OPINION
This сase arises from the tragic February 2007 crash of an Army Special Operations Aviation Regiment helicopter in Afghanistan. Plaintiffs, who include those injured and the heirs of those killed in the crash, appeal from the district court’s dismissal of AT Engine Controls (ATEC) for lack of personal jurisdiction and from the court’s summary judgment in favor of The Boeing Company (Boeing), Honeywell International, Inc. (Honeywell), and Goodrich Pump and Engine Control (Goodrich). We have jurisdiction pursuant to 28 U.S.C. § 1291, and we affirm.
I.
In February 2007, an Army-operated MH-47E Chinook helicopter crashed in the Kabul Province of Afghanistan. The helicopter was transporting military personnel to Bagram Airbase when it encountered snow, rain, and ice. Then, without warning, one of the Chinook’s engines suddenly shut down, and the aircraft crashed. Eight servicemen were killed and fourteen were severely injured.
Two investigations into the cause of the crash revealed that it occurred after one of the helicopter’s two engines suddenly flamed out. An initial Army investigation suggested that the aircraft’s engine control system — the Full Authority Digital Electronic Control (FADEC) — unexpectedly shut down, causing the engine to fail. According to investigators, the engine’s Digital Electronic Control Unit (DECU) — the onboard computer that controls fuel flow to the engine — malfunctioned due to some kind of electrical anomaly.
A second investigation, conducted primarily by the manufacturers of the MH-47E, suggested that the crash occurred for a different reason. Accоrding to these *858 investigators, the aircraft’s engine flamed out because it ingested an inordinate amount of water and ice during the inclement weather. This investigation further suggested, however, that the flameout might have been avoided if the MH-47E’s ignition system had been equipped with a continuous or automatic relight feature, which would have allowed the engine to restart automatically in the event of a water- or ice-induced flameout.
Six months after the crash, Plaintiffs filed an action against the contractors that designed and manufactured the allegedly defective aircraft. These contractors include: Boeing, which designed the helicopter’s airframe; Honeywell, which designed and built the engines (including the ignition system); Goodrich, which designed the FAJDEC and was responsible for the DECU; and ATEC, a British company that designed the hardware and software for the DECU.
Initially, Plaintiffs sought relief in California state court, alleging that defendants were liable on theories of product liability, negligence, wrongful death, and loss of consortium. Boeing, however, quickly removed the action to federal court pursuant to the Federal Officer Removal Statute, 28 U.S.C. § 1442(a), which allows federal officers and agents to remove state-law claims to federal court by asserting a federal defense.
In a series of written orders, the district court rejected each of Plaintiffs’ claims. First, in a March 10, 2009 order, the district court ruled that it lacked personal jurisdiction over ATEC. Then, in January 2010, the district court granted summary judgment to Boeing, Honeywell, and Goodrich (collectively the Contractors).
Getz v. Boeing Co.,
II.
In resolving Plaintiffs’ appeal, we turn first to the district court’s dismissal of ATEC, the British company, for lack of personal jurisdiction. According to Plaintiffs, ATEC is subject to personal jurisdiction in California pursuant to Federal Rule of Civil Procedure 4(k)(2). This Rule, which is commonly known as the federal long-arm statute, permits federal courts to exercise personal jurisdiction over a defendant that lacks contacts with any single state if the complaint alleges federal claims and the defendant maintains suffiсient contacts with the United States as a whole. Rule 4(k)(2), titled “Federal Claim Outside State-Court Jurisdiction,” provides:
For a claim that arises under federal law, serving a summons or filing a waiver of service establishes personal jurisdiction over a defendant if:
(A) the defendant is not subject to jurisdiction in any state’s courts of general jurisdiction; and
(B) exercising jurisdiction is consistent with the United States Constitution and laws.
The only question presented here is whether Plaintiffs satisfy the first part of Rule 4(k)(2). That is, do any of their claims against ATEC — pure state-law claims for product liability, negligence, wrongful death, and loss of consortium— arise under federal law?
Until now, we have not examined the precise parameters of the arising-under-federal-law element of Rule 4(k)(2). Wе need not, however, navigate through uncharted terrain without a compass. Here, the commentary to the Rule and the well-reasoned decisions of our sister circuits agree that Rule 4(k)(2)’s reach is limited to substantive federal claims.
