All public types

Selected operating mode of an automatic direction finder.

Aircraft-wide selectable afterburner power level.

A named air-data computer.

A deployable air-driven electrical generator that is distinct from the aircraft's ram-air-turbine emergency generator.

Direction of the aircraft's motion relative to the surrounding air mass.

Display unit selected for a cockpit air-temperature indication.

A named pilot, copilot, or standby air-temperature sensor.

Immutable simulator-neutral view of the clearances currently granted by the simulator's air-traffic-control service.

Immutable advisory for an upcoming simulator-managed controller handoff.

Direction of a simulator-managed airport traffic pattern.

Immutable simulator-neutral description of the runway currently assigned by simulator-managed air traffic control.

Signed main-gear position in the simulator-managed ATC runway coordinate system. The provider's native X/Y/Z names remain below the SDK.

Immutable next-waypoint assignment from simulator-managed air traffic control.

Stable root for the currently loaded aircraft. Child component objects are generation-bound and replaced atomically when the aircraft changes.

Aircraft-authored aerodynamic and static-pitch reference characteristics.

A provider-neutral airborne starting point for the user aircraft. USI applies all fields as one simulator operation.

Describes autopilot-channel access points captured for one loaded-aircraft graph. Unknown entries remain usable when a provider exposes a channel but cannot prove its physical installation.

Provides developer-friendly APU selections without exposing simulator switch enums, generator numbering, or pneumatic variable names.

Describes the named radio access points exposed for the currently loaded aircraft. Counts use the developer-facing one-based component names (for example, Com1). Installation states distinguish authoritative equipment discovery from a provider's addressable radio slots.

Load factors resolved along the aircraft's normal, axial, and lateral body axes, in multiples of standard gravity.

Provides developer-friendly occupant-facing state without exposing simulator-native switch or canopy names.

Stable IDs for the initial aircraft capability-discovery surface.

Aircraft-authored center-of-gravity limits relative to the aircraft reference point using signed aircraft axes and the selected length unit.

Current center-of-gravity position relative to the aircraft reference point in signed aircraft axes using the session's selected length unit.

Provider-authored classifications of the loaded aircraft. Multiple flags may be present because, for example, a cargo aircraft may also be an airliner or military aircraft.

A named aircraft clock. Time-of-day values reuse USI's normalized simulator clock; presentation state remains an aircraft-avionics fact.

The presentation selected on an aircraft clock.

Installation evidence captured for this component's aircraft graph.

Describes whether an aircraft component still belongs to the currently loaded aircraft graph.

Provider-neutral cause of the current aircraft crash state.

Describes a newly reported crash of the user aircraft.

Provides developer-friendly aircraft dynamics without exposing SimVars or DataRefs.

Configured component counts for the currently loaded aircraft's electrical system. These authoritative installed counts are distinct from the number of discoverable logical access points in a component collection.

Automated pilot-assistance state for the currently loaded aircraft.

Developer-facing flight-plan abstraction for the currently loaded aircraft. Native GPS and FMS implementations are reconciled here.

Exact force and moment decomposition reported by the provider's flight model. Sources remain separate so totals are not confused with causes.

Stable metadata for one loaded-aircraft fuel selector.

Loaded-aircraft fuel-selector topology, only returned when a count is established.

Side of an aircraft fuel system.

Stable metadata for one loaded-aircraft fuel tank.

Describes the fuel tanks observable for the loaded aircraft. Public tank numbers are stable, one-based identities and never expose a provider's native array slot or SimVar selector.

Provides developer-friendly identity and configuration values for the currently loaded user aircraft without exposing simulator-native names.

A provider-neutral identity snapshot for a loaded aircraft.

One typed value supplied when invoking an aircraft interaction.

The type of one argument accepted by an aircraft interaction.

Describes one observed aircraft-authored interaction change.

One typed position in an aircraft interaction's invocation schema.

A typed value published by an aircraft-authored interaction.

The value shape published by an aircraft-authored interaction.

Stable metadata for one authored landing-gear assembly.

Describes the landing-gear assemblies authored for the loaded aircraft. Public numbers are stable and one-based; provider array slots remain an implementation detail.

