Pre impact impact point flashes/explosions

[SHERITON HOTEL]

Has it been proved that the flashes/explosions visible in daylight at both twin tower impact points 9/11 were pre or post impact and have their causes been explained? Dave Von Kleist seemed pretty emphatic that they were pre-impact in his DVD/video 'In Plane Sight'.

[SHERITON HOTEL]

BUMP! I found a very good picture of the pre impact flash on the south tower on the web but now can't find the url. It clearly showed the impact point flash to be PRE impact but also showed the entire impact floor(60th?) blowing out on the south tower side counterclockwise side from impact side, if I've explained that clearly enough. Caveat that these things of course can be doctored.