First, the commentary explains that Rule 4(k)(2) was enacted to “correct[] a
*859
gap in the enforcement of federal law.” Fed.R.Civ.P. 4(k)(2), Advisory Committee Note. Under the former rules for service of process, federal courts looked to state law, even in federal question cases, whenever a federal statute was silent about the proper mechanism for service.
Id.; see also Omni Capital Int'l v. Rudolf Wolff & Co.,
Rule 4(k)(2) eliminates this anomaly. Whereas foreign defendants lacking sufficient contacts with any single state could previously avoid responsibility for civil violations of our federal laws, the revised Rule allows federal courts to exercise jurisdiction over these defendants, subject only to the limitations of the Fifth Amendment’s due process clause. Id. In this manner, Rule 4(k)(2) provides aggrieved plaintiffs with a mechanism for vindicating their federal rights in cases involving defendants that lack single-state contacts, but who possess minimum contacts with the United States as a whole. Id.
However, Rule 4(k)(2) was narrowly tailored so as to avoid conflict with the Fourteenth Amendment’s jurisdictional limits in eases alleging only state-law claims:
This narrow extension of the federal reach applies only if a claim is made against the defendant under federal law. It does not establish personal jurisdiction if the only claims are those arising under state law or the law of another country, even though there might be diversity or alienage subject matter jurisdiction as to such claims.
Id. (emphasis added). Thus, in order to preserve the proper constitutional balance, Rule 4(k)(2) is available only to plaintiffs who allege a “federally created cause of action.” 4 Charles Alan Wright & Arthur R. Miller, Federal Practice and Procedure § 1068.1 (3d ed.1998).
Those circuits to аddress Rule 4(k)(2) have followed the approach set forth in the commentary. The Fifth Circuit, for instance, has limited the Rule to “substantive federal law claims.”
World Tanker Carriers Corp. v. MIV Ya Mawlaya,
Based on the commentary and this authority, we hold that Plaintiffs’ claims for product liability, negligence, wrongful death, and loss of consortium do not arise under federal law for purposes of Rule 4(k)(2). None of these purely state-law claims alleges any violation of a federal right and none seeks “the enforcement of federal law.”
See
Fed.R.Civ.P. 4(k)(2), Advisory Committee Note. Unfortunately for Plaintiffs, their complaint simply does not assert any “substantive federal law claim” or a claim that finds its “roots in a federal source.”
See World Tanker Carriers,
Despite the non-federal basis of their complaint, Plaintiffs insist that their claims arise under federal law because the Con
*860
tractors removed this action pursuant to the Federal Officer Removal Statute.
See
28 U.S.C. § 1442(a) (permitting federal officers and agents to remove an otherwise state-law action to federal court by raising a federal defense). According to Plaintiffs, their claims became substantively federal when the Contractors asserted a federal defense in their removal petition. The problem, at least for Plaintiffs, is that the Supreme Court’s deсision in
Arizona v. Manypenny,
Here, the “underlying law to be applied” is California state law. The only federal interest аt issue — the Contractors’ eligibility for a federal defense — has no bearing on Plaintiffs’ ability to vindicate a
federal
right and it does not constitute an essential element of Plaintiffs’ well-pleaded complaint.
See Cal. Shock Trauma Air Rescue v. State Compensation Ins. Fund,
As for Plaintiffs’ allegations that ATEC might nonetheless have minimum contacts with California, which they assert independently of their reliance on Rule 4(k)(2), we reject Plaintiffs’ contention that the district court should have permitted additional jurisdictional discovery on this issue. “[Wjhere a plaintiffs claim of personal jurisdiction appears to be both attenuated and based on bare allegations in the face of specific denials made by the defendants, the Court need not permit even limited discovery.”
Pebble Beach Co. v. Caddy,
III.
We turn now to the main issue presented in this appeal: whether Plaintiffs’ state-law claims are barred by the government cоntractor defense. This defense protects government contractors from tort liability that arises as a result of the contractor’s “compliance] with the specifications of a federal government contract.”
In re Hanford Nuclear Reservation Litig.,
The Supreme Court established the framework of the government contractor defense in
Boyle v. United Technologies Corp.,
A.
Under
Boyle’s
first element, a contractor must demonstrate that the government “approved reasonably precise specifications.”
Id.
As we explained in
Snell v. Bell Helicopter Textron, Inc.,
the government’s approval of a particular specification must be more than a cursory “rubber stamp” approving the design.
