Sec. 90.403  General operating requirements.

    (a) Licensees of radio stations in the private land mobile radio 
services shall be directly responsible for the proper operation and use 
of each transmitter for which they are licensed. In this connection, 
licensees shall exercise such direction and control as is necessary to 
assure that all authorized facilities are employed:
    (1) Only for permissible purposes;
    (2) Only in a permissible manner; and
    (3) Only by persons with authority to use and operate such 
equipment.
    (b) In carrying out their responsibilities under Sec. 90.403(a), 
licensees shall be bound by the provisions of the Communications Act of 
1934, as amended, and by the rules and regulations of the Commission 
governing the radio service in which their facilities are licensed; and 
licensees may not, through written or oral agreements or otherwise, 
relieve themselves of any duty or obligation imposed upon them, by law, 
as licensees.
    (c) Except for stations that have been granted exclusive channels 
under this part and that are classified as commercial mobile radio 
service providers pursuant to part 20 of this chapter, each licensee 
must restrict all transmissions to the minimum practical transmission 
time and must employ an efficient operating procedure designed to 
maximize the utilization of the spectrum.
    (d) Communications involving the imminent safety-of-life or property 
are to be afforded priority by all licensees.
    (e) Licensees shall take reasonable precautions to avoid causing 
harmful interference. This includes monitoring the transmitting 
frequency for communications in progress and such other

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measures as may be necessary to minimize the potential for causing 
interference.
    (f) Stations licensed in this part shall not continuously radiate an 
unmodulated carrier except where required for tests as permitted in 
Sec. 90.405, except where specifically permitted by this part, where 
specifically authorized in the station authorization, or on an as needed 
basis in the Radiolocation Radio Service.
    (g) The radiations of the transmitter shall be suspended immediately 
upon detection or notification of a deviation from the technical 
requirements of the station authorization and until such deviation is 
corrected. For transmissions concerning the imminent safety-of-life or 
property, the transmissions shall be suspended as soon as the emergency 
is terminated.
[ 43 FR 54791 , Nov. 22, 1978;  44 FR 32220 , June 5, 1979, as amended at  59 FR 59965 , Nov. 21, 1994]