Aircraft-authored lateral center-of-gravity limits expressed as signed rightward distances relative to the aircraft reference point using the session's selected length unit.

Minimum and maximum load factors attained over the provider's current observation interval, in multiples of standard gravity.

Aircraft-authored longitudinal center-of-gravity limits expressed as percent mean aerodynamic chord.

Immutable, simulator-neutral snapshot of the aircraft's aerodynamic and three-axis translational/angular motion.

Provides developer-friendly aircraft oxygen state without exposing provider-native DataRefs or override mechanisms.

Stable metadata for one loaded-aircraft payload station.

Describes the payload-station graph configured by the loaded aircraft. Station numbers are one-based public identities and never expose a simulator's native array or SimVar index.

Provides aircraft performance limits in stable aviation units without exposing simulator-native configuration names.

Provides actual cabin pressurization telemetry in stable aviation units.

Broad simulator-neutral classification of the user aircraft's primary propulsion system. Provider-specific engine subtypes are intentionally normalized into stable categories.

Normalized operating condition of an aircraft radio.

Body-axis position using the developer's selected length unit.

A position relative to the aircraft authoring origin, expressed in feet along developer-facing forward, rightward, and upward body axes.

Describes a provider-reported user-aircraft relocation.

Identifies why the simulator repositioned the user aircraft.

Aircraft rotational inertia divided by aircraft mass, expressed about the conventional roll, pitch, and yaw axes using the selected area unit.

Aircraft rotational inertia about its conventional axes, including the provider's documented cross-coupled term, using the session's selected moment-of-inertia unit.

Kind of flight sensor protected by a named heater.

Flight-deck position served by a named sensor.

Provides developer-friendly state for the currently loaded user aircraft without exposing simulator-native names or scalar encodings.

Normalized contamination condition of the surface beneath the aircraft.

One active physical contact between the aircraft and a surface. Provider slot numbers are intentionally omitted from this observation model.

Normalized physical surface beneath the user aircraft.

Preference-aware physical measurements for the principal aircraft systems. Unit-bearing numeric operations remain available for deterministic algorithms.

Provider-neutral aircraft systems display.

Aircraft-system page selected on a multifunction systems display.

Side of the aircraft tailplane represented by a component.

Normalized operating mode for an aircraft transponder.

Provides vacuum-system measurements in stable aviation units.

Provides developer-friendly aircraft warning state without exposing simulator-native annunciator names.

Stable identity for one configured water-ballast tank.

Loaded-aircraft water-ballast tank topology.

Provides aircraft weight and balance measurements in stable aviation units.

Flight-deck window protected by a named electric heater.

Side of the aircraft wing represented by a component.

One stable structural region of the loaded aircraft. Native section counts and failure encodings are intentionally hidden.

Stable structural regions of the loaded aircraft.

Published top-level metadata for one airport instrument approach.

The published final approach fix and authored procedure values.

The published navigation type of an instrument approach.

The authored approach-light system installed for a runway end.

Enabled approach and runway-end lighting for one runway end.

A published entry route from an initial fix into an approach.

A published communication frequency for an airport.

The operational service carried by an airport frequency.

Provider-neutral descriptive and topology metadata for an airport.

A provider-neutral airport reference from simulator scenery data.

Published object totals for an airport facility. A null value means the provider does not publish that category; zero means it explicitly publishes that no objects of the category exist.

Provider-neutral geometry and authored areas for one helipad.

A provider-neutral active jetway and optional parking association.

The provider-authored extension size of an active jetway.

The authored visual style of an active jetway.

A provider-neutral aircraft parking position at an airport.

The operational purpose and supported aircraft size of a parking position.

A provider-neutral published departure or arrival procedure.

An enroute-specific path into or out of an airport procedure.

The phase of flight served by a published airport procedure.

A runway-specific path into or out of an airport procedure.

Provider-neutral geometry and identity for one physical runway.

One operational end of a physical runway.

An enabled authored pavement area associated with a runway end.

A provider-neutral position from which an aircraft can start.

The authored operational purpose of an airport start position.

