Envelope Protection Patents: Who Leads, Where the Gaps Are 2026
- Concentrated at the top. The five leading assignees together hold 62.6% of all 163 records in scope, and the top ten hold 79.1% — a field with little room for a new entrant to out-file the incumbents.
- Filing has cooled from its 2018 peak. 2018 recorded 30 filings, the high point of the window; by the last complete year the pace had fallen 33% between 2021 (18) and 2024 (12).
- Drone and ground-installation branches stay thin. B64U (unmanned aircraft) appears in only 5.5% of records and B64F (ground installations) in 4.3% — both far behind the aircraft-equipment and control classes that dominate filing.
Filing growth compares 2021 (18 records) with 2024 (12) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 163 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This dataset tracks 163 published patent records filed against a search built around stall protection systems, flight envelope protection and load factor limiting, cross-referenced with angle-of-attack sensing, stick pusher mechanisms, buffet boundary detection and bank angle limiting. The scope spans 2015 through the 2026-07-31 cut-off, covering both fixed-wing commercial aircraft systems and a smaller set of unmanned aerial vehicle applications.
Filing concentrates in aircraft equipment and control classes, with receiving offices led by the United States and the European Patent Office, followed by Canada and Germany. Because publication typically lags filing by around 18 months, the most recent one to two years in any trend line understate actual filing activity.
Let an AI agent run this analysis on your own technology
Pick a task. Every answer cites the patents behind it.
Filing trends and technology composition
Publication counts and IPC classification data for the 163 records in scope, drawn directly from the search corpus.
Filing trend: a 2018 peak, then a cooling curve
Filings rose from 9 in 2017 to a peak of 30 in 2018. The last complete year in the window shows the pace down 33% from 2021 (18) to 2024 (12); 2025 and 2026 figures are still filling in as publications catch up to filing dates.
Where the claims sit: aircraft equipment and control dominate
B64D (aircraft equipment) and B64C (aeroplanes and helicopters) each cover close to half of all records — 49.7% and 49.1% respectively — with G05D (control of non-electric variables) close behind at 36.8%. Sensing-adjacent classes G01P and G01C sit in the 18-20% range, while B64U (drones) and B64F (ground installations) remain in single-digit territory.
Shares are the percentage of the 163 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Envelope Protection and Stall Prevention with Eureka
This page is one run against one query. Ask Eureka your own question about envelope protection and stall prevention and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
US8620495B2 — Air data stall protection system
An electronic multi-function probe (MFP) is provided for positioning adjacent an aircraft skin. The electronic MFP includes a plurality of pressure sensing ports and an electronics housing. Positioned within the electronics housing are air data processing circuitry and stall protection system processing circuitry. The air data processing circuitry is configured to generate air data parameters, including airspeed and altitude, as a function of pressures at the plurality of pressure sensing ports. The stall protection system processing circuitry of the electronic MFP is configured to detect stall conditions as a function of angle of attack and at least one air data parameter.Filed by Rosemount Aerospace Inc., granted 2013-12-31.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6332105B1 | Neural network based automatic limit prediction and avoidance system and method | 53 |
| 2 | US9849999B1 | Avionics interface | 47 |
| 3 | US5803408A | Autopilot/flight director stall protection system | 47 |
| 4 | US5836546A | Autopilot/flight director underspeed protection system | 38 |
| 5 | US20160114903A1 | Flight envelope protection system for unmanned aerial vehicles | 30 |
| 6 | US5746392A | Autopilot/flight director underspeed protection system | 28 |
| 7 | US20160096616A1 | Methods and apparatus for providing servo torque control with load compensation for pilot in the loop | 27 |
| 8 | US20170060141A1 | Aircraft stall protection system | 26 |
| 9 | US20080147255A1 | Air Data Stall Protection System | 26 |
| 10 | US20190127079A1 | Aircraft stall warning/protection with time-varying maximum angle of attack settings for icing conditions | 24 |
Citation counts favour older records that have had more time to accumulate references — read them as a signal of influence within this search corpus, not as a measure of current technical importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
Put your own technology through the same analysis
Eureka on the web
When you want the answer in the next five minutes.
The agent works the prompt against patents and technical literature, citing every source.
Run your analysis now →MCP server & REST API
When it has to run inside your own pipeline.
Patent search, landscape analysis and assignee resolution as MCP tools. Drop them into any agent framework, or call REST directly.
Browse MCP servers →What the filing pattern tells you
Reading the concentration, trend and classification data together points to a field where the core stall-protection and envelope-limiting claims are largely staked out, with newer activity pushing outward into sensing integration and unmanned platforms.
A small group holds most of the claim space
The five leading assignees combined account for 62.6% of all 163 records in scope, and the top ten extend that to 79.1%. For a new entrant, this means the foundational stall-detection and envelope-limiting mechanisms are likely already claimed by an incumbent; differentiation has to come from adjacent sensing or integration approaches rather than the core control logic.
