Backward vector is fixed at X=-1, Y=0, Z=0

[snook91 (snook9)]

Here you will find some print of the Forward Vector, when I press S key (backward key) (the axis value is -1 in that case).
X=0.998 Y=0.065 Z=0.000
X=1.000 Y=-0.008 Z=0.000
X=0.998 Y=0.065 Z=0.000
X=1.000 Y=-0.008 Z=0.000
X=0.998 Y=0.065 Z=0.000
X=1.000 Y=-0.008 Z=0.000
X=0.998 Y=0.065 Z=0.000
X=1.000 Y=-0.008 Z=0.000
X=0.998 Y=0.065 Z=0.000