A National Transportation Safety Board report on the 2016 hot air balloon crash that killed all 16 people aboard finds that the pilot's "pattern of poor decision-making" was to blame. But the safety board also reserves some culpability for an FAA policy that exempts commercial balloon operators from needing medical certification."The pilot's poor decisions were his and his alone," said NTSB Chairman Robert Sumwalt during the board's meeting on Tuesday. "But other decisions within government, dating back decades, enabled his poor decision to fly with impairing medical conditions, while using medications that should have grounded him."That pilot was Alfred "Skip" Nichols, 49, the owner of Heart of Texas Balloon Rides. He launched the balloon just before 7 a.m. on July 30, 2016. The report found that Nichols had checked the weather an hour and 50 minutes before launch, but did not check again as fog developed and conditions deteriorated.The report outlines mistakes Nichols made at every turn that morning in central Texas: the decision to launch, to not land the balloon when he had good opportunities to do so, and to then climb above the clouds. When he finally made the decision to land, his visibility was poor. On its descent, the balloon struck power lines, killing Nichols and all 15 passengers."The power lines have been there for years — they're like 15 stories tall," NPR's John Burnett reported last year. "And the pilot lived about 10 miles away .... he knew the route."NTSB medical officer Dr. Nicholas Webster said Tuesday that Nichols was probably impaired by Valium, oxycodone, and enough Benadryl to mimic the blood-alcohol level of a drunken driver, the Associated Press reported.The safety board found that Nichols' ability to make safe decisions was likely affected by depression, attention deficit hyperactivity disorder, and "the combined effects of multiple central nervous system-impairing drugs."It also pointed to the FAA's exemption of commercial balloon pilots from medical certification requirements as problematic, and recommended the FAA remove it. That exemption "eliminated the potential opportunity" for an aviation medical examiner to identify Nichols' medical conditions and medications, or make the FAA aware of Nichols' history of drug- and alcohol-related offenses.The FAA has been pressured by the NTSB since at least 2014 to strengthen its balloon oversight.As NPR's Merrit Kennedy previously reported,