The trustees of four employee benefit funds appeal the district court’s judgment for the employer in their action under the Employee Retirement Income Security Act (“ERISA”), 29 U.S.C. § 1132 (1976 & Supp.' V 1981), to enforce payment of trust fund contributions. We reverse.
FACTS AND PROCEEDINGS BELOW
McGoldrick, the owner of a consulting engineering firm, signed a short form collective bargаining agreement with Local Union No. 12 of the International Union of Operating Engineers (“Local 12”). The short form agreement incorporates by reference the Master Survey Agreement, which obligates the employer to make contributions to the several trusts at specified rates for “hours worked by (or paid) each еmployee under this Agreement....” 1
McGoldrick had one full-time salaried union employee who split his work time between surveying, which is covered under the Master Survey Agreement, and office work, which is not. At the time of contracting, a Local 12 representative and McGoldrick discussed the required contributions. The district court found that the parties agreed orally that McGoldrick would contribute to the trust funds based only on the minimum hours necessary for his employee to maintain eligibility for benefits. McGoldrick reported and contributed to the trusts based on 200 hours per calendar quarter,, the minimum hours necessary for benefit eligibility.
The trustees filed suit.under section 301 of the Labor Management Relations Act, 29 U.S.C. § 185 (1976), and ERISA, 29 U.S.C. § 1132(e) (1976), to collect allegedly delinquent contributions. After a bench trial, the district court found no liability for delinquent contributions and awаrded McGol-drick attorney’s fees.
The district court stated the issue as whether the Master Survey Agreement re *996 quires the employer of a salaried union member to make fringe benefit contributions for a 40-hour week when the employee actually does union-covered work for substantially fewer hours. The district court held that the Mаster Survey Agreement was ambiguous on this point. The court then found the oral understanding between Local 12 representatives and McGoldrick at the time of contrаcting controlled the interpretation of the Master Survey Agreement.
The trustees appeal the judgment for McGoldrick. They also appeal the award of attorney’s fees in the event the judgment is affirmed. If the judgment is reversed, the trustees claim a right to fees for themselves under 29 U.S.C. § 1132(g)(2) (Supp. IV 1981).
ISSUES
1. Did the district court err in relying on oral understandings between union officials and the employer to interpret employee benefit provisions in the Master Survey Agreement?
2. Were attorney’s fees properly awarded?
STANDARD OF REVIEW
The interpretation of a contractual provision is a question of law reviewed
de novo. Construction Teamsters Health and Welfare Trust v. Con Form Construction Corp.,
INTERPRETING EMPLOYEE BENEFIT PROVISIONS
Federal law governs рarties’ rights in actions such as this under the Labor Management Relations Act.
Waggoner v. Dallaire,
A collective bargaining agreement is nоt governed by the same principles of interpretation applicable to private contracts.
Transportation-Communication Employees Uniоn v. Union Pacific Railroad Co.,
Section 302(c)(5) of the Labor Management Relations Act, 29 U.S.C. § 186(c)(5) (1976 & Supp. V 1981), permits employer contributions to employee welfare trust funds, but requires that the detailed basis on which such payments are made be set forth in writing.
San Pedro Fishermen’s Welfare Trust Fund v. Di Bernardo,
*997 In light of the statutory requirement of written employee benefit trust provisions, the legislative purpose underlying the statute, and the cases in our circuit, the district court erred in applying oral understandings to interpret the disputed language.
Employee benefit provisions in the industry-wide Master Labor Agreement similar tо these at issue here have been interpreted by this court for split-work employees such as McGoldrick’s employee.
Waggoner v. C & D Pipeline Co.,
In light of these holdings, interpretation of the disputed language in the Master Survey Agreement is controlled by interpretations of similar language in the Master Labor Agreement.
See Transportation-Communication Employees,
McGoldrick may have been misled by Local 12 representatives'. Under the prevailing law, however, that does not affect his obligation to the employee benefit trusts.
E.g., Dallaire,
ATTORNEY’S FEES
The district court relied on 29 U.S.C. § 1132(g)(1) (Supp. V 1981), as amended in 1980, as authority for awarding attorney’s fees to McGoldrick. We need not decide whether an аward of attorney’s fees to a prevailing employer is proper since we find the trustees prevail on the issue appealed. However, 29 U.S.C. § 1132(g)(2) (Supp. V 1981) now makes the award of attorney’s fees mandatory when the trustees prevail in actions to enforce and collect benefit fund contributions.
Di Bernardo,
The judgment of the district court is REVERSED and the case REMANDED for further proceedings consistent with this opinion.
Notes
. This language is taken from Article XV, Health & Welfare Fund, of the Master Survey Agreement. The languagе in the provisions for the other three employee benefit funds is iden-tical in all relevant respects.
. We note that McGoldrick asserted other defenses at trial, but the district court did not rule on them. The parties did not brief or argue the other defenses on appeal and we decline to rule on them. Any issue not expressly or impliedly disposed of on appeal is left open for the trial court’s reconsideration on remand. Beltran v.
Myers,
We think it preferable that district courts make findings of fact and conclusions of law after a bench trial on every issue presented to it. Such a practice would make appellate re *998 view more efficient and avoid piecemeal appeals. In this case, however, it is necessary for us to remand for further proceedings in the trial court.