§  87.219   Automatic operations.

   (a) A station operator need not be present when an automated unicom is
   in operation.

   (b) Unicoms operating in an automated mode must comply with the
   requirements of paragraphs (1)-(5) of this section, in addition to the
   requirements applicable to non-automated unicom operations.

   (1) An automated unicom must transmit only in response to interrogating
   signals from aircraft, including but not limited to the brief keyed RF
   signals specified in § 87.187(y).

   (2) An automated unicom must monitor the unicom frequency prior to
   transmission, and provide a brief delay between the aircraft's
   interrogating signal and the automatic unicom's response.

   (3) Automated advisory transmissions must be as brief as possible, and
   must never exceed one minute in length.

   (4) An automated unicom may not provide weather information at an
   airport that has an operational, FAA-certified, automatic weather
   facility, unless the unicom itself is certified by the FAA.

   (5) If weather information is provided by an automated unicom:

   (i) Weather sensors must be placed in order to adequately represent the
   weather conditions at the airport(s) to be served;

   (ii) The weather information must be proceeded by the word "advisory;"

   (iii) The phrase "automated advisory" must be included when the weather
   information was gathered by real-time sensors or within the last
   minute; and,

   (iv) The time and date of the last update must be included when the
   weather information was not gathered within the last minute.

   (c) Only one automated unicom may be operated at an uncontrolled
   airport. Prior to the operation of an automated unicom at an airport
   with more than one unicom licensee, all of the licensees at that
   airport must sign a letter of agreement stating which licensee(s)
   control the automated unicom operations, and, if control is to be
   shared among several operators, how that control will be divided or
   scheduled. The original or a copy of the letter of agreement must be
   kept with each licensees' station records. Within 90 days of the date
   upon which a new unicom operator is licensed at an airport where more
   than one unicom is authorized, and an automated unicom is being
   operated, an amended letter of agreement that includes the new
   licensee's signature must be signed or automated unicom operations must
   cease.

   [ 64 FR 27475 , May 20, 1999]

Subpart H--Aeronautical Multicom Stations