Plaintiffs argue that the necessary specifications are lacking with respect to the following design features of the MEN17E Chinook: (i) the engine’s ignition system, (ii) the FADEC-DECU, and (iii) the aircraft itself.
1.
According to Plaintiffs, the ignition system was defective because it was manufactured without a continuous relight function, which would have allowed the engine to restart automatically in the event of a water-induced flameout. Upon careful review of the record, we are confident that the United States Army approved reasonably precise specifications for this aspect of the MH-47E’s ignition system, which was manufactured by Honeywell.
Under the terms of its contract with the Army, Honeywell was required to construct the MH-47E’s engine pursuant to “Military Specification AV-E-8593D.” This provision, which is titled “General Specification for Engines, Aircraft, Turbo-shaft, and Turboprop,” provides design criteria, performance expectations, and mandatory quality assurance testing for all military aircraft. Among other things, the Army’s specification includes diagrams and drawings for engine controls; engine configuration requirements; and tests for the engine’s ignition system. Specification AV-E-8593D also required Honeywell to submit a proposed “complete engine specification” for governmental approval.
Honeywell did just that when it submitted its Prime Item Development Specifications to the Army. These specifications contain numerous drawings, figures, and schematics for the engine used in the MH-47E Chinook. They also provide a detailed description of the allegedly defective ignition system. Most importantly, at least for purposes of resolving this appeal, Honeywell’s specifications explicitly state: “Continuous duty ignition capability is not provided.” Hence, the specifications explicitly identify the “design of the particular feature at issue” and expressly observe that feature’s absence.
See Snell,
It is also clear that the Army’s approval of this specification resulted from careful deliberation, not a “rubber stamp.”
See
*862
Snell,
We also reject the notion that the approved specifications constitute mere performance criteria, instead of design specifications.
See In re Haw. Fed. Asbestos Cases,
2.
The Army also approved reasonably precise specifications for the design of the FADEC-DECU, which, again, is the engine control system and computer that allegedly malfunctioned immediately prior to the February 2007 crash. According to the undisputed record, Goodrich — the contractor directly responsible for this component — provided Army personnel with lengthy and detailed design specifications describing both the FADEC (the control system as a whole) and the DECU (the FADEC’s onboard computer). Among other things, these specifications include complex diagrams and design drawings of the FADEC, a description of fault monitoring procedures for the DECU, algorithms for troubleshоoting, and a system for engine fail detection.
Undisputed affidavit evidence also establishes that the Army carefully reviewed these specifications, scrutinized their content, and evaluated the reported test results before approving Goodrich’s specifications. Army engineers attended regular technical meetings pertaining to the FADEC-DECU throughout the procurement process. These engineers also issued formal requests for information pertaining to various design aspects of the FADEC system and called periodic meetings to discuss and test the fuel control design, software design, and the design of the electronics (that is, the DECU). At one point, Army engineers even rejected the “FADEC control system specification,” insisting that Goodrich address certain technical concerns. Such critical and substantive review ultimately culminating in approval is the type of careful consideration necessary to demonstrate that the government made a discretionary decision when it approved the FADEC-DECU.
See Butler,
Plaintiffs present no contrary evidence. Instead, they rely heavily on a single statement contained in Goodrich’s approved specifications for the FADEC-DECU:
Specific implementations used to describe the functional requirements throughout this document are for informational understanding only. Actual implementations used to meet these requirements will be at the discretion of *863 the designer unless specifically stated otherwise.
According to Plaintiffs, the government could not have exercised actual discretion over the design because that discretion was left to Goodrich. There are at least two flaws in Plaintiffs’ argument. First, the statement at issue cannot reasonably be construed as a broad grant of discretion over the final product. Rather, discretion was limited to “implementation” of the specific design requirements contained within the approved specifications and thus does not defeat the government contractor defense.
See, e.g., McKay v. Rockwell Int’l Corp.,
Contrary to Plaintiffs’ view, it makes no difference, for purposes of our analysis, that a similar engine control system had previously been developed for Great Britain’s Royal Air Force. Although
Boyle
makes the government contractor defense inapplicable when “a federal procurement оfficer orders, by model number, a quantity of stock helicopters that happen to be equipped with” a particular design feature,
If we were to hold otherwise, the potential for increased liability could dissuade contractors from providing the United States with sophisticated military equipment that they had initially designed for another nation’s armed forces. This ultimately would put the United States military at a competitive disadvantage: either the government would be unable to obtain necessary equipment or it would be forced to pay higher prices to offset the contractor’s increased risk of liability. Therefore, we are persuaded by the Eleventh Circuit’s recent decision in
Brinson v. Raytheon Co.,
3.
