Derivation of the airplane speed at the September 11 attacksjwr47

There is a lot of conspiracy theories in the September 11 attacks at the WTC Towers in New York.Therefore I decided to do my own calculations from my own observance.

At 9:03 a.m., another five hijackers crashed United Airlines Flight 175 into the southern facade ofthe South Tower (2 WTC)1.

Officially the flight involved a Boeing 767-200, whose speed by radar registrations had beenspecified as 944 km/h at low altitudes.

I however decided to derive the speed from my own calculations which depended on the availableYouTube videos. My calculated speed (684 km/h) is considerably (27,5%) lower than 944 km/h asit has been derived from radar monitoring2. At 1000 feet the max operating speed is claimed to be is360 knots3 (666km/hour). And according to my (rather inaccurate) calculations this speed would bearound the allowable limit for this type of airplane.

I didn't really question the problems of molten steel and iron in the remains of the buildings as thecrashing buildings must have been sliding along metallic pillars and had to produce large amount offriction energy. These friction temperatures must have produced very high temperatures causingmelting processes.

The molten materials dropping from the windows may have been lead, which may have been usedfor thermopane windows which is molten at rather low temperatures...

Flight recordings

The airplane may be traced as a small blip at the top right side of the images in the Youtube videolabeled New 911 Footage 4. Although there is a better video with higher resolution I preferred thisone, which has not been edited during the flight episode.

I reconstructed the 11 seconds long downward path in sequential image by image patterns asfollows:

• 2:14 – 1st image of the attacking plane at the top right side of the photograph• 2:15 – 2nd image of the attacking plane• 2:16 – 3rd image – the attacking airplane is hitting the upper smog layer• 2:17 – 4th image – the attacking airplane is crossing the horizon's line• 2:19 – 5th image - airplane is crossing upper building at the other side of the river - • 2:20 – no image – the airplane is invisible in the smog• 2:21 – 6th image - airplane crosses the upper corner of the burning North Tower (1 WTC)• 2:22 – no image – the airplane is invisible behind the towers• 2:23 – no image – the airplane is invisible behind the towers• 2:24 – no image – the airplane is invisible behind the towers• 2:25 - First explosion marker at the South Tower (2 WTC)

In 11 seconds the airplane reaches the South Tower (2 WTC) and reveals the explosion.

1 Events 2 #4 (permalink) to Boeing 767 Max speed at sea level? 3 Boeing 767 Max speed at sea level? 4 New 911 Footage -- There Is No Plane - From Another Helicopter

Sinking movement (78.3 km/hour)

In 4 seconds the airplane sinks approximately 87m from 416m to 329m from the top right of thenorth tower to the impact point. Therefore the sinking speed is approximately 21.8m / second or78.3 km/hour.

Extrapolating linear movements the first image of the film is 21.8 x 11 = 240m higher than theimpact location (329m) at the South Tower. The first image therefore should be located at analtitude of approximately 329 + 240 = 569m.

Lateral movement (136.8 km/hour).

From A typical floor layout and elevator arrangement of the WTC towers we may read the towerwidth W = 208 feet, or approximately 70m.

The lateral distance at the position of the attacking airplane at the first image is approximately 6W =6 x 70m = 420m away from the impact location at the South Tower (2 WTC). The lateral movementof the airplane is approximately 420/11 = 38m/second or 136.8 km/hour.

In the (invisible – behind the towers) end phase the lateral movement of 100m is being covered in 4seconds, at a speed of 25m/s or 90km/hour. This slowdown is caused by corrections of the course.

Forward movement (684 km/hour)

The impact angle of the airplane at the south tower is approximately 78° for which the cosine (78°)~ 0.21. Therefore the forward speed should be around 5 times higher than the lateral speed(38m/second).

→ The forward speed should be around 5 x 38m/second = 190 m/s or 684 km/hour, which doesnot include the (neglected) component of the sinking speed.

My calculated speed (684 km/h) is considerably (27,5%) lower than 944 km/h as it has beenderived from radar monitoring5. At 1000 feet the max operating speed is claimed to be is 360 knots6

(666km/hour). And according to my (rather inaccurate) calculations this speed would be around theallowable limit for this type of airplane.

5 #4 (permalink) to Boeing 767 Max speed at sea level? 6 Boeing 767 Max speed at sea level?

Detailed tracing events

In this case the distance of the airplane to the towers at the first image should have beenapproximately 190 x 11 = 2090m . Each second the distance is reduced by 190 meters.

I reconstructed a table with these distances as follows

• 2:14 – 1st image of the attacking plane at the top right side of the photograph – the distance to the towers now is approximately 11 x 190 = 2090m. The airplane may have been 569m above sea level over the statue of liberty, which is approximately located at a distance of 2000 m from the towers. The size of the blip may be comparable to the size of liberty's head.

