Trade Secrets

AvidAir v. Rolls-Royce: Legends, NDAs, and the Modest Bar for Reasonable Secrecy

The Eighth Circuit held that proprietary markings and confidentiality agreements were enough to keep aircraft-overhaul documents secret, even though much of their content was publicly available.

July 21, 2025
A turbine helicopter engine on a maintenance stand in a hangar
The dispute turned on overhaul instructions for the Rolls-Royce Model 250 helicopter engine. Shutterstock
Educational content, not legal advice. This article explains general legal concepts. It does not create an attorney–client relationship. For your specific situation, consult a licensed attorney.

AvidAir Helicopter Supply, Inc. v. Rolls-Royce Corp., 663 F.3d 966 (8th Cir. 2011), No. 10-3444, decided December 13, 2011, is a clean, modern statement of how little a trade-secret owner must do to satisfy the reasonable-measures element — and a reminder that public availability of some of an asset’s content does not defeat secrecy in the asset as a whole. The panel of Circuit Judges Melloy, Smith, and Benton affirmed a judgment for Rolls-Royce entered after a jury awarded $350,000 in actual damages and the district court issued a permanent injunction requiring AvidAir to return the disputed materials.

The technology at issue was the maintenance literature for the Rolls-Royce Model 250, a turbine engine used in civilian and military helicopters. Rolls-Royce distributed its overhaul and repair procedures — including techniques and material specifications — through Distributor Overhaul Information Letters, or DOILs, which it supplied only to its Authorized Maintenance Centers under confidentiality terms. AvidAir, an independent overhaul shop that worked on the engine’s compressor module, obtained DOILs through a maintenance center and used them. When Rolls-Royce objected, AvidAir sued for a declaration that the DOILs were not protectable; Rolls-Royce counterclaimed for misappropriation. The case applied state Uniform Trade Secrets Act principles, and the Eighth Circuit’s affirmance has since become a frequently cited authority on both the secrecy-measures element and the compilation theory.

At a glance

  • Case: AvidAir Helicopter Supply, Inc. v. Rolls-Royce Corp., 663 F.3d 966 (8th Cir. 2011), No. 10-3444
  • Decided: December 13, 2011 (Melloy, Smith, Benton, JJ.)
  • Subject: Distributor Overhaul Information Letters for the Rolls-Royce Model 250 helicopter engine
  • Disposition: Affirmed judgment for Rolls-Royce; jury verdict of $350,000 in actual damages plus a permanent injunction
  • Core holdings: Reasonable efforts to maintain secrecy “need not be overly extravagant, and absolute secrecy is not required”; proprietary legends and confidentiality agreements are recognized indicators of secrecy; and a compilation of public and proprietary information can be a protectable trade secret

Reasonable efforts need not be “overly extravagant”

AvidAir’s principal attack was that Rolls-Royce had not done enough to keep the DOILs secret and that their contents were, in substance, public knowledge in the overhaul community. The Eighth Circuit rejected the framing. The standard, the court explained, is reasonableness, not perfection: “Reasonable efforts to maintain secrecy need not be overly extravagant, and absolute secrecy is not required.” That phrasing matters because it places AvidAir’s argument in the right register. The question was never whether the DOILs could conceivably have leaked, but whether Rolls-Royce’s chosen measures were a sensible response to the risk.

Two measures carried the day. First, Rolls-Royce stamped the documents with proprietary-rights legends. Second, it distributed them only to Authorized Maintenance Centers bound by an AMC Agreement that prohibited disclosure of confidential materials. The court treated these as the kind of ordinary, recognized indicia that courts routinely credit: “The use of proprietary legends on documents or the existence of confidentiality agreements are frequently-considered factors in establishing or denying a trade secret claim.” Taken together, restricted distribution plus contractual confidentiality plus conspicuous marking comfortably satisfied the reasonableness threshold.

The opinion is therefore a useful counterweight to decisions that read the secrecy element aggressively. It confirms that a defensible program does not require vaults, biometric access, or exotic controls. Mark the documents, limit who receives them, and bind the recipients — and you have a record that supports the element.

