The purpose of this amendment to Part 192 of Title 49 of the Code of Federal Regulations is to broaden the definition of the term "service line" contained in § 192.3. This amendment is based on a notice of proposed rulemaking (OPS notice 71-1) issued on May 24, 1971, and published in the FEDERAL REGISTER (36 FR 9667) on Mlay 27, 1971. Interested persons were afforded an opportunity to participate in the rulemaking by submitting written information, views, or arguments. The opinions and data presented in the comments that were subsequently received have been fully considered and are reflected in this final rule.