RR NDB
One need not be an expert. At impact, most of the a/c was in structural chaos, and there was no horizontal component after some milliseconds. The debris ended up tight and probably in some sort of teardrop shape, from above. After that which would sink, sank, what formed was a conga line of debris, subject to current alone, no wind, trajectory, nor "Heading". The debris field may have been 600 meters across, maybe not, but what is seen on the bottom is the "target" established upon sinking, subject to rate differences. The trajectory below the surface was down, probably to a precision of 99.9 per cent. Travelling two and one half miles vertically and 600 meters horizontally, if the debris field was as tight as 600 meters, that there was no dispersion is indicative of almost no current, for if there was, there would be a dispersion, heavy to light, etc. The debris field found on the seabed suggests not dispersion but coalescence. Here the "intact at impact" is reinforced, since to fall on to such a small target from 2.5 miles away means that most of the debris at least started its journey as a joined mass.
It may be a language thing, but I doubt it. An object in free fall has a Trajectory, not a heading.
Has one found the second, Starboard engine??