OPINION
In this child support appeal, Maureen Keating, a pro se litigant, challenges the trial court’s modification order. The order, which was prompted by a motion from the Child Support Enforcement Division (CSED), provided for less on-going support than the father, Terence Traynor, had earlier agreed to pay. 1 Keating argues that the *696 trial court should have classified Traynor’s future permanent fund dividends as ongoing support in accordance with the stipulation she and Traynor executed in May 1989. Keating also claims that “[n]o evidence was introduced as to Traynor’s ability to pay” and that the “order was entered without due regard [for her child’s] needs.” Brief of Appellant at 10.
CSED argues that Keating is not a proper party to bring this appeal because she assigned her support rights to the agency, and the trial court never formally granted her request to intervene in the action. The agency also claims that the trial court acted within its discretion in modifying its earlier child support order without making findings of fact for the record.
As a threshold matter, we hold that Keating’s appeal is permissible because she clearly had a right to intervene
2
and, as a
pro se
litigant, she should have been instructed by the trial court on the proper procedures for intervention. In a letter to the trial judge, Keating sought permission to intervene and specifically asked the judge to inform her whether she had to “make this request by a formal pleading.” Under
Breck v. Ulmer,
Nevertheless, appellate review of the trial court’s modification order is hampered by the trial court’s failure to make factual findings.
See
Civil Rule 52(a);
see also Headlough v. Headlough,
Moreover, it appears that the trial court modified the support award without following Civil Rule 90.3 guidelines. The trial judge never once referred to Civil Rule 90.3 in any of his child support orders nor does it appear that the guidelines were followed. Keating and Traynor arrived at the $1,500 plus permanent fund dividend level of on-going support in their private stipulation. The fact that the trial judge used the $1,500 figure as the amount of ongoing support in the modification order indicates that the award was not calculated based on Traynor’s current income.
We have held that a parent may not waive the requirements of Rule 90.3 by private agreement.
Bergstrom v. Lindback,
*697 Accordingly, we remand this case so that the trial court may recalculate the child support obligation pursuant to Rule 90.3 and make appropriate findings of fact. 3 The trial court should also formally grant Keating intervenor status.
The modification order is VACATED, and the case is REMANDED with instructions.
Notes
. The trial court’s original support order, which was based on a settlement agreement between *696 Keating and Traynor, provided for on-going support in the amount of $1,500 for each six-month period plus Traynor’s yearly permanent fund dividend. The modification order reduced Traynor’s on-going child support obligation to $1,500 for each six-month period.
. Once CSED sought to modify the prior support order, partly to insure that the state would be reimbursed before any arrearages would be paid, Keating’s interests diverged from CSED. She had an interest in arrearages as well as in obtaining the highest level of on-going support for her son. Based on our review of CSED's supporting memorandum, we conclude that this interest was inadequately represented by CSED and could have been impaired as a consequence of the proposed modification. Keating’s informal request for intervenor status, written within a few days of CSED's motion to modify the support award, must be considered timely. Consequently she meets the requirements for intervention of right. See Civil Rule 24(a).
. Keating also argues in this appeal that Tray-nor’s permanent fund dividends should be applied to reduce child support arrearages before the state is allowed to reimburse itself for past public assistance. She maintains that any other distribution is violative of federal law. As to money that the state has already recovered, Keating’s argument lacks merit. Our statutes make clear that once on-going support is properly established, any excess amount can be applied to reimburse the state before arrearages are paid because an Aid to Families with Dependent Children recipient assigns "all rights to accrued and continuing support that the applicant ... may have sought from all sources.” AS 47.25.345 (1990).
In
In re Stovall,
