diff --git a/projects/ngx-sub-form/src/lib/helpers.ts b/projects/ngx-sub-form/src/lib/helpers.ts
index d7e99685..55e7304b 100644
--- a/projects/ngx-sub-form/src/lib/helpers.ts
+++ b/projects/ngx-sub-form/src/lib/helpers.ts
@@ -155,7 +155,7 @@ export function createFormDataFromOptions<ControlInterface, FormInterface>(
 export const handleFArray = <FormInterface>(
   formArrayWrappers: FormArrayWrapper<FormInterface>[],
   obj: FormInterface,
-  createFormArrayControl: NgxSubFormArrayOptions<FormInterface>['createFormArrayControl'] | null,
+  createFormArrayControl: Required<NgxSubFormArrayOptions<FormInterface>>['createFormArrayControl'],
 ) => {
   if (!formArrayWrappers.length) {
     return;
@@ -177,11 +177,7 @@ export const handleFArray = <FormInterface>(
     }
 
     for (let i = control.length; i < value.length; i++) {
-      if (createFormArrayControl) {
-        control.insert(i, createFormArrayControl(key as ArrayPropertyKey<FormInterface>, value[i]));
-      } else {
-        control.insert(i, new FormControl(value[i]));
-      }
+      control.insert(i, createFormArrayControl(key as ArrayPropertyKey<FormInterface>, value[i]));
     }
   });
 };
diff --git a/projects/ngx-sub-form/src/lib/ngx-sub-form.ts b/projects/ngx-sub-form/src/lib/ngx-sub-form.ts
index 5491ed3d..601f586c 100644
--- a/projects/ngx-sub-form/src/lib/ngx-sub-form.ts
+++ b/projects/ngx-sub-form/src/lib/ngx-sub-form.ts
@@ -1,3 +1,4 @@
+import { FormControl } from '@angular/forms';
 import isEqual from 'fast-deep-equal';
 import { getObservableLifecycle } from 'ngx-observable-lifecycle';
 import { EMPTY, forkJoin, Observable, of, timer } from 'rxjs';
@@ -14,7 +15,13 @@ import {
   tap,
   withLatestFrom,
 } from 'rxjs/operators';
-import { isNullOrUndefined } from './shared/ngx-sub-form-utils';
+import {
+  ArrayPropertyValue,
+  isNullOrUndefined,
+  OneOfControlsTypes,
+  TypedAbstractControl,
+  TypedFormControl,
+} from './shared/ngx-sub-form-utils';
 import {
   createFormDataFromOptions,
   getControlValueAccessorBindings,
@@ -25,6 +32,7 @@ import {
 import {
   ComponentHooks,
   ControlValueAccessorComponentInstance,
+  CreateFormArrayControlMethod,
   FormBindings,
   FormType,
   NgxFormOptions,
@@ -36,8 +44,9 @@ import {
 } from './ngx-sub-form.types';
 
 const optionsHaveInstructionsToCreateArrays = <ControlInterface, FormInterface>(
-  options: NgxSubFormOptions<ControlInterface, FormInterface>,
-): options is NgxSubFormOptions<ControlInterface, FormInterface> & NgxSubFormArrayOptions<FormInterface> => true;
+  options: NgxFormOptions<ControlInterface, FormInterface> & Partial<NgxSubFormArrayOptions<FormInterface>>,
+): options is NgxSubFormOptions<ControlInterface, FormInterface> & NgxSubFormArrayOptions<FormInterface> =>
+  !!options.createFormArrayControl;
 
 // @todo find a better name
 const isRoot = <ControlInterface, FormInterface>(
@@ -181,19 +190,18 @@ export function createForm<ControlInterface, FormInterface>(
       ? lifecyleHooks.onDestroy.pipe(mapTo(null))
       : EMPTY;
 
