Earlier this month I noted the decision of the Court of Appeal for England and Wales in Lufthansa Technik AG v. Astronics Advanced Electronic Systems, [2026] EWCA Civ 964, and said that I would return with a more detailed, possibly two- or three-part analysis, focusing on the court’s handling of disgorgement of profits, double recovery, and prejudgment interest. This post is the first part of that series, in which I will lay out the essential facts and set the stage for discussion of the general principles for calculating the profit to be disgorged.
The facts, in brief, are as follows. Lufthansa owned European Patent (UK) No. 0 881 145, relating to “an apparatus that supplies electrical power to a socket that can be used by aircraft passengers for equipment such as laptops, mobile phone chargers and the like” (para. 2). “The invention comprises a safety feature which detects whether a plug has been properly inserted before supplying power from a remote unit to the socket,” and “is useful where it is desired to supply passengers with high-voltage AC power rather than low-voltage DC power” (id.). “The infringing acts concern the supply of EmPower Fusion systems incorporating the patented safety feature,” which “feature is implemented by an outlet unit or socket, an inseat power supply unit . . . and a cable that connects the two together (“the Primary Components”). The Primary Components can be used in conjunction with a number of additional components (“the Secondary Components”), the most important of which is the master control unit,” which “is usually located within the electronics bay of the aircraft and controls the distribution of power to a variety of downstream systems” (para. 5). Astronics made the Primary and Secondary Components, which it sold to providers such as Panasonic, who “in turn sold integrated IFE [In-Flight Entertainment] systems incorporating the Primary and Secondary Components to airlines” (para. 6). Astronics also sold the Primary Components directly to airlines, e.g. for use on shorter-haul flights, and in such cases companies such as Safran incorporated those components into airline seats (id.).
Although the patent expired in 2018, litigation concerning the English, German, and French designations of EP `145 has been going on for some time. The judgment of the Patents Court finding the defendants to have infringed issued in 2020, and in 2022 Lufthansa elected for an account of profits. In 2024, the Patents Court held that Astronics was liable in the amount of US$4.42 million, Panasonic in the amount of US$7,384, and Safran (as subsequently revised) in the amount of $US 567,800. In 2025, the Patents Court issued another decision awarding interest and declining “to make an order requested by the Defendants with a view to preventing double recovery by Lufthansa in proceedings in France and Germany” (para. 8). Lufthansa appeals the profits awards against Astronics and Panasonic (it argues they should be higher). The three defendants appeal the award of interest and the order concerning double recovery, and Astronics and Panasonic appeal an aspect of the 2024 judgment concerning whether a 1998 license Lufthansa granted to a third party (KID Systeme) was exclusive (which would affect the amount of profit to be awarded for a portion of the relevant time period).
There are additional facts set forth early on in Lord Justice Arnold’s opinion, concerning the development of an in-seat power supply unit by, and the issuance of related patents to, Olin Aerospace (later spun off as Primex Technologies, which was later acquired by General Dynamics, which later sold the unit to Astronics); the development by Lufthansa of the patented technology in suit; Lufthansa’s partnering with KID Systeme, a division of Airbus, to build its own in-seat power supply unit, as memorialized in a 1998 Teaming Agreement and a later, 2014 Teaming Agreement; and the 2003 settlement of litigation between Airbus/KID and General Dynamics concerning possible infringement of what were originally the Olin patents by Airbus/KID, and possible infringement of Airbus/KID’s “right of exclusive use” of the patent in suit by General Dynamics (paras. 12-35). During the relevant time period, Astronics’ AC power system outsold KID’s, and by 2018 the former’s market share was 87.9% (para. 36).
On then to the principles concerning disgorgement of profits. Early on, Lord Justice Arnold sets out the rationale for the remedy as follows:
53. It is debatable whether the remedy of an account of profits for infringement of an intellectual property right is accurately described as a restitutionary one, although it can certainly be viewed as a remedy for unjust enrichment. For this reason, some scholars prefer to term the remedy “disgorgement”. Either way, the remedy should be distinguished from using the infringer’s profits as either evidence of, or a proxy for, the damages suffered by the right owner, as some legal systems do. It is well established that the purpose of the remedy is not to punish the infringer. On the other hand, it has been recognised by some courts that deterrence is part of the rationale, since an award of damages may in some circumstances leave the infringer better off than if it had not infringed, whereas an account of profits cannot have that effect: see, for example, Nova Chemical Corp v Dow Chemical Co [2022] SCC 43, [2022] 3 SCR 352 at [44]-[48] (Rowe J).
