Specifications

SECTION II
MODEL 560 AIRPLANE AND SYSTEMS
ENGINE STARTING
Depressing either engine start button closes the respective start relay and provides DC power to the
engine starter. Power to close the solenoid start relays and energize ignition comes from the battery bus
requiring the battery switch to be in the BATT position. Automatic ignition sequencing takes place with
both engine ignition switches in the NORM position and throttles out of cutoff.
A white light in each starter button indicates power on the contacts of the respective start relay. The
starter operation is terminated when the speed sensor in the generator control unit removes power from
the start relay at approximately 38% N
2
RPM. The automatic start sequence can be terminated at any
time by pushing the cockpit START DISG switch located between the start buttons which will open the
start relay and halt the start sequence. During engine start, if the generators are online and the generator
output exceeds battery voltage and/or is in parallel with the other generator (within 40 amperes), the
starter/generator reverts to generator operation. The power relay closes and supplies power to the
respective DC bus. Current will then flow from either main DC bus through the battery bus, battery relay
and hot battery bus, providing battery charging.
The airplane is equipped with a cross start capability which utilizes the generator of an operating
engine to assist starting the second. This is accomplished by both start relays closing when the second
start is initiated routing power through the hot battery bus to the other engine. On all cross starts, the
operating engine should be set to GND IDLE HIGH to ensure proper torque on the generator shaft. Cross
generator start capability is disabled with weight off the left main gear squat switch in order to prevent
cross starts in flight.
I 56OMB-01 Configuration AA 2-39