September 11 attack. Was it a plane?

I was just fascinated by this video sent to me claiming that no plane was involved in the Twin Towers attack on Sept 11


Various arguments was given that it was not a plane which could smash thorough a building made of steel and concreate.

This fascinated me too, whether or not they were the two planes that brought down such massive and strong buildings as the Twin Towers as I sat on my hospital bed watching the video.

So I thought I should sit up and analyse the logical aspect of the controversy although I am not an expert on planes, buildings or on explosives.

First, I need to make a search to find out what was the maximum weight of a Boeing 767 with 51 passengers, 9 crew and 5 hijackers in one of the planes belonging to United Airlines on a flight from Logan Airport to Los Angeles that fatal morning.

I then searched to find the maximum load a Boeing 767 can carry, iincluding fuel, and found it was 179,000 kg.

Let us now assume this was the load including 65 people inside. Let us make a rough estimate for both planes to be roughly the same to make calculations easier. We need to assume both planes were roughly the same.

A search showed the US government calculation gave the first plane flying at 494 mph when it smashed into the first tower, and the second plane at 586 mph

But an analysis by MIT showed a slightly lower velocity.

Let us take the figures released by the US government.

United States uses the old Imperial standard of measurement instead of in the SI unit. So converting their speed, it was 220.84 meters per second for the first plane, and 261.97 m / s for the second one

Now let us look at the kinetic energy for both planes in flight that morning of Sept 11 at these speeds with a mass of 179,000 kg.

Using the equation E = 1/2 m v squared, where m = mass of the plane, and v = velocity; it turns out that first plane would have acquired a kinetic energy of 4,364,942,351 Jolues when it smashed into the first tower.

The second plane, released a power of 6,142,231,141Jolues when it slammed into the second tower.

Now the power of one metric ton of TNT is 4,184 million Joules.

This means the energy released by the first plane as it smashed into the 1st tower is equivalent to 1.04 metric tons of TNT, and the second plane with a slamming force of 1.47 metric tons of TNT

As last, this is as far I can go as I am not a structural engineer, especially one who need to specialize in building demolishing work using explosives. I am only a medical scientist and a clinician, not a structural engineer.

However, I thought to myself the fuselage and the wings to the best of my knowledge are made of either aluminium, or aluminium alloy, titanium, carbon composites such as graphite epoxy or carbon fibre reinforced polymer, all of which are much lighter and less dense than a tower made of steel and concrete.

As such I would have thought a plane travelling at that speed would have been smashed into smithereens outside the towers before it can even penetrate a tower of steel and concrete. But I admit I do not exactly know

Even if it could, I cannot tell how much TNT would be needed to smash it right through a building of concrete and steel. Would one ton of TNT be sufficient?

Even if the planes managed to smash into the towers and spill aviation fuel inside the burning of the fuel can be seen outside, and the fire can only spread upwards from the upper floors.

How could the fires burn downwards and weaken the entire structure from the bottom floor to cause the entire towers to collapse down to ground zero?

The fuel and fire cannot be burning from the bottom upwards since the planes hit the upper top floors, not from the bottom.

If this is not possible, then we need to know if it was an inside job using explosives inside the two towers rather than blown up from outside by the plhanes?

However, I am talking of the initial impact only which is the most important, but not the collapse of the entire towers from the heat of burning fuels

But if the planes managed to smash in and spill burning fuel inside. then it may explain why the towers collapsed after that which may suggest it was actually the planes, and not explosives within the building.

But as I said earlier we need to consider whether or not the temperature of burning aviation fuel was hot enough to melt steel and concrete, especially the steel structure are normally insulated by concrete outside which are poor conductors of heat

The melting point of steel is between 1,370 - 1500 deg C, but may be softened at around 538 deg C. The temperature of burning jet fuel in air is between 427 - 816 deg C.

However, the steel structures are normally embedded inside concrete which shields the steel from the burning jet fuel if there were. Hence the possibility that the steel were insulated by the concrete.

If the steel structures were all insulated embedded within concrete structures outside they would have been protected by the concrete walls.

The steel within may not even be able to able to reach a critical temperature for it to be soften,let alone melt. Of course I am not an expert on building structure and the effects of intense heat on them.So my argument is only theoretical. Only a real study or some experiments can answer that?


Then again why should the fire and weakening of the upper floors affect structures on the lower floors until both towers collapsed right down to ground level? I only asked myself this question after seeing the video sent to me by friends in the Whatsapp.

Since there are so many senior structural engineers in my Whatsapp group who sent me that video, I like them to take over from here after my argument given above.

I would be interested in their structural analysis since they told me the towers were not brought down by plane as I have all the while read

Thank you.

Lim jb