TM 10-3930-669-10 2-2.  OPERATOR INSTRUMENTS. Table 2-2.  Instruments Key Instrument Function 1 Ammeter Gauge Indicates amperage drawn on electrical system during operation. 2 Fuel Level Gauge Indicates level of fuel in fuel tank. 3 Engine Oil Pressure Gauge Indicates engine oil pressure in pounds-per-square inch (psi) and kilopascals (kPa). 4 Engine Temperature Gauge Indicates engine temperature in degrees Fahrenheit and Celsius. 5 Air Restriction Indicator Gauge Indicates condition of air filter in inches of Hg.  Button is for resetting indicator. 6 Hour Meter Indicates engine operating hours only. 7 Transmission Oil Temperature Gauge Indicates transmission oil temperature in degrees Fahrenheit and Celsius. 2-7