SpeedThe bar on the left represents your current indicated air speed in knots. If you have selected km/h or mi/h in settings a second value will display above with the speed in these units. On the Device Location Services (GPS) datasource the IAS is equal to your ground speed. Below the bar is the speed displayed in mach. If your data source has auto-pilot the number above the bar represents the dialed air speed.
Vertical SpeedThe bar on the right represents the vertical speed and its needle moves up or down depending on whether you are climbing or descending. The number just below is the vertical speed in feet per minute.
AltitudeThe right bar just next to vertical speed is the altitude bar. The number in the centre is the altitude in feet. If metres are selected as units, a second box will appear with these.
Under it is the currently configured barometric pressure and on top the auto-pilot dialed altitude, if available.
Auto-Pilot BarIf your data source has auto-pilot (such as simulator flights) the top bar will display the auto-pilot status with information of which modes are engaged or armed.
Attitude IndicatorRight in the centre is the attitude indicator with information concerning the horizon, roll and pitch.
ILS / VOR Guidance
By tuning an ILS or VOR frequency in NAV1, NAV2 or the FMC, and by intercepting it within its range, vertical and lateral deviation bugs will be displayed right and below the attitude indicator, aiding a precision approach.
Finally on the bottom (or on the right side, depending on the orientation) is the compass with your heading. If auto-pilot is available the magenta number will also display the dialed auto-pilot heading.
When using the Device Location Services data source a CAL button appears in the PFD screen; pressing this button calibrates the attitude indicator to 0/0 at the current device's position.
RC - Remote Control
RC or remote control mode is available as a button on PFD screens of simulator data sources. You can engage it by clicking on it once and disengage it by clicking again.
When engaged, RC mode converts your device into a remote joystick / yoke with which you can control the aircraft. One second after being selected it auto-calibrates at the device's current position. From then on, lift the iPhone or iPad to raise or lower the nose of the plane and move it sideways to roll. If your device has a built-in gyro such as the one that can be found on the iPhone and iPod 4's, rotating it horizontally will also control the rudder. When finished, just deselect RC and move your device freely.
Usage Notes:1) When in RC mode the device acts as a remote joystick so it conflicts with any existing devices. This means that if you pull the joystick left and the phone right they will counter-cancel each other.