The Mode Control Panel (MCP) is the most direct way of sending commands to the aircraft you're flying.  The Mode Control Panel can manipulate the three main factors of flight:  Speed, Heading, and Altitude.  The MCP (777 Style) is a more advanced and realistic MCP, modeled after the MCP used in current-day Boeing 777 aircraft. 

The interface of the 777 MCP follows a different color scheme than the other flight deck controls in MACS.  Active buttons are indicated by a pale yellow light, inactive buttons are indicated by a pale grey light, and the buttons with dark grey lights are not operable at all.  It is also important to note that, unlike the regular MCP, the 777 MCP's display fields for speed, heading, and altitude do not display FMS commanded values or not necessarily current values either, they only display MCP target values.  These displayed values are always shown in white.  For more information on the relationship between Mode Control Panel guidance and Flight Management System (FMS) guidance, see the MCP vs. FMS section in the MCP page.

An actual MCP in a Boeing 777 aircraft has knobs and wheels that a pilot can twist, flip, and turn.  Those same control manipulations have been translated into 2-dimensional controls here in MACS.  To turn the speed, heading, and altitude knobs, simply left-click with your mouse on the + and - signs (or L and R signs) on either side of the knobs.  Both the heading and speed knobs are also buttons if clicked in their center.  Now let's go through the different information displayed in the 777 MCP.

SPEED INFORMATION:

Here we see that the aircraft is in Speed Select (SPD SEL) mode.  This is indicated by the presence of a speed value in the speed display field.  When a value is displayed here, the aircraft is flying to this speed.  To engage SPD SEL mode, click the button in the center of the speed knob (labeled "SEL" for SPD SEL).  Once in SPD SEL mode, you can adjust the 777 MCP speed target by clicking the + and - signs on either side of the speed knob.  The SEL button is a toggle button: clicking it when your aircraft is already in SPD SEL mode will disengage SPD SEL mode and engage Vertical Navigation (VNAV) mode.

You can also switch the 777 MCP speed field's display from mach numbers to indicated air speed (IAS).  You can toggle between these two units by simply clicking the small button that is labeled "IAS" on the left and "MACH" on the right.

The 777 MCP can also be used to engage the self-spacing guidance for following a lead aircraft.  The spacing (SPC) button on the 777 MCP requires the proper inputs be in place in the Self-Spacing Panel.  Once the Self-Spacing Panel is set up properly, you can engage the self-spacing guidance by clicking the 777 MCP's SPC button.  Notice that being in Self-Spacing mode also puts your aircraft in SPD SEL mode.  The SPC button is a toggle button: clicking it when your aircraft is already in Self-Spacing mode will disengage self-spacing, but will leave your aircraft engaged in SPD SEL mode.

HEADING INFORMATION:

Here we see that the aircraft is in Heading Select (HDG SEL) mode.  This is indicated by the 777 MCP's LNAV button being inactive.  When in HDG SEL mode, your aircraft is flying to the value displayed in the heading display field.  Once in HDG SEL mode, you can adjust the 777 MCP target heading by clicking on the L and R letters on either side of the heading knob.  You can engage HDG SEL mode by either clicking the button in the center of the heading knob (lableled "SEL" for HDG SEL), or by clicking the 777 MCP's active LNAV button. These two buttons are toggle buttons: clicking them when your aircraft is already in HDG SEL mode will disengage HDG SEL mode and engage Lateral Navigation (LNAV) mode.

While your aircraft is turning, it has not yet reached its MCP target heading.  During this period your aircraft is in HDG SEL mode.  When the true heading and MCP target heading of an aircraft in HDG SEL mode are the same, that aircraft is then in Heading Hold (HDG HOLD) mode.  This mode is indicated by the active heading hold button (labeled "HOLD") in your aircraft's 777 MCP.   HDG HOLD can also be used if your aircraft is mid-turn and you want to immediately hold at the current heading.  To do this, simply click the 777 MCP's heading HOLD button.  To disengage HDG HOLD mode, simply click the 777 MCP's inactive LNAV button.

You can also switch the 777 MCP heading field's display from heading to track.  You can toggle between these two units by simply clicking the small button that is labeled "HDG" (heading) on the left and "TRK" (track) on the right.

ALTITUDE INFORMATION:

The image above shows that AAL 776 is out of VNAV mode and in Flight Level Change (FLCH) mode.  This is indicated by the inactive VNAV button and active FLCH button.  You can engage FLCH mode by clicking the 777 MCP's inactive FLCH button or by clicking the 777 MCP's active VNAV button.  To disengage FLCH mode, simply do the reverse:  click the 777 MCP's active FLCH button or the 777 MCP's inactive VNAV button.   When your aircraft is in FLCH mode, you can adjust the 777 MCP target altitude by clicking the + and - signs on either side of the altitude knob.  Note that the altitude knob has two modes of operation:  AUTO and 1000.  If the radio button to the left of the label "1000" is selected, your altitude knob adjustments will always increment by 1000 feet for each click of either the + or - signs.  If the radio button to the right of the label "AUTO" is selected, then the increments of your altitude knob adjustments depend on your aircraft's phase of flight (this is indicated in your aircraft's PFD).  The following table explains the increment values for each phase of flight.

Altitude hold works exactly the same as heading hold.  While your aircraft is descending or climbing, it is in FLCH mode.  When the true altitude and MCP target altitude of an aircraft in FLCH mode are the same, that aircraft is then in VNAV Altitude Hold (VNAV HOLD) mode.  This mode is indicated by the active VNAV altitude hold button (labeled "HOLD") in your aircraft's 777 MCP.   VNAV HOLD can also be used if your aircraft is mid-climb or mid-descent and you want to immediately hold at the current altitude.  To do this, simply click the 777 MCP's VNAV altitude HOLD button.  To disengage VNAV HOLD mode, simply click the 777 MCP's inactive VNAV button.  If you click the VNAV altitude HOLD button when your aircraft is already in VNAV HOLD mode, your aircraft will disengage VNAV HOLD mode, but will still be engaged in FLCH mode.

During a descent or climb, you can adjust the vertical speed (VS) of your aircraft by engaging Vertical Speed (V/S) mode.  To engage V/S mode during a descent or a climb, simply click the vertical speed and flight path angle button (labeled "VS/FPA").  When in V/S mode, your aircraft is flying to the value displayed in the vertical speed display field.  Once in V/S mode, you can adjust the 777 MCP target vertical speed by clicking on the up and down arrows below the vertical speed display field.  To disengage V/S mode, simply click the 777 MCP's inactive VNAV button.  If you click the VS/FPA button when your aircraft is already in V/S mode, your aircraft will disengage V/S mode, but will still be engaged in FLCH mode.

You can also switch the 777 MCP vertical speed's display from vertical speed to flight path angle.  You can toggle between these two units by simply clicking the small button that is labeled "V/S" (vertical speed) on the left and "FPA" (flight path angle) on the right.

Note that in MACS' 777 MCP, the auto pilot (AP) and auto throttle (AT) functions cannot be disengaged.  There are two auto pilot buttons labeled "A/P" and one button labeled "A/T".  You'll notice they are always pale yellow, indicating they're active.  Also, the flight director (FD), auto pilot disengage, localizer, and approach functions cannot be engaged.  There are two switches that have "F/D ON" and "OFF" labels, one button labeled "A/P DISENGAGE", one button labeled "LOC", and one button labeled "APP".  You'll notice they are always dark grey, indicating they're inoperable.

Finally, to better understand the 777 MCP's controls, try using it simultaneously with the regular MCP.  You'll notice that the controls in the 777 MCP properly reflect equivalent controls in the regular MCP.