chris van cleef reports. >> reporter: the 2012 report kept secret until now, found 61% of air traffic controllers admitted to catching themselves about to doze off on the job. nearly 1 in 5 told nasa researchers they had experienced what amounts to a close call while directing air traffic within the previous 12 months. more than half felt their fatigue was a factor. the report followed a 2006 accident in lexington, kentucky, four people died after a commuter airplane crashed after taking off from the wrong runway. the national transportation safety board considered air traffic controller fatigue as a factor. then ntsb chair and cbs news analyst sent a letter to the faa in 2007 asking them to look at the issue. >> i'm curious to know why the faa, after getting a good study by nasa, which offered 17 recommendations to help prevent the fatigue issues that they are being plagued with right now, why that hadn't been made public and why they have not told us how many of these 17 recommendations they implemented. >> reporter: this memo dated last year said the faa did not accept the nasa rep