I think that refraction fields would come standard on the Sentinels as long as there's not an elite armsman who wants to carry the field instead.  (I'm going to rule that most walkers are piloted by armsmen wearing flak armor and refraction fields borrowed from reserve elites)<br/><br/>Piloting a walker is essentially similar to normal ground combat circumstances, except that the enemy has to make a called shot to target you (personally).  If they attack your walker, they roll an attack with a +10 bonus, and have to contend with your walker's 20 points of armor.  A walker is armed with an autocannon that has the following statistics:<br/><br/>Range: 300 meters    Rate of Fire: Single/3 Semi-Auto/5 Full-Auto    Damage: 4d10+5     Penetration: 4    Clip: 60    Reload Time: 2 full actions.<br/><br/>Since you don't have walker training, you suffer a -10 penalty on attacks with the autocannon (factoring in your MIU)  You can also dodge while piloting the walker, though dodging suffers a -10 penalty due to the walker's size (effectively negated by your MIU)<br/><br/>If you want to take advantage of the fact that the walker can move up to 45 kilometers per hour, you'll have to make piloting checks, which is the main circumstance in which you'll have to make tests