Everyone aboard the helicopter and jet — flying from Wichita, Kansas — died when the two aircrafts collided and plummeted into the icy Potomac River. There wasn’t one single cause for the crash, according to testimony from National Transportation Safety Board investigators on Tuesday during an hourslong hearing. Some were escorted out, including two in tears, as they saw an animation recreating some of the final moments of their loved ones’ lives. Chief among them is a bill that would require aircraft to have advanced locator systems to help prevent collisions, which NTSB has recommended for years. “You had choices, and you chose to pay it forward.”Many families on Wednesday doubled down on the need for reforms.