Advanced Materials segment gross margin was 30.3% compared to 33.0% for the prior-year period. Segment gross profit was $33.8 million compared to $39.5 million in the prior-year period. The decrease in segment gross profit was principally due to a $4 million reduction in gross profit on decreased sales of elastomer materials for defense applications. The decrease in gross profit on sales of defense technologies was due to lower sales and production inefficiencies of flare countermeasures.
Selling, general and administrative expenses (which include corporate expenses) totaled $98.6 million, or 21.5% of sales, and $94.7 million, or 20.1% of sales, for the first fiscal quarter of 2013 and 2012, respectively. The 1.4 percentage point increase in selling, general and administrative expense as a percentage of sales was principally due to lower sales volumes. The $3.9 million increase in selling, general and administrative expenses mainly reflected higher corporate compensation expense and professional fees for regulatory compliance and acquisitions.
Research, development and engineering spending was $23.1 million, or 5.0% of sales, for the first fiscal quarter of 2013 compared with $26.4 million, or 5.6% of sales, for the first fiscal quarter of 2012. The decrease in research, development and engineering spending principally reflects lower spending on avionics systems. Fiscal 2013 research, development and engineering spending is expected to be in the range of approximately 5% to 5.25% of sales.
Segment earnings (operating earnings excluding corporate expenses and other income or expense) for the first fiscal quarter of 2013 totaled $55.2 million, or 12.1% of sales, compared with $50.0 million, or 10.6% of sales, for the first fiscal quarter in 2012.
Avionics & Controls segment earnings were $18.6 million, or 10.6% of sales, in the first fiscal quarter of 2013 and $20.1 million, or 11.2% of sales, in the first fiscal quarter of 2012, mainly reflecting a $3 million decrease in avionics systems and a $2 million decrease in communication systems, partially offset by an increase in control systems. Avionics systems earnings were impacted by decreased gross profit, partially offset by lower spending on research, development and engineering. Communication systems earnings were mainly impacted by decreased gross profit on lower sales of embedded communication intercept receivers.
Sensors & Systems segment earnings were $19.0 million, or 11.1% of sales, for the first fiscal quarter of 2013 compared with $6.8 million, or 4.0% of sales, for the first fiscal quarter of 2012, principally reflecting the $12.0 million inventory fair value charge discussed above. Sensors & Systems also benefited by strong earnings from increased sales of power systems, partially offset by weaker earnings from decreased sales of advanced sensors for the aftermarket.
Advanced Materials segment earnings were $17.6 million, or 15.8% of sales, for the first fiscal quarter of 2013 compared with $23.1 million, or 19.3% of sales, for the first fiscal quarter of 2012, primarily reflecting decreased gross profit on lower sales of elastomer materials for defense applications.
Interest expense for the first fiscal quarter of 2013 was $10.4 million compared with $11.5 million for the first fiscal quarter of 2012, reflecting lower borrowings.
The income tax rate was 8.5% compared with 10.1% for the first fiscal quarter of 2013 and 2012, respectively. In the first fiscal quarter of 2013, the Company recognized $3.7 million of discrete tax benefits principally related to the following items. The first item was approximately $1.5 million of tax benefits due to the retroactive extension of the U.S. federal research and experimentation credits. The second item was approximately $2.2 million of tax benefits related to the settlement of U.S. and foreign tax examinations. In the first fiscal quarter of 2012, the Company recognized $2.3 million of discrete tax benefits due to a change in French tax laws associated with the holding company structure and the financing of the Souriau acquisition. The income tax rate differed from the statutory rate in the first fiscal quarter of 2013 and 2012, as both years benefited from various tax credits and certain foreign interest expense deductions.
It is reasonably possible that within the next twelve months approximately $5.1 million of tax benefits associated with research and development tax credits, capital and operating losses that are currently unrecognized could be recognized as a result of settlement of examinations and/or the expiration of a statute of limitations.
26