EASA says it plainly. DO-311A §2.4.5.5's thermal runaway containment test "was developed for lithium batteries that provide power to other aircraft systems or equipment" — not propulsion batteries (MOC VTOL.2440 §1). Citing it alone in a propulsion pack DVP misrepresents the regulatory posture.
The compliance path runs through MOC VTOL.2440, which requires four prerequisites before either containment approach is available: DO-311A §2.1 general requirements, software assurance per AMC 20-115, hardware assurance per AMC 20-152, and a full SAE ARP 4761 safety assessment including FHA, SSA, FMEA, and common cause analysis. The SSA must demonstrate that catastrophic failure is extremely improbable and does not result from a single failure of the propulsion battery system.
The applicant selects a containment path only after satisfying that prerequisite stack. Both paths require ≥20% of cells to achieve thermal runaway during test, a threshold DO-311A §2.4.5.5 does not impose. EASA added it because the base test can pass with as few as two cells in TR, which it identified as insufficient for propulsion-scale packs.
A DVP row citing "DO-311A §2.4.5.5" without the MOC VTOL.2440 prerequisite stack and the 20% cell threshold is incomplete. DO-311A is a useful baseline for the containment test itself, but the qualification requires the full MOC VTOL.2440 structure around it.
Last verified: 2026-07-24. Source: EASA Easy Access Rules for small category VCA, MOC VTOL.2440 (originated MOC-3 SC-VTOL Issue 2, June 2023; consolidated October 2025). MOC-4 SC-VTOL Issue 2 (July 2025) does not amend MOC VTOL.2440.
MOC VTOL.2440 prerequisite stack (§4), all required before either containment path:
- DO-311A §2.1 general requirements and §3 installation considerations evaluated
- Software functions validated per AMC 20-115
- Hardware functions validated per AMC 20-152
- SAE ARP 4761 safety assessment (FHA, SSA, FMEA, CCA)
- Non-propagation evidence per §7(a) test guidelines
Approach #1 — DO-311A path (§5): DO-311A §2.4.5.5 test per §2.2.2.4, but ≥20% of cells must achieve TR
Approach #2 — CSFL path (§6): Continued safe flight and landing demonstration; ≥20% of cells triggered into TR within ~1 minute simultaneously
Non-propagation test conditions (§7(a)): Pre-trigger stabilization at 55°C or max operating temp (whichever higher) · aged/degraded test articles · minimum 8-hour post-TR monitoring · cell-level TR characterization across heating rates of 5–20°C/min
"Battery Thermal Runaway" trigger definition (§3(g)): TR of 2 cells affecting a common adjacent 3rd cell, or TR of ≥3 cells in the same battery/module
Explicitly not covered by MOC VTOL.2440 (§1): External short circuit · available capacity/energy · protection function testing · crashworthiness · HV signage