Prosecution Insights
Last updated: April 18, 2026
Application No. 18/486,535

IN-FLIGHT EMISSIONS AND CONTRAIL CONTROL SYSTEM

Final Rejection §103
Filed
Oct 13, 2023
Examiner
HUANG, DAVID Z
Art Unit
2855
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Rtx Corporation
OA Round
2 (Final)
80%
Grant Probability
Favorable
3-4
OA Rounds
2y 7m
To Grant
93%
With Interview

Examiner Intelligence

Grants 80% — above average
80%
Career Allow Rate
546 granted / 685 resolved
+11.7% vs TC avg
Moderate +14% lift
Without
With
+13.7%
Interview Lift
resolved cases with interview
Typical timeline
2y 7m
Avg Prosecution
28 currently pending
Career history
713
Total Applications
across all art units

Statute-Specific Performance

§101
2.3%
-37.7% vs TC avg
§103
46.6%
+6.6% vs TC avg
§102
16.0%
-24.0% vs TC avg
§112
27.9%
-12.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 685 resolved cases

Office Action

§103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claims 1, 3-11, and 13-20 are rejected under 35 U.S.C. 103 as being unpatentable over Swann et al. (US 2023/0193777 A1) (hereinafter Swann). Regarding claim 1, Swann teaches an aircraft (see Abstract) comprising: a gas turbine engine configured to ingest a first mass flow and to exhaust a second mass flow [gas turbine engine 10 having air intake and producing an exhaust plume 141] (Para [0392, 0545], see Figs. 23 or 25); and an optically-based contrail control system [exhaust sensor 151] configured to determine an amount of scattered energy contained in the second mass flow, to determine flow characteristics of the second mass flow based at least in part on molecular components contained in the second mass flow [count particles using laser scattering] (Para [0575], see Fig. 23 or 25), and to determine a level of emissions exhausted from the gas turbine engine based at least in part on a combination of the amount of scattered energy and the flow characteristics [determination module 152 to compare a measured exhaust parameter or parameters to a look-up table to determine corresponding characteristics of the fuel being used by the gas turbine engine] (Para [0580, 0585], see Fig. 23 or 25), wherein the optically-based contrail control system performs at least one emission reduction action [controlling the operating parameters of the aircraft or gas turbine engine according to the one or more contrail parameters; reduced emissions may permit reduced contrail formation whilst reducing environmental impact] (Para [0202-0204, 0406]). Swann fails to teach wherein the system compares the level of emissions to an emissions threshold set to form a target amount of contrails and wherein the system performs at least one emission reduction action in response to the level of emissions exceeding the emissions threshold. Swann additionally teaches wherein measured exhaust parameters associated with the level of emissions are compared to expected exhaust parameter thresholds to determine one or more fuel characteristics (Para [0580]) and that the determined one or more fuel characteristics are then utilized to control the operating parameters of the aircraft or gas engine (Para [0604-0606, 0608-0626]) wherein it is advantageous to perform at least one emission reduction action to reduce environmental impact of a given mission (Para [0406]). It would have been obvious to a person having ordinary skill in the art at the time of the filing of the invention to modify Swann such that the optically-based contrail control system compares the level of emissions to an emissions threshold set to form a target amount of contrails and wherein the system performs at least one emission reduction action in response to the level of emissions exceeding the emissions threshold, in order to control emissions of the engine to match acceptable environmental impacts of a given mission. Regarding claim 11, Swann teaches a method of determining exhaust emissions and reducing contrail formation produced by an aircraft (Para [0406], see Abstract), the method comprising: exhausting a mass flow from a gas turbine engine of the airplane [gas turbine engine 10 producing an exhaust plume 141] (Para [0545], see Figs. 23 or 25); and determining, by an optically-based contrail control system [exhaust sensor 151], an amount of scattered energy caused by the energy interacting with particulates contained in the mass flow [count particles using laser scattering] (Para [0575], see Fig. 23 or 25); determining, by the optically-based contrail control system, flow characteristics of the mass flow based at least in part on molecular components contained in the mass flow [count particles using laser scattering] (Para [0575], see Fig. 23 or 25); and determining, by the optically-based contrail control system, a level of emissions exhausted from the gas turbine engine based at least in part on a combination of the amount of scattered energy and the flow characteristics [determination module 152 to compare a measured exhaust parameter or parameters to a look-up table to determine corresponding characteristics of the fuel being used by the gas turbine engine] (Para [0580, 0585], see Fig. 23 or 25). Performing at least one emission reduction action [controlling the operating parameters of the aircraft or gas turbine engine according to the one or more contrail parameters; reduced emissions may permit reduced contrail formation whilst reducing environmental impact] (Para [0202-0204, 0406]). Swann fails to teach comparing the level of emissions to an emissions threshold set to form a target amount of contrails and performing the at least one emission reduction action in response to the level of emissions exceeding the emissions threshold. Swann additionally teaches wherein measured exhaust parameters associated with the level of emissions are compared to expected exhaust parameter thresholds to determine one or more fuel characteristics (Para [0580]) and that the determined one or more fuel characteristics are then utilized to control the operating parameters of the aircraft or gas engine (Para [0604-0606, 0608-0626]) wherein it is advantageous to perform at least one emission reduction action to reduce environmental