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Broader Claim Construction Upheld: Specification and Prosecution History Indicate That When the Patentees Wrote “Heading,” They Meant “Bearing”

July 03, 2007
Mulcahy, John M.

Decision icon Decision

Last Month at the Federal Circuit - August 2007

Judges: Bryson (author), Plager (dissenting), Gajarsa

[Appealed from: D. Del., Judge Thynge]

In Honeywell International, Inc. v. Universal Avionics Systems Corp., Nos. 06-1406, -1435 (Fed. Cir. July 3, 2007), the Federal Circuit affirmed the district court’s construction of disputed terms and upheld the jury’s verdict that Universal Avionics Systems Corporation (“Universal”) had infringed Honeywell International, Inc.’s (“Honeywell”) patent.

Honeywell asserted U.S. Patent No. 4,914,436 (“the ’436 patent”) against Universal. The ’436 patent is drawn to a system that enables an aircraft’s ground proximity warning system during final approach to a runway. The patented system stores the coordinates of various runways and defines an area (called the “enabling envelope”) around each runway, within which an aircraft is deemed to be on final approach. In order to better discriminate whether the aircraft is actually on final approach, the system also determines whether the aircraft is aligned with the runway and expands the radius of the enabling envelope. When the system determines that the aircraft has entered the enabling envelope, the ground proximity warning system is enabled.

The parties disputed the proper construction of the terms “heading of the aircraft,” “enabling envelope,” and “ground proximity warning system,” as used in claim 1 of the ’436 patent (the only claim at issue). The district court uniformly adopted Honeywell’s constructions and denied Universal’s motion for SJ of noninfringement. At trial, the jury found that Universal infringed claim 1 and the district court entered judgment accordingly. Universal appealed.

The term “heading of the aircraft” was not used in the original specification, but was added to claim 1 of the ’436 patent during prosecution in order to distinguish the prior art. Although the claim term “heading of the aircraft” conventionally indicates the compass direction the aircraft is flying, the district court construed the phraseto refer instead to the direction to the aircraft from a runway, which would normally be referred to as the aircraft’s “bearing” from the runway.

On appeal, the Federal Circuit affirmed the district court’s construction. The Court noted that the specification referred to the calculation of the alignment of the aircraft with the runway as an “important feature of the present invention.” The Court found that “[i]f Universal’s construction were adopted, the disclosed embodiment would not relate to any limitation of the claimed invention, despite the clear link between the alignment computation discussed in the specification and the alignment computation called for by the claims.” Slip op. at 6. The Court also concluded that “[t]he prosecution history confirms that when the patentees wrote ‘heading,’ they meant ‘bearing.’” Id.

With respect to the term “enabling envelope,” Universal argued that arguments made during prosecution disclaimed coverage of a system, like the accused system, that issues a ground proximity alert based on the aircraft’s distance from the airport. The Federal Circuit, however, affirmed the district court’s broader construction of the term. The Court found that the arguments cited by Universal could be read to support both Universal’s and Honeywell’s proposed constructions. “Because the passage is ambiguous, we conclude that it does not constitute a sufficiently clear and deliberate statement to meet the high
standard for finding a disclaimer of claim scope.” Id. at 11-12.

Universal further argued that the term “ground proximity warning system” should have been construed to exclude systems that issue ground proximity alerts based on airport distance. The Federal Circuit, however, held that the ’436 patent used this term generically to describe any system that warns of ground proximity. Thus, the Court held that “the district court properly declined to limit the term ‘ground proximity warning system’” as proposed by Universal.

In a dissenting opinion, Judge Plager wrote that the patentee “did not clearly signal the necessary intent to depart from the ordinary meaning of ‘heading.’” Plager Dissent at 3. Judge Plager noted that, during prosecution, the patentee had also used the term “heading” in its conventional sense. “This inconsistent usage undercuts the argument that the applicants intended to adopt a different definition for the term ‘heading.’” Id. at 2. Judge Plager concluded that “[t]his is not a case . . . in which the patentee implicitly redefined a claim term by using it throughout the written description in a manner consistent with an unconventional meaning. Here the patentees did not use the term at all in the written description.” Id. (citation omitted).