Can't push data into array using event method

Ionic Framework ionic-v3
1

I have an ionic template with a checkbox .The condition is that once the value checked , the value should pass into the user_filter array(user_filter array already declared and working well). While i clicked on the select box the console1 value displayed but the console 2 not , means the data doesn’t entered in the array .Does any one know the reasons! …
<

<ion-item>
                    <ion-label>Non A/C</ion-label>
                    <ion-checkbox (click)="choose_type('type','Non A/C',$event)"></ion-checkbox>

                </ion-item>

choose_type(type: string, value: any, event: { target: { checked: boolean; }; }) {

 console.log('Inside choose type function'); //console1
    let index;
     console.log('Boolean value',event.target.checked);
    if (event.target.checked === true) {
 console.log('Inside ture value'); //console2
       console.log('Value checked true');
        this.user_filter[type].push(value);

    }
     else
      {
        index = this.user_filter[type].indexOf(value);
        this.user_filter[type].splice(index, 1);
    }
    console.log('User filter array',this.user_filter);
}