He then moves on to causation:
55. As [Patents Act] section 61(1)(d) makes clear, the profits for which an infringer must account are the profits “derived by him from the infringement”. Thus the profits must have been caused by the infringing acts. It is common ground that this involves both factual causation and legal causation. It is also common ground that, to this extent, the same principles are applicable to accounts of profits as to damages for patent infringement: see Imperial Oil Ltd v Lubrizol Corp (1996) 71 CPR (3d) 26 at 30 (Canadian Federal Court of Appeal), Celanese International Corp v BP Chemicals Ltd [1999] RPC 203 at [37] (Laddie J) and OOO Abbott v Design and Display Ltd [2016] EWCA Civ 98, [2016] FSR 27 at [14] (Lewison LJ). . . .
57. It was common ground before the judge that the “but for” test of factual causation required consideration of a hypothetical counterfactual world in which the Defendants had adopted the nearest non-infringing alternative (“NIA”) to the arrangement claimed in the Patent. As explained in slightly more detail below, the Defendants argued that, had they not infringed, they could and would have made an alternative outlet unit referred to as the 1171M. The judge found that the Defendants had established this on the balance of probabilities, but that the 1171M would still have fallen within the claims of the Patent. Thus the Defendants failed to establish the only NIA for which they contended. Accordingly, the judge found that the profits claimed by Lufthansa had been factually caused by the Defendants’ infringing acts.
58. There is no challenge by the Defendants to the judge’s finding of factual causation. It should nevertheless be noted that the Defendants no longer support the proposition that factual causation in an account of profits for patent infringement requires consideration of an NIA. The Defendants consider that factual causation is a much simpler question: what profits were the consequence of the pleaded acts which were held to infringe? In the present case the infringing acts consisted of the supply of the Primary Components in the United Kingdom. Those supplies led to the profits being made which the parties’ accounting experts were able to identify as being consequent on those acts, including profits made by the supply of Secondary Components.
The next portion of the opinion sets out the trial judge’s analysis of the causation issue. As summarized by Lord Justice Arnold, the trial judge found “that Astronics would not have made the profits in issue but for the infringement of the Patent for which Morgan J had held Astronics liable. Secondly, he found at [452]-[465] that, but for the supply of the Components to Safran and Safran connecting them together and incorporating them into airline seats, Panasonic would not have made the profits in issue. Thirdly, he found at [466] that Safran would not have made the profits in issue but for the infringement of the Patent for which Morgan J had held Safran liable” (para. 63). However, the trial judge also found that legal (proximate) causation was lacking, because the features of the patented invention were only some of the many other features that were necessary to the functional and commercial success of the infringing system (para. 64). The same reasoning applied to Panasonic; as for Safran, the plaintiff conceded that apportionment would be appropriate, so the court didn’t believe it to be necessary to decide legal and proximate causation with respect to that defendant (para. 65). The trial judge nevertheless concluded that, despite the lack of proximate causation as to Astronics and Panasonic, Lufthansa was entitled to an apportioned amount of these firms’ profits. “He noted at [574] that the Defendants had pleaded four alternative ways of apportioning their profits: (i) patent counting, (ii) the cost of the Components, (iii) the causative effects of the Patent and other factors and (iv) by reference to the 2014 Teaming Agreement [under which Lufthansa granted KID a non-exclusive license, see para. 39] (para. 71). Ultimately, the trial court derived an implicit royalty rate from the 2014 Teaming Agreement, of 21% deducting all overheads or 13% deducting incremental overheads only. He applied the 13% rate to Astronics’ and Panasonic’s profits, resulting in the $4.42 million and $7.384 million figures noted above (paras. 73-75).
From these conclusions, Lufthansa raises four grounds for appeal. “Ground 1 is that, having correctly carried out a differential profits analysis, the judge was wrong then to make an apportionment of the Defendants’ total profits because those approaches are alternatives. Ground 2 is that the judge erred in his approach to legal causation. Ground 3 is that the judge wrongly applied the test for legal causation. Ground 4 is that, even if he was right to apportion the Defendants’ profits, the judge erred in his approach to apportionment” (para. 77).
Long story short: Lord Justice Arnold concludes that it was appropriate to carry out an apportionment analysis on the facts of the present case; that the judge’s approach to legal causation was erroneous, but that he was correct to apportion nonetheless; and that the method used by the judge for apportionment was correct, though with a correction to be made with regard to the effect of the original (1998) Teaming Agreement. Why? That will be the subject of my next installment.