APU STARTING IN EXTREMELY COLD WEATHER - Continued
14. Open side APU door
and open AFW
plenum door (13)
To avoid damaging radio
components, turn off all
switches before starting
Turn all electrical and
radio switches off
switch and personnel
Make sure APU
(14) is OFF.
Turn FUEL SHUT OFF switch (15) ON. The LOW OIL PRESSure lamp (16)
will light until APU engine starts.
Turn PREHEAT switch (17) to MOMentary ON. Hold switch ON for 2 min-
TO avoid excessive demand on batteries, do not crank
engine longer than 1 minute at a time. Do not attempt
to start APU for longer than 5 minutes total. if APU
doesnt start in 5 minutes, notify Organizational Main-
While holding PREHEAT switch (17) ON, position and hold START switch (18)
to MOMentary ON. Hoid both switches ON until APU engine starts or until 30
seconds have passed.
If APU engine does not start within 30 seconds, release START
switch (18), but continue to hold PREHEAT switch ON for an-
other minute. After allotted time, turn START switch ON again.
if engine still does not start, turn FUEL SHUTOFF switch OFF
and allow APU to heat for an additional 15 to 30 minutes and
repeat steps 14 through 17. Troubleshoot APU if engine has not
started after this action.