impact of a given mission (Para [0406]). It would have been obvious to a person having ordinary skill in the art at the time of the filing of the invention to modify Swann such to further comprise comparing the level of emissions to an emissions threshold set to form a target amount of contrails and performing the at least one emission reduction action in response to the level of emissions exceeding the emissions threshold, in order to control emissions of the engine to match acceptable environmental impacts of a given mission. Regarding claims 3 and 13, Swann as applied to claims 1 and 11 above teaches the claimed invention, in addition to wherein the at least one emission reduction action includes at least one of controlling at least one operating parameter of the aircraft to reduce at least one of the level of emissions exhausted from the gas turbine engine and a formation of contrails produced by the gas turbine engine [controlling the operating parameters of the aircraft or gas turbine engine according to the one or more contrail parameters; reduced emissions may permit reduced control formation whilst reducing environmental impact] (Para [0202-0204, 0406]). Regarding claims 4 and 14, Swann as applied to claims 1 and 11 above teaches the claimed invention, in addition to wherein the flow characteristics includes one or a combination of velocity, density, temperature, and pressure [atmospheric condition parameters may include the ambient pressure, temperature, and/or vapour pressure] (Para [0581]). Regarding claims 5 and 15, Swann as applied to claims 1 and 11 above teaches the claimed invention, in addition to wherein the molecular components include one or a combination of oxygen, nitrogen, and water [trace substance parameters for determining fuel characteristics; nitrogen, water] (Para [0509]). Regarding claims 6 and 16, Swann as applied to claims 1 and 11 above teaches the claimed invention, in addition to wherein the optically-based measurement system comprises: an optical sensing unit configured to detect the scattered energy [exhaust sensor may comprise a condensation particle count measurement device; count particles using laser scattering] (Para [0575], see Fig. 25); and a controller in signal communication with the optical sensing unit, the controller configured to determine the level of emissions [determination module 152 to compare a measured exhaust parameter or parameters to a look-up table to determine corresponding characteristics of the fuel being used by the gas turbine engine] (Para [0580, 0585]) and to adjust the at least one operating parameter of the aircraft to reduce at least one of the level of emissions exhausted from the gas turbine engine and the formation of contrails produced by the gas turbine engine [controlling the operating parameters of the aircraft or gas turbine engine according to the one or more contrail parameters; reduced emissions may permit reduced control formation whilst reducing environmental impact] (Para [0202-0204, 0406]). Regarding claims 7 and 17, Swann as applied to claims 6 and 16 above teaches the claimed invention, in addition to wherein the optical sensing unit comprises an energy source configured to direct energy into the second mass flow; and an optical sensor configured to detect the amount of scattered energy caused by the energy interacting with particulates contained in the second mass flow [laser scattering measurement method; CPC device arranged to count particles using laser scattering after the particles have increased in size] (Para [0575]). Regarding claims 8 and 18, Swann as applied to claims 7 and 17 above teaches the claimed invention, in addition to wherein the energy source directs the energy at a target area; and wherein the optical sensor, senses an energy spectrum at the target area resulting from the energy [measurement on exhaust gases before emission by the engine, as they flow through the engine core, or once they have exited the engine; laser scattering measurement] (Para [0568, 0575]). Regarding claims 9 and 19, Swann as applied to claims 8 and 18 above teaches the claimed invention, in addition to wherein the energy source is coupled to a body of the aircraft and is remotely located from the gas turbine engine] (Para [0546], see Fig. 23). Regarding claims 10 and 20, Swann as applied to claims 8 and 18 above teaches the claimed invention, in addition to wherein the energy source is disposed within an inlet of the gas turbine engine [exhaust sensors 151 may be located within the respective gas turbine engine 10 so that it is arranged to perform a measurement on exhaust gas before it is emitted by the engine] (Para [0568]). Response to Arguments Regarding newly amended claims 1 and 11, Applicant argues that the cited prior art fails to teach the newly amended limitations regarding comparing the level of emissions to an emissions threshold set to form a target amount of contrails. In response to the amendment, the prior art rejection has been modified from a 102 rejection to a 103 rejection. Although Swann fails to explicitly teach the newly amended limitations, it would have been obvious to a person having ordinary skill in the art at the time of the filing of the invention to arrive at the newly amended limitations based on the teachings of Swann. See updated prior art rejections above. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to DAVID Z HUANG whose telephone number is (571)270-5360. The examiner can normally be reached Monday - Friday, 9:00 AM - 5:00 PM EST. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Kristina Deherrera can be reached at 303-297-4237. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /DAVID Z HUANG/Primary Examiner, Art Unit 2855
Read full office action

Prosecution Timeline

Oct 13, 2023
Application Filed
Sep 27, 2025
Non-Final Rejection — §103
Jan 30, 2026
Response Filed
Apr 04, 2026
Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
80%
Grant Probability
93%
With Interview (+13.7%)
2y 7m
Median Time to Grant
Moderate
PTA Risk
Based on 685 resolved cases by this examiner. Grant probability derived from career allow rate.

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