Application platform: eVTOL / eCOTL propulsion battery packs (energy storage systems for lift and thrust) Last verified: June 27, 2026
Governing Instruments
| Instrument | Version | Scope |
|---|---|---|
| RTCA DO-311A | December 2017 | MOPS for rechargeable lithium batteries/systems permanently installed on aircraft. Supersedes DO-311 (2008) and DO-347 (2013). |
| RTCA DO-347 | December 2013 | Certification test guidance for small/medium rechargeable lithium batteries (single-cell 2–60 Wh, multi-cell 2–300 Wh). Superseded by DO-311A but still referenced via AC 20-184 Appendix F routing for specific test sections. |
| FAA AC 20-184 | October 2015 | Guidance on testing and installation of rechargeable lithium battery systems on aircraft |
| EASA MOC-3 SC-VTOL Issue 2 | June 2023 | Propulsion battery thermal runaway — VTOL category enhanced |
| EASA MOC-4 SC-VTOL Issue 2 | July 2025 | Non-propulsion ESD hazard control, ESS performance in mission context |
| EASA MOC SC-VTOL Issue 2 | May 2021 | ESS crash resistance — VTOL.2325(a)(4) |
| EASA SC E-19 | January 2020 | Special Condition for Electric/Hybrid Propulsion Systems |
| RTCA DO-160G | 2010 | Environmental conditions and test procedures for airborne equipment. EASA MOC documents reference "RTCA DO-160/EUROCAE ED-14" without edition specifier; AC 20-184 references DO-160G specifically. Confirm required edition with certifying authority. |
| EUROCAE ED-289 | Edition year not confirmed; referenced by EASA MOC documents without edition specification | Guidance on accessible energy determination for eVTOL battery systems |
| UN 38.3 | Rev. 7 | Transport testing for lithium batteries |
The Three-Layer Evidence Architecture
No single standard governs eVTOL propulsion ESS qualification. The evidence chain stacks three distinct layers, and conflating them is the structural error in DVP planning that produces certification rejections months after test hardware has been committed.
Layer 1: Equipment-level MOPS. DO-311A sets minimum operational performance standards for rechargeable lithium batteries installed on aircraft, including qualification tests and the thermal runaway containment test (§2.4.5.5). DO-160G provides the environmental test framework. FAA AC 20-184 routes to DO-311A for large batteries (≥60 Wh single-cell or ≥300 Wh multi-cell). DO-311A was written for batteries that power aircraft systems and equipment — avionics, lighting, auxiliary loads. An eVTOL propulsion pack measured in tens to hundreds of kWh exceeds the "Large" threshold by orders of magnitude, and the standard's test scope reflects the original context, not the propulsion role.
Layer 2: Installed-ESS safety evidence. EASA MOC-3 SC-VTOL Issue 2 governs propulsion battery thermal runaway testing under VTOL.2440. EASA states explicitly that DO-311A's containment test "was developed for lithium batteries that provide power to other aircraft systems or equipment" and "did not necessarily consider the particularities of battery systems intended to be used for electric and hybrid aircraft propulsion." The regulator is documenting a scope mismatch in its own foundational standard. EASA addresses it by offering two test approaches (detailed in the safety rows below). MOC-4 SC-VTOL Issue 2 governs non-propulsion ESD separately under VTOL.2525, accepting DO-311A "complemented with a risk assessment at aircraft level."
EASA requires both non-propagation AND containment evidence for propulsion batteries. DO-311A permits an OR relationship between these two demonstrations. This divergence determines test scope, test article count, and schedule. Reconcile it before the DVP is baselined.
Layer 3: Crash resistance. EASA MOC SC-VTOL Issue 2, VTOL.2325(a)(4), sets crash-survivability requirements for the ESS installation. The 15.2 m drop test and 15-minute containment criterion apply to the ESS as installed, meaning the surrounding structure and installation context are part of the test article. This layer is independent of Layers 1 and 2.
One secondary source (Tier 3, June 2025) states that AC 20-184 is no longer accepted by the FAA and that AC 20-184A exists only as an unpublished draft. This could not be verified against a primary FAA document. Confirm current AC status directly before building DVP routing on AC 20-184 Appendix F.
