sales decrease discussed above. Gross profit in the Asset Management Solutions segment decreased $52.1 million to $29.4 million, or 63.9%, for the six months ended June 30, 2023, compared to the six months ended June 30, 2022. The gross profit decrease is mainly attributable to lower revenue generated for the six months ended June 30, 2023, as noted above.
Aircraft gross profit margins decreased to 27.6% for the six months ended June 30, 2023, from 38.0% for the six months ended June 30, 2022, due to lower margin on Flight Equipment sales and USM sales. Engine gross profit margin was 39.5% for the six months ended June 30, 2023, a decrease from 46.3% for the six months ended June 30, 2022, which was primarily the result of lower margins on Flight Equipment sales, partly offset by higher margins on USM sales and leasing activity.
TechOps
Our revenue from TechOps decreased by $11.2 million, or 15.3%, to $62.1 million for the six months ended June 30, 2023, compared to the prior year period. The decrease was primarily driven by the sale of Flight Equipment during 2022, which was purchased and controlled by the TechOps segment prior to its ultimate sale, along with improved component repair activities and heavy MRO services.
Cost of sales in TechOps decreased $6.2 million, or 11.7%, to $47.0 million for the six months ended June 30, 2023, compared to the prior year period, driven by costs generated from the sale of Flight Equipment of $16.0 million during the six months ended June 30, 2022, partially offset by cost associated with revenue fluctuations noted above. Gross profit in TechOps decreased $5.0 million, or 25.0%, for the six months ended June 30, 2023, compared to the six months ended June 30, 2022, driven by the profit generated from the sale of Flight Equipment of $7.5 million, partially offset by higher gross profit of $2.4 million on MRO services. Gross profit margin decreased to 24.3% for the six months ended June 30, 2023 compared to 27.5% for the six months ended June 30, 2022, and was largely attributable to the margin generated from the sale of Flight Equipment of 31.9% for the six months ended June 30, 2022, partially offset by improved margins on MRO services of 23.7% for the six months ended June 30, 2023, compared to 23.6% during the six months ended June 30, 2022.
Selling, General and Administrative Expenses
Selling, general and administrative expenses increased $5.0 million, or 10.7%, to $52.3 million for the six months ended June 30, 2023, compared to the prior year period. The increase was mostly related to Company-wide cost of living adjustments, additional headcount, along with higher facility and legal costs incurred in the normal course of business.
Change in Fair Value of Warrant Liability
We account for our private warrants as a liability at their fair value, with changes in fair value recognized in our results from operations for the period. The fair value of our private warrants is determined using a Black Scholes option pricing model. For the six months ended June 30, 2023, we recorded a $1.1 million change in fair value of the warrant liability income, compared to a $0.1 million income in the prior year period.
Interest Income (Expense), Net
Interest income, net for the six months ended June 30, 2023 was $1.4 million and was primarily related to interest earned on cash deposits. Interest expense, net for the six months ended June 30, 2022 was $0.4 million, and was primarily related to unused balance fees on the Revolving Credit Agreement.
Income Taxes
The effective tax rate for the six months ended June 30, 2023 was 45.6% compared to 20.1% for the six months ended June 30, 2022. The difference between the effective tax rate and the statutory tax rate of 21% for the six months ended June 30, 2023 is primarily due to the impact of state income taxes and non-deductible executive compensation, offset by the foreign derived intangible income deduction and R&D credits. The difference between the effective tax rate