Fairchild Industries Inc. yesterday reported net earnings for the second quarter of $5.57 million (30 cents per share), down considerably from last year's second-quarter earnings of $11.89 million (64 cents). Revenues fell to $220.3 million compared with $303.3 million in the same quarter a year before.

The company said the drop in earnings reflected an anticipated decline in deliveries of the A10 aircraft to the Air Force and depressed markets for commercial turboprop aircraft, aerospace fasteners and tooling for plastics. The company said it anticipates some improvement in its commercial and industrial business because of the impact of the economic recovery.

Manor Care Inc. reported a 67 percent increase in profits for its recently ended fiscal year. Higher earnings were also posted by United Services Life Insurance, the Student Loan Marketing Association, A. H. Robins Co., Robertshaw Controls Co., First American Savings and Loan Association, and Dominion Bankshares Corp.

Manor Care reported record profit of $17.18 million ($1.04) for the fiscal year ended May 31. Net income for fiscal 1982 was $10.28 million (68 cents). The company's revenues for the 1983 fiscal year also set a record at $345.65 million compared with $261.35 million in the previous year.

Net income in the fourth quarter was $4.96 million (28 cents) compared with $3.19 (21 cents) a year before on revenues of $84.29 million, compared with $90.22 million for the same quarter a year before.

The company, which owns a chain of nursing homes and hospitals and the Quality Inns lodging chain, said the earnings growth came from its health-care segment and an increase of $3.89 million in pre-tax capital gains in 1983.

The Student Loan Marketing Association, known as Sallie Mae, said second-quarter earnings were up 83 percent to $16.3 million from $8.9 million. Profits for the first half climbed 72 percent to $28.5 million from $16.5 million. Sallie Mae operates a secondary market in government-insured student loans.

United Services Life, an affiliate of International Bank of Washington, said second-quarter profits totaled $5.02 million (81 cents) up from $3.91 million (63 cents) in the same period a year earlier. Revenues of the insurance company grew to $40.45 million from $31.27 million.

For the first half of the year, United Services earned $8.81 million ($1.41) on revenues of $79.42 million, up from $7.22 million ($1.16) on revenues of $61.7 million.

A. H. Robins, the Richmond pharmaceutical company, reported earnings of $13.49 million (55 cents) for the second quarter of 1983 on sales of $136.33 million. In the second quarter of 1982, the company earned $10.91 million (45 cents) on sales of $116.02 million. The company said the second-quarter results showed the strength of the firm's domestic operations.

Robertshaw Controls of Richmond reported net income of $3.43 million (96 cents) on sales of $91.17 million compared with earnings of $1.57 million (45 cents) on sales of $85.47 million in the same quarter a year ago. The company said that several of its major markets have shown continued improvement and that increased consumer demand for new housing, automobiles and appliances have aided sales.

First American Savings and Loan reported earnings for the second quarter of 1983 of $647,625 ($1.61) compared with a loss of $277,979 (69 cents) in the same quarter in 1982. The company credited lower interest rates and increased loan originations for the improvement.

Dominion Bankshares reported second-quarter net income of $6.5 million (67 cents), up from net income of $4.9 million (50 cents) in the comparable quarter a year previous.