Currently on a B2 moving drills, if the pad is snow or ice covered, like more often than not this time of year, I always do the test at 70% first to make sure nothing untoward is going to happen, ie spin or slide off the pad before I advance fuel control to the flight gate. If it is all good I then perform the check at 100%. And I always double check collective lock before I hit the teat switch. Bit off thread but I also know of a company here in Canada a few years ago doing annual PPC;s. While doing autos when the pole was dropped it somehow managed to engage the lock. Boys didn;t realise until time to pull at bottom of auto, resulting in hard landing and tail boom laying on ground, luckily no casualties......
