Aircraft Engine Starting Systems Patents: Top Companies & Trends 2026
- 72.4% of all 105 records in scope sit with the top five assignees, so most of this claim space is already staked out by a small group.
- Filings grew 60% from 2021 to 2024, the last complete filing year, pointing to renewed engineering investment rather than a mature, settled field.
- F02C gas-turbine plant claims cover 77.1% of records while narrower mechanisms like gearing (F16H, 4.8%) and lubrication (F01M, 2.9%) stay comparatively under-claimed.
Filing growth compares 2021 (5 records) with 2024 (8) — 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 105 records in scope (CR5), not by the ranked leaders only.
What this patent set covers
This landscape covers 105 published records matching air turbine starter, engine start valve and cross-bleed start terminology cross-referenced against starter clutch, cutout speed, starter torque, hung start, sprag clutch and starter oil seal language. The intersection is deliberately narrow: it captures the mechanical and control logic of getting a gas-turbine engine turning, not general engine design. Coverage runs from 2015 through the 2026-07-31 cut-off, so the most recent filing years are still incomplete in the public record.
Because publication typically lags filing by around 18 months, 2025 and 2026 figures understate real filing activity in those years; the last year that can be read as a complete picture is 2024.
Filing trends and technology composition
Two views of the same 105-record dataset: how filing activity has moved year over year, and which IPC subclasses carry the claims.
Filing trend
Annual filings ran from 8 in 2017 to a peak of 11 in 2023, with 2021's 5 filings climbing to 8 by 2024 — a 60% rise over that span. 2026 shows only 1 filing so far, which reflects publication lag rather than a slowdown.
Technology composition
F02C (gas-turbine plants) appears in 77.1% of the 105 records, confirming that most filings frame the starting system around the engine architecture itself. F16D (clutches and brakes, 14.3%) and F02N (engine starting, 9.5%) show the mechanical decoupling and control logic is a distinct, smaller cluster, while F16H (gearing, 4.8%) and F01M (lubrication, 2.9%) are thin by comparison.
Shares are the percentage of the 105 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Aircraft Engine Starting Systems with Eureka
This page is one run against one query. Ask Eureka your own question about aircraft engine starting systems and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative and most-cited filings
Air turbine starter torque control system (US11655765B2)
The system controls an air turbine starter through more than one speed/torque curve during startup. A controller commands the starter control valve to hold a regulated pressure in line with a first curve so the gas turbine engine spins up without exceeding a design torque limit, then switches to a second, higher-pressure curve to shorten the overall startup duration.Filed by Parker-Hannifin, published 2023-05-23.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4871296A | Decoupler shaft and air turbine starter having such a decoupler | 95 |
| 2 | US6059085A | Shaft decoupler | 79 |
| 3 | US5123239A | Method of starting a gas turbine engine | 77 |
| 4 | US5267433A | Air turbine starter having a dual clutch | 64 |
| 5 | US20030035718A1 | Non-contacting clearance seal for high misalignment applications | 62 |
| 6 | US5042963A | Dual range air turbine starter | 56 |
| 7 | US5245820A | Air turbine starter with passive hydraulic capacitor | 47 |
| 8 | US6629816B2 | Non-contacting clearance seal for high misalignment applications | 44 |
| 9 | US4542722A | Combined engine-starter and accessory drive system | 44 |
| 10 | US20090199567A1 | Decoupler devices to prevent backdrive in air turbine starters | 38 |
Citation counts reward older filings that have had more time to accumulate references; treat them as a signal of influence on the field, not of current commercial weight.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns stand out once family counts, citation weight and filing dates are read together.
The field is held by a small group
With the top five assignees accounting for 72.4% of all 105 records and the top ten reaching 98.1%, new entrants are filing into space that a handful of established aerospace suppliers already occupy densely. A freedom-to-operate review here is not optional.
Activity is rising, not cooling
Filings climbed from 5 in 2021 to 8 in 2024, a 60% increase over three years, and 2023 was the peak year on record at 11 filings. That is not the profile of a settled technology area; engineering teams are still actively filing around starter control and clutch mechanisms.
Foundational mechanics still anchor the field
The most-cited record, US4871296A on the decoupler shaft and air turbine starter, carries 95 citations, and three of the five most-cited filings concern shaft decoupling or dual-clutch mechanisms. Later filings build on this mechanical core rather than replacing it.
