Asset Management Solutions
Sales in the Asset Management Solutions segment decreased $1.6 million or 5.1%, to $29.3 million for the three months ended March 31, 2021, from $30.8 million for the three months ended March 31, 2020. This was primarily due to a $3.8 million, or 26.6%, decrease in revenues from Aircraft, partially offset by a $2.2 million, or 13.3%, increase in revenues from Engines. The decrease in Aircraft revenues is primarily attributable to decreased activity in the B747 product line as a result of lower leasing activity in the amount of $3.2 million. The increase in Engines revenues is primarily attributable to increased activity in the PW4000 product line as a result of higher trading volume, resulting in an increase of $8.2 million, partially offset by lower leasing and USM sales in the CF6-80, V2500, and CFM56 product lines totaling $6.3 million. The reductions in leasing and USM sales are attributable to the global decrease in demand for flight hours in response to the COVID-19 pandemic.
Cost of sales in Asset Management Solutions segment decreased $3.4 million or 17.8%, to $15.7 million for the three months ended March 31, 2021, compared to $19.1 million for the three months ended March 31, 2020. The decrease in cost of sales was primarily driven by the sales decrease discussed above. Gross profit in the Asset Management Solutions segment increased $1.8 million or 15.5%, to $13.6 million for the three months ended March 31, 2021, from $11.8 million for the three months ended March 31, 2020. The margin increase is mainly attributable to higher margins generated on flight equipment sales.
Aircraft gross profit margins increased to 42.7% for the three months ended March 31, 2021, from 25.7% for the three months ended March 31, 2020 due to higher margins generated by flight equipment sales as noted above. Engines gross profit margins was 48.5% for the three months ended March 31, 2021, a decrease from 48.8% for the three months ended March 31, 2020, which was primarily the result of lower leasing revenues driven by lower asset utilization by many of our customers.
TechOps
Our revenue from TechOps increased by $2.9 million or 10.9%, to $29.2 million for the three months ended March 31, 2021, compared to $26.3 million for the three months ended March 31, 2020. The increase was primarily driven by increased demand for maintenance and storage programs, including preservation work, as a result of the increase in fleet groundings due to reduced passenger flight volume related to COVID-19.
Cost of sales in TechOps increased $0.1 million or 0.7%, to $22.9 million for the three months ended March 31, 2021, from $22.8 million for the three months ended March 31, 2020, which is directly related to improved margins. Gross profit in TechOps increased $2.7 million or 77.6%, to $6.2 million for the three months ended March 31, 2021, compared to $3.5 million for the three months ended March 31, 2020. The increase in gross profit is primarily attributable to increased contributions from maintenance and storage programs. Gross profit margin increased to 21.4% for the three months ended March 31, 2021 compared to 13.4% for the three months ended March 31, 2020, and was largely attributable to an overall change in the product mix of the segment as a result of the COVID-19 pandemic.
Selling, General and Administrative Expenses
Selling, general and administrative expenses increased $0.1 million, or 0.8% to $13.3 million for the three months ended March 31, 2021, as compared to $13.2 million for the three months ended March 31, 2020. The increase was mostly related to additional headcount in TechOps and public company costs, which was partially offset by cost saving initiatives implemented in response to the COVID-19 pandemic.