The painted marking authored along one side of a taxiway path.

The direction from which a hold-short marking applies.

A complete airport surface graph with authored taxiway names.

The routing role authored for a taxiway network node.

An edge in an airport's provider-neutral surface-routing graph.

The permitted traversal direction of a taxiway graph edge.

The operational purpose of an airport surface path.

A node in an airport's provider-neutral surface-routing graph.

The operational meaning of an airport taxiway graph point.

An installed visual approach-slope indicator beside a runway end.

The authored visual approach-slope indicator arrangement.

Aircraft-installed airshow-smoke equipment. Provider variables, events, and toggle commands remain below this absolute-state contract.

The aircraft's alternate static-air source for pressure-sensitive flight instruments.

Visual state of the pilot altimeter's altitude-alert indication.

Aircraft exposure to ambient smoke in the simulated world. This is separate from smoke emitted by the aircraft and from camera-local smoke density.

A named pilot, copilot, or standby angle-of-attack sensor.

A named area-navigation system, including inertial or long-range navigation equipment when that is the provider's installed source.

A named attitude and heading reference system.

Physical sensor source supplying an attitude indication.

Aircraft-wide audio-panel and intercom behavior. Individual receiver audio selections and volumes remain on their named radio components.

Crew position served by a named aircraft audio panel.

Kind of transmitter selected at a crew audio panel.

Simulator-neutral transmitter selection for one crew audio panel. The communication radio is the same named object found in the avionics graph.

Selected automatic-braking mode.

Reported automatic power-reserve state, not a pilot-selected power setting.

Aircraft-wide automatic power reserve. Installation evidence and current status are separate; discovering this logical component does not prove it is installed.

Aircraft-wide automatic thrust-reverser selection.

Source that requires the autopilot's upcoming altitude capture.

Source from which altitude-hold acquired its current reference.

One discoverable autopilot computer/channel in the currently loaded aircraft. Public numbering is one-based; native channel identities remain below USI.

Operational state of one autopilot/flight-director channel.

Installed real-world autopilot configuration family.

Configured pitch guidance selected when the autopilot needs a default mode.

Configured roll guidance selected when the autopilot needs a default mode.

Aircraft reference used to establish the autopilot's front course.

Autopilot guidance computer selected to fly the aircraft.

Common flight-guidance state and targets at one observation point. Detailed active-mode identities are null when a provider does not expose an authoritative summary.

Reference that supplies the autopilot's heading-mode target.

Current simulator-neutral lateral flight-guidance behavior.

Navigation receiver currently feeding the pilot-side autopilot guidance.

Direction of a manual pitch-trim correction requested by the autopilot.

Aircraft sensor source feeding an autopilot reference axis.

Reference slot selected by a multi-slot autopilot target.

Common targets shown in the aircraft's primary autopilot selector windows. Both speed representations are retained because aircraft may expose and transition between indicated-airspeed and Mach targets independently. Mach is null when the active provider/selector has no separate Mach target.

Observable outputs produced by the autopilot's internal self-test. These outputs remain distinct from the selected test state.

Unit selected for the autopilot's speed-reference control.

Target pair presented by the autopilot's lateral and vertical selectors.

Current simulator-neutral vertical flight-guidance behavior.

Normalized active autothrottle guidance behavior.

A discoverable left- or right-side pump that transfers fuel from auxiliary tanks to feeder tanks.

Selected operating mode of an auxiliary fuel-transfer pump.

Provider-neutral avionics equipment-cooling system.

Common health behavior for a named integrated-avionics hardware unit.

WGS-84 Earth-centered, Earth-fixed position in selected length units.

WGS-84 Earth-centered, Earth-fixed aircraft coordinates in meters.

Three-axis motion in the earth-relative east/up/north frame.

A long-duration named aircraft elapsed-time counter.

Selected operating mode of an engine electric fuel pump.

A named provider-neutral electric gyro system.

A named electrically driven aircraft hydraulic pump.

A controllable connection between aircraft electrical buses.

One discoverable semantic electrical circuit. Provider circuit names, indexes, buses, and breaker representations remain below this object.