• 2:15 – 2nd image of the attacking plane• 2:16 – 3rd image – the attacking airplane is hitting the upper smog layer• 2:17 – 4th image – the attacking airplane is crossing the horizon's line• 2:19 – 5th image - airplane is crossing upper building at the other side of the river - • 2:20 – no image – the airplane is invisible in the smog• 2:21 – 6th image - airplane crosses the upper corner of the burning North Tower (1 WTC) –

the distance to the impact zone now is approximately 4 x 190 = 760m• 2:22 – no image – the airplane is invisible behind the towers• 2:23 – no image – the airplane is invisible behind the towers• 2:24 – no image – the airplane is invisible behind the towers• 2:25 - First explosion marker at the South Tower (2 WTC)

At 2:21 (the 6th image) the airplane still is only a blip and in this film its size cannot be identified.The distance to the towers now is approximately 4 x 190 = 760m.

Second source of the approaching airplane.

A second source is 9 11 Actual crash footage of 2nd plane, which provides a better resolution and isfilming the objects at approximately the same angles.

The attacking airplane comes in (at the upper right corner) at 1:11 minutes at the video-counter andreaches the upper right corner of the North Tower at 1.17 minutes. The approaching time in thisvideo is 6 seconds and more or less matches the approaching time (7 seconds) in New 911 Footagefrom 2:14 up to 2:21.

The the video replays the approaching airplane at 1.21 up to 1:43 at a reduced speed. The blip isabout the size of one tenth (7m) of the width of the North Tower (70m). At that position (1:43minutes) the airplane must have been at a distance of 760m from the towers.

At 3:53 the approaching plane may be observed more clearly at another angle. The airplane is in ahorizontal position and the size more or less matches the 7m diameter of the fuselage we haveidentified at the image of 1:43 minutes).

Illustration 1: Size of the approaching airplane

Illustration 2: Airplane approaching at 3:43 minutes

Angle of the airplane's course

The impact angle of the airplane at the south tower is approximately 78°. Therefore the forwardspeed should be around 5 times higher than the lateral speed.

Officially by radar recorded air speed7

From Pilots for 9/11 Truth Website the speed data from ASR (Radar) Data via the NTSB are:

• American 11: - (WTC North Tower) 796 km/h (430Kts) • United 175: - (WTC South Tower) 944 km/h (510Kts)• B757 - American 77: (Pentagon) 462kts

7 #4 (permalink) to Boeing 767 Max speed at sea level?

Illustration 3: World Trade Center 9-11 Attacks Illustration with Bird's-eyeImpact Locations – public domain

Deriving the height of the impact locations

The WTC towers are 416m high8. The first plane hits the North Tower at 0.97H (362m) and thesecond plane hits the South Tower at 0.79H = 329m.

8

Illustration 4: World Trade Center 9-11 Att (public domain)

Sequential images of the attacking airplane

Illustration 5: 2:14 - first image of the attacking plane at the top right side of the photograph

Illustration 6: 2:15 – second image of the attacking plane

Illustration 7: 2:16 - attacking airplane is hitting the upper smog layer

Illustration 8: 2:18 Horizon - attacking airplane is crossing the horizon's line

Illustration 9: 2:19 - attacking airplane is crossing the upper building at the other side of the river

Illustration 10 2:21 – attacking airplane crosses the upper corner of the burning North Tower

Illustration 11: 2:25 First explosion marker at the left tower

Other notes to the Twin Towers at 9/11

I didn't really question the problems of molten steel and iron in the remains of the buildings as thecrashing buildings must have been sliding along metallic pillars and had to produce large amount offriction energy. These friction temperatures must have produced very high temperatures causingmelting processes.

The molten materials dropping from the windows may have been lead, which may have been usedfor thermopane windows which is molten at rather low temperatures...

The melting point of steel (1)

I found some WTC-specifications in Twin Towers New York, including the melting point of steel.

“The steel used in the Twin Towers was of low carbon alloy of iron and extensively (mainlyiron). Low alloy steel was used because the beams can be thinner without decreasing itsstrength and can thereby obtain more useful area. The melting point of this steel is around700 th”

The melting point of steel (2)

Addendum (8/26/2011): I answered this question many years ago and it has been referencedin many different web sites and reports. There has been one misrepresentation that has comefrom that. Many sites refer to the difference in the melting point of steel and the burningtemperature of jet fuel as proof that the World Trade Center could not have fallen from theaircraft fires. What those authors fail to note is that while steel melts at around 1,370°C(2500°F) it begins to lose its strength at a much lower temperature. The steel structure of theWorld Trade Center would not have to melt in order for the buildings to lose their structuralintegrity. Steel can be soft at 538°C (1,000°F) well below the burning temperature of jetfuel. 9

9 Questions and Answers - What's the melting point of steel?