N4903F - 1979 Aircraft Aircraft Registration

**This case was revised 6/10/2005 and 2/24/2016. Refer to the public docket for this accident for details.** The failure of the pilot of N4903F, the Cessna 172, and the pilot of N759XA, the Cessna 182, to see and avoid each other while operating in Class E airspace, resulting in a midair collision. Contributing to the accident was the lack of traffic information being provided to the pilot of the Cessna 182 about known traffic in the vicinity, because the controller forgot about the Cessna 172' s reported path and altitude, and the Cessna 172 pilot's change of his transponder code, which precluded the possibility of an ATC collision alert before the accident.