Requirements Matrix
Energy Density and Capacity
| Parameter | Status | Source | Detail |
|---|---|---|---|
| Minimum gravimetric energy density (Wh/kg) | Gap | No governing standard | No standard specifies a minimum pack-level energy density. Vehicle- and mission-defined. DVP must derive from mission analysis. |
| Accessible energy under load | Borrowed | EUROCAE ED-289 via MOC-4 SC-VTOL Issue 2, VTOL.2105(d) (Tier 1). MOC-4 routes to ED-289 for ESS performance characterization including aging, SOC, and thermal effects on accessible energy. | ED-289 provides methodology for determining accessible energy. Guidance framework only; no threshold value. |
Power Capability (C-Rates by Flight Phase)
No governing standard specifies C-rate acceptance criteria by flight phase, for either discharge or charge. Every discharge value below is Tier 3, derived from published engineering analyses of parametric vehicle models. The DVP must derive a vehicle-specific discharge profile from flight mechanics analysis. These values provide orientation for early-stage sizing.
| Flight Phase | C-Rate Range | Status | Source |
|---|---|---|---|
| Cruise | 0.75–1.5C discharge | Inferred | Kim et al., Joule 2021 (Tier 3): 200 Wh/kg pack, battery weight fraction 0.3, parametric across multirotor configurations |
| Hover (takeoff/landing) | 2.5–4.5C discharge | Inferred | Kim et al. 2021 (Tier 3): same assumptions; C-rates increase with lower specific energy or smaller battery weight fraction |
| Takeoff segment | ~4C discharge | Inferred | Agrawal et al., ACS Energy Letters 2019 (Tier 3): 245 Wh/kg cell, 73-mile mission, 1000–2500 kg GTOM |
| Landing segment | ~4.8–5C discharge | Inferred | Agrawal et al. 2019 (Tier 3): higher C-rate reflects lower SOC and voltage during landing phase |
| Rapid initial climb (pulse) — research reference, non-operational | ~15C for 45 sec | Inferred | Dixit et al., ACS Energy Letters 2024 (Tier 3): materials-science study replicating extreme climb demands. Not a commercial mission profile. Included for cell-level degradation awareness only; do not use as a DVP test parameter without vehicle-specific justification. |
| Parameter | Status | Source | Detail |
|---|---|---|---|
| Turnaround charge rate | Gap | No governing standard | No standard specifies pack-level charge rate limits for eVTOL. Fleet turnaround charging profiles are program-defined based on operational cadence and thermal management architecture. No published Tier 3 analysis of eVTOL-specific fast-charge profiles was identified in this research pass. |
For calibration: average EV battery discharge is approximately 0.3C highway, 0.1C city. An eVTOL propulsion battery averages approximately 1C over an 80 km trip (Kim et al. 2021). The discharge profile is structurally different from any ground-vehicle application. Borrowing EV cycle profiles for eVTOL DVP testing is a category error.
Cycle Life and Calendar Life
| Parameter | Status | Source | Detail |
|---|---|---|---|
| Minimum cycle count | Gap | No governing standard | No standard sets a minimum. Program-defined based on fleet economics and mission cadence. |
| Aging characterization method | Borrowed | EUROCAE ED-289 via MOC-3 SC-VTOL Issue 2 (Tier 1). MOC-3 routes to ED-289 for aging cycle test methodology and specimen qualification for thermal runaway testing. | MOC-3 permits aged battery systems to serve as thermal runaway test samples "when the applicant demonstrates a proper aging and degradation." ED-289 provides methodology. |
| Calendar life | Gap | None | No threshold. ICA per DO-311A §1.12 must address aging, but no calendar limit is specified. |
Operating Envelope
| Parameter | Status | Source | Detail |
|---|---|---|---|
| Temperature and altitude | Borrowed | DO-160G Section 4 (Tier 1) | Categories range from A1 (pressurized, -15°C to +55°C) to D3 (unpressurized, -55°C to +85°C at 21,300 m). No eVTOL-specific category mapping exists. Applicant selects and justifies category by installation zone. |
| Temperature variation | Borrowed | DO-160G Section 5 (Tier 1) | Standard rapid temperature change profiles. No eVTOL-specific profile. |
| Humidity | Borrowed | DO-160G Section 6 (Tier 1) | Standard categories apply. |
Mechanical
| Parameter | Status | Source | Detail |
|---|---|---|---|
| Operational vibration | Borrowed | DO-160G Section 7 (Tier 1); MOC-4 VTOL.2160 (Tier 1) | DO-160G profiles exist for fixed-wing and rotorcraft. No published category exists for multi-rotor eVTOL. EASA MOC-4 documents the mismatch: "VTOL aircraft having Lift/Thrust Units with variable rpm" generate different harmonic frequency ranges with "potentially different phases between LTUs." The effect of these combinations on natural frequencies must be investigated. DVP must define a program-specific vibration profile and justify category selection. |
| Crash safety vibration | Borrowed | DO-160G Section 8 (Tier 1) | Safety-critical equipment vibration. Standard categories apply. |
| Crash-resistance loads (cabin-installed ESD) | Settled | MOC SC-VTOL Issue 2, VTOL.2325(a)(4) §4 (Tier 1) | Upward 4g, Forward 16g (18g CTOL), Sideward 8g, Downward 20g, Rearward 1.5g. The MOC document as publicly available does not specify whether these are ultimate or limit loads. Confirm against full SC-VTOL text before committing to structural DVP entries. |
| Crash-resistance loads (above/adjacent ESD) | Settled | MOC SC-VTOL Issue 2, VTOL.2325(a)(4) §4(c) (Tier 1) | Upward 1.5g, Forward 12g, Sideward 6g, Downward 12g, Rearward 1.5g. Same ultimate-vs.-limit ambiguity applies. |
| Drop test | Settled | MOC SC-VTOL Issue 2, VTOL.2325(a)(4) §3 (Tier 1) | Drop height ≥15.2 m (50 ft); non-deforming surface; ESS charged to most critical condition; enclosed in representative surrounding structure; orientation ±10° of horizontal axis; free drop. |
Safety
The three-layer architecture and the FAA/EASA divergence concentrate their consequences here.
