Airplane Flight Manual Supplement

Hawker Beechcraft C90A and C90GT King Air 190-00682-02 Rev. C
Page 86 of 95
ENGINE INSTRUMENTATION
Engine instruments, located in a window on the left side of the MFD, are grouped according to their
function. The G1000 engine gauges are constructed and arranged to emulate the mechanical gauges
they replaced. At the top, the ITT (Interstage Turbine Temperature) indicators and torquemeters are
used to set take-off power. Climb and cruise power are established with the torquemeters and propeller
tachometers while observing ITT limits. Gas generator (N
1
) operation is monitored by the gas generator
tachometers. The lower grouping consists of the fuel flow indicators and the oil pressure/temperature
indicators.
The engine transducers send their signals to the Garmin GEA (Engine and Airframe LRU) where the
analog signals are converted to digital signals where the engine parameters are displayed on the MFD.
There are two GEAs, one for each engine. The GEAs operate on 28vdc power supplied by the triple fed
bus and are protected by circuit breakers normally located on the left side circuit breaker panel labeled
ENG INST. Some configurations will have the ENG INST circuit breakers located on the right side circuit
breaker panel.
The ITT indicator gives a reading of engine gas temperature between the compressor turbine and the
power turbines. A digital indication combined with the pointer gives a resolution of 1
O
C.
The torquemeters give an indication in foot-pounds of the torque being applied to the propeller. A digital
indication combined with the pointer gives a resolution of 5 ft-lbs.
The propeller tachometer reads directly in revolutions per minute. A digital indication combined with the
pointer gives a resolution of 10 rpm.
The N
1
or gas generator tachometer is in percent of rpm, based on a figure of 37,500 rpm at 100%.
Maximum continuous gas generator speed is limited to 38,100 rpm or 101.5% N
1
. A digital indication
combined with the pointer gives a resolution of 0.1% rpm.
The fuel flow indicators give an indication of fuel consumption in pounds of fuel per hour. A digital
indication combined with the pointer gives a resolution of 1 lb/hr.
The oil pressure indicator displays oil pressure (in PSI). A digital indication combined with the pointer
gives oil pressure a resolution of 1 psi.
The oil temperature indicator displays oil temperature (in Degrees Celsius). A digital indication
combined with the pointer gives oil temperature a resolution of 1
O
C
A propeller synchroscope located above and between the propeller tachometers, gives an indication of
synchronization of the propellers. When the propellers are operating at the same rpm, the display will
show stationary diamond symbols. As one propeller begins to turn faster than the other propeller, the
diamonds will begin to move towards the faster turning propeller and transition into an arrowhead pointing
towards the faster turning propeller. The transition to a full arrowhead is complete when the propeller
speed difference is equal to 50 rpm. This instrument aids the pilot in obtaining synchronization of the
propellers.