Take Care When Relying on Non-Self-Enabling References

In Raytheon Techs. Corp. v. General Electric Co., 20-1755 (Fed. Cir. Apr. 16, 2021) (precedential), the Federal Circuit issued a rare reversal of a PTAB final determination of obviousness because the principal reference used in the obviousness combination was not “self-enabled,” and no other record evidence cured that defect.

Raytheon owns U.S. Patent No. 9,695,751. The ’751 patent is directed to a multi-stage, geared, gas turbine aircraft engine. The independent claims include traditional features of gas-turbine engines like a fan, a compressor section, a combustor, and a fan-driven turbine section. The claims also include a “speed change system,” which refers to internal gearing between the turbine section and fan section. General Electric (“GE”) petitioned for inter partes review of the ’751 patent.

The “key distinguishing feature” of the ’751 patent claims, according to the court, was the recitation of a “power density” range for the engine that the patent describes as being “much higher than in the prior art.” GE’s primary reference in the IPR was a 1987 NASA technical memorandum (“Knip”). That reference envisioned superior performance characteristics for a future “advanced [turbofan] engine” that would incorporate “all composite materials.” According to the court, those advanced materials “allowed the author of Knip to assume aggressive performance parameters for an ‘advanced engine,’ including then-unachievable pressure ratios and turbine temperatures.” On the record developed before the PTAB, such an all-composite engine was unattainable as of the ’751 patent’s invention date.

GE did not dispute that Knip relied on revolutionary materials that were unavailable as of the invention date to support the disclosed aggressive performance parameters. Nor did GE argue that a skilled artisan could have achieved those aggressive performance parameters by some other means. Rather, GE argued that the issue of whether Knip enabled its advanced engine was “irrelevant” to the question of whether a skilled artisan “reviewing Knip could make the ’751 Patent’s engine (using any already available materials) without undue experimentation.”

The issues before the court on appeal were whether Knip was an enabling reference; and if not, could it nonetheless support an obviousness case. To tee up its analysis, the court observed that “[t]here is usually no dispute about whether an asserted prior art reference is ‘self-enabling.’” It also observed that “there is no absolute requirement for a relied-upon reference to be self-enabling in the § 103 context, so long as the overall evidence of what was known at the time of invention establishes that a skilled artisan could have made and used the claimed invention.” But “if an obviousness case is based on a non-self-enabled reference, and no other prior art reference or evidence would have enabled a skilled artisan to make the claimed invention,” the court reiterated that on those facts, “the invention cannot be said to have been obvious.”

Here, the court determined that Knip was not a self-enabling reference. The court explained that such references can be used to provide a motivation to combine, and they can be used to supply claim elements enabled by other prior art or evidence. But where the primary reference is not enabling as to the relied-upon disclosure, and no other evidence cures that defect, it cannot prove unpatentability—whether for obviousness or anticipation. So where a party relies on speculative or forward looking embodiments in a prior art reference, it should provide additional evidence to support enablement, or risk the same fate GE suffered here.