Deployment of "Fiber In The Loop" (FITL) involves more than the simple replacement of copper media with optical fiber -it requires the introduction of additional equipment, primarily related to the optoelectronics obviously necessary for fiber optic transport, and a careful re-examination of maintenance strategies. Although the end-tc-end service availability objective (99.99%) is not changed in proposed Bellcore criteria, FITL leads to a new "hypothetical reference circuit" and subsequent reallocation of maximum downtimes assigned to different network elements This paper reviews these changes and identifies some critical system and component issues.