VICTORVILLE (AP) — Crews are using a pair of water-dropping helicopters in the fight against a Southern California desert wildfire that started as a controlled burn. San Bernardino County Fire spokeswoman Tracey Martinez said Wednesday that the 185-acre blaze is chewing through heavy growth in a Mojave riverbed that hasn’t burned for years. The fire, which is sending up thick plumes of black smoke, is 30 percent surrounded and all threat to homes has ended.