Experiments have been conducted to assess the feasibility of autonomously detecting crack growth in an aircraft lap-joint using acoustic emission (AE) sensors. In a lap-joint the crack must be detected early and reliably so that a repair can be made at a reasonable cost, and unnecessary inspections can be eliminated. The location of the crack initiation is known to within a few fastener holes, making detection using AE possible. Representative waveforms from cracked lap-joint specimens, as well as results from a simpler specimen are presented. A method for distinguishing crack waveforms from fretting waveforms and noise sources is discussed. A self-organizing map is investigated as a means to identify crack signals. Lessons learned, and suggestions for future work are presented.