Most claims sit at the engine-system level
F02C classification touches 77.1% of the 105 records, far ahead of the next-largest class, F01D turbines at 22.9%. Narrower mechanism classes such as F16H gearing (4.8%) and F01M lubrication (2.9%) are comparatively thin, which is where specific mechanical claims have more room.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to aircraft engine starting systems, with the prior art for and against each one.
Assignee landscape and collaboration signals
The ranked assignee list returned by the dataset holds 16 companies; it is not a top-50 or top-100 list, it is the full set the data endpoint surfaces for this search.
One filer sets the pace
The leading assignee holds 41 of the 105 records in scope, well ahead of fifth place at 7 and tenth place at 4. That gap between first and the rest of the ranked list is the clearest concentration signal in this dataset.
A steep drop after the leaders
By tenth place, filing counts fall to 4 records, and the top ten together still only reach 98.1% of all 105 records. Entrants below that line are filing single-digit counts into a field the leaders already dominate.
Corporate family filings cluster together
The strongest co-assignee pairing in the dataset links two related Rolls-Royce entities across 9 shared records, reflecting how large aerospace groups file jointly across corporate structures rather than through a single legal entity.
| Assignee | Recent year | YoY |
|---|---|---|
| Rolls-Royce Corp | 1 | — |
| Rolls-Royce North American Technologies Inc | 1 | — |
| Honeywell International Inc | 0 | — |
| Pratt & Whitney Canada Corp | 0 | — |
| Sundstrand Corp | 0 | — |
| Hamilton Sundstrand Corp | 0 | — |
| Rolls-Royce plc | 0 | — |
| General Electric Co | 0 | — |
Where to take this analysis
The dataset points to a concentrated field with active recent filing and a few thinner mechanical branches. The next step is usually narrower than a full landscape re-run.
Check freedom-to-operate against the leader's portfolio
With one assignee holding 41 of 105 records, any new starter clutch or torque-control design should be checked against that portfolio specifically before drafting claims.
Run a freedom-to-operate check in EurekaDraft into the under-claimed gearing and sealing branches
F16H and F01M classes sit well below the F02C core in record share, which is where narrower mechanical claims may have more room to stand.
Explore white space in EurekaTrack the Rolls-Royce filing cluster
The strongest co-assignee pair in this dataset links two Rolls-Royce entities; watching joint filings across corporate structures can flag where a competitor is consolidating claim positions.
Monitor assignee activity in EurekaCommon questions about this patent landscape
One assignee leads the ranked list with 41 of the 105 records in scope, well ahead of the fifth-ranked assignee at 7 records and the tenth at 4. The top five assignees together hold 72.4% of all records, and the top ten reach 98.1%, so filing activity is heavily concentrated among a small number of aerospace suppliers rather than spread evenly across the 16 companies in the ranking. Anyone entering this space should expect to review that leader's portfolio closely.
Yes. Filings rose from 5 in 2021 to 8 in 2024, a 60% increase over three years, and 2023 was the highest filing year recorded at 11. The apparent drop-off in 2025 and 2026 reflects publication lag, since patent applications typically surface in public records around 18 months after filing, not a genuine slowdown in engineering activity.
An air turbine starter uses compressed air, often from cross-bleed or ground carts, to spin a turbine that starts the main gas-turbine engine, and the mechanism typically includes a clutch to decouple once the engine reaches self-sustaining speed. This dataset's search terms centre on that mechanism, which is why F02C gas-turbine plant classification appears in 77.1% of the 105 records and why the most-cited filings, including US4871296A and US6059085A, concern shaft decouplers and clutch design.
The thinner IPC classes point to it: F16H gearing and transmissions covers only 4.8% of records and F01M engine lubrication just 2.9%, both well below the F02C core at 77.1%. Sub-areas such as starter gearbox ratio design, oil seal wear monitoring, and cross-bleed valve sequencing logic show comparatively little dedicated claim coverage relative to the core starter and clutch mechanisms, making them worth a closer prior-art check before assuming the space is occupied.
US11655765B2, assigned to Parker-Hannifin, claims an air turbine starter torque control system that switches between at least two speed/torque curves during startup, holding a regulated pressure via a starter control valve to avoid exceeding a design torque limit before moving to a higher-pressure curve to cut startup time. It specifically covers this staged dual-curve control approach, so a new design that uses a single fixed curve, a different control variable such as flow rate, or a different valve architecture would sit outside its literal claim scope, though a full claim chart is needed before relying on that distinction.
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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.