NTSB Chairman Deborah A. P. Hersman testified  on the status of the ongoing investigation into the mid-air collision over the Hudson River. The collision occurred on August 8 between a helicopter and an airplane.  All 9 persons on board both aircraft were killed.  Chairman Hersman provided an overview of the ongoing investigation based on facts that have been identified to date. The testimony did not provide any analysis or conclusions on what may have caused the accident.