§  22.879   Interference resolution procedures.

   This section applies only to commercial aviation ground stations
   transmitting in the 849–851 MHz band, other than commercial aviation
   ground stations operating under the authority of a license originally
   granted prior to January 1, 2004.

   (a) Initial notification. Commercial aviation air-ground system
   licensees may receive initial notification of interference from
   non-cellular part 90 licensees in the 800 MHz band pursuant to
   § 90.674(a) of this chapter.

   (1) Commercial aviation air-ground system licensees shall join with
   part 90 ESMR licensees and Cellular Radiotelephone Service licensees in
   utilizing an electronic means of receiving the initial notification
   described in § 90.674(a) of this chapter. See § 22.972.

   (2) Commercial aviation air-ground system licensees must respond to the
   initial notification described in § 90.674(a) of this chapter as soon as
   possible and no later than 24 hours after receipt of notification from
   a part 90 public safety/CII licensee. This response time may be
   extended to 48 hours after receipt from other part 90 non-cellular
   licensees provided affected communications on these systems are not
   safety related.

   (b) Interference analysis. Commercial aviation air-ground system
   licensees—who receive an initial notification described in § 90.674(a)
   of this chapter—shall perform a timely analysis of the interference to
   identify the possible source. Immediate on-site visits may be conducted
   when necessary to complete timely analysis. Interference analysis must
   be completed and corrective action initiated within 48 hours of the
   initial complaint from a part 90 public safety/CII licensee. This
   response time may be extended to 96 hours after the initial complaint
   from other part 90 non-cellular licensees provided affected
   communications on these systems are not safety related. Corrective
   action may be delayed if the affected licensee agrees in writing (which
   may be, but is not required to be, recorded via e-mail or other
   electronic means) to a longer period.

   (c) Mitigation steps. Any commercial aviation air-ground system that is
   responsible for causing unacceptable interference to non-cellular part
   90 licensees in the 800 MHz band shall take affirmative measures to
   resolve such interference.

   (1) Commercial aviation air-ground system licensees found to contribute
   to unacceptable interference, as defined in § 22.877, shall resolve such
   interference in the shortest time practicable. Commercial aviation
   air-ground system licensees must provide all necessary test apparatus
   and technical personnel skilled in the operation of such equipment as
   may be necessary to determine the most appropriate means of timely
   eliminating the interference. However, the means whereby interference
   is abated or the technical parameters that may need to be adjusted is
   left to the discretion of the commercial aviation air-ground system
   licensee, whose affirmative measures may include, but not be limited
   to, the following techniques:

   (i) Increasing the desired power of the public safety/CII signal;

   (ii) Decreasing the power of the commercial aviation air-ground system
   signal;

   (iii) Modifying the commercial aviation air-ground system antenna
   height;

   (iv) Modifying the commercial aviation air-ground system antenna
   characteristics;

   (v) Incorporating filters into the commercial aviation air-ground
   system transmission equipment;

   (vi) Changing commercial aviation air-ground system frequencies; and

   (vii) Supplying interference-resistant receivers to the affected public
   safety/CII licensee(s). If this technique is used, in all
   circumstances, commercial aviation air-ground system licensees shall be
   responsible for all costs thereof.

   (2) Whenever short-term interference abatement measures prove
   inadequate, the affected part 90 non-cellular licensee shall,
   consistent with but not compromising safety, make all necessary
   concessions to accepting interference until a longer-term remedy can be
   implemented.

   (3) When a part 90 public safety licensee determines that a continuing
   presence of interference constitutes a clear and imminent danger to
   life or property, the licensee causing the interference must
   discontinue the associated operation immediately, until a remedy can be
   identified and applied. The determination that a continuing presence
   exists that constitutes a clear and imminent danger to life or
   property, must be made by written statement that:

   (i) Is in the form of a declaration, notarized affidavit, or statement
   under penalty or perjury, from an officer or executive of the affected
   public safety licensee;

   (ii) Thoroughly describes the basis of the claim of clear and imminent
   danger;

   (iii) Was formulated on the basis of either personal knowledge or
   belief after due diligence;

   (iv) Is not proffered by a contractor or other third party; and,

   (v) Has been approved by the Chief of the Public Safety and Homeland
   Security Bureau or other designated Commission official. Prior to the
   authorized official making a determination that a clear and imminent
   danger exists, the associated written statement must be served by
   hand-delivery or receipted fax on the applicable offending licensee,
   with a copy transmitted by the fastest available means to the
   Washington, DC office of the Commission's Public Safety and Homeland
   Security Bureau.

   [ 70 FR 19311 , Apr. 13, 2005, as amended at  71 FR 69038 , Nov. 29, 2006]