28-22 Low-Fuel Switch Assembly
CAUTION
Avoid contaminating bladder interior. Cover arms with sleeves
and use lint-free gloves when working inside bladder.
A. Schematic
Refer to Figure 98-1 or 98-2 for (single) low fuel warning installation wiring schematic.
Refer to Figure 98-33 for (dual) low fuel warning installation wiring schematic.
B. Removal
1. Defuel helicopter per § 12-42.
2. Open baggage compartment door. Remove G248 (battery compartment) cover.
3. Refer to Figure 28-1. Remove D277-6 clamp or cut and discard safety wire
securing A729 tube to G930-1 drain assembly. Remove screws securing G930-
4 retainer and drain assembly to G250-1 sump tray.
4. Remove fuel cap. Carefully capture A521-2 (single) or A521-4 (dual) switch
assembly body with clean mechanical fingers (avoid capturing float).
5. Inside baggage compartment, remove nut, washer assembly, and spacer securing
switch assembly to tray. Disconnect F049 harness assembly from switch
assembly at connectors; extract switch assembly pins from housing.
6. Carefully pull switch assembly through (fuel cap) opening, avoiding fuel sender.
Install fuel cap and tape bladder opening.
C. Installation
1. Lubricate (new) MS29512-05 packing with A257-6 grease and install packing
over switch assembly threads.
2. Refer to Figure 28-1. Remove fuel cap. Tape A521-2 (single) or A521-4 (dual)
switch assembly wiring to 4-ft length of lockwire; insert other end of wire through
fuel cap opening and through switch assembly opening. Carefully grip switch
assembly body with mechanical fingers and lower switch assembly to bottom
of bladder. Inside baggage compartment, remove tape, guide wiring through
opening, and install spacer, washer assembly, and nut securing switch assembly
to G250-1 sump tray. Special torque nut per § 20-33 and torque stripe per Figure
5-1. Remove tape and lockwire. Release and remove mechanical fingers, and
install fuel cap.
3. Assemble switch assembly pins in housing per Figure 98-1; connect F049 harness
assembly to switch assembly at connectors. Fit wiring through gap in G930-1
drain assembly seal; install G930-4 retainer and screws securing retainer and
drain assembly to tray. Verify security. Seal gap in drain assembly seal where
wires pass thru using B270-5 sealant.
Page 28.10 Chapter 28 Fuel System JUL 2020
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