. >> for more information about the sixth floor museum at dealy pl plaza at jfk.org. american history tv all weekend every weekend on c-span3. this past mopped the national archives released an audio recording on air force one soon after president kennedy was assassinated. the recording made as the airplane travels from dallas to washington includes conversations among pilots, aides, lyndon johnson, and others, and includes over 0 minutes of audio not previously part of the public record. here's an excerpt. >> c-140. 497. last three numbers. he's inbound. his code name is grandson and i want to talk to him. >> grandson. okay, sir. we'll see what we can do. we're real busy with air force one right now. >> okay. you don't have the capability to work more than one, huh? >> we're running air force one on two different frequencies, we're getting two different patches at one time right now an that's all we can do. what is your drop, sir? are you drop off the washington switch? >> i have to drop 303 or 79225. it will be too late. >> what is your name again, sir? >> colonel d