189.3—Kinds of messages accepted or relayed.
(a)
Flight Service Stations may accept for transmission over FAA communication systems any messages concerning international or overseas aircraft operations described in paragraphs (a) (1) through (6) of this section. In addition, Flight Service Stations may relay any message described in this section that was originally accepted for transmission at an FAA Flight Service Station outside the 48 contiguous States, or was received from a foreign station of the Aeronautical Fixed Telecommunications Network that, in normal routing, would require transit of the United States to reach an overseas address:
(iii)
Messages originated by an aircraft operating agency of immediate concern to an aircraft in flight or about to depart; and
(i)
Concerning the operation or maintenance of facilities essential to the safety or regulatory of aircraft operation;
(i)
Addressed to the point of intended landing and to not more than two other addressees in the general area of the route segment of the flight to which the message refers, containing information required for weight and balance computation and remarks essential to the rapid unloading of the aircraft;
(iv)
Concerning changes in the collective requirements for passengers, crew, or cargo of aircraft en route or about to depart, if the changes are caused by unavoidable deviations from normal operating schedules and are necessary for flight regularity;
(vi)
Concerning parts or materials urgently needed to operate aircraft en route or scheduled to depart within 48 hours; or
(vii)
Concerning pre-flight arrangement of air navigation services and, in the case of non-scheduled or irregular operations, operational servicing of aircraft scheduled to depart within 48 hours.
(2)
Messages originated by and addressed to aircraft operating agencies or their representatives that directly bear on the efficient and economic conduct or day to day operations, if adequate non-United States communications facilities are not available and the messages concern—
(i)
Matter described in paragraph (b)(1) of this section, but not meeting the time limitations described in paragraph (b)(1) of this section;
(ii)
Aircraft parts, equipment, or supplies, air navigation or communications, or essential ground facilities;
(xi)
Reservations, when originated by aircraft operating agencies to secure space required in transport aircraft.