| Parameter | Status | Source | Detail |
|---|---|---|---|
| Thermal runaway containment | Borrowed | DO-311A §2.4.5.5 (Tier 1, paywalled); MOC-3 SC-VTOL Issue 2, VTOL.2440 Approach #1 (Tier 1) | EASA Approach #1: test per DO-311A §2.4.5.5 per requirements of §2.2.2.4. ≥20% of cells must achieve thermal runaway. EASA states explicitly this test was not written for propulsion-scale batteries and may impose an energy/weight ratio penalty inconsistent with propulsion applications. The standard is borrowed; the scope mismatch is regulator-documented. |
| Thermal runaway containment, CSFL alternative | Settled (EASA only) | MOC-3 SC-VTOL Issue 2, VTOL.2440 Approach #2 (Tier 1) | Battery Thermal Runaway Containment for Continued Safe Flight and Landing Time Tests. ≥20% of cells must achieve thermal runaway. Must demonstrate thermal runaway management at system and installation level ensuring CSFL per MOC VTOL.2330. |
| Non-propagation evidence | Settled (EASA only) | MOC-3 SC-VTOL Issue 2, VTOL.2440 (Tier 1) | Required in addition to containment. EASA mandates both non-propagation AND containment. DO-311A permits OR. For dual-certification programs, the EASA requirement governs because it is the more demanding. |
| Post-crash fire protection | Settled | MOC SC-VTOL Issue 2, VTOL.2325(a)(4) §3(f) (Tier 1) | Structural damage must not lead to fire, leakage of harmful fluids/fumes/gases; OR any fire/leakage must be contained ≥15 minutes in non-occupied areas outside the evacuation path. |
| Water operations energy retention | Settled | MOC VTOL.2430(a)(6) §2(a)(2) (Tier 1) | ESS must retain stored electrical energy ≥15 minutes. Applies to VTOL certified for water operations or emergency flotation. |
| Safety assessment | Settled | DO-311A §2.1 (Tier 1, paywalled); MOC-3 SC-VTOL Issue 2 (Tier 1) | Battery System Safety Assessment: FHA, FTA, FMEA, CMA per SAE ARP 4761 (Tier 1 standard; clause-level detail per L-SYS analysis, Tier 2). Critical control/protective function hardware per DO-254 DAL A, software per DO-178 DAL A (FAA) or AMC 20-152/AMC 20-115 (EASA). |
| Latent manufacturing defect mitigation | Settled | DO-311A §2.1.7 via MOC-3 SC-VTOL Issue 2 (Tier 1) | Referenced as prerequisite to thermal runaway testing. |
| Overcharge (protection enabled) | Settled | AC 20-184 Appendix F (Tier 1), mapping DO-311 §2.3.18 | Test required. Clause number derives from AC 20-184's mapping of DO-311 (pre-DO-311A). DO-311A may have renumbered this section. Verify against DO-311A full text before citing in DVP. |
| Short-circuit (protection enabled/disabled) | Settled | AC 20-184 Appendix F (Tier 1), routing to DO-347 §§2.3.8–2.3.9 | Both protection-enabled and protection-disabled tests required. DO-347 is superseded by DO-311A but remains in the AC 20-184 routing chain for these specific tests. |
Environmental Protection
| Parameter | Status | Source | Detail |
|---|---|---|---|
| Salt fog | Borrowed | DO-160G Section 14 (Tier 1) | Standard test. Category by installation zone. |
| Fluid susceptibility | Borrowed | DO-160G Section 11 (Tier 1) | Standard categories. |
| IP rating | Gap | None | DO-160G does not use IP ratings. Waterproofness testing exists (Section 10) but IP-equivalent classification is outside the aviation qualification framework. |
EMC
| Parameter | Status | Source | Detail |
|---|---|---|---|
| RF susceptibility (radiated/conducted) | Settled | DO-160G Section 20 (Tier 1) | Standard categories. |
| RF emissions | Settled | DO-160G Section 21 (Tier 1) | Standard categories. |
| Lightning indirect effects | Settled | DO-160G Section 22 (Tier 1); MOC-4 VTOL.2515 references IEL group testing | Standard categories. |
Transport
| Parameter | Status | Source | Detail |
|---|---|---|---|
| Transport classification and testing | Settled | UN 38.3 Rev. 7 (Tier 1) | Standard lithium battery transport tests. Required for shipping cells and packs regardless of end application. |
Gaps Summary
Eight parameter classes carry gaps or documented scope mismatches requiring program-defined DVP entries.
