why there where no esplosion over the impact

l read that some people did not beleave the story of bomb explosing inside the WTC because there where no explosion above the impact zone... my explanation is that even if those plane would have hit many floor lower than they did , the impact and explosion that occur probably cut off all cable linking to any charges above the impact zone. and l even ask my self if those charges where not suppose to exploded in the same time as the impact of the plane so no whitness could have ear or talk about explosion. it could be the reason why some talk about a military helicopter that was up there just before it realy start to explose , maybe they had to pass by to activate manuelly whit a remote these charges. some one had to be close to activated these charges at the good time and select those charges above the impact to not explode.sorry for my english l'am doing my best

How would anyone know whether or not charges went off? There was a giant fireball, and concrete dust and aluminum cladding and etc. shot out everywhere from the impacted points. I'm not sure anyone would really notice, and it's not like you have to cut the same places again with cutter charges.