Complex sentence: As well, the flight crew was unaware that pry-bars were part of the standard rescue gear aboard the aircraft, and thus were unable to assist at least six individuals who became trapped inside the aircraft after the crash until the rescuers had arrived.
Split into simpler sentences: As well, the flight crew was unaware that pry-bars were part of the standard rescue gear aboard the aircraft. Thus they were unable to assist at least six individuals trapped inside the aircraft by the crash, until rescuers had arrived.