S201 AFM
7 - AIRPLANE AND SYSTEMS
DESCRIPTION
7.10 - FUEL SYSTEM
27/06/2019
SONAIR-S2-D-MAN-006
Page : 7-78
Rev. : A
7.10.2
FUEL SELECTOR
Fuel tank feed selection is enabled by a red coloured, three-position (RIGHT,
LEFT, OFF) rotary fuel selector valve, located at the bottom centre of the
instrument panel / front of centre console. Refer to the instrument panel layout
in paragraph 7.5.
An additional round knob must be pulled to move the selection lever through a
detent to the OFF position, preventing inadvertent closure (OFF selection) of the
valve.
7.10.3
FUEL PUMPS
Fuel feed is through two electric pumps. Each pump operates in parallel thanks
to the installed check valves (Non Return Valve).
The main fuel pump is connected directly to the Alternator 1 and the battery,
using a diode bridge. The pump is not operated when Alternator 1 and Battery
Master switch are off.
The auxiliary fuel pump is connected to the main bus which is supplied in power
by Alternators 1 and 2, as well as by the Battery.
If the main pump fails, the auxiliary fuel pump can be operated via power from
the main bus, provided that the charge relay remains energised / is not failed,
the master switch is on and there is no failure of the power supply to the main
bus.
If power to the main bus is unavailable, or the charge relay fails, the charge
system is disconnected from the main bus and battery. In this case the auxiliary
pump is not operative.
WARNING
At least one fuel pump must be operational at all times during flight for
the engine to be operational! With no pump operational engine
stoppage will occur due to fuel starvation.