While they do not identify any additional defect, Plaintiffs argue that “the helicopter as a whole” was defective. As far as we can tell, this argument is premised on the theory that Boeing, which was contracted to configure the aircraft, delivered a final product containing a defective ignition system and/or FADEC-DECU. *864 We reject Plaintiffs’ argument for the reasons expressed above: the government approved reasonably precise design specifications for both of these component parts.
B.
We turn now to the second element of the government contractor defense. That element requires a defendant to establish that the product conformed with approved specifications.
Boyle,
Following our sister circuits’ lead, we hold that the operative test for conformity with reasonably precise specifications turns on whether “the alleged defect ... exist[ed] independently of the design itself.”
Miller v. Diamond Shamrock Co.,
Upon careful review of the record, we conclude that the MH-47E conformed with the approved specifications for both the ignition system and the FADEC-DECU. The government invested years in reviewing, developing, and testing both the MH-47E and its engine. When the finished helicopter was delivered, Army officials again carefully examined the engine, inspected the airсraft’s component parts, conducted test flights, and administered rigorous tests and examinations to ensure conformity. Army officials then executed a DD Form 250 — a Material Inspection and Receiving Report — for both the ignition system and the FADEC-DECU. Through that form, the Army officially certified “that all articles delivered [were] inspected and found to conform in all respects ... to all applicable blueprints, specifications, and standards.” Because Plaintiffs do not present any evidence of a latent manufacturing defect that was undiscovered at the time of acceptance, the government’s careful scrutiny and subsequent certification of the MH-47E provide sufficient proof of conformity.
See Miller,
In an effort to ovеrcome summary judgment, Plaintiffs place great emphasis on a post-accident email addressed to the Contractors. In it, an Army officer expressed frustration with the Contractors over their failure to provide a promised “inpui/output table” to Army personnel. Apparently, this table would have measured “the electrical parameters used by the DECU to control” the engines on the MH-47E. The email states:
For the record, the request for the I/O table was made because a FA-DEC/DECU Electrical Interface Control Document was apparently never written during the design, development, and testing of the FADEC System. Action item 33/34 directly requested that Boeing and Honeywell provide the Aircraft to DECU and the Engine to *865 DECU I/O, respectively, contractually required to be delivered back in 1988. We are still waiting for the [sic] a copy of the data delivered by either company that met that specific contractual obligation.
This email leaves unclear how the absence of a 1988 I/O table has any bearing on whether the DECU conformed with reasonably precise design specifications.
See Boyle,
In addition, while the MH-47E Chinook’s engine obviously did not perform like it was supposed to—the aircraft’s engine stalled midflight—this does not preclude the Contractors from establishing the defense. Here, Plaintiffs are quick to point out that the government contracted for a helicopter that would have maintained flight in the adverse weather conditions encountered by the MH-47E. Likewise, they assert that “the failure or shutdown of one engine” was not supposed to “compromise the remaining engine or
safety of flight systems.”
The problem for Plaintiffs is that “[n]oneonformanee with a specification means more than that the ultimate design feature does not achieve its intended goal.”
Kerstetter,
The government contractor defense does not depend upon satisfaction of some general performance goal. Otherwise, “[a] product involved in a design-induced accident would, as a definitional matter, always be deemed not to comply with such generalities since no performance specifications approved by the government would purposely allow a design that would result in an accident.”
Kleemann v. McDonnell Douglas Corp.,
C.
The final element of the government contractor defense requires government contractors to warn the United States “about the dangers in the use of the equipment that were known to the [contractor] but not to the United States.”
Boyle,
We conclude that the Contractors satisfied this final requirement. With respect to the potential for a water- or ice-induced flameout, it is clear that the Army was already aware of this particular risk.
*866
As Honeywell points out, a 1990 Army Field Manual stated explicitly that “[t]urbine engines sometimes tend to flameout” and that “ingestion of ice broken loose at the engine inlet may cause such a situation.” In addition, the Army was well aware of an automatic relight feature to overcome this problem. The Chief of the Aviation Engineering Directorate, which approved the design specifications for the MH-47E, stated in his undisputed affidavit that “automatic re-light ... technology has always been known to the Army, but the Army elected not to include it” on the Chinook line of helicopters. Moreover, because the approved specifications affirmatively acknowledged the absence of a continuous relight function, Plaintiffs cannot seriously argue that the Army was unaware of that component’s existence.
