php - Why does time() malfunction after midnight in my MySQL query?

Question

I have two tables that my Query affects. The tables are called flightSched & Alteration. In both tables the arrivalTime column is of type TIME.

The query runs just fine until the $CurrentTimePlus4Hours variable elapses midnight. When this happens, the query doesn't yield any records, although the table has data ranging from all times of the day and night. Find below my code.

$currentDay = date('l');
$CurrentTimeMinus30min = date('H:i:s', strtotime('-30 minutes'));
$CurrentTimePlus4Hours = date('H:i:s', strtotime('+240 minutes'));

$query2  = "SELECT * FROM flightSched WHERE don = '$currentDay' 
                 AND depOrArriv='Arrival' 
                 AND arrivalTime BETWEEN '$CurrentTimeMinus30min' AND '$CurrentTimePlus4Hours'
                 ORDER BY arrivalTime ASC ;";

$query2 .= "SELECT * FROM Alteration WHERE don = '$currentDay' 
                 AND depOrArriv='Arrival'
                 AND arrivalTime BETWEEN '$CurrentTimeMinus30min' AND '$CurrentTimePlus4Hours'
                 ORDER BY arrivalTime ASC ;";

/* execute multi query */
if ($mysqli->multi_query($query2)) {

        do
        {
                if ($result = $mysqli->store_result()) {
                  while ($row = $result->fetch_array()) {
        echo "<tr " . $variable . "><td>"; 
        echo '<img src="php/displayImage.php?id=' . $row['id'] . ' "align="middle" width="110" height="35" >' . "&nbsp;&nbsp;&nbsp;  "
             . $row['flightNo'] ;
        $flightNo = $row['flightNo'];
        echo "</td><td>"; 
        echo $row['airline'];
        echo "</td><td>"; 
        echo $row['origin'];
        echo "</td><td>"; 
        echo $row['arrivalTime'];
        echo "</td><td>"; 
        echo $row['status'];
        echo "</td></tr>"; 

        if ($variable == 'id=basicBoard')
        {
        $variable = 'class=alt';
        //echo $variable;
        } 
    elseif ($variable == 'class=alt')
        {
        $variable = 'id=basicBoard';
        //echo $variable;
        } 
                  }
                  $result->free();
               }
               /* print divider */
               if ($mysqli->more_results()) {
            //    printf("-----------------</br>");
               }

        }
        while (@$mysqli->next_result());
echo "</table> <br/> <br/>";

}

I have tried to figure out why this happens but failed to fix the issue. Can someone kindly point out where I am going wrong in the code?