December 28, 2009
Two thoughts on the Christmas bombing attempt
Two things came to me today.
Why blow up an airplane on landing?
#1) - Landing and taking off are the two times when the airframe is under maximum stress. If you wanted to ensure the biggest bang for the buck, you would detonate at these times otherwise, you might just blow a big hole in the side and do nothing else.
Why blow up an airplane on landing?
#2) -
Newton's First Law and basic airplane operation.
#2a) - An object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force. Even if the object becomes a loose collection of formerly airplane-shaped objects, it is still subject to the First Law and will continue on its flightpath.
#2b) - when taking off, you want the wind at your back so as to gain from the speed of the wind and to need less runway. When landing, you want to land into the wind so it slows you down (relative to the ground surface) and you need less runway.
The upshot is that you have a bunch of planes stacked up at the windy end of the runway, waiting to take off in between airplanes coming in to land.
If Abdulmutallab had been successful and if Flight 253 did explode, the debris would have flown toward the airplanes sitting there waiting to take off.
This is war and Abdulmutallab needs to be pumped for whatever information he has and then be executed by a firing squad -- preferably with bullets dipped in pigs blood. The fact that he has a civil lawyer is a mockery of the Body of Laws this Nation was founded upon...
Posted by DaveH at December 28, 2009 8:54 PM
...second nit...
I cannot 100% vouch for the physics here, but my suspicions are that you get more bang for your buck at altitude.
It may give airframe stress at landing time, but at altitude you have a pressure vessel. Commercial jets are pressurized to somewhere equivalent to about 8000ft altitude. At altitudes above that the pressure differential should actually help rip the plane apart.
Plus the altitude is a sure weapon if the airframe does come apart. There have been some pretty remarkable crashes on landing that had relatively high survival rates. Survival from 35,000 feet is pretty much nil if the airframe fails.
I was a pilot...
One small nit to pick: You always take off into the wind (unless you're on a slope, then you take off downhill). Think about it. The wind is 20 mph. You need 70 mph to lift off. Standing still you have 20, you need only to accelerate another 50, and you're off.
Then during the climb-out the headwind gives you an effective higher angle of climb, too, as your groundspeed is reduced by the headwind component while your rate of climb does not change, being X feet per minute, lower groundspeed equals steeper angle.
Planes landing and planes taking off all show up at the same end of the runway although most major airports have parallel runways, often landing on one and taking off on the other.
MC