AMC1 ACNS.D.ELS.065 Antenna Diversity
ED Decision 2013/031/R
(a) The aircraft maximum cruising true airspeed may be determined using one of the 3 following options:
(1) Where the Aircraft Flight Manual or Pilot’s Operating Handbook gives more than one table of true airspeed values for a range of temperatures, the table which gives the maximum true airspeed, should be used;
(2) For some aircraft, the maximum cruising true airspeed is not obtained at the maximum operating altitude. In those cases, the maximum true airspeed has to be considered and not the true airspeed at maximum operating altitude;
(3) Aircraft which do not state the maximum cruising true airspeed under ISA conditions in their Aircraft Flight Manual or Pilot’s Operating Handbook, may use the following alternative method to calculate maximum cruising true airspeed:
(i) Use the maximum operating values of altitude and airspeed (i.e. VNO, or VMO/MMO as applicable) quoted in the Limitations section of the Aircraft Flight Manual or Pilot’s Operating Handbook to calculate the maximum cruising true airspeed of the aircraft. If the aircraft is unpressurised, an altitude of 8 000 feet may be used as the maximum ‘normal’ operating altitude.
(ii) For example, using a maximum ‘normal’ operating altitude of 2 400 m (8 000 feet) for an unpressurised aircraft, and a maximum operating airspeed of 110 m/s (215 knots), (as stated in the Aircraft Flight Manual or Pilot’s Operating Handbook, e.g. VNO = 110 m/s (215 knots)) then the aircraft has an equivalent TAS capability of 128 m/s (250 knots) in the ICAO Standard atmosphere. The calculation may be made using a pilot’s TAS computer.
(b) For airships, the applicant should demonstrate the need or otherwise for antenna diversity. The demonstration should be based on the construction techniques and size of the airship.
(c) The transponder DDP should indicate the letter ‘d’ in the transponder capability declaration to indicate antenna diversity capability.
EASA aviation regulations for airborne communication, navigation, and surveillance (ACNS) address antenna diversity. Aircraft true airspeed calculation uses flight manual data, prioritizing maximum values. Airships require antenna diversity justification based on construction. Transponder capability declaration must indicate antenna diversity with the letter "d".
* Summary by Aviation.Bot - Always consult the original document for the most accurate information.
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