Numbers May Tell Better Story

By Semperpapa

On 5 March 2010, an article was published by the BBC regarding the failed attempt to bring down Flight 253 over Detroit by Umar Farouk Abdulmutallab, the Nigerian terrorist better known as the “panties bomber”.
The report, part of a series the BBC is putting together on the subject of air travel safety, claims that a test performed indicates that even in the event that the attack would have succeeded, the damage to the plane would have been not severe enough to bring down the aircraft and that the crew would have been able to land safely.

The test was conducted by one Dr. John Wyatt, an international terrorism and explosive adviser to the United Nations. According to the article, the test was a controlled explosion of the same type and quantity of pentaerythritol (or PETN) explosive attached to the rear-end of a dummy.
The results were that the explosion would have not succeeded in perforating the skin of the aircraft and that the structural integrity would have been uncompromised allowing the crew to execute a safe landing. Most likely, the report concludes, the passenger next to the terrorist and the terrorist would have not survived and the smoke in the cabin would have been intense, while the passengers in proximity to the explosion could have suffered severe hearing damage.

Well so far so good.

But then the article says that the test was conducted on a 747 type aircraft and that is when my engineer’s alarm went off.
I am just a mechanical engineer, not a structural or aircraft engineer, but understand enough about the physics of things and my memory is not bad enough not to see a problem with the “experiment” parameters.

So the test was conducted on a Boeing 747, but the aircraft in question on Christmas Day was an Airbus 330. Even if it is not a clear case of apples and oranges, the difference in the two aircrafts is enough for me to discount the test results as pointless.

The major heartburn I have is the fact that a Boeing 747 is a much larger aircraft than the A330. Here are some comparisons:
Length: 76 m (747); 63 m (A330) that’s a difference of 13 m or approximately 40 feet.
Wing Span: 68 m (747); 60 m (A330) a difference of 8 m or approximately 25 feet.
Height: 19 m (747); 17 m (A330) or approximately 6 feet difference.

But probably the most telling difference is the weight of the aircrafts. The 747 could have a gross weight at takeoff of 442 tons (that’s approximately 975,000 lb) compared to the maximum take off weight for the A330 of 233 tons or about 47% less.

One does not need to be an aeronautical engineer, or even an engineer at all, to realize that the same quantity of a certain explosive would do a lot less damage to an object of such greater mass. And the experiment does not take into consideration the difference in dynamic loads that an airframe is under during flight, as the test was obviously conducted on the ground.

So the experiment conducted by Dr. Wyatt means absolutely nothing to me.
But the worst part of this whole thing is that the BBC is going to use this kind of creative science to tell an ignorant public that the action of Abdulmutallab was not that bad and that really the lives of the 289 people on that flight and of those on the ground weren’t really in danger.

What is the point of a pseudo-scientific experiment if the parameters used for it are flawed? Is it just another episode of the campaign of apology for Islamic terrorism that the BBC has been conducting?
Or maybe Dr. Wyatt is one of those scientists who also participated in “proving” Global Warming. The fact alone that he is an adviser for the United Nation should have sounded my alarm immediately.

Just my thoughts!