STARTING THE APU IN EXTREMELY COLD WEATHER (continued)
Open side APU door (p. 2-142) and APU plenum door (20), and close side APU door.
To avoid damaging radio components, turn off all electrical and radio switches before starting the
Turn OFF all electrical and radio switches (except MASTER switch and personnel heater switches).
Make sure APU GENerator switch (26) is OFF.
Turn FUEL SHUT OFF switch (21) to ON. The LOW OIL PRESSure lamp (24) will light until APU engine starts.
Turn PREHEAT switch (22) to MOMentary ON. Hold switch ON for 2 minutes.
To avoid excessive demand on batteries, do not crank engine longer than I minute at a time. Do
not attempt to start the APU for longer than 5 minutes total. If the APU doesnt start in 5 minutes,
notify Unit maintenance.
While holding PREHEAT switch (22) at ON, position and hold START switch (25) at MOMentary ON. Hold both
switches at ON until 30 seconds have passed, then release. APU should start.
If APU engine does not start, hold PREHEAT switch (22) at ON for another minute. After allotted time, repeat step
21. If engine still does not start, turn FUEL SHUT OFF switch (21) to OFF and allow the APU to heat for an
additional 15-30 minutes and repeat steps 18 through 21. Troubleshoot the APU if engine has not started after this