This Korean Air 787-9 Dreamliner is seen taking off one Saturday afternoon from Paine Field on a production flight test. It was lightly loaded so it was off the ground pretty rapidly and was already cleaning up the gear as it came toward me. The wheels are braked before the gear comes up to stop them spinning before they enter the bay. This can result in a burst of brake dust that blows clear in the slipstream and the shadow of the brake dust showed up clearly. As they continued the climb out, they actually lowered the gear again. I think this was to cool the brakes given they had done a high-speed taxi run prior to the takeoff.