MENU/PLAN/VNAV Sub-mode

This sub-mode allows you to set the aircraft‟s leg vertical airspeed (in meters per second –Vy m/s), altitude of leg, (in meters - Hм), and the leg distance to/from the waypoint (in kilometers -Skm). To access the VNAV sub-mode page, press the EDIT FSK button from the main PLAN sub-mode page and select the VNAV option from the pop-up menu. Press the EDIT FSK button again to enter the page. The bottom part of the screen will display information boxes for entering the altitude values and distances from waypoints.

3-49: Selecting MENU/PLAN/VNAV sub-mode

3-50: MENU/PLAN/VNAV sub-mode page

1. Waypoint altitude

2. Distance from/to WPT. (“-” to reach the altitude “S” km before the WPT, “+” to reach the altitude “S” km after the WPT OVER

3. WPT callsign

4. WPT number

5. Vertical speed

The information field displays the following boxes:

 Information – Waypoint number and callsign

 Entered by the operator – Distance from waypoint and route leg altitude

 Automatically calculated from entered values – Aircraft vertical speed

As values are entered, the ABRIS automatically plots a rectilinear profile of climb or descent from the leg start WPT to the leg end WPT. The start point is the initial leg WPT where the flight altitude is set (Hм). The end point is the terminal leg WPT, the distance from/to it (Skm) and the sign of this distance (“-” to reach the altitude “S” km before the WPT, “+” to reach the altitude “S” km after the WPT OVER) is taken into account. A profile with a permanent gradient is plotted from the start point to the end point. After pressing the ENTER FSK button, the ACFT VERTICAL SPEED - Vy m/s, is automatically calculated and displayed – white if the value does not exceed the rated value set in the ACFT PERF and yellow if the value is exceeded. The entered flight information is used in the VERTICAL NAVIGATION sub-mode for calculating the CLIMB and DESCENT points. This sub-mode is available in-flight from the FPL mode.

Use the following procedure for entering values: To enter Skm and Hм values, use the cursor manipulator to select a line for editing, either press the cursor manipulator axially or press the EDIT FSK button. To switch to the next character, press the cursor manipulator axially, and to start editing of the next field, press the ►► FSK button. The value is recorded in the plan after pressing the ENTER FSK button. After this is done, the flight altitude fields are filled in automatically, from the current field to the route terminal point.

3-51: Entering flight altitude values for the first waypoint

3-52: Results of automatic filling in of flight altitude fields on the route legs

This mode enables you to reach an altitude (at a constant vertical speed) over several waypoints without using a stepped process. To reach an altitude at a constant vertical speed, follow these steps:

1. Enter a value in the Hм field of the route leg that you wish to start the altitude planning from.

2. Use the cursor manipulator to switch the active field to the next leg and press the CLEAR FSK button. Perform this operation successively for the entire intermediate route legs that require altitude planning.

3. For a route leg where the set altitude will be reached, enter its value.

4. Press the ENTER FSK button and the screen will display the calculated flight altitudes for the route legs and vertical speeds.

3-53: Clearing flight altitude values for the intermediate altitudes

3-54: Input of the final desired altitude

This will result in calculating the vertical speed needed to reach a desired altitude. If the aircraft PERF values are exceeded, the altitude values will be shown in yellow.

3-55: Results of automatically reaching the set altitude without steps