See Boyle,
Plaintiffs nonetheless insist that issues of fact remain because the Army had never heard of an engine
actually
flaming out due to water or ice ingestion. The problem for Plaintiffs is that the Contractors were equally unaware of any prior incidents. At most, Plaintiffs’ evidence suggests that the Contractors should have been aware of the alleged defect.
Boyle,
however, does not require a contractor to warn about dangers of which it merely should have known.
To the extent that the crash may have occurred as a result of an electrical anomaly with the FADEC-DECU, summary judgment is likewise appropriate. According to Plaintiffs, the Contractors should have warned of this potential defect because they were aware of other Chinook aircraft that had experienced engine anomalies prior to the February 2007 crash. A review of these other incidents, however, makes clear that all of these aircraft were MH^47Es. Because the MH-47E is operated exclusively by the United States Army, government personnel were necessarily aware of the potential problem prior to the crash. Again,
Boyle
does not require government contractors to warn of dangers that were already known to the United States.
IV.
Our analysis to this point leaves us with just one additional issue tо resolve: whether Plaintiffs can state a claim against the Contractors for allegedly violating their state-law duty to warn of dangers of which the Contractors should have known. Although federal courts, including ours, have unanimously held that the government contractor defense may preempt these types of claims, a contractor cannot defeat a failure-to-warn claim simply by establishing the elements of the
Boyle
defense as it applies to design and manufacturing defect claims.
See e.g., Butler,
[W]hen state law would otherwise impose liability for a failure to warn, that law can be displaced when the contractor can show that: (1) the government exercised its discretion and approved certain warnings; (2) the contractor provided the warnings required by the government; [and] (3) the contractor warned the government about dangers in the equipment’s use that were known to the contractor but not to the government.
Oliver,
According to Plaintiffs, the Contractors violated their duty to warn because they knew or should have known of an electrical problem with the FADEC-DECU, but failed to provide timely warnings to the operators of the MH-47E Chinook.
It is beyond dispute that the “government exercised its discretion” when it selected relevant warnings for the MH-47E.
Oliver,
The Contractors easily satisfy the second and third elements of the government contractor defense as it applies to Plaintiffs’ state-law failure to warn claims. The second element — providing the warning required by the government — is satisfied by the Contractor’s delivery of the Operator’s Manual. As for the final element— whether the Contractors “warned the government about dangers in the equipment’s use that were known to the [C]ontraetоr[s] but not to the government” — this element is satisfied for the reasons explained earlier in connection with Plaintiffs’ design and manufacturing defect claims: the Contractors and the government had equal awareness of the allegedly undisclosed risks.
See Oliver,
We are not persuaded by Plaintiffs’ suggestion that our decisions in
Butler
and
Hawaii Federal Asbestos
limit the defense to cases in which the government specifically forbids warnings altogether or to instances where the government explicitly dictates the content of the warnings adopted. These cases only require that governmental approval (or disapproval) of particular warnings “conflict” with the contractor’s “duty to warn under state law.”
Butler,
Y.
Finally, we address two evidentiary issues. First, we hold that the district court did not abuse its discretion in declining Plaintiffs’ request for additional discov
*868
ery pursuant to Federal Rule of Civil Procedure 56(f). Here, Plaintiffs failed to “proffer sufficient facts to show that the evidence sought exists, and that it would prevent summary judgment.”
Blough v. Holland Realty, Inc.,
Similarly, the district court did not abuse its discretion by entering summary judgment based on the MH-AUE’s Operator’s Manual, which the Contractors submitted for the first time in their reply to the motion for summary judgment. According to Plaintiffs, the district court was not permitted to consider this evidence without first giving them an opportunity to respond.
Provenz v. Miller,
VI.
We have considered each of Plaintiffs’ arguments challenging the district court’s dismissal of ATEC for lack of personal jurisdiction and its summary judgment in favor of the Contractors. None of these arguments are persuasive.
Finally, because the government contractor defense bars each of Plaintiffs’ state-law claims, we need not consider the Contractors’ alternative argument — based on the combatant activities exception — for upholding the district court s summary judgment.
See Morse v. Frederick,
AFFIRMED.
