Fuel Low Press light

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

transfer 100#/minute.

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

independent measure.

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.

FUEL SYSTEM

2-3