} // End modeButton click.

        private void hdgTrkTextBox_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Enter)
            {
                e.SuppressKeyPress = true;
                PMDG777Aircraft.SetHeading(hdgTrkTextBox.Text);
            }
        } // End hdgTrkTextBox KeyDown.
        } // End levelChangeButton_Click.

        private void altitudeTextBox_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Enter)
            {
                PMDG777Aircraft.SetAltitude(altitudeTextBox.Text);
                e.SuppressKeyPress = true;
            }
        } // End altitudeTextBox_KeyDown.
 private void speedTextBox_KeyDown(object sender, KeyEventArgs e)
 {
     if (e.KeyCode == Keys.Enter)
     {
         e.SuppressKeyPress = true;
         if (Aircraft.pmdg777.MCP_IASMach.Value < 10)
         {
             float.TryParse(speedTextBox.Text, out float mach);
             FSUIPCConnection.SendControlToFS(PMDG_777X_Control.EVT_MCP_MACH_SET, PMDG777Aircraft.CalculateMachParameter(mach));
         } // End mach.
         else if (Aircraft.pmdg777.MCP_IASMach.Value > 10)
         {
             int.TryParse(speedTextBox.Text, out int speed);
             FSUIPCConnection.SendControlToFS(PMDG_777X_Control.EVT_MCP_IAS_SET, speed);
         } // End airspeed.
     }     // End key check.
 }         // End key down event.
        } // End form load.

        private void interveneButton_Click(object sender, EventArgs e)
        {
            PMDG777Aircraft.VerticalSpeed_FPAIntervene();
        } // End intervene
        }             // End mode.

        private void vsFpaTextBox_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Enter)
            {
                e.SuppressKeyPress = true;
                if (Aircraft.pmdg777.MCP_VSDial_Mode.Value == 0)
                {
                    ushort.TryParse(vsFpaTextBox.Text, out ushort vs);
                    FSUIPCConnection.SendControlToFS(PMDG_777X_Control.EVT_MCP_VS_SET, PMDG777Aircraft.CalculateVerticalSpeedParameter(vs));
                }
                else
                {
                    float.TryParse(vsFpaTextBox.Text, out float FPA);
                    FSUIPCConnection.SendControlToFS(PMDG_777X_Control.EVT_MCP_FPA_SET, (int)PMDG777Aircraft.CalculateFPAParameter(FPA));
                }
            } // End key check.
        }     // End vsFPATextBox KeyDown event
        } // End key down event.

        private void modeButton_Click(object sender, EventArgs e)
        {
            PMDG777Aircraft.ToggleVsFPAMode();
        }             // End mode.
        } // End vNavButton_Click.

        private void levelChangeButton_Click(object sender, EventArgs e)
        {
            PMDG777Aircraft.ToggleLevelChange();
        } // End levelChangeButton_Click.
        } // End AltitudeBox.

        private void vNavButton_Click(object sender, EventArgs e)
        {
            PMDG777Aircraft.ToggleVNav();
        } // End vNavButton_Click.
        } // End AltitudeButton_Click.

        private void altitudeHoldButton_Click(object sender, EventArgs e)
        {
            PMDG777Aircraft.ToggleAltitudeHold();
        } // End AltitudeBox.
 private void altitudeButton_Click(object sender, EventArgs e)
 {
     PMDG777Aircraft.AltitudeIntervene();
     Tolk.Output("Altitude intervene");
 } // End AltitudeButton_Click.
        } // End LNavButton click.

        private void modeButton_Click(object sender, EventArgs e)
        {
            PMDG777Aircraft.ToggleHeadingTrack();
        } // End modeButton click.
        } // End headingButton click.

        private void hdgHoldButton_Click(object sender, EventArgs e)
        {
            PMDG777Aircraft.ToggleHeadingHold();
        } // End heading hold button click.
        } // End form keydown.

        private void interveneButton_Click(object sender, EventArgs e)
        {
            PMDG777Aircraft.HeadingIntervene();
            Tolk.Output("Heading intervene.");
        } // End headingButton click.