Unable to get firstclass value for aircraft

[NWA1999]

Hi,

I'm trying to code functionality within the PIREPData class to divide the inputted passenger amount up into first class, business class,  and economy class,  all randomized but all passengers will make it.  Here's what I've coded 

  $ac = OperationsData::getAircraftByReg($pirepdata['aircraft']);
        $rem=$pirepdata['load'];
        if ($rem<=$ac->firstclass) {
          $first=rand(0,$rem);
          $rem-=$first;
        }
        else {
          $first=rand(0,$ac->firstclass);
          $rem-=$first;
        }
            
        if ($rem<=$ac->busclass) {
          $bus=rand(0,$rem);
          $rem-=$bus;
        }
        else {
          $bus=rand(0,$ac->busclass);
          $rem-=$bus;
        }
          $econ=$rem;
          $rem-=$econ;
          $pirepdata['fclasscount']=$first;
          $pirepdata['bclasscount']=$bus;
          $pirepdata['eclasscount']=$econ;

However all passengers get put in economy. I know my issue is lines like $ac->firstclass, and $ac->busclass. What should these lines be? These values are in my  SQL aircraft table as firstclass, and busclass  columns of each row (aircraft) .

 

Thanks 

Robbie