Net Takeoff Flight Path: Takeoff flight path used to determine obstacle clearance. Uses net climb gradients to climb to a height of 1500 feet above the runway surface.
OAT or TEMP: Outside Air Temperature or Ambient Air Temperature. The free air static temperature, obtained either from ground meteorological sources or from in flight temperature indications adjusted for instrument error and compressibility effects.
O'CURRENT: Overcurrent.
O'TEMP: Overtemperature.
PAV: Pressure Adjusting Valve.
PFD: Primary Flight Display.
PMA: Permanent Magnet Alternator.
PSI: Pounds-per-Square Inch.
PSIG: Pounds-per-Square Inch Gage.
Payload: Weight of occupants, cargo and baggage.
Position Correction: A correction applied to indicated airspeed or altitude to eliminate the effect of the location of the static pressure source on the instrument reading. No position corrections are required when using performance section charts in Section VII since all airspeeds and altitudes in this section are presented as "indicated" values except for stall speeds which are presented as "calibrated" values.
Pressure Altitude: Altitude measured from standard sea level pressure (29.92 inches Hg) (standard datum plane) by a pressure or barometric altimeter. It is the indicated pressure altitude corrected for position and instrument error. In this manual, altimeter instrument errors are assumed to be zero.
RAT: Ram Air Temperature. The ram air temperature as read from the EICAS. This must be corrected for ram air temperature rise to obtain true outside air temperature.
REF: Reference.
Reference Datum: An imaginary vertical plane at or near the nose of the airplane from which all horizontal distances are measured for balance purposes.
Reference Zero: The point in the takeoff flight path at which the airplane is 35 feet (dry runway) or 15 feet (wet runway) above the takeoff surface and at the end of the takeoff distance required.