1. Power capability (discharge). No standard specifies discharge rate requirements by mission phase. All published values are Tier 3 engineering analyses of parametric vehicle models. ED-289 provides methodology for accessible energy characterization but sets no C-rate thresholds. The DVP must derive a vehicle-specific discharge profile from flight mechanics.
2. Power capability (charge). No standard specifies pack-level charge rate limits for eVTOL. Fleet turnaround charging profiles are entirely program-defined. No published engineering analysis of eVTOL-specific fast-charge requirements was identified in this research pass.
3. Cycle life and calendar life. No minimum cycle count or calendar life threshold in any governing standard. ED-289 provides aging characterization guidance. Program-defined based on fleet economics and operational cadence.
4. Energy density. No minimum specified anywhere. Entirely vehicle- and mission-defined.
5. DO-160G category selection. Temperature, altitude, and vibration categories must be selected and justified by the applicant. No published mapping exists for eVTOL propulsion battery installations. The vibration mismatch for multi-rotor variable-rpm configurations is explicitly documented by EASA in MOC-4. EASA MOC documents reference "RTCA DO-160/EUROCAE ED-14" without specifying edition; AC 20-184 references DO-160G (2010) specifically. Confirm required edition with certifying authority.
6. Thermal runaway test scope. DO-311A §2.4.5.5 was not written for propulsion-scale batteries. The regulator has documented this. EASA offers two approaches under VTOL.2440. Programs targeting dual FAA/EASA certification must reconcile the AND vs. OR requirement for non-propagation and containment evidence.
7. SC E-19 propulsion battery MOC boundary. Industry analysis (Tier 3, November 2025) indicates current SC E-19 MOC priorities focus on engine-only components, with propulsion batteries excluded from published Level 2 MOCs. The boundary between SC E-19 and SC-VTOL for propulsion battery certification is program-specific. Verify with EASA directly.
8. FAA AC 20-184 currency. If AC 20-184A has superseded AC 20-184, the FAA routing structure in this card requires re-verification. Confirm current AC status at the FAA document library before building DVP routing on AC 20-184 Appendix F.
Standards body activity: EASA continues publishing MOC issues under SC-VTOL. MOC-5 Issue 1 was in public consultation as of July 2025; no finalized Issue 2 located as of June 27, 2026, though MOC-5 does not address propulsion battery requirements. RTCA SC-225 maintains DO-311A. The FAA powered-lift final rule (2025) includes battery system failure provisions, but clause-level text was not publicly accessible in this research pass. The regulatory architecture for eVTOL propulsion ESS qualification exists and is maturing, but the foundational equipment-level standard is being applied beyond its design scope, and the regulator has said so in published guidance. The DVP must carry that knowledge explicitly. DO-311A treated as settled coverage for propulsion-scale systems is the kind of assumption that survives internal reviews and fails at certification.
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AC 20-184A draft status: One secondary source claims AC 20-184 is no longer accepted by the FAA and that AC 20-184A exists only as an unpublished draft, which would invalidate the Appendix F routing structure used in this card.
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EASA MOC-5 finalization timeline: MOC-5 SC-VTOL Issue 1 entered public consultation in July 2025 with no finalized Issue 2 publicly posted as of June 27, 2026, though its scope does not cover propulsion battery or ESD requirements.
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SC E-19 propulsion battery boundary: Industry analysis from November 2025 indicates EASA's current SC E-19 MOC priorities exclude propulsion batteries from published Level 2 MOCs, leaving the certification boundary between SC E-19 and SC-VTOL program-specific and unresolved.
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ISO 13482 Edition 2 progress: The robotics safety standard ISO 13482:2014 is flagged for revision, with ISO/FDIS 13482 at Stage 50.00 covering service robots in personal and professional/commercial applications but still not addressing battery-pack qualification.