A knowledgeable and long time student of the Lockerbie affair asked me this morning about the time-lapse between the “explosion” and the break-up of PA 103.
Here is the official plot of the debris (Figure B-4 of the AAIB Report). Allow me to explain these data as well as the black dots and the red and green lines which I have added .
The northern trail (red crosses) is mostly made of parts that belong to the back of the plane while the southern trail (green crosses) is essentially the front part of the plane. (The plane broke up at the rather infamous section 41.)
The black dots are the Radar return of the plane. Point A is the last “normal” return before break-up. I added the last three previous return.
Three seconds after the last (normal) return (point A), a loud noise is recorded. Knowing the speed and the trajectory of the plane, one can locate this event at point B.
Now, the AAIB uses a line going through the southern debris to estimate the position of the plane at the time of the break-up: Point C. The time between point B and C is about one second, two at most.
However, I want to point out the following fact.
The direction of the trails is given by the wind which was of course blowing in the same direction for both trails.
The direction of the northern trail is easily determined: 255°.
Now, if you draw a line going through the largest chunk of the green debris AND parallel to the northern trail, this line intercept the plane trajectory right at point B.
What does it mean? It means that it is entirely plausible that the plane broke up at the time the loud sound was recorded.
It is thus very likely that the only sound recorded is the sound of the break-up and no sound of the “explosion” was recorded.