12.5.6.9 Engine Starting
The starting process is initiated by selecting an engine position using the SELECT switch from
the Engine Start control panel. The starting process is initiated by depressing the START button.
The power source (which feeds the main buses for the supply of the starter/generator) for the
starting process can be different. Therefore, the availability of different power sources results in
the following starting modes:
• Starting from batteries
• Generator assisted starting
• Starting from DC external power
• APU assisted starting
In all cases the BATTERY MASTER, MAIN BATT, AUX BATT, STBY BATT and MAIN BUS TIE
switches are selected on prior to start.
a) Starting from Batteries
Only the main and auxiliary batteries, in parallel, participate in the starting process. The standby
battery is diode isolated from to the left main, to ensure an acceptable level of voltage on the
essential buses during engine start.
NOTE: Observe starter cranking limits.
NOTE: After an aeroplane NiCad battery start, the charge rate for fully serviceable batteries
will decrease after approximately three minutes.
NOTE: Battery temperatures and charging rates must be continuously monitored on the
MFD Electrical page, while charging.
b) Generator Assisted Starting
The generator assisted starting is usually performed, after the start up of an engine is finished (in
any mode of starting). After the right DC generator is connected to the right main bus, together,
in parallel with the batteries, will perform starting of the other engine.
During the start process and 15 seconds following it, the DC GCUs will be supplied with a ‘CUR-
RENT LIMIT’ signal. This will limit the current the opposite side generator will contribute to the
starting and also to limit the current the starter/generator (in generating mode) will supply to the
loads.
Dash8 - Q400 - Electrical
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