BMS F-16C/D 4.34, Руководство по эксплуатации самолета

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T.O. BMS1F-16CM-1 BMS 4.34 Change 2.00
BMS 4.34 Dash 1
© Red Dog 2012-2019
Page: 122
The normal path of a drop of fuel in either the A/L or F/R system would be:
From the external tank to the wing tank to the fuselage tank to the reservoir fuselage tank to the
engine.
This path is illustrated on the image above by the dark red or dark green arrows.
So the external wing tank(s) always empty first into the relevant internal wing tank.
The wing tank transfers to the relevant fuselage tank: Right wing goes to Forward fuselage and Left
wing goes to Aft fuselage tank).
Each fuselage tank transfers to its relevant reservoir tank before being fed to the engine.
The only exception to that as noted above is the centreline external tank that feeds both wing tanks at
the same time.
The normal path of a drop of fuel at filling (on the ground for Hotpit refuel
– or in the air during A/A
refuel) would be: from the receptacle to the centreline tank (if carried) to the wing tank and to the
external wing tanks if carried. This path is illustrated on the image above by grey arrows.
1.7.1. Fuel SHUTOFF valve.
The fuel shutoff valve illustrated on the image above allows the engine to be starved of fuel. That
valve is driven by the MASTER FUEL switch located on the FUEL panel on the left side console.
The switch has two positions MASTER and OFF and is guarded in the MASTER position. In some air
forces it is even securely wired and cannot be moved by the pilot unless in an emergency.
In BMS that switch is in MASTER at all times as well, especially at ramp start. You should never shut
down the engine by shutting off the fuel valve. You would only shut it off in case of emergency to
prevent a fire when crash landing for instance.
1.7.2. Fuel pumps
The primary transfer system for fuel through tanks and to the engine is by gravity and siphoning
but it is also
backed up by pumps as gravity wouldn’t drain a tank fully and wouldn’t work correctly in
negative G situations. Fuel pumps therefore operate at the same time and independently of gravity
feed.
Fuel is pumped from both reservoir fuselage tanks to the Fuel Flow Proportioner (FFP) which adjusts
flow rates from both the F/R and A/L systems to maintain the balance of fuel and hence the centre of
gravity (CG) position. The FFP is driven by the A hydraulic system.
It is thus possible to have fuel imbalance problems occurring even when pumps are operating if there
is a failure on hydraulic BUS A which drives the FFP.