Ken Giacobbe
Executive Vice President and Chief Financial Officer at Howmet Aerospace
Thank you, John. Let's move to Slide 5. All markets continue to be healthy with revenue in the quarter up 18% year-over-year and 3% sequentially. Commercial aerospace continued to lead the growth with an increase of 23% year-over-year, driven by all three aerospace segments.
Commercial aerospace has grown for nine consecutive quarters and stands at 47% of total revenue. Commercial aerospace portion of total revenue is expected to increase due to the developing widebody recovery, strong backlog of commercial aircraft orders and spares growth. Spares for commercial aerospace continued to increase sequentially and are now trending to be approximately 95% of 2019 levels at year-end. Defense aerospace was up 17% year-over-year, driven by the F-35 in legacy fighter programs.
Sequentially, defense aerospace was up 4% year-over-year, driven by engine products. Commercial transportation, which impacts both the Forged Wheels and Fastening Systems segments, was up 8% year-over-year and up 2% sequentially driven by higher volumes. Finally, the industrial and other markets were up 20% year-over-year, driven by oil and gas, up 36%; IGT, up 20%; and general industrial, up 11%. Sequentially, these markets were up 4% with general industrial up 9%; oil and gas up 4%; and IGT flat. In summary, another very strong quarter across all of our end markets.
Now let's move to Slide 6. Starting with the P&L and enhanced profitability, revenue, EBITDA and earnings per share, all exceeded the high end of the guidance in the second quarter. Revenue was $1.65 billion, up 18% year-over-year. EBITDA was $368 million, up 16% year-over-year, including net head count additions in Q2 of approximately 380 employees, which builds on additions made in Q1.
Year-to-date, net head count additions are approximately 865, which are in line with our targets. EBITDA margin was 22.3%. Adjusting for the year-over-year inflationary cost pass-through of approximately $25 million. EBITDA margin was 22.7% and the flow-through of incremental revenue to EBITDA was approximately 22%, while absorbing near-term recruiting, training and production costs. Earnings per share was $0.44 which was up 26% year-over-year. The second quarter represented the eighth consecutive quarter of growth in revenue, EBITDA and earnings per share.
Moving to the balance sheet. The ending cash balance was healthy at $536 million after generating $188 million of free cash flow which was our best Q2 of free cash flow generation. We continue to expect strong positive free cash flow in the second half of 2023. $118 million of free cash flow generation was allocated to common stock repurchases and dividends.
Net debt to EBITDA improved to a record low of 2.5 times, while bond debt is unsecured and at fixed rates, which will provide stability of interest rate expense into the future. Our next bond maturity is in October of 2024. Finally, we amended our $1 billion revolver through 2028, while realizing lower fees and a more favorable financial covenant. The revolver remains undrawn.
Moving to capital allocation. We continue to be balanced in our approach. In the quarter, capital expenditures were $41 million with a focus on automation. Capital installed prior to COVID-19 puts us in a good position to support continued commercial aerospace recovery.
In the second quarter, we repurchased $100 million of common stock at an average price of $44.52 per share, retiring approximately 2.2 million shares. This was the ninth consecutive quarter of common stock repurchases. Share buyback authority from the Board of Directors stands at approximately $822 million. Since separation in 2020, we have repurchased more than $1 billion of common stock.
We continue to be confident in free cash flow. In the second quarter, the quarterly stock dividend was $0.04 per share after it was doubled in the fourth quarter of last year. Finally, we issued a note to redeem $200 million of our 2024 debt tower with cash on hand. The redemption is expected to be complete at the end of September and will lower our annualized interest cost by approximately $10 million.
As you will recall, we repurchased approximately $176 million of bonds last quarter, which will lower annualized interest costs by an additional $9 million. Therefore, year-to-date, bond repurchases are expected to decrease annualized interest costs by approximately $19 million.
Now let's move to Slide 7 to cover the segment results for the second quarter. Engine Products continued its strong performance since the second quarter represented the eighth consecutive quarter of year-over-year growth in revenue and EBITDA. Revenue was $821 million, an increase of 26% year-over-year. Commercial aerospace was up 23%, Defense/aerospace was up 41%, and both markets were driven by higher build rates and spares growth. IGT was up 20%, and oil and gas was up 36%, as demand continues to be strong.
EBITDA increased 25% year-over-year to a record for the segment of $223 million. EBITDA margin was 27.2%, despite the addition of approximately 350 net new employees year-to-date and approximately 90 net additions in Q2. Across all of the aerospace segments, net headcount additions are needed for the continued revenue ramp, but do carry near-term recruiting, training and production costs. Finally, in the second quarter, the Engine's team finalized a new five-year collective bargaining agreement in our Whitehall, Michigan facility.
Let's move to Slide 8. Fastening Systems year-over-year revenue increased 19%. Commercial aerospace was 19% higher as the widebody recovery starts to take effect. Defense aerospace was up 24%, commercial aerospace was up 17% and general industrial was up 16%. Year-over-year segment EBITDA increased 14% as volume increases were partially offset by the addition of 430 net new employees year-to-date and approximately 215 net additions in Q2.
Now let's move to Slide 9. Engineered Structures year-over-year revenue was up 8% with commercial aerospace up 31%, driven by higher build rates in approximately $25 million of Russian titanium share gain. Defense aerospace was down 33% year-over-year, driven by customer inventory corrections. Segment EBITDA decreased 23% year-over-year, while margins declined 410 basis points. The lower EBITDA was driven by higher costs associated with additional headcount as well as operational costs for planned production rate increases, which were unrecovered due to production bottlenecks in one plant. Net head count additions in the quarter were approximately 50 employees. Finally, in the third quarter, the Structures' team finalized a new four-year collective bargaining agreement at our Niles, Ohio facility, which was ahead of schedule.
Now let's move to Slide 10. Forged Wheels revenue year-over-year increased 7%. The $19 million increase in revenue year-over-year was driven by a 6% increase in volume. Segment EBITDA increased 8% year-over-year, despite the interruption of raw material for our Wheels plant in Hungary due to a nine-day strike at our Arconic Corporation supplier, which has now been resolved. Margin increased 30 basis points due to the impact of lower aluminum prices and inflationary cost pass-through.
Finally, let's move to Slide 11. We continue to be focused on improving our capital structure and liquidity. In July, we issued a notice to redeem $200 million of our 2024 debt tower with cash on hand, which is expected to be completed by the end of September. The October 2024 debt tower would be approximately $705 million after the redemption. Since the separation in 2020, including the redemption just announced in July, we will have paid down approximately $2.15 billion of debt with cash on hand and lowered our annualized interest costs by more than $120 million. Gross debt is expected to be less than $3.8 billion after the redemption in September, while long-term debt continues to be unsecured in it fixed rates.
Finally, we amended our $1 billion five-year unsecured revolving credit facility through 2028. The amendment provides lower fees and more favorable covenants. Details can be found in the 10-Q, which is expected to be filed later today. The revolver remains undrawn.
Lastly, before turning it back to John, let me highlight one item in the appendix on Slide 18. It covers our operational tax rate, which was approximately 22.6% for the quarter. The second quarter rate represents approximately a 500 basis point improvement in the operational tax rate since the separation in 2020.
Now, let me turn it back to John for the outlook and summary.