NCA ‘earn’ their stripes the same way a commission is earned in the RAF; through hard work and the ability to pass through the filters to the operational side of training. Ground trades also need to pass the same filters to get to SNCO however the holes START pretty big in their mesh and pretty much anyone with the right attitude can walk through them. As the screw tightens along the way the good guys pass through the ever-tighter scrutiny becoming SNCO’s as the less able falls away.