Direct Final Rule announced by NTSB narrows focus of notification requirement in 49 C.F.R. § 830.5(a)(10) concerning certain resolution advisories. After changes takes effect, operators will only be required to report ACAS resolution advisories issued when aircraft is being operated on instrument flight rules flight plan and compliance with advisory is necessary to avert substantial risk of collision between two or more aircraft. Public can comment by January 14, 2016.