This paper discusses the use of internal inspection tools and in particular the more recent use of ultrasonic internal inspection technology to assist in the identification and repair of Narrow Axial External Corrosion (NAEC) on a large diameter crude oil pipeline. Intensive internal inspection and repair programs undertaken by the pipeline operator in the last two years have significantly improved the integrity of an aging pipeline exhibiting some unique corrosion problems. The use of ultrasonic technology has proven to be a reliable, effective and valuable
tool for identifying NAEC, helped the operator to complete a large amount of remedial work on the pipe line in a relatively short period of time and successfully complete a hydrotest without failure.