Last month's midair collision near Washington D.C. killed 67 people aboard a passenger plane and Black Hawk helicopter. The NTSB says an instrument for determining altitude in the helicopter may have been inaccurate and the pilots may not have heard some calls from the control tower. More local videos here: https://youtube.com/@9news Subscribe to NEXT: https://youtube.com/@Nexton9NEWS Stay connected: 9NEWS Website: https://www.9news.com/ Facebook: https://www.facebook.com/ilike9news Twitter: https://twitter.com/9NEWS Instagram: https://www.instagram.com/9newsdenver/ Download the 9NEWS App: https://www.9news.com/appredirect/ Sign up for the 9NEWSLETTER: https://www.9news.com/email 9NEWS (KUSA) is located in Denver, Colorado.