Reaffirming that a person of ordinary skill in the art must have been able to actually create a disclosure at the time of invention in order for it to serve as an obviousness reference, the US Court of Appeals for the Federal Circuit reversed a decision by the Patent Trial & Appeal Board (the Board) in an inter partes review (IPR), concluding that a patent covering certain turbofan engine technology was not rendered obvious by a prior art publication that could not be realized into practice. Raytheon Techs. Corp. v. General Electric Co., Case No. 20-1755 (Fed. Cir. Apr. 16, 2021) (Chen, J.)

The issue on appeal was relatively straightforward. In an IPR, GE challenged as obvious a Raytheon patent that covered a specific design of geared gas turbine engine that provided for a “power density” higher than previously invented turbine engines. The patent defined “power density” as a “sea-level-takeoff thrust” divided by the engine turbine volume. During the IPR, GE relied on a 1987 NASA technical memorandum as art and argued that the reference, which envisioned superior performance characteristics based on an advanced engine that was made entirely of composite materials, rendered the challenged claims obvious. The parties did not dispute that this engine was unattainable in 1987, and may still be impossible today, because the envisioned composite materials do not yet (and may never) exist. The memorandum disclosed several performance factors, but not power density, sea-level-takeoff thrust or turbine volume. Nonetheless, GE argued, and the Board agreed, that the memorandum disclosed performance parameters that would have permitted an ordinarily skilled artisan to derive power densities that would have fallen within the range claimed in Raytheon’s patent.

On appeal, the Federal Circuit agreed with Raytheon, concluding that the imaginary engine of the NASA memorandum could not serve as an invalidating reference. In reversing the Board, the Federal Circuit reiterated two bedrock principles of obviousness law:

• An obviousness reference must be enabled by the knowledge of an ordinarily skilled artisan at the time of the invention (but need not be self-enabling).

• An invention cannot be rendered obvious by a non-self-enabling reference if no other prior art evidence or reference enables the non-self-enabling reference.

In addition, when a reference’s enablement is challenged, the party offering the reference bears a burden to establish that the reference, itself or in combination with other contemporaneous knowledge, was enabled.

Applying these principles here, the Federal Circuit determined that GE had not met its burden to show that the memorandum was indeed enabled. The Board, wrongly in the Court’s view, focused solely on whether an ordinarily skilled artisan was taught the parameters to ascertain a power density, rather than whether the prior art disclosed a turbofan engine possessing the requisite power density. Finding no evidence in the record to conclude that “a skilled artisan could have made the claimed turbofan engine with the recited power density,” the Court reversed.

Practice Note: Although this case does not break new obviousness ground, it reinforces the general rule that the prior art used in an obviousness analysis must satisfy the ultimate obviousness inquiry of whether an ordinarily skilled artisan at the time of the invention could have actually created the claimed subject matter.