A Nonorthogonal System

A Nonorthogonal System
You're on a helicopter tour of the Grand Canyon when the pilot, who made
the obvious mistake of eating fish for lunch, suddenly groans and faints.
Fortunately, he left you hovering 100 feet above the ground. You rationalize
that the collective pitch lever[2] controls overall lift, so lowering it slightly
will start a gentle descent to the ground. However, when you try it, you
discover that life isn't that simple. The helicopter's nose drops, and you
start to spiral down to the left. Suddenly you discover that you're flying a
system where every control input has secondary effects. Lower the
left-hand lever and you need to add compensating backward movement to
the right-hand stick and push the right pedal. But then each of these
changes affects all of the other controls again. Suddenly you're juggling an
unbelievably complex system, where every change impacts all the other
inputs. Your workload is phenomenal: your hands and feet are constantly
moving, trying to balance all the interacting forces.
[2] Helicopters have four basic controls. The cyclic is the stick you hold in your right hand. Move it, and the helicopter
moves in the corresponding direction. Your left hand holds the collective pitch lever. Pull up on this and you increase the
pitch on all the blades, generating lift. At the end of the pitch lever is the throttle. Finally you have two foot pedals, which
vary the amount of tail rotor thrust and so help turn the helicopter.
Helicopter controls are decidedly not orthogonal.