Stable semantic role of an aircraft electrical load circuit.

A named aircraft electrical inverter.

Named electrical power-line access point; connection is not evidence of voltage or load.

Named electrical relay access point. Installation is Unknown without topology evidence; coil power, attached-line connection and breaker state are separate.

The cockpit electrical voltmeter, distinct from direct battery, bus or generator measurements.

A cockpit voltmeter source selected by aircraft-authored electrical-panel semantics.

A role-aware provider-neutral electronic flight-instrument system.

Stable role of an electronic flight-instrument system.

One coherent navigation solution presented by an electronic flight display.

The aircraft's primary and optional secondary pitch-control surfaces.

The aircraft's combined pitch-and-roll elevon surface system.

The aircraft's deployable emergency electrical generator, when installed.

A named engine and airframe interface unit.

Aircraft engines currently targeted by shared flight-deck controls.

Aircraft-wide oil and radiator cooling-flap controls, separate from each engine's cowl flap. Logical discovery does not confirm physical installation.

A named engine-driven aircraft hydraulic pump.

Preference-aware physical quantities for a named propulsion unit.

Broad simulator-neutral classification of a named engine's propulsion technology. Provider-specific engine subtypes are intentionally normalized into stable categories.

Aircraft-wide engine starting mode.

Aircraft-wide engine-starting selections.

Aircraft-authored engine thermal references in selected temperature units.

Aircraft-authored engine thermal-model reference temperatures, all in Celsius. These are model configuration, not measured temperatures or failure limits. References for a propulsion technology need not apply to every installed engine.

Simulator-rendered exhaust presentation for the loaded aircraft. This is distinct from engine operating state and from ambient-smoke exposure.

Jettisonable external fuel-tank equipment. Provider tank identities and release commands remain below this simulator-neutral aircraft component.

Reason reported by the aircraft's landing-gear warning system.

Preference-aware physical quantities generated from canonical explicit-unit operations.

Named generator access point. Its number identifies an electrical source, not an engine association; discovery does not establish installation.

Provider-neutral formatting for geographic coordinates.

Provider-neutral geodetic position with mean-sea-level altitude.

Normalized phase of an instrument approach in the primary navigator.

Geometry used by the active instrument-approach segment.

Normalized navigation-aid type of a loaded instrument approach.

Operational role of the current instrument-approach waypoint.

Current lateral/vertical service level of satellite navigation guidance.

Radio-frequency field selected for entry on an integrated navigator.

Geodetic position calculated by a satellite-navigation receiver.

Named satellite-navigation receiver guidance. The component represents the same aviation concept whether its provider is a GPS, integrated FMS, or another area-navigation implementation.

Source driving a navigator's vertical-guidance indication.

Provider-neutral automatic sequencing state of the primary navigator.

Provider-neutral effectiveness state of applied ground deicing.

An external ground source supplying pneumatic air to the aircraft.

Reason reported by the ground-proximity warning system.

Simulator-neutral access to primary airframe structural health. Provider-native structural slots remain below this surface.

Simulator-neutral access to aircraft autopilot and flight-guidance state.

Simulator-neutral access to auxiliary-power-unit selections.

Simulator-neutral access to occupant-facing cabin state.

Simulator-neutral pilot flight-control inputs for the user aircraft.

Provides simulator-neutral aerodynamic and motion values for the user aircraft.

Simulator-neutral access to aircraft-generated visual effects and their installed equipment.

Developer-facing electrical system and named component collection.

Simulator-neutral indexed engine controls and state for the user aircraft. Engine indexes are zero-based.

Simulator-neutral access to automated pilot assistance for the loaded aircraft. Provider AI names and enum ordering remain below this contract.

The flight plan being flown by the user aircraft, independent of the simulator or installed navigator that owns the native plan.

Simulator-neutral access to aircraft fuel state.

Simulator-managed services requested for the currently loaded aircraft. Successful requests confirm acceptance, not arrival or completed servicing.

Simulator-neutral access to aircraft hydraulic state.

Simulator-neutral, zero-based indexed access to aircraft ice-protection state.

