available to a pilot, but also how the information is displayed.  In addition to the improvement in system reliability, which  increases overall safety, EFDs have decreased the overall cost  of equipping aircraft with state-of-the-art instrumentation.  Primary electronic instrumentation packages are less prone  to failure than their analogue counterparts. No longer is it  necessary for aircraft designers to create cluttered panel  layouts in order to accommodate all necessary flight  instruments. Instead, multi-panel digital flight displays  combine all flight instruments onto a single screen that is  called a primary flight display (PFD). The traditional “six  pack” of instruments is now displayed on one liquid crystal  display (LCD) screen.  Configured similarly to traditional panel layouts, the ASI  is located on the left side of the screen and is displayed as  a vertical speed tape. As the aircraft increases in speed, the  larger numbers descend from the top of the tape. The TAS is  displayed at the bottom of the tape through the input to the air  data computer (ADC) from the outside air temperature probe.  Airspeed markings for V$_{X}$, V$_{Y}$, and rotation speed (V$_{R}$) are  displayed for pilot reference. An additional pilot-controlled  airspeed bug is available to set at any desired reference speed.  As on traditional analogue ASIs, the electronic airspeed tape  displays the color-coded ranges for the flap operating range,  Advances in technology have brought about changes in the  instrumentation found in all types of aircraft; for example,  Electronic Flight Displays (EFDs) commonly referred to  as “glass cockpits.” EFDs include flight displays such as  primary flight displays (PFD) and multi-function displays  (MFD). This has changed not only what information is  Figure 8-11.  Blocked static system.  Airspeed Tape  Electronic Flight Display (EFD)  30.0 29.9 29.8  Pitot tube  Blockage  Static port  Frozen altimeter  Constant zero indication on VSI  Inaccurate airspeed indications  3600 3500 3400 3300 3200 3100 ° XPDR  5537 IDNT LCL10:12:34 INSET  PFD  OBS  CDI  DME  XPDR IDENT TMR/REF  NRST  ALERTS  VOR 1  270  2  1  1  2  4300  4200  4100  3900  3900  3800  4300  20 80 4000 4000  130  120 110 90  80  70  1 100 9 TAS 106KT  OAT  6°C NAV1 108.00  113.00  NAV2 108.00  110.60  134.000 118.000 COM1  123.800 118.000 COM2  $_{WPT }$_ _ _ _ _ _$_{ DIS }$_ _ ._ $_{NM DTK }$_ _ _$_{°T}$ TRK 360° Attitude indicator Altimeter  Horizontal situation indicator  Vertical speed indicator (VSI)  Slip skid indicator  Airspeed indicator  Turn indicator  VOR 1 270 ° 270 ° Slip/skid indicator  Turn rate indicator tick marks  Turn rate trend vector  Figure 8-12.  Primary flight display (PFD). Note that the actual location of indications vary depending on manufacturers.  8-12 