We're off to a great start in the first half of fiscal 2021 with our second quarter revenue increasing 12%, adjusted EBITDA up 41%, and adjusted earnings per share up 109% compared to the prior year quarter.
Highlighting this success is our increased cash generation profile coupled with our EBITDA margin expansion in both CPP and HBP, which increased 220 and 190 basis points, respectively over the prior year period.
The AMES strategic initiative remains on schedule for completion by the end of 2023 and we reiterate our expectation to realize annual cash savings of $30 million to $35 million, and inventory reductions of the same magnitude when the benefits of the initiative are fully realized.
Earlier this month Telephonics was awarded $162 million five-year support contract from Lockheed Martin for our multi-mode maritime surveillance radars for the U.S. Navy's MHR-60R (sic) MH-60R maritime helicopters.
We continue to see additional opportunities for our products in domestic applications as well as through the MH-60 Romeo foreign military sales to countries like South Korea and Greece.
Backlog in the quarter was $354 million with trailing 12-month book-to-bill of 1.1 times.
We've delevered to 3.1 times net debt-to-EBITDA marking two full turns of improvement over the prior year period.
Additionally, we have $176 million in cash and $363 million available on our revolving credit facility providing ample liquidity and putting us in an excellent position to capitalize on our active pipeline of acquisition opportunities.
Earlier today, our Board authorized an $0.08 per share dividend payable on June 17, 2021 to shareholders of record on May 20, 2021.
This marks the 39th consecutive quarterly dividend to shareholders, which has grown at an annualized compound rate of 17% since we initiated in 2012.
Steve has served as the President of Clopay with distinction for the past 12 years, and has been part of Clopay since 2001.
During his tenure, Steve navigated Clopay through the financial crisis of 2009 and subsequently has transformed the business into the industry leader it is today through building the company's facilities, equipment products, technologies, people and culture.
Revenue increased by 12% to $635 million and adjusted EBITDA increased 41% to $67.8 million, both in comparison to the prior year quarter.
Adjusted EBITDA margin increased 220 basis points to 10.7%.
Gross profit on a GAAP basis for the quarter was $170 million, increasing 12% over the prior year quarter.
Excluding restructuring-related charges, gross profit was $174 million increasing 13.2% over the prior year quarter with gross margin increasing 30 basis points to 27.4%.
Second quarter GAAP selling, general, administrative expenses were $127 million compared to $226 million in the prior year quarter.
Excluding restructuring-related charges from both periods selling, general and administrative expenses were $123 million or 19.3% of revenue compared to $122 million or 21.5% in the prior year quarter.
Second quarter GAAP net income was $17 million or $0.32 per share compared to the prior year period of $1 million or $0.02 per share.
Excluding items that affect comparability from both periods, current quarter adjusted net income was $25 million or $0.48 per share compared to $10 million in the prior year or $0.23 per share.
Corporate and unallocated expenses excluding depreciation were $12 million in the current year quarter in line with the prior year second quarter.
Our effective tax rate excluding items that affect comparability from all periods for the quarter was 30% and for the year-to-date period it was 31.1%.
Capital spending was $12 million in the second quarter compared to $9 million in the prior year quarter.
Depreciation and amortization totaled $15.9 million for the second quarter compared to $15.7 million in the prior year second quarter.
Regarding our segment performance, Q2 revenue for CPP and HBP increased over the prior-year quarter by 21% and 16%, respectively while DE decreased 26% or 19% excluding the impact of SEG disposition.
Adjusted EBITDA for CPP and HBP increased over the prior year by 50% and 31%, respectively, Defense Electronics decreased 48%.
During the second quarter AMES incurred pre-tax restructuring-related charges were approximately $7.5 million supporting the AMES strategic initiative, capital expenditure supporting the initiative was $3.2 million in the quarter.
The total cost for the facility consolidation will be approximately $4 million, which will primarily consist of capital expenditures occurring in 2021.
Regarding our balance sheet and liquidity, as of March 31, 2021, we had net debt of $883 million and leverage of 3.1 times as calculated based on our debt covenants.
This is a two turn reduction from our prior year second quarter and a 0.3 turn reduction from our fiscal year-end.
Our cash and equivalents were $176 million and debt outstanding was $1.06 billion.
Borrowing availability under the revolving credit facility was $360 million subject to certain loan covenants.
The guidance provided on our November call was revenue of approximately $2.4 billion and adjusted EBITDA, excluding unallocated one-time charges related to AMES and Telephonics initiative of $285 million or better.
As a result of our substantial outperformance in the first half of the year and with consideration to this year's Q3 and Q4 comparatives to strong prior year quarter results, we are expecting our fiscal 2021 performance will be substantially above our original guidance and in line with our trailing-12 months.
That produced approximately $2.5 billion of revenue and $320 million of adjusted EBITDA, excluding unallocated and one-time charges.

Summary:
Revenue increased by 12% to $635 million and adjusted EBITDA increased 41% to $67.8 million, both in comparison to the prior year quarter.
Second quarter GAAP net income was $17 million or $0.32 per share compared to the prior year period of $1 million or $0.02 per share.
Excluding items that affect comparability from both periods, current quarter adjusted net income was $25 million or $0.48 per share compared to $10 million in the prior year or $0.23 per share.