CM Sundstrand

Defense of Sundstrand in the Supreme Court

• The case starts with a great description of the problem at hand: “The patents at issue claim technology to control airflow surge in “APUs.” An APU is a gas turbine engine often used in the tail end of aircraft. Because APUs face rapidly changing demand levels for compressed air during flight, they must control against “surges.” A surge is an aerodynamic phenomenon, which occurs when airflow through the compressor is too low. In a surge condition, the airflow cannot exit the compressor. Instead, the airflow surges back into the compressor, potentially damaging the APU.”
• The key to this case is the foreseeability criterion. While Honeywell did invent the APU technology first, it was clear in their patent that they were aware of the issues that would arise and the ways to control them from a process standpoint. It was common knowledge and there was also a prior precedent for this technology established in earlier patents. The IGVs and their positions were something that an ordinary design engineer for these engines could come up with as a solution to the problem of surges.
• In the first description, it is obvious that Honeywell was well aware of this issue. They knew that surges were a problem for this product, and any product like this one, and that the surges could be avoided with a simple institution of age old “Venetian blinds” for air control. As an expert testified, this is something that any engineer designing the engine could have come up with, with the optimal positions of the IGVs readily available in literature. In fact, even Honeywell's expert stated the following in response to a question: “Q: In fact, going back to the 1970s, it was Honeywell's understanding that in order to efficiently control surge, you would need to take into account inlet guide vane angle and input into your surge control system. Correct? A: Well, by using this information you can incrementally improve the operation of a surge controller, yes.” Honeywell was well aware of the necessity of using IGV in the APUs, but they neglected to patent it. Therefore, it is not infringing to produce a system using IGVs because it is not equivalent. It is a better product that does not have the same problems as the previous invention.
• The court states the following on the foreseeability criterion: “The foreseeability criterion presents an objective inquiry, asking whether the ... equivalent would have been unforeseeable to one of ordinary skill in the art ... Usually, if the alleged equivalent represents later-developed technology (e.g., transistors in relation to vacuum tubes, or Velcro (R) in relation to fasteners) or technology that was not known in the relevant art, then it would not have been foreseeable.” Nothing can change the fact that the innovation applied by Sundstrand was an old technology that had been in use since the 1970's. Because of this simple fact, it cannot be considered an equivalent because this factor was not mentioned in Honeywell's patent. The innovation was not something that completely blind-sided the industry. It was a development that was in use in other areas, but could easily be extrapolated to serve the same purpose for controlling surges in APUs. This shows that the invention of Honeywell was not equivilent with the invention Sundstrand came up with.
• “Because Honeywell did not show that the alleged equivalent was unforeseeable at the time of the narrowing amendment or that the narrowing amendment bore no more than a tangential relation to the alleged equivalent, this court affirms.” This is the correct ruling in this case because any engineer worth his weight could have designed this particular solution, and it was omitted from the original patent document where it could have easily been included. There should be no overturning of this ruling in the Supreme Court because of the cut and dry nature of the foreseeability. It was clear to anyone of ordinary skill in the art that this is the solution to the problem of surges in APUs. Because of this, Sundstrand should not be able to file for a patent, but Honeywell should not be able to prosecute them for infringing upon the patent for the original APUs.