THE HOUSE has passed a bill authorizing $760 million in loans to help homeowners who have lost their jobs and can't meet their mortgage payments. It's a serious problem, but a flawed solution.

The plan would require homeowners to contribute at least 38 percent of disposable income to their mortgage payments. The balance would come in up to 36 months of HUD-administered loans, to be repaid if and when family income rebounds or the house is sold. One or more family members must be involuntarily unemployed. There is no income ceiling, but there is a ceiling-- a high one--on the disposable assets an applicant may have. There is a modest limit on the size of the original mortgage.

The $760 million would serve an estimated 100,000 families, but the demand could be much higher. During 1982 alone, there were nearly 200,000 foreclosures. Federal agencies estimate there are currently 230,000 to 250,000 mortgages delinquent by three or more months. The problem is endemic to communities hit hardest by the recession and declining industries. Some of the affected families have truly major adjustments to make in their lives: their jobs are not coming back.

Still, the House scheme raises some bewildering questions. For instance, how can banks and other lenders be induced to continue present voluntary efforts to give strapped homeowners a break, if there is reason to believe that the feds will pick up the load? The bill's exhortations aren't likely to convince the banks to go along. Furthermore, to be eligible, you have to be delinquent in your mortage payments--a perverse incentive.

Then there is the matter of fairness. What about all of the extra eligible people left when the $760 million runs out; not to mention the people who lost their homes last year? And renters, whose median family income is only half that of owners, and who tend to be in more recession-prone jobs?

The painful fact is that it is simply not possible to immunize every group in the society against the losses inflicted by economic crisis. Those at the bottom have the first claim for relief. Congress can provide the most help for all by doing its part to make the recovery as broad and enduring as possible.