FUEL SERVICING
GENERAL
Fuel servicing includes those procedures neces-
sary for refueling and adding anti-icing additive.
Fueling is accomplished through a filler in
the top of each tip tank. When gravity refuel-
ing, fuel flows from the tip tanks into the wing
tanks. The fuselage tank is filled by use of
the wing electric standby boost pump(s).
The wide range of temperatures to which jet
fuels are exposed in flight results in sub-
stantial changes in the water solubility of
the fuel and, consequently, in the amount of
free water which must be coped with by the
blending with anti-ice additives. The addi-
tive functions as a freeze-point depressant.
Another important characteristic of this jet
fuel additive is its action as a biocidal agent
which prevents fungal and bacterial growth
in fuel systems and fuel tanks. Thus, when
used in proper amounts, it provides both
anti-icing and microbial growth protection
in a single additive.
Prolonged storage of the airplane will result
in a water buildup in the fuel which “leaches
out” the additive. An indication of this is when
an excessive amount of water accumulates in
the fuel tank sumps. Refer to Section II,
“Normal Operating Procedures,” of the AFM
for checking fuel additive.
SAFETY PRECAUTIONS
The airplane should be fueled only in areas
which permit free movement of fire equipment.
Assure that the fuel truck is grounded to an ap-
proved grounding source. Attach a ground
from fuel truck to airplane nose gear uplatch
roller and ground fuel nozzle to tip tank ground
jack (Figure 5A-9).
APPROVED FUELS AND FUEL
DENSITY ADJUSTMENTS
Approved Fuels
Refer to Section I of the AFM for a listing of
approved fuels. Jet A, Jet A1, Jet B conform-
ing to ASTM ES 2-74, “Emergency Standard
Specification for Aviation Turbine Fuels,” may
be used as temporary fuels until further notice.
Fuel Density Adjustments
If optimum engine acceleration is desired, the
density adjustment knob on the front of the fuel
control unit should be readjusted to the fuel
density setting for the fuel type being used.
Refer to the AFM for recommended fuel con-
trol adjustment knob positions (density setting)
for each fuel type.
5A-14
FOR TRAINING PURPOSES ONLY
LEARJET 20 SERIES PILOT TRAINING MANUAL
FlightSafety
international
Figure 5A-9. Airplane Grounding Points
