I assume you mean FAA AC 90-89, found at:
http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/ACNumber/D08FA9393154B636862569BA006F6D7F?OpenDocumentwhich will apparently not tiny url since it goes direct to pdf document. Youwill probably have to cut and past url togther if you want to go to it.Sorry about that.jofarr, soddy tn----- Original Message -----> The FAA publishes a circular with very detailed advice on flight testing.