TM  1-1520-240-10            4-1-25 8.   MODE   1-4/DCLT   switch   —   DCLT   (1D through 4D). The first DCLT mode that will appear is “1D” (Declutter Mode 1). NOTE If MODE 1-4/DCLT switch is toggled to DCLT a second time the display will cycle back to the DCLT’s  normal  mode  (1N-4N).  The  MODE 1-4/DCLT switch must be set to MODE 1-4 to advance to another normal mode. 9.   Repeat steps 4 through 7, for declutter. 10.   Mode 1-4/DCLT switch — As required. 11.   Repeat steps 4 through 10 until all desired modes are programmed. 12.   P-PGM/CP-PGM/OP switch — OP. WARNING An improperly adjusted barometric altim- eter will result in an improperly set HUD barometric altitude display. NOTE Barometric altimeter set to the most current altimeter settings, field elevation. 4-1-37.  Adjustment  of  Barometric  Altitude,  Pitch, and Roll. 1.   Ensure  P-PGM/OP/CP-PGM  switch  is  in the OP position. 2.   ADJ/ON/OFF switch — Pull and set to ADJ. NOTE Changes to barometric altimeter settings will require a corresponding change to the HUD barometric altitude. Each 0.01 inch change in pressure equals 10 feet. 3.   ADJ blinking in display — Check. 4.   INC/DEC switch — As required for BARO ALT. 5.   BIT/ACK switch — ACK. 6.   Repeat steps 3 through 5 for pitch and roll. 7.   ADJ/ON/OFF switch — ON. 4-1-38.  In-flight Operation. WARNING Whenever the symbology displayed in the DU is suspected of being incorrect the pi- lot will compare the data with the aircraft instrument indicator and take appropriate action. WARNING Excessive  brightness  of  the  symbology display   may   impair   vision   outside   the cockpit. WARNING Interruption  of  electrical  power,  such  as change over from APU generator to NO. 1 and NO. 2 generators and vice versa, will cause  DU  to  default  to  minimum  bright- ness  and  normal  MODE  1N.  Any  adjust- ments  made  to  the  barometric  altitude, pitch  and  roll  prior  to  flight  will  be  lost, thereby  decreasing  the  accuracy  of  the barometric altitude, pitch and roll. 1.   BRT/DIM switch — As desired. NOTE Whenever the symbology is interfering with the  outside  visibility,  declutter  may  be  se- lected to remove symbology. 2.   MODE 1-4/DCLT switch — As required. 4-1-39.  System Shutdown Procedure. 1.   Set ADJ/ON/OFF switch —OFF. 2.   Turn off ANVIS. WARNING CCU ADJ/ON/OFF switch must be OFF be- fore  connecting  or  disconnecting  quick- release connector. WARNING Do not disconnect DU by pulling on the cable  connected  to  the  PSCU.  The  DU could be damage or the cable may sepa- rate from the PSCU creating an explosive atmosphere hazard.