Filing has pulled back from its 2018 high
After peaking at 30 filings in 2018, activity has settled into a lower band, falling 33% from 18 filings in 2021 to 12 in 2024. This does not necessarily mean the technology is exhausted — dense prior art in the core mechanisms may simply be pushing new filers toward narrower, more defensible claims.
Drone-specific envelope protection is thinly claimed
Unmanned aerial vehicle applications (B64U) appear in only 5.5% of the 163 records, and ground installation support (B64F) in just 4.3%. Given growing commercial drone deployment, envelope protection logic adapted for autonomous or remotely piloted platforms remains one of the least crowded corners of this landscape.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to envelope protection and stall prevention, with the prior art for and against each one.
Who holds the claim space
The assignee ranking covers 38 companies, counted by records in scope. Filing is led by a single dominant assignee, with a clear drop to the next tier and a long tail of single- and double-digit filers.
One assignee accounts for roughly a third of the field
The top-ranked assignee holds 52 of the 163 records in scope — well ahead of fifth place at 6 and tenth place at 4. This gap suggests a long-running, systematic filing programme around core stall protection and envelope limiting rather than opportunistic filing.
A sharp drop after the leader
Fifth place holds 6 records and tenth place holds 4 — a steep decline from the leader's 52. The mid-tier assignees include commercial aircraft OEMs and avionics suppliers, each maintaining a modest but active filing presence rather than competing head-on for volume.
Many single-digit filers round out the field
Beyond the top ten, the remaining assignees in the 38-company ranking each hold small numbers of records. This long tail includes specialist sensor makers and newer entrants, some showing recent-year activity even as legacy leaders show none in the latest year.
| Assignee | Recent year | YoY |
|---|---|---|
| Lilium GmbH | 1 | — |
| The Boeing Company | 0 | — |
| Gulfstream Aerospace Corp | 0 | — |
| Thales Canada Inc | 0 | — |
| Rosemount Aerospace Inc | 0 | — |
| Airbus (SAS) | 0 | — |
| Volvo Truck Corporation | 0 | — |
| Embraer SA | 0 | — |
Where to take this analysis
The data points to a concentrated core and a thinner unmanned-systems edge. The next steps depend on whether you are assessing freedom to operate or looking for filing openings.
Map the leader's claim boundaries
With one assignee holding 52 of 163 records, a claim-by-claim review of its core stall-protection and envelope-limiting patents will show exactly how much room remains for a differentiated filing.
Explore claims in Eureka →Track the drone-adjacent branch
B64U records sit at just 5.5% of the field. Monitoring new filings in this subclass over the next few publication cycles will show whether incumbents or new entrants move first into UAV envelope protection.
Set up monitoring in Eureka →Common questions on this landscape
One assignee leads with 52 of the 163 records in this dataset, well ahead of the rest of the field — fifth place holds 6 records and tenth place holds 4. The top five assignees combined account for 62.6% of all records, and the top ten reach 79.1%, so filing is heavily concentrated at the top rather than spread evenly across the 38 ranked companies. This concentration typically means the foundational control-logic claims are already staked out by the leader, leaving newer filers to work around narrower or adjacent claims.
Filing peaked at 30 records in 2018 and has since settled lower, falling 33% from 18 filings in 2021 to 12 in 2024 — the last year in this dataset that can be treated as a complete count. Figures for 2025 and 2026 look lower still, but that reflects publication lag of roughly 18 months rather than an actual drop in filing activity. Anyone drawing conclusions from the most recent one to two years should treat those numbers as provisional undercounts.
The clearest gaps sit in classes with low record shares relative to the field's core: unmanned aerial vehicle applications (B64U) appear in only 5.5% of the 163 records, and ground installation support (B64F) in just 4.3%, against roughly 49% each for the two dominant aircraft-equipment and aeroplane classes. Sub-areas such as UAV-adapted stall detection, bank angle limiting for autonomous platforms, and buffet boundary sensing integration are correspondingly thin. These are the branches where a first-mover claim is more likely to clear prior art cleanly.
US8620495B2, assigned to Rosemount Aerospace Inc., covers an electronic multi-function probe combining air data processing circuitry and stall protection processing circuitry in a single housing, detecting stall conditions from angle of attack and other air data parameters. It matters because it ties sensor hardware and stall-detection logic into one integrated unit rather than treating them as separate systems, which raises the bar for anyone trying to patent a similar combined-probe approach. Anyone designing a new air data probe with onboard stall logic should review its claim scope closely before finalizing a design.
The United States leads with 61 filings, followed by the European Patent Office at 40, then Canada at 14 and Germany at 12, with Austria and the WIPO PCT route each at 7. This distribution reflects where the major commercial aircraft OEMs and avionics suppliers pursue protection first, typically the US and Europe, before extending coverage through PCT or national-phase filings elsewhere. Filers targeting freedom to operate in this field should prioritize clearing US and EPO prior art first.
Research Envelope Protection and Stall Prevention in depth with Eureka
Go past this page: query the whole envelope protection and stall prevention corpus yourself, in your own scope.
Every answer comes back with patent numbers you can open.
Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.