14 CFR 91.183 : Aeronautics And Space (§ 1.1 To Parts 1311-1399) — (§ 60.1 To Parts 108-109) — Federal Aviation Administration, Department Of Transportation (Continued) (§ 60.1 To Parts 108-109) — Air Traffic And General Operating Rules (§ 91.1 To Parts 108-109) — General Operating And Flight Rules (§ 91.1 To Appendix G To Part 91) — Flight Rules (§ 91.101 To §§ 91.195-91.199) — Instrument Flight Rules (§ 91.167 To §§ 91.195-91.199) — IFR communications.

Unless otherwise authorized by ATC, the pilot in command of each aircraft operated under IFR in controlled airspace must ensure that a continuous watch is maintained on the appropriate frequency and must report the following as soon as possible -

(a) The time and altitude of passing each designated reporting point, or the reporting points specified by ATC, except that while the aircraft is under radar control, only the passing of those reporting points specifically requested by ATC need be reported;

(b) Any unforecast weather conditions encountered; and

(c) Any other information relating to the safety of flight.