TM 55-6930-212-10 8-48.  On CRT page 020, environmental conditions (items 13 through 20) can be edited within the limits shown in table 8- 8. 8-49.  PARAMETER FREEZE. 8-50.  Aircraft flight parameters can be frozen selectively at the IOS by editing lines 1 through 12 on current conditions page  020.    Frozen  parameters  are  flagged  by  an  asterisk  (*).    To  freeze  a  parameter,  type:  LINE  NO.,  SPACE,  *, ENTER.  To unfreeze a parameter, type: LINE NO., SPACE, ENTER. 8-51.  SOUND LEVELS. 8-52.    The  environmental  aircraft  sound  level  (O  9)  can  be  changed  by  editing  the  current  conditions  table  on  the auxiliary information display (AID).  To change sound level, type 20, ENTER.  The appropriate line can then be edited. This  process  requires  use  of  the  keyboard  to  type:  LINE  NO.,  SPACE,  0-9,  ENTER.    The  sound  level  can  also  be reduced to its lowest level by pressing AURAL CUE VOL-LO switchlight. Table 8-8.  Editable Environmental Conditions CRT Page 020 Line No. Abbreviation Description Ranges 13 FUEL Total fuel quantity 0 - full capacity 14 LAT Ownship latitude N/S deg., min., sec. 15 LONG Ownship longitude E/W deg., min., sec. 16 CG Center of gravity Depends on gross wt variable 250 - 400 17 GRWT Gross weight 27,890 - 60.000 lb 18 BARO Barometric pressure 27 - 31,99999 in. Hg 19 OAT Outside air temperature -50 - +500C 20 WV Wind velocity 0 - 64 knots 21 WD Wind direction 0 - 360° 22 TRB LVL Turbulence level 0 - off, 9 - max. 23 SND LVL Sound level 0 - off. 9 - max. 24 GRND PWR Connected to external ON - off ground power 25 CAIRNS WX Selects ATIS weather 0 - off. 1-4 message message 26 SEAT SHAKER Activates seat shaker on - off 27 ICING ENABLE If OAT below freezing, On - off allows simulated ice to degrade flight performance 28 REFILL EXP Refills expendable stores On - off NOTE Expendable stores include battery charge, APU start accumulator, flares, and precharge of cargo hook. 29 CLR SAVED PLOTS Takes saved plots On - off back to zero 30 NVG VIS TRAINING Prevents unexpected selec- On - off tion of normal scene illu- mination during NVG training 8-32