Primary Inverter Regulator Secondary Inverter Left Main Bus Left Generator Bus Left Generator Starter Right Generator Starter Battery Charging Bus Left Essential Bus Right Essential Bus Right Main Bus Regulator Right Generator Bus AMPS 0 100 200 300 400 AMPS 0 100 200 300 400 DC VOLTS 0 28 35 Current Limiter Circuit Breaker Bus Over Voltage Cutout Left Battery G.P.U. − + Right Battery Figure 14-10.  Simplified schematic of turboprop airplane electrical system. at a constant power. On a warm or hot day, maximum  temperature limits may be reached at a rather low altitude,  making it impossible to maintain high horsepower to higher  altitudes. Also, the engine’s compressor section has to  work harder with decreased air density. Power capability is  reduced by high-density altitude and power use may have  to be modulated to keep engine temperature within limits. rpm that is not high enough for the engine to continue to run  without help from the starter. This is usually the result of  low battery power or the starter not turning the engine fast  enough for it to start properly. Takeoffs in turboprop airplanes are not made by automatically  pushing the power lever full forward to the stops. Depending  on conditions, takeoff power may be limited by either torque  or by engine temperature. Normally, the power lever position  on takeoff is somewhat aft of full forward. In a turboprop airplane, the pilot can close the throttles(s) at  any time without concern for cooling the engine too rapidly.  Consequently, rapid descents with the propellers in low pitch  can be dramatically steep. Like takeoffs and departures,  approach and landing should be accomplished in accordance  with a standard approach and landing profile.  [Figure 14-12] Takeoff and departure in a turboprop airplane (especially a  twin-engine cabin-class airplane) should be accomplished  in accordance with a standard takeoff and departure  “profile” developed for the particular make and model.  [Figure 14-11]  The takeoff and departure profile should be  in accordance with the airplane manufacturer’s recommended  procedures as outlined in the Federal Aviation Administration  (FAA)-approved Airplane Flight Manual and/or the Pilot’s  Operating Handbook (AFM/POH). The increased complexity  of turboprop airplanes makes the standardization of procedures  a necessity for safe and efficient operation. The transitioning  pilot should review the profile procedures before each takeoff  to form a mental picture of the takeoff and departure process. A stabilized approach is an essential part of the approach  and landing process. In a stabilized approach, the airplane,  depending on design and type, is placed in a stabilized descent  on a glidepath ranging from 2.5 to 3.5°. The speed is stabilized  at some reference from the AFM/POH—usually 1.25 to 1.30  times the stall speed in approach configuration. The descent rate  is stabilized from 500 fpm to 700 fpm until the landing flare. Landing some turboprop airplanes (as well as some piston  twins) can result in a hard, premature touchdown if the engines  are idled too soon. This is because large propellers spinning  rapidly in low pitch create considerable drag. In such airplanes,  For any given high horsepower operation, the pilot can expect  that the engine temperature will climb as altitude increases  14-10