Definition:Breach of warranty endorsement (AVN 46B)
📝 Breach of warranty endorsement (AVN 46B) is a standard endorsement used in aviation insurance to modify the strict consequences that would otherwise follow from an insured's breach of a policy warranty. Under traditional insurance law — particularly in common-law jurisdictions such as England and Wales — any breach of warranty, however minor or unrelated to the loss, can discharge the insurer from liability entirely. AVN 46B softens this harsh result by providing that a breach of warranty will not void coverage unless the breach actually contributed to the loss or damage in question. The endorsement is a fixture of the London market and is widely adopted in aviation placements globally.
🔧 In practice, AVN 46B is appended to hull and liability policies — and crucially to aviation war risk write-back coverages — to ensure that inadvertent or technical breaches of conditions relating to airworthiness, pilot qualifications, geographic operating limits, or maintenance schedules do not automatically eliminate coverage. For example, if an airline's policy contains a warranty requiring a valid airworthiness certificate and the certificate briefly lapses due to an administrative delay unrelated to a subsequent accident, AVN 46B would prevent the insurer from declining the claim on that ground alone, provided the lapse did not contribute to the loss. The endorsement effectively shifts the burden to the insurer to demonstrate a causal nexus between the breach and the insured event, a significantly higher bar than simply pointing to non-compliance.
💡 The inclusion or absence of AVN 46B in a policy can have multimillion-dollar consequences, and it is a point of active negotiation between brokers and underwriters during placement. Some underwriters resist attaching the endorsement to certain coverage sections — particularly war risk write-backs — to preserve the deterrent effect of strict warranty compliance, while brokers argue that the modern regulatory environment and the complexity of airline operations make inadvertent breaches virtually inevitable. In jurisdictions that have reformed insurance contract law to mitigate the severity of warranty breaches — such as the UK's Insurance Act 2015 — AVN 46B remains relevant because it provides a contractually explicit and well-understood standard that parties prefer over reliance on statutory provisions whose judicial interpretation may still be evolving.
Related concepts: