ALBANY, N.Y. (AP) _ An engineer says officials ignored his recommendation to dump more rocks as erosion protection around footings of the New York State Thruway bridge that collapsed April 5, killing 10 people.

The testimony came on the last of three days of hearings by the National Transportation Safety Board on the collapse that spilled cars and a tractor- trailer into the swirling, rain-swollen Schoharie Creek.

Much of Thursday's session focused on the state's renovation of the bridge in 1980.

Barton Colwell, an engineer with the firm of Setson-Harza of Utica, N.Y., testified he examined the bridge in 1977 and recommended to New York State Thruway Authority officials that 600 cubic yards of 600-pound stones, or riprap, be placed around the bridge piers.

''Some of the riprap was not there,'' Colwell testified. ''We recommended that they replace the lost riprap.''

When the state issued the renovation contract, the recommendation for the stones was missing. Colwell said state officials never discussed their reasons for not following the recommendation.

Robert Donnaruma, an assistant chief engineer with the Thruway Authority, testified that neither he nor his colleagues could recall why the recommendation was not in the contract.

Engineers E.V. Richardson of Colorado State University and Peter Deming testified Wednesday that additional riprap might have averted the collapse.

Raymond Robertson, the Thruway inspector who examinined the bridge nearly a one year before it collapsed, told the board of inquiry he found ''no indication everything wasn't fine.''

However, Robertson, who is now retired, said that the water was too deep for him to probe the support piers, and that he recommended an underwater inspection.