Examples in specification, file history implicitly redefine claim term; infringement affirmedJuly 5, 2007

In a second case before the Federal Circuit in just over a month, competing avionics manufacturers Honeywell and Universal Avionics Systems were parties to a decision, this time with Honeywell coming out on top. The court affirmed the district court's claim construction of several terms in Honeywell's patent, which resulted in the court affirming the verdict of infringement.

Notably, the court held that the use of a term in a manner inconsistent with its ordinary meaning in the specification and prosecution history was sufficient to redefine it for purposes of claim construction. The term at issue was "heading," which was held in the context of the patent to mean "bearing."

The patent in suit relates to a system for warnings when an aircraft is on final approach to an airport runway. Previously, such systems relied on wing flap position for activation; the patented system does not rely on the position of the flaps to activate, but instead relies on, among other things, the distance between the aircraft and nearby runways.

Claim 1 of the patent was asserted, and contains the disputed claim terms (disputed terms emphasized):

1. A system for use in an aircraft for providing an enabling envelope for a ground proximity warning system for an aircraft comprising:[1] a first source of signals representative of the longitude and latitude of an airport; [2] a second source of signals representative of the current longitude and latitude of said aircraft; [3] means responsive to said first source of signals representative of the longitude and latitude of said airport and said second source of signals representative of the current longitude and latitude of said aircraft for [a] computing the distance of said aircraft from said airport and [b] providing an enabling envelope for enabling the warning system as a function of said distance of the aircraft with respect to said airport; [4] a source of signals representative of the relative angular position of a particular runway with respect to the heading of the aircraft; and [5] means responsive to said first and second sources of signals for providing a signal representative of the alignment of the aircraft with the runway by determining the angle between the runway and the heading of the aircraft.

Universal Avionics' noninfringement positions were entirely dependent on its claim construction arguments. It contended the district court improperly construed three terms: "heading of the aircraft," "enabling envelope," and "ground proximity warning system."

Heading of the aircraft

This term's construction was the most controversial, resulting in a dissent from one of the judges on the panel. The majority held that "heading of the aircraft" had been used in such a manner that it did not mean "heading" at all, but instead meant "bearing." Ordinarily, a craft's "heading" is the direction in which it is pointing, and its "bearing" is the direction from an observer to the craft.

The majority acknowledged that claim terms are typically given their ordinary meaning. However, the court found that the usage of the terms in the specification and prosecution history supported a differing construction of "heading." Specifically, the court noted that the specification describes "the claimed system’s alignment determination as depending on the direction of the aircraft from the runway (i.e., what is conventionally known as the aircraft’s bearing), not the direction in which the aircraft is pointing (i.e., what is conventionally known as the aircraft’s heading)." The specification also disclosed no other form of alignment.

Further, the prosecution history also uses "heading" in this manner. There, the patentees also described that the alignment information was based on the "heading" of the aircraft, defined as the line formed between a point on the runway and the aircraft. Once again, while this would ordinarily be termed the "bearing," this contrary usage led the majority to agree with the district court that "heading," as used in the claim, actually meant "bearing."

Judge Plager dissented from this conclusion, and would have construed "heading" to have its ordinary meaning, as there was an insufficiently clear redefinition of the term in his opinion.

Enabling envelope

The court also affirmed the district court's construction of "enabling envelope," which was "activating or turning on a set of limitations within which an aircraft can perform safely and effectively." Universal asserted that statements made during prosecution disclaimed systems that used airport distance in determining whether to issue a proximity warning. The court disagreed, holding that because the statements made in the prosecution history could be interpreted in multiple ways, they fell short of the "clear and deliberate statement" required to find a disclaimer of claim scope.

Ground proximity warning system

In a last-ditch effort to avoid infringement, Universal argued that only ground proximity warning systems that were approved by the FAA at the time the patent application was filed could fall under the claims. Because none of these systems used distance from airports to trigger alerts, Universal argued that it could not infringe. The court quickly rejected this argument, holding that the patent never limits the phrase "ground proximity warning system" to just particular systems or systems in use at the time the application was filed. Instead, the term is used in the generic sense to describe systems "that provide warning or advisory indications in the event of hazardous flight conditions."

Because the court affirmed the district court's claim construction in all respects, it also affirmed the infringement verdict, as Universal's noninfringement arguments were entirely based on its claim construction arguments.

To read the full decision in Honeywell Int'l, Inc. v. Universal Avionics Sys. Corp., click here.

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