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Old 25th Jun 2002, 13:00
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FailedTesting
 
Join Date: Jun 2002
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Red face 3d spatial testing Failure

I had just sat a military flight aptitude test and failed the 3d spatial testing module.

The reasons I failed are below and begin with my understanding and reasoning.

My main concern is the statement "RELATIVE TO THE PILOT"


First of all, in a 3 dimensional environment, there are 3 axis, commonly referred to X,Y and Z and can only have 1 reference point (0,0,0) the 3d graph.

Now each of these axis has a positive and negative component.

Relative to a human, If a human starts at the centre (ie x,y and z all = 0) and moves to a point where x = -1 y = 0 and z = 0 then relative to his starting position he has moved left.

By the same reasoning the following points are such
1,0,0 = right and 0,1,0 = up and 0,0,1 = forward

For the purpose of this all we are interested in is they y-axis.

Putting this into flight terms, and to be relative to the pilot, to achieve a point where y=1 the pilot pulls back on the stick. The 3d graph (ie x.y and z) is always the same way around relative to the pilot.


If a pilot is flying normally straight and level, at an altitude of 1000, ie y = 1000(which is relative to the environment) and wishes to be at an altitude of 2000 ie y = 2000(relative to the environment) he pulls back on the stick (Towards the pilot relative to the pilot).

The reason both y components are relative to the environment and not the pilot is because they are measured from environments 3d graph (gravity) and not the pilot’s. Unfortunately they both have the same values at this point.

To put this is a pilot’s perspective, or relative to the pilot, if the pilot is between the earth and the moon, and wishes to increase y by the same value he would pull the stick towards the body. (If the resulting movement was the same)

Here is where it gets tricky

Now to explain the ambiguity is that if the human is upside down, than relative to that person, the y-axis is also upside down, or changed by 180 degrees.

Now we have two 3d graphs, one relative to the pilot, which is 180 degrees different from that that is measured by the environment he is in, in this case gravity. Another way to explain it is that if we have 1 plane at 1000ft asl heading east straight and level on the equator, and another plane on the other side of the world in the same position and heading, in the 3d environment which is NOT relating to gravity they are in fact heading in opposite directions, and in two different positions on the 3d graph. If both planes gain altitude, in 3d space they are going in different directions again, or you might say they are getting further away from each other.

Now in the test it states that all movements are relative to the pilot, which is an incorrect statement.

Upon reflection, I'm sure they even stated that up meant gaining altitude, however I might be wrong, which is the opposite of "in relation to the pilot and adds to the ambiguity.

In short what I have tried to explain that is up in RELATION TO THE PILOT in 3d space, is always stick back towards the body, however up in RELATION TO THE ENVIRONMENT could be forward stick away from the body, if the plane is upside down.

I know now that the testing questions are wrong, or more importantly worded wrongly, and may I say what a disappointment that is. I now know, after failing how to answer the questions they way the military want.

All I can say is RELATIVE TO THE PILOT MY A##

Anyways, on another point, all this testing was done on a computer.
Having a fixed wing and helicopters licence for nearly ten years, and with 5 years in the computer industry experience, I am bewildered why these spatial tests are still in 2d, I mean you have the ability to have 3d imaging there, why not use it, but that may be another story?

Waiting for 12 months to pass........................
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