PS Magazine - TB 43-PS-684
PS, The Preventative Maintenance Monthly
ISSUE 684
NOVEMBER 2009
10
PS 684
NOV 09
Dear Editor,
I’ve got some ideas that will help your readers that work on HEMTT
fuel tankers. Your article on page 16 of PS 664 (Mar 08) about
M978 tankers not taking fuel did not address the problem that many
tankers are experiencing. The problem we’ve seen in our Aviation
Ground Support unit is debris in the pressure line going from under
the V12 precheck valve to the V19 valve’s top level (jet sensor) shut
off venturi.
Debris in the system stops the fuel from spraying across the
venturi. Then no pressure
-or not enough pressure-goes out the
output side of the V19 and down to the V14 pilot valve which opens
the V10 valve.
Some tankers have foaming in the V19 box. We’ve seen foaming
through the manhole cover while trying to bottom load or recirculate.
Foaming is caused mostly by air getting into the fuel line on the input
side of the V19. It’s also caused by loose brass elbows on the side
of the V19.
Circulation
For newly RESET HEMTT -A2 tankers, and generally for all HEMTT
tankers that fail to recirculate or bottom load, do this. Trace the
plastic lines connected to the V19 to make sure they are installed
properly. By the way, you’ll find a picture of these lines in the HEMTT
maintenance and parts manuals. The picture in the HEMTT parts
manual has the right and left sides reversed.
Use this schematic
to troubleshoot
tanker fuel system
Tanker Trouble-
hey sarge!
we got a
problem
with the
Tanker!!
shooting Tips
I’ll tell you
and then I’ll
tell PS.
how Do I get
the fuel to
recirculate?
here we
go again!
M978 HEMTT…
684.10-11.indd
1-2
10/1/09
4:46:12 PM
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