Tempest Technologies Inc. of Herndon, citing two large one-time charges, reported losses for the fiscal year and fourth quarter ended March 31.

The computer services company, which modifies computers and peripheral equipment to comply with a federal government standard for protection against electronic surveillance, called the Tempest standard, said it lost $1.3 million in the fiscal year, compared with a profit of $316,000 (4 cents a share) in fiscal 1989.

Revenue fell 5.4 percent during the fiscal year, to $8.1 million from $8.6 million.

For the fourth quarter, Tempest lost $1.2 million, compared with a profit of $148,000 (2 cents) in the fiscal 1989 fourth quarter. Its revenue fell 26 percent in the quarter, to $1.97 million from $2.66 million.

Tempest, majority-owned by another Herndon-based company, C3 Inc., said it took a $348,000 charge for the write-down of inventory and set aside $890,000 for its remaining obligation on the lease of its Spring Park facility in Herndon after deciding it would no longer use the building.

The continued slowdown in defense spending and overall softness in the market for Tempest-standard computers also cut into revenue, said Tempest. It added that it is developing new products to diversity into non-defense businesses and expects that strategy to help in the future.