STUDENT GUIDE T-39N/G NATOPS
3. X-FEED: Used for single-engine or if a boost pump has failed. Both x-feed valves
open; both boost pumps ON (even if one Engine Master is off).
4. If balancing is required with X-FEED selected, put the heavy wing high to gravity
H. FUEL LOW PRESS light
1. Either a wing mounted boost pump or the engine driven centrifugal boost pump has
failed. If the light stays ON - Engine driven centrifugal boost pump failed; select NORM. If
the light goes OUT - Wing mounted boost pump has failed.
I. Quantity indicator
1. Two fuel quantity gauges on center instrument panel are primary fuel quantity indicators.
2. Three-position fuel quantity indicator switch located right of pilot's yoke:
a. RH IND RH WING/LH IND AUX -RH gauge indicates right wing fuel quantity.
LH gauge indicates fuselage (aux) fuel quantity.
b. TOTAL-Each gauge indicates half of fuselage and it's respective wing fuel quantity.
c. TEST-Causes fuel quantity indicator needles to rotate counter-clockwise to check
FUEL LEVEL LOW lights (300#)
d. FUEL LEVEL LOW LIGHT is solely a function of gauge reading, not an
3. T-39N only - Digital fuel remaining indicators for co-pilot and each student station.
Accuracy +80# (advisory indicators only)
J. Fueling (Sec 1, part III, Aircraft Servicing)
1. Single point - right wing, inboard, leading edge. (At 50 psi, all tanks fill in 12 mins.)
2. Gravity - port is above right engine; hold wingtip flapper valves (located inside
overwing gravity filler ports) open for ventilation. Each wing can also be filled separately
through overwing gravity filler ports.