H55 clears regulatory hurdle for aviation propulsion batteries with EASA-witnessed test campaign — Switzerland

H55 announced completion of a regulator-witnessed propulsion battery test campaign that addresses a central technical and regulatory hurdle for electric and hybrid aircraft: demonstrating that high-energy lithium cells can be integrated and contained safely at the propulsion-module level. The work was executed using serial-conforming hardware produced under validated processes, not laboratory prototypes, and included authority-observed thermal runaway tests conducted without fire propagation. Over a six-month effort H55 generated more than one hundred test articles, capturing environmental, safety, functional, and performance data under defined worst-case failure modes; the company plans to submit the final reports to the European regulator in the first quarter of 2026. Technically, H55’s architecture emphasizes cell-level monitoring, redundancy, and active/passive mitigations to detect and contain initiating faults at their origin rather than relying on pack-level assumptions. That approach yields both operational telemetry and deterministic failure data, which regulators and insurers require to move from subjective program-level estimates to actuarially tractable risk models. Strategically, an authority-aligned reference module that demonstrates containment across credible failure scenarios reduces the unit-certification risk that historically forced one-off, program-specific testing and underwriting. With EASA engagement and an agreement to share agreed means of compliance with the U.S. FAA, the results have the potential to be leveraged across markets, lowering incremental certification cost for OEMs and enabling insurers to price fleet deployments more predictably. For aircraft manufacturers and integrators this changes the economics: a validated, repeatable energy storage architecture can be reused across platforms, allowing certification evidence to compound rather than be reinvented per program. Investors and lessors stand to gain clearer loss-exposure profiles that support financing and resale markets; operators and trainers can plan fleet rollouts with tighter timelines. The demonstration does not by itself deliver type certificates for aircraft, but it materially de-risks the battery-module step that has been the gating constraint for many projects. Operational credibility is reinforced by H55’s track record in electric flight testing, which the company cites to show systems-level experience feeding into test protocols and production readiness. The next technical and administrative milestones will be formal acceptance of the test reports by EASA, subsequent alignment with FAA processes, and evidence of multiple OEMs adopting the module as a common baseline. If those follow-through steps succeed, the industry could shift from bespoke battery qualification toward platformized, certifiable battery systems that scale across training, regional, and demonstrator aircraft. The campaign therefore represents both a technical validation and an institutional inflection point for certifiable electric propulsion.