Good points by all.. I would think the only killers would be some sort of drug, DUI, or medical problem. If you just couldn't nail your TACAN point to points, but showed the problem was fixed later through lots of hours with other companies, you should be OK.. One would think.. Also, be prepared how to answer it in an interview.

When I went through Navy UPT in the late 80s, we had lots of guy wash out. Many went to other sevices or went to time building jobs and continued to fly. Sometimes budget considerations force the sevices to RIF (Reduction in Forces). When this happens the standards are changed in flight school so more guys wash.. That's what happened to the guys I knew.