Offpath Descent

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The LEGS pages should reflect the planned arrival procedure. If a published arrival procedure is required for reference while being radar vectored, or the arrival is momentarily interrupted by a heading vector from ATC, the offpath descent circles provide a good planning tool to determine drag and thrust requirements for the descent.

The outer circle is referenced to the end of descent point, using a clean configuration and a direct path from the airplane position to the end of descent waypoint constraint. The inner circle is referenced to the end of descent point using speedbrakes. A separate waypoint may be entered on the OFFPATH DES page as a reference for the descent circles.

Both circles assume normal descent speed schedules, including deceleration at transition altitude, but do not include waypoint speed and altitude constraints.

ECON SPD or SEL SPD - Shows the current target descent speed.

ECON SPD
  • economy speed based on cost index
  • shows CAS or Mach


    • SEL SPD -
  • shows when intermediate level off required below an existing speed constraint
  • shows when flight crew enters speed
  • CAS or Mach value may be entered.
  • page title changes to ACT XXXKT DES or ACT M.XXX DES
  • < ECON prompt appears at line 51- to allow selection of economy descent speed
    • SPD TRANS - The transition speed is usually 10 knots less than the destination airport limiting speed from the navigation database. When no airport limit speed exists, the default speed of 240 knots is shown. The transition altitude is the point that the transition speed is active for the destination airport. When no altitude exists in the navigation database, the default of 10,000 feet is shown. Blanks when the transition has occurred. Can be deleted.
    SPD RESTR - Speed restrictions not associated with specific waypoints are manually entered on this line. Dashes before entry by flight crew. Valid entry is a CAS and altitude (example 240/8000). An entry creates a modification.
    DES - Shows the DES page.

    Standard | 11.43.4 | FORECAST>