would be capable of pulling off this stunt. If not, we are definitely looking in the wrong place....
1. Does anyone here have actual experience using airliner autotrim systems?
2. If so, is the above scenario at all plausible given the autotrim systems used in today's airliners?!?