; and (2) operate under instrument flight rules enroute to the destination. (c) Limitation Without a written finding of necessity, based on objective and historical evidence of imminent threat to safety, the Administrator shall not promulgate any operation specification, policy, or guidance document pursuant to this section that is more restrictive than, or requires procedures that are not expressly stated in, the regulations. (d) Covered air carrier defined In this section, the term covered air carrier means an air carrier operating in a noncontiguous State under part 121 of title 14, Code of Federal Regulations. 517. Public aircraft eligible for logging flight times The Administrator shall issue regulations modifying section 61.51(j)(4) of title 14, Code of Federal Regulations, so as to include aircraft under the direct operational control of forestry and fire protection agencies as public aircraft eligible for logging flight times. 518. Aircraft Registry Office The Administrator shall designate employees at the Aircraft Registry Office in Oklahoma City, Oklahoma, as excepted employees in the event of a shutdown or emergency furlough to ensure that the office remains open for the duration of the lapse in Federal Government appropriations to the Federal Aviation Administration. 519. FAA data transparency Section 45303 of title 49, United States Code, is amended by adding at the end the following: (g) Data transparency (1) Air traffic services initial data report (A) Initial report Not later than 6 months after the date of enactment of the FAA Reauthorization Act of 2018 , the Administrator and the Chief Operating Officer of the Air Traffic Organization shall, based upon the most recently available full fiscal year data, complete the following calculations for each segment of air traffic services users: (i) The total costs allocable to the use of air traffic services for that segment during such fiscal year. (ii) The total revenues received from that segment during such fiscal year. (B) Validation of model (i)