The investigation into one of the worst-ever hot air balloon crashes moves into a new phase next month, with an investigative hearing by the National Transportation Safety Board (NTSB).

The pilot and all 15 passengers aboard a hot air balloon died on July 30 of this year when the aircraft crashed into a field after striking high voltage power lines near Lockhart, Texas.

The hearing is scheduled for Dec. 9, 2016, from 9 a.m. to 4 p.m., in the NTSB Board Room and Conference Center, 420 10th Street SW, Washington, D.C., 20594.

The preliminary report for the investigation is available at http://go.usa.gov/xkuST and information about the NTSB’s investigation of the accident is available at http://go.usa.gov/x8362.

The NTSB conducts public investigative hearings to gather sworn testimony from witnesses and to allow public observation of the investigative process.