Leaks and breaches do not automatically defeat secrecy

AvidAir’s second move was to argue that because the DOILs had in fact escaped — it had obtained them, after all, through a maintenance center — Rolls-Royce’s measures had failed and the secrecy was gone. The court declined to let a breach of confidence by a third party retroactively destroy the owner’s reasonable efforts. As the panel put it, “misplaced trust in a third party who breaches a duty of confidentiality does not necessarily negate efforts to maintain secrecy.” Successful misappropriation, in other words, is not proof that the owner’s precautions were unreasonable. If it were, the very fact of a theft would immunize the thief — an obviously self-defeating rule.

This is the practical heart of the decision. Owners distribute sensitive material to partners, vendors, and licensees all the time; the law of trade secrets exists precisely to police what those recipients do with it. A regime in which any downstream breach extinguished protection would gut the doctrine for exactly the relationships it is meant to govern. AvidAir holds the line: the relevant inquiry is whether the owner took reasonable steps ex ante, not whether those steps proved impervious to a faithless intermediary.

A compilation can be secret even if its pieces are not

The third holding addresses a recurring defense in technical-document cases. AvidAir argued that the DOILs largely restated information available in the public domain, so there was nothing secret to protect. The court rejected the reductionist premise. The protectable value of a compilation, it reasoned, derives from “the expenditure of time, effort, and expense involved in its compilation,” not from the ratio of secret to public content within it. Even if a competitor could, in principle, reassemble the procedures from scattered public sources, the assembled, validated, FAA-relevant whole that Rolls-Royce produced was itself the asset.

The proprietary legends and the AMC confidentiality regime reinforced this conclusion in a subtle way: they “contradicted” AvidAir’s claim that the information was public, because Rolls-Royce’s own conduct treated the documents as confidential and constrained their circulation. The compilation theory and the secrecy-measures analysis thus worked together. The measures both qualified the documents for protection and rebutted the public-domain narrative.

Open questions

The opinion sets a generous floor but does not chart the ceiling of what “public” content can swallow. At some point a “compilation” becomes so thin — so dominated by freely available material arranged in an obvious way — that protecting it fences off the public domain; AvidAir credits the effort of compilation without specifying when effort runs out as a justification. The decision also leaves unresolved how far the “breach by a third party does not negate secrecy” principle extends when the owner knew of repeated leaks and did nothing: at what point does tolerated, recurring loss become unreasonable inaction? And in heavily regulated fields like aviation, the interaction between mandatory disclosure to regulators and continued trade-secret status remains a live tension the court did not fully map.

Implications

  • A modest program suffices. Conspicuous proprietary legends plus confidentiality agreements with controlled recipients can satisfy the reasonable-measures element without elaborate physical security.
  • Mark and restrict distribution. The combination of marking documents and limiting them to bound recipients does double work: it establishes secrecy and rebuts a public-domain defense.
  • A third party’s breach is not your forfeiture. Downstream leaks by a faithless intermediary do not automatically negate the owner’s reasonable efforts — the doctrine exists to remedy exactly those breaches.
  • Compilations are protectable. Owners can claim the assembled, validated whole even when individual components are public, anchoring the claim in the time and expense of compilation.
  • Regulated industries should still mark. FAA or other regulatory involvement does not, by itself, strip confidentiality; conspicuous legends help preserve status alongside required disclosures.

Frequently asked questions

Did it matter that the DOIL content was partly public? No. The court held that a compilation’s protectability turns on the time, effort, and expense of assembling it, not on how much of the content is independently public. The validated, assembled whole was the trade secret.

Does a leak prove the owner’s security was unreasonable? No. The Eighth Circuit held that a third party’s breach of a confidentiality duty does not necessarily negate the owner’s reasonable efforts. Misappropriation is the harm the law remedies, not evidence that protection was forfeited.

What measures did Rolls-Royce actually take? It marked the DOILs with proprietary-rights legends and distributed them only to Authorized Maintenance Centers bound by an agreement prohibiting disclosure of confidential materials. The court found those steps reasonable.

Authorities and sources