# US 12,214,870 B2 · Inflight reduced engine operation, engine restart, and associated alerts > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,214,870 B2 - Document ID: US12214870B2 - Status: Granted - Kind: B2 - Application number: 17/941,776 - Filed: 2022-09-09 - Published: 2024-03-14 - Granted: 2025-02-04 - Earliest claimed: 2022-09-09 - Assignees: Textron Innovations Inc. - Applicants: Textron Innovations Inc. - Inventors: Bharath Ramamurthy - Web page: https://patentgrep.com/patent/US12214870B2 ## CPC - B64C 27/04: Helicopters - B64D 27/24: using steam or spring force (jet aircraft B64D27/16) - B64D 31/00: Power plant control systems; Arrangement of power plant control systems in aircraft - B64D 45/00: Aircraft indicators or protectors not otherwise provided for - B64D 43/00: Arrangements or adaptations of instruments - B64D 2045/0085: {Devices for aircraft health monitoring, e.g. monitoring flutter or vibration} - B64C: AEROPLANES; HELICOPTERS - B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT ## Abstract In certain embodiments, a rotorcraft includes a first engine, a second engine, a primary engine-start system for the first engine, a fast-start engine-start system for the first engine, and a computer system. The computer system is configured to detect a failure of the second engine during a reduced engine operation (REO) flight mode in which the first engine has been intentionally shut down inflight and the second engine is to remain operational, and to automatically initiate, in response to detecting the failure of the second engine during the REO flight mode, an automatic restart of the first engine using the fast-start engine-start system. ## Claims ### Claim 1 A rotorcraft, comprising: a first engine; a second engine; a primary run/off switch for the first engine; a reduced engine operation (REO) on/off switch configured to send, in response to being positioned in an on position, an engine shutoff signal, the REO on/off switch being distinct from the primary run/off switch for the first engine; and a computer system configured to: receive the engine shutoff signal; and command, in response to receiving the engine shutoff signal, the first engine to shut off to enter an REO flight mode in which the first engine has been intentionally shut down inflight and the second engine is to remain operational, the primary run/off switch for the first engine remaining in the on position while the first engine is shut down during the REO flight mode. ### Claim 2 (depends on 1) The rotorcraft of claim 1, wherein the computer system is configured to prevent the REO on/off switch from sending the engine shutoff signal unless REO preconditions are met. ### Claim 3 (depends on 1) The rotorcraft of claim 1, wherein, to command the first engine to shut down to enter the REO flight mode, the computer system causes an engine fuel management module (FMM) shutoff valve for the first engine to close to terminate a flow of fuel to the first engine and thereby shut down the first engine, an airframe fuel shutoff valve remaining open while in the REO flight mode. ### Claim 4 (depends on 1) The rotorcraft of claim 1, wherein the computer system is further configured to: cause the REO on/off switch to be held in an on position during REO flight mode; and disable, in response to detecting that an REO flight mode disabling condition is met, the REO flight mode by deenergizing the REO on/off switch that is held in the on position while in the REO flight mode, deenergizing the REO on/off switch causing the REO on/off switch to move to an off position and thereby remove the command to the first engine to shut down. ### Claim 5 (depends on 4) The rotorcraft of claim 4, wherein the computer system is further configured to: detect, following detecting that the REO flight mode disabling condition is met, that the REO flight mode remains active; and directly disengage, in response to detecting that the REO flight mode remains active, the REO flight mode. ### Claim 6 (depends on 1) The rotorcraft of claim 1, wherein: the rotorcraft comprises: a primary engine-start system for the first engine, the primary run/off switch for the first engine being part of the primary engine-start system for the first engine; and a fast-start engine-start system for the first engine; and the computer system is further configured to: detect a failure of the second engine during the REO flight mode in which the first engine has been intentionally shut down inflight and the second engine is to remain operational; and automatically initiate, in response to detecting the failure of the second engine during the REO flight mode, an automatic restart of the first engine using the fast-start engine-start system. ### Claim 7 (depends on 6) The rotorcraft of claim 6, wherein during the automatic restart of the first engine, positions of one or more control components for initiating a start of the first engine using the primary engine-start system are unaffected by the automatic restart of the first engine using the fast-start engine-start system. ### Claim 8 (depends on 7) The rotorcraft of claim 7, wherein: the one or more control components for initiating a start of the first engine using the primary engine-start system comprise an engine start switch; and automatically initiating, in response to detecting the failure of the second engine during the REO flight mode, the automatic restart of the first engine using the fast-start engine-start system comprises controlling circuitry to selectively power the fast-start engine-start system rather than the primary engine-start system. ### Claim 9 (depends on 8) The rotorcraft of claim 8, wherein: the circuitry to selectively power the fast-start engine-start system rather than the primary engine-start system comprises: an auxiliary start relay; a start contactor; and a start isolation contactor; and controlling circuitry to selectively power the fast-start engine-start system rather than the primary engine-start system comprises controlling the auxiliary start relay to energize the start contactor to provide electrical power to either the primary engine-start system or the fast-start engine-start system, a state of the start isolation contactor causing the electrical power to be distributed to the fast-start engine-start system to thereby automatically initiate the automatic restart of the first engine using the fast-start engine-start system. ### Claim 10 (depends on 6) The rotorcraft of claim 6, wherein the computer system is further configured to: detect a failure of the automatic restart to start the first engine; annunciate, in response to detecting the failure of the automatic restart, the failure of the automatic restart to start the first engine; and attempt, in response to receiving a manual restart activation signal, a manual restart of the first engine using the fast-start engine-start system. ### Claim 11 (depends on 10) The rotorcraft of claim 10, wherein a control for manually initiating the manual restart activation signal is located on one or more of: a cyclic control stick; or a collective control stick. ### Claim 12 (depends on 10) The rotorcraft of claim 10, wherein attempting, in response to receiving the manual restart activation signal, comprises providing electrical power to the fast-start engine-start system from a battery and providing electrical power to an engine ignitor from a battery.