+  const createFormArrayControl: Required<NgxSubFormArrayOptions<FormInterface>>['createFormArrayControl'] =
+    optionsHaveInstructionsToCreateArrays<ControlInterface, FormInterface>(options) && options.createFormArrayControl
+      ? options.createFormArrayControl
+      : (key, initialValue) => new FormControl(initialValue);
+
   const sideEffects = {
     broadcastValueToParent$: registerOnChange$.pipe(
       switchMap(onChange => broadcastValueToParent$.pipe(tap(value => onChange(value)))),
     ),
     applyUpstreamUpdateOnLocalForm$: transformedValue$.pipe(
       tap(value => {
-        handleFormArrays<FormInterface>(
-          formArrays,
-          value,
-          optionsHaveInstructionsToCreateArrays<ControlInterface, FormInterface>(options)
-            ? options.createFormArrayControl
-            : null,
-        );
+        handleFormArrays<FormInterface>(formArrays, value, createFormArrayControl);
 
         formGroup.reset(value, { emitEvent: false });
 
@@ -241,7 +249,6 @@ export function createForm<ControlInterface, FormInterface>(
     get formGroupErrors() {
       return getFormGroupErrors<ControlInterface, FormInterface>(formGroup);
     },
-    // todo
-    createFormArrayControl: (options as any).createFormArrayControl,
+    createFormArrayControl,
   };
 }
diff --git a/projects/ngx-sub-form/src/lib/ngx-sub-form.types.ts b/projects/ngx-sub-form/src/lib/ngx-sub-form.types.ts
index d219548f..18bad61d 100644
--- a/projects/ngx-sub-form/src/lib/ngx-sub-form.types.ts
+++ b/projects/ngx-sub-form/src/lib/ngx-sub-form.types.ts
@@ -7,6 +7,7 @@ import {
   Controls,
   ControlsNames,
   NewFormErrors,
+  OneOfControlsTypes,
   TypedFormGroup,
 } from './shared/ngx-sub-form-utils';
 import { FormGroupOptions } from './shared/ngx-sub-form.types';
@@ -33,18 +34,20 @@ export interface NgxSubForm<FormInterface> {
   readonly formGroup: TypedFormGroup<FormInterface>;
   readonly formControlNames: ControlsNames<FormInterface>;
   readonly formGroupErrors: NewFormErrors<FormInterface>;
-  readonly createFormArrayControl: any;
+  readonly createFormArrayControl: CreateFormArrayControlMethod<FormInterface>;
 }
 
+export type CreateFormArrayControlMethod<FormInterface> = <K extends ArrayPropertyKey<FormInterface>>(
+  key: K,
+  initialValue: ArrayPropertyValue<FormInterface, K>,
+) => FormControl;
+
 export interface NgxRootForm<ControlInterface> extends NgxSubForm<ControlInterface> {
   // @todo: anything else needed here?
 }
 
 export interface NgxSubFormArrayOptions<FormInterface> {
-  createFormArrayControl?: (
-    key: ArrayPropertyKey<FormInterface>,
-    value: ArrayPropertyValue<FormInterface>,
-  ) => FormControl;
+  createFormArrayControl?: CreateFormArrayControlMethod<FormInterface>;
 }
 
 export interface NgxSubFormRemapOptions<ControlInterface, FormInterface> {
diff --git a/src/app/main-rewrite/listing/listing-form/vehicle-listing/crew-members/crew-members.component.ts b/src/app/main-rewrite/listing/listing-form/vehicle-listing/crew-members/crew-members.component.ts
index 99c98c34..434ecdb0 100644
--- a/src/app/main-rewrite/listing/listing-form/vehicle-listing/crew-members/crew-members.component.ts
+++ b/src/app/main-rewrite/listing/listing-form/vehicle-listing/crew-members/crew-members.component.ts
@@ -27,10 +27,7 @@ export class CrewMembersComponent {
     fromFormGroup: (formValue: CrewMembersForm): CrewMember[] => {
       return formValue.crewMembers;
     },
-    createFormArrayControl: (
-      key: ArrayPropertyKey<CrewMembersForm> | undefined,
-      value: ArrayPropertyValue<CrewMembersForm>,
-    ) => {
+    createFormArrayControl: (key, value) => {
       switch (key) {
         case 'crewMembers':
           return new FormControl(value, [Validators.required]);