jQuery Grid Plugin - jqGrid

im trying to add some useful functionality in my jQgrid, and i need to get keydown on arrow keys. But cellEdit functionality which makes navigation with keys posible - overriding anything I try.

what I want to achieve for start:

    
         cellEdit:true,
         datatype:"json",
         loadComplete : function(){
         $(document).keydown(function( fn ){
             var key = fn.keyCode;
             
             if( key == 40 )
                 console.log('Down Key Pressed');

             if( key > 47 && key < 107)
                 console.log('1-9/A-Z Key Pressed');
             }
         },

this code will return 1-9/A-Z Key Pressed but WILL NOT return anything on arrow keys press;

any ideas why this is a thing and how can I work around it?