Chapter 4 ________________________________________________________________ Operation  
VAISALA_______________________________________________________________________ 81 
ICAOQNH 
The ICAOQNH command selects the calculation formula and 
rounding method used for QNH and QFE calculations. 
For calculation formulas, see Appendix A, Calculation Formulas, on 
page 133. 
ICAOQNH [?] [ON/OFF] 
where: 
?  = Displays the current ICAOQNH status. 
ON  = ICAO QNH calculation formula, QNH and QFE values 
rounded down to nearest integer. Only units [hPa] and [mmHg] 
are available for QNH and QFE. 
OFF = Default QNH calculation formula, no rounding other than 
specified with FORM command on page 70. All pressure units 
for QNH an
d QFE are available. 
 
NOTE 
Although ICAOQNH is ON, you can use the FORM command (on 
page 70) to force the display of decimal places on QNH and QFE 
values. Because of ICAOQNH rounding, these decimal places are 
always filled with zeros. 
 
Query syntax: 
>ICAOQNH ? 
ICAO QNH       : OFF 
> 
Prompt syntax: 
>ICAOQNH 
ICAO QNH       : OFF ? ON 
> 
Command line syntax: 
>ICAOQNH OFF 
ICAO QNH       : OFF 
>