Federal Circuit addresses claim construction, on-sale and public use bars, and DJ jurisdictionMay 26, 2007

In a decision Friday, the Federal Circuit vacated in part a district court's claim construction of a several terms as well as its decision to find no infringement of patents owned by Honeywell. The court did, however, affirm the district court's retention of jurisdiction over the several withdrawn claims and the decision that Honeywell's pre-critical date activities were not barring sales or public uses under § 102(b).

More details of Honeywell Int'l Inc. v. Universal Avionics Sys. Corp. after the jump.

The patents in suit (the '080, '009, '570, '060, and '592 patents) relate to avionics systems called "enhanced ground proximity warning systems." These systems sense approaching terrain that may be in the flight path of an aircraft and provide the pilot with a warning to make an appropriate change in course to avoid a crash.

The Federal Circuit vacated the district court's claim construction of five terms: "look ahead distance," "terrain floor boundary," "signals representative of," "alert envelope," and "highest Hmax and Hmin." The court first disposed of Universal's argument that it did not have jurisdiction to consider the construction of three of the five contested terms because the district court did not rely upon them when determining the issue of infringement.

Look ahead distance

The district court construed "look ahead distance" to mean "a distance along the ground track of the aircraft that marks the outer limit of each alert envelope that is a function of aircraft speed and time to complete an evasive maneuver." Honeywell argued that the court improperly read the limitation "time to complete an evasive maneuver" into the claim. The court found that usage within the patent makes clear that the purpose of the "look ahead distance" limitation encompasses time to make an evasive maneuver.

However, the court held that even though the district court's claim construction was correct, the grant of summary judgment of noninfringement was improper. Specifically, there was at least a genuine issue of material fact, because the alleged infringing devices were also set to alert and then provide time for an evasive maneuver. The court remanded to the district court the question of whether the allegedly infringing devices did in fact infringe under this claim construction.

Terrain floor boundary

The district court construed this term to mean "a boundary that extends downwardly below the aircraft which is proportional to the distance to the closest runway." The Federal Circuit also affirmed this construction, finding that this construction did not improperly import limitations from the specification into the claims.

Once again, however, the court held that even though the district court's construction was correct, its summary judgment of noninfringement on this claim element was improper. Specifically, the court noted that when the plane deviates from the flight plan, Universal's software redefines the destination as the airport and runway "with the closest Runway Threshold." Further, Sandel's CEO testified that Sandel's "clearance buffer" "is based on both the distance of the airplane from and the altitude of the airplane above the weighted average distance of the nearest runways or airport reference points." Thus, a redetermination of the infringement issue for this term was necessary.

Signals representative of

The district court construed this term to mean "[t]he signals received by the apparatus are instantaneous values of the recited variables; i.e. they indicate the numerical value of that variable at a given sampling time." The Federal Circuit found that this interpretation was unduly narrowed based on its perception of the invention, specifically that the invention was limited to instances where the pilot reads these signals. The court instead held that the "signals" represent the inputs into the system regarding aircraft speed, position, and flight angle not a data representation of numerical or instantaneous signals, and thus the term was erroneously limited to numerical or instantaneous values rather than simply inputs into the system for processing into appropriate warnings.

Alert envelope

The patents at issue require a "first alert envelope" and a "second alert envelope." The district court construed "first alert envelope" as a "term of art in avionics and means an at least 2-dimentional region in the vertical plane surrounded by a continuous boundary." The Federal Circuit disagreed with the district court's construction elaborating that the claim explains itself as to its meaning. "Alert envelope" is defined later in the claim to be "determined as a first function of the flight path angle, said look ahead distance, and a terrain floor boundary." Because of this elaboration in the claim, further construction was not required.

Highest Hmax and Hmin

The district court construed this term to require "that the display show a numeric value for the highest and lowest points." As with "signals representative of," the Federal Circuit held that this construction requiring numeric values unduly narrowed the claim to only systems where the display shows this data, rather than were the data is just processed by the system. Further, claim 21, which depends from claim 1 (the claim having this element) requires that the display be numeric. As a result, based on claim differentiation, the court reversed the district court's construction.

Topping off the tank, the court affirmed the district court's decisions that the patents were not invalid under § 102(b) based on prior sales and public uses. Regarding the on-sale bar, the court found that Honeywell's pre-critical date activity failed both prongs of the Pfaff test. In order for a pre-critical date sale to be invalidating, the invention must be (1) the subject of a commercial sale or offer for sale and (2) "ready for patenting" before the critical date.

On-sale bar

Before the critical date, Honeywell engaged in testing of its equipment, and stated that if, and only if, the tests were successful, Honeywell would sell the system under certain specified commercial terms. The court held that this was not a barring sale, because there was ample evidence that the system was still undergoing testing at this stage, and therefore these pre-critical date negotiations and proposals were for the purpose of experimentation, even though the tests were successful and no further mo

← Return to Filewrapper

Stay in Touch

Receive the latest news and updates from us and our attorneys.

Sign Up