I can't access currect class properities

export abstract class ControlInterface<
    A extends {} = {},
    I extends ControlInterfaceModel = ControlInterfaceModel,
> extends Endpoint {
    declare attributes: A;
    declare instance: I;

    constructor(socketAddress: socketAddress) {
        super(socketAddress);
        RunService.Heartbeat.Connect((delta) => {
            this.update(delta);
        });
    }
public abstract update(delta): void;

export abstract class ControlInterface<
    A extends {} = {},
    I extends ControlInterfaceModel = ControlInterfaceModel,
> extends Endpoint {
    declare attributes: A;
    declare instance: I;

    constructor(socketAddress: socketAddress) {
        super(socketAddress);
        RunService.Heartbeat.Connect((delta) => {
            this.update(delta);
        });
    }
public abstract update(delta): void;

export class RudderComponent extends ControlInterface<IAttributes, Rudder> {
        public idk = 1;  
    constructor() {
        const address: socketAddress = {
            address: 5,
            direction: directions.INPUT,
            port: inputPorts.AIRSHIP_SPEED,
        };
        super(address);
    }

        update(delta) {
          // for some reason I can access in this method to delta but not to idk
          }

export class RudderComponent extends ControlInterface<IAttributes, Rudder> {
        public idk = 1;  
    constructor() {
        const address: socketAddress = {
            address: 5,
            direction: directions.INPUT,
            port: inputPorts.AIRSHIP_SPEED,
        };
        super(address);
    }

        update(delta) {
          // for some reason I can access in this method to delta but not to idk
          }