The points raised by RKOwens in his video are akin to points raised by RepresentativePress.org in their article "WTC Pre-Collapse Bowing Debunks 9/11 'Controlled Demolition' Theory."
In the case of the North Tower we are told that "police chopper pilots reported seeing the warning signs - an inward bowing of the building facade - at least eight minutes before it collapsed," with one of the pilots repordedly stating, "it's not going to take long before the north tower comes down,'' 20 minutes before it collapsed.
It might be argued that since the police chopper pilot had a better view and saw the buckling of the perimeter columns that he was able to make a more unique and accurate prediction of the situation, however, he made his statement about collapse at 10:06 a.m. and his statement about buckling at 10:21 a.m. So, whatever "telltale signs" he may of seen at 10:06 a.m., it wasn't yet the buckling of any columns, which after all is the crux of this argument.
In a post on 911blogger.com that asks for any refutation of the article on Representative Press many problems with the bowing scenario are pointed out, here are three very good ones:
1) It is only an initial event, and does not provide any explanation for the global collapse events.The following is an except from the essay "A Hypothetical Blasting Scenario - A Plausible Theory Explaining the Controlled Demolition of the Twin Towers Using Aluminothermic Incendiaries and Explosives with Wireless Ignition Means.":
2) Its cause is based purely on speculation. The bowing may have occurred, but there is no evidence that supports that fire alone could have caused this, let alone after only a few minutes of fire.
3) If this was so obvious, why wasn't it the FIRST theory of collapse and not the THIRD theory of collapse?
Stage 1: Thermate Melts and Corrodes Core Steelwork
During Stage 1, extending from up to 10 minutes before T-0, thermate coatings on key parts of the core structure steelwork are ignited via the wireless ignition control system. The two areas attacked are: the core columns on a few floors below the crash zone, just above where most of the columns transition from box columns to wide-flange beams; and the inner portions of the hat truss that connect it to the core.
The thermal/corrosive attack on these two portions of the structure leaves the entire block of the core structure above the upper mechanical equipment floor "floating," with no major steel members to transfer its gravity loads to the lower portion of the core or to the perimeter walls: it is now supported by the web-trussed floor diaphragms. The upper core block now exerts massive inward forces on the perimeter walls due to the high degree of leverage involved in the translation of the core block's gravity loads into pulling on the perimeter walls. It is these forces that produce the inward bowing of portions of perimeter walls that NIST claims are due merely to the sagging of floor diaphragms still supported by the core.