That said, we still reported a loss for the quarter of $0.06 per share.
On an earnings per share basis, as I mentioned earlier, we lost $0.06 per share versus our guidance range of a loss between $0.23 and $0.30.
This quarter, favorable metal prices provided a benefit of over $20 million or about $0.19 per share in total and $0.08 more than the metal price assumptions used for our Q1 guidance.
As I mentioned earlier, we're seeing continued modest demand recovery for our jet engine forgings and the first signs of recovery for our other jet engine materials.
First quarter 2021, year-over-year decremental margins were 16% for ATI overall, marking a significant improvement from prior quarters.
It's worth noting that we've maintained this key metric below 30% in each pandemic-impacted quarter to date.
We were awarded a contract for roughly $40 million of specialty nickel alloy sheet materials for use in a pipeline off the coast of South America.
Although jet engine sales declined significantly versus a robust prior year quarter, they grew nearly 30% sequentially.
As I noted earlier, we recently won a contract worth roughly $40 million for nickel alloy clad pipe materials to be produced and shipped in the second half of 2021.
As a whole, ATI lost $0.06 per share in Q1, well ahead of our expected loss range heading into the quarter.
But as an encouraging sign that we have seen the bottom, HPMC sales increased nearly 10% sequentially.
This growth was led by nearly 30% gain in commercial jet engine sales and a 17% pickup in defense sales.
We're encouraged by these trends and expect them to continue expanding across 2021, and as domestic travel rates increase.
Within our jet engine sales, highly profitable next-generations forgings and materials comprised over 40% of the Q1 total, up from 35% and 19% in the prior two quarters, respectively.
Turning to AA&S, segment revenues decreased 16% year-over-year largely due to a 25% decrease in Specialty Rolled Products, or SRP, business unit sales.
Sales at our STAL JV increased by over 50% year-over-year, fueled by demand for consumer electronics and elevated automotive production in China.
Looking at the sequential revenue change, AA&S sales improved 4%, largely due to SRP's 15% increase in standard value stainless products, which generate minimal profit.
It's important to note that nearly 75% of the SRP Q1 EBITDA was due to rising nickel and, to a lesser degree, ferrochrome prices in the quarter.
If this unpredictable benefit is removed, SRP earned an EBITDA margin of about 2% and generated a loss after appropriately considering depreciation and interest charges.
Before jumping to the balance sheet, I want to highlight that we've limited year-over-year decremental margins to 16% this quarter.
During the market chaos, we've maintained a strong total liquidity, ending the first quarter with roughly $540 million in cash and about $360 million of ABL availability.
Despite not being able to provide Q2 earnings guidance, we remain confident in our full year 2021 free cash flow guidance range of $20 million to $60 million, excluding pension contributions.
Last quarter, we announced that we anticipated contributing $87 million to the pension plans in calendar 2021.

Summary:
That said, we still reported a loss for the quarter of $0.06 per share.
On an earnings per share basis, as I mentioned earlier, we lost $0.06 per share versus our guidance range of a loss between $0.23 and $0.30.
As I mentioned earlier, we're seeing continued modest demand recovery for our jet engine forgings and the first signs of recovery for our other jet engine materials.
As a whole, ATI lost $0.06 per share in Q1, well ahead of our expected loss range heading into the quarter.
We're encouraged by these trends and expect them to continue expanding across 2021, and as domestic travel rates increase.