ASP.NET MVC framework : requested unknown parameter

I get an error, that I don't understand. I have many tables, that use exactly the same code with only changed Ajax call. And there is no error.

Please help. I am going crazy.....

When I call the table, I see this error:

DataTables warning: table id=myTable - Requested unknown parameter 'ACtype' for row 0.

Screenshot

Here is the index view:

@{
    ViewBag.Title = "Index";
}

<h2>Part 3: Custom multicolumn server-side filtering in jQuery DataTables.</h2>
<div style="width:90%; margin:0 auto">
    @* Search Area *@
    <div style="background-color:#f5f5f5; padding:20px">
        <h2>Search Panel</h2>
        <table>
            <tbody>
                <tr>
                    <td>ACNo</td>
                    <td><input type="text" id="ACNo" /></td>
                    <td>ServiceType</td>
                    <td><input type="text" id="ServiceType" /></td>
                    <td>ACSubType</td>
                    <td><input type="text" id="ACSubType" /></td>

                    <td>
                        <input type="button" value="Search" id="btnSearch" />
                    </td>
                </tr>
            </tbody>
        </table>
    </div>
    @* jQuery DataTables *@
    <div>
        <table id="myTable" class="table table-responsive table-striped">
            <thead>
                <tr>


                    <th>ACNo</th>
                    <th>ScheduleTime</th>
                    <th>EstimateTime</th>
                    <th>ActualTime</th>
                    <th>ChocksTime</th>
                    <th>FlightNo</th>
                    <th>ServiceType</th>
                    <th>ACtype</th>
                    <th>ACSubType</th>
                    <th>IsPax</th>
                    <th>Airport</th>
                    <th>Gate</th>
                    <th>BayNo</th>
                    <th>Airline</th>
                    <th>Description</th>
                    <th>Displace</th>
                    <th>IsArrival</th>
                    <th>JoinDate</th>
                </tr>
            </thead>
        </table>
    </div>
</div>

@* jQuery DataTables css *@
<link href="//cdn.datatables.net/1.10.9/css/jquery.dataTables.min.css" rel="stylesheet" />
@* jQuery *@
@section Scripts{
    <script src="//cdn.datatables.net/1.10.9/js/jquery.dataTables.min.js"></script>
    <script>
        $(document).ready(function () {

            //jQuery DataTables initialization
            $('#myTable').DataTable({
                "processing": true, // for show processing bar
                "serverSide": true, // for process on server side
                "orderMulti": false, // for disable multi column order
                "dom": '<"top"i>rt<"bottom"lp><"clear">', // for hide default global search box // little confusion? don't worry I explained in the tutorial website
                "ajax": {
                    "url": "/home/LoadData",
                    "type": "POST",
                    "datatype": "json"
                },
                "columns": [

                    { "data": "ACNo", "name": "ACNo", "autoWidth": true }, //index 1
                    { "data": "ScheduleTime", "name": "ScheduleTime", "autoWidth": true },             //index 2
                    { "data": "EstimateTime", "name": "EstimateTime", "autoWidth": true },         //index 3
                    { "data": "ActualTime", "name": "ActualTime", "autoWidth": true },               //index 4
                    { "data": "ChocksTime", "name": "ChocksTime", "autoWidth": true },   //index 5
                    { "data": "FlightNo", "name": "FlightNo", "autoWidth": true }, //index 6
                    { "data": "ServiceType", "name": "ServiceType", "autoWidth": true }, //index 7
                    { "data": "ACtype", "name": "ACtype", "autoWidth": true },             //index 8
                    { "data": "ACSubType", "name": "ACSubType", "autoWidth": true },         //index 9
                    { "data": "IsPax", "name": "IsPax", "autoWidth": true },               //index 10
                    { "data": "Airport", "name": "Airport", "autoWidth": true },   //index 11
                    { "data": "Gate", "name": "Gate", "autoWidth": true }, //index 12
                    { "data": "BayNo", "name": "BayNo", "autoWidth": true }, //index 13
                    { "data": "Airline", "name": "Airline", "autoWidth": true },   //index 14
                    { "data": "Description", "name": "Description", "autoWidth": true },             //index 15

                    { "data": "Displace", "name": "Displace", "autoWidth": true },         //index 17
                    { "data": "IsArrival", "name": "IsArrival", "autoWidth": true },   //index 16
                    { "data": "JoinDate", "name": "JoinDate", "autoWidth": true },               //index 18
                ]
            });

            //Apply Custom search on jQuery DataTables here
            oTable = $('#myTable').DataTable();
            $('#btnSearch').click(function () {
                //Apply search for Employee Name // DataTable column index 0
                oTable.columns(0).search($('#ACNo').val().trim());
                //Apply search for Country // DataTable column index 3
                oTable.columns(6).search($('#ServiceType').val().trim());
                //hit search on server
                oTable.columns(8).search($('#ACSubType').val().trim());

                oTable.draw();
            });
        });
    </script>
}

Here is the controller:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Linq.Dynamic;
using Newtonsoft.Json.Linq;

namespace MVCDatatable.Controllers
{
    public class HomeController : Controller
    {
        //
        // GET: /Home/
        public ActionResult Index()
        {
            return View();
        }

        [HttpPost]
        public ActionResult LoadData()
        {
            //jQuery DataTables Param
            var draw = Request.Form.GetValues("draw").FirstOrDefault();
            //Find paging info
            var start = Request.Form.GetValues("start").FirstOrDefault();
            var length = Request.Form.GetValues("length").FirstOrDefault();
            //Find order columns info
            var sortColumn = Request.Form.GetValues("columns[" + Request.Form.GetValues("order[0][column]").FirstOrDefault() 
                                    + "][name]").FirstOrDefault();
            var sortColumnDir = Request.Form.GetValues("order[0][dir]").FirstOrDefault();
            //find search columns info ACNo
            var acNo = Request.Form.GetValues("columns[0][search][value]").FirstOrDefault(); 
            var serviceType = Request.Form.GetValues("columns[6][search][value]").FirstOrDefault();
            var acSubType = Request.Form.GetValues("columns[8][search][value]").FirstOrDefault();

            int pageSize = length != null ? Convert.ToInt32(length) : 0;
            int skip = start != null ? Convert.ToInt16(start) : 0;
            int recordsTotal = 0;

            using (AirportDBEntities dc = new AirportDBEntities())
            {
                var v = (from a in dc.ArrivalFlight select a);

                //SEARCHING...
                if (!string.IsNullOrEmpty(acNo))
                {
                    v = v.Where(a=>a.ACNo.Contains(acNo));
                }

                if (!string.IsNullOrEmpty(serviceType))
                {
                    v = v.Where(a => a.ServiceType == serviceType);
                }

                if (!string.IsNullOrEmpty(acSubType))
                {
                    v = v.Where(a => a.ACSubType == acSubType);
                }

                //SORTING...  (For sorting we need to add a reference System.Linq.Dynamic)
                if (!(string.IsNullOrEmpty(sortColumn) && string.IsNullOrEmpty(sortColumnDir)))
                {
                    v = v.OrderBy(sortColumn + " " + sortColumnDir);
                }

                recordsTotal = v.Count();
                var data = v.Skip(skip).Take(pageSize).ToList();
                return Json(new { draw = draw, recordsFiltered = recordsTotal, recordsTotal = recordsTotal, data = data }, 
                    JsonRequestBehavior.AllowGet);
            }
        }
    }
}