The Garmin G1000 is an electronic flight instrument system (EFIS) typically composed of two display units, one serving as a primary flight display, and one as a multi-function display. Manufactured by Garmin Aviation, it serves as a replacement for most conventional flight instruments and avionics. Introduced in June 2004, the system has since become one of the most popular integrated glass cockpit solutions for general aviation and business aircraft. Components An aircraft with a basic Garmin G1000 installation contains two LCDs (one acting as the primary flight display and the other as the multi-function display) as well as an integrated communications panel that fits between the two. These displays are designated as a GDU, Garmin Display Unit. Beyond that, additional features are found on newer and larger G1000 installations, such as in business jets. This includes: A third display unit, to act as a co-pilot PFD An alphanumeric keyboard An integrated flight director/autopilot (without it, the G1000 interfaces with an external autopilot) Depending on the airplane manufacturer and whether or not a GFC 700 autopilot is installed, the G1000 system will consist of either two GDU 1040 displays (no autopilot), a GDU 1040 PFD/GDU 1043 MFD (GFC 700 autopilot installed), or a GDU 1045 PFD/GDU 1045 MFD (GFC 700 autopilot installed with VNAV). The GDU 1040 is the standard base bezel with no autopilot/flight director mode selection keys below the heading bug. The GDU 1043 has autopilot/flight director keys for all GFC 700 modes except VNAV. The GDU 1045 is essentially identical to the GDU 1043 except for the addition of an autopilot/flight director mode for VNAV. Depending on how the units are installed, an MFD failure may, or may not, affect autopilot or flight director use. If a GDU 1040 is used as a PFD in an airplane equipped with a GFC 700 autopilot, a failure of the MFD (which houses the autopilot mode selection keys) will leave the autopilot engaged, but the modes cannot be changed because no autopilot keys are present on the PFD. But, if an MFD failure occurs in an airplane with the GFC 700 autopilot and either a GDU 1043 or a GDU 1045 bezel installed as a PFD, the pilot will have full use of the autopilot through the keys on the PFD. Both the PFD and MFD each have two slots for SD memory cards. The top slot is used to update