For example, for a two-stroke liquid-cooled engine, the  manufacturer may require instrumentation to monitor engine  exhaust gas temperatures (EGT), water temperatures, and  revolutions per minute (rpm). Additionally, for a four- stroke engine, the manufacturer may additionally require oil  temperature and pressure gauges. For a simple two-stroke air- cooled engine, the manufacturer’s requirement may be EGT,  cylinder head temperature (CHT) and rpm instrumentation.  Generally, most electrical or engine controls are located on  the dashboard unless required to be reached by the instructor  for fl ight instruction.  Dashboards are as varied as the manufacturers and the  purpose of the aircraft, from simple to complex. Classical  analog gauges are common, but digital instruments are  becoming more popular with light-sport aircraft (LSA).  by the manufacturer with a portable GPS added in the  middle. Electrical components are neatly arranged along the  top. Large analog airspeed (left) and altitude (right) fl ight  instruments are installed in the middle with the portable  GPS installed between the two. The bottom stack consists  of the basic engine instruments for a simple two-stroke air- cooled engine: RPM for power (top), CHT (middle) and  EGT (bottom).  Overall, no instrumentation is required for E-LSA, but for  S-LSA an airspeed indicator is usually required, and engine  manufacturers require certain instruments be installed on the  aircraft to monitor the performance of the particular engine. The specific theory of operation and details of instruments is  covered in the Pilot’s Handbook of Aeronautical Knowledge,  and is a prerequisite to this section on flight instruments. The  altimeter is the most important flight instrument and should  be on every WSC aircraft. It is used to maintain the proper  altitude at airports, during cruise, and provides other aircraft  position information for the safety of all.  The vertical speed indicator (VSI) is one tool to assist the pilot  with the performance of the aircraft. The airspeed indicator  (ASI) is used to optimize performance of the aircraft, compare  predicted to actual performance, and to operate within the  limitations of the aircraft.  A global positioning system (GPS) is typically used as a  navigation and flight aid for most WSC aircraft. A magnetic  compass is commonly used as a primary navigation system  or as a backup when a GPS system is used.  There is a variety of engine instruments that are used. The  most basic is the engine rpm, which determines the power  of the engine. Specific engine instruments are discussed in  the powerplant section.  Instrument panels vary greatly from the basic to the complex.  Figure 3-44  depicts a standard instrument panel supplied  more advanced analog panel with a user radio and GPS  added is shown in  Figure 3-45. Airspeed, vertical speed  indicator, and altitude large fl ight instruments are along   Flight Instruments   Navigation Instruments   Engine Instruments   Instrument Panel Arrangements Engine Hours Starter Airspeed CHT RPM EGT GPS Master Altitude Accessories Plug Figure 3-44. Basic analog flight and engine instruments. 3-17