Any jump plane, or plane that is planning on opening the doors at anytime requires all on board to wear parachutes. All dropzone pilots wear super minimalist small backpack sized reserve chutes just because its required, would be terrifying to actually jump one of those. its very lucky no one was killed in that, especially the pilots, I read that the second plane got caught in the first plane's wash which is not necessarily human error but an obvious risk when flying in close proximity