Simulator-neutral identity and configuration of the currently loaded user aircraft.

Discovers advanced interactions published by the currently loaded aircraft. Normal aircraft systems should be accessed through their typed USI components.

Simulator-neutral state and controls for the lifting envelope of a lighter-than-air aircraft.

Simulator-neutral access to aircraft lighting state and health.

Simulator-neutral access to aircraft oxygen-system state.

Simulator-neutral access to the loaded aircraft's configured performance limits.

Simulator-neutral access to aircraft pneumatic-source selections.

Simulator-neutral access to actual cabin pressurization state.

Simulator-neutral state of the currently loaded user aircraft.

Simulator-neutral access to aircraft vacuum-system state.

Simulator-neutral access to active aircraft warning state.

Provider-neutral aircraft armament, targeting, and defensive-aids access. Native station indexes, DataRefs, and momentary commands remain below this contract.

Simulator-neutral access to aircraft weight and balance state.

Provides simulator-neutral capability discovery without exposing native SimVar, DataRef, command, or event identifiers.

A typed named channel shared through the selected simulator.

Provides discoverable access to simulator-managed air-traffic-control state.

Simulator-managed presentation assets for installed aircraft and liveries.

Simulator-neutral audio output and mixer preferences.

Simulator-provided avionics rendering. Positive names hide native suppression switches and keep provider cleanup rules below the SDK.

Simulator-neutral current-view state and deterministic view actions.

Simulator-neutral access to the simulated clock.

Simulator-owned presentation-unit preferences. Physical SDK values remain normalized regardless of these user-interface choices.

Simulator-neutral atmospheric conditions at the user aircraft.

Discovers loaded in-process simulator extensions and communicates through the documented USI extension-notification protocol where the provider supports it.

Configures simulator-generated equipment failures without exposing provider failure registries, codes, or native commands.

Simulator-owned rendering and visual-effect preferences. These controls are independent from aircraft lighting and from camera/view selection.

Discovers physical input devices through the selected simulator.

Simulator-neutral flight and loaded-content lifecycle. Provider event names, callback structures, and plugin messages remain below this contract.

Simulator-owned media capture without exposing provider commands, windows, frame buffers, or native output paths.

Observes simulator-managed mission progress without exposing native mission structures, identifiers, or callback records.

Observable simulator-managed network-session state. This service does not expose provider sockets, peer arrays, native addresses, or data-output slots.

Creates one simulator-neutral provider implementation. Applications use the same and object model regardless of which provider supplies it.

Simulator-owned realism and flight-model policies. These settings determine how the simulator behaves; they are not current aircraft damage or dynamics.

Controls simulator replay playback through one provider-neutral service. Replay files remain owned by the selected simulator; USI does not translate one simulator's replay format into another's.

Simulator-owned policies that alter the normal consumption of aircraft resources. These settings are not physical aircraft-system state.

User preferences controlling simulator-generated safety alerts. These are distinct from actual aircraft warning and caution state.

Loads and saves complete simulator flight-state files through one provider-neutral service. File contents remain owned by the selected simulator; USI does not translate one simulator's saved-flight format into another's.

Starts optional simulator-managed aviation scenarios.

Opens provider-neutral named data channels shared with other simulator clients or plugins. The same API is used for Microsoft Flight Simulator and X-Plane.

Simulator-neutral runtime state whose native delivery mechanism may be a readable value, a system event, or another provider-specific transport.

Observes AI, multiplayer, and externally injected nearby aircraft.

Explicit simulator-owned user-interface navigation without exposing native windows, handles, menu identifiers, or toggle-only commands.

Simulator-neutral virtual-reality presentation and input state.

Geographic and physical-world queries owned by the simulator.

Provider-neutral aircraft ice-detection equipment.

A named pneumatic source selected to supply air-driven instruments.

Stable aircraft location of an instrument-air source.

Aircraft-authored warning, caution, and normal operating bands for one instrument. The owning API method defines the engineering unit.

Guidance signals supplied by integrated approach navigation.

A named integrated avionics processing unit.

A named integrated navigator containing satellite-navigation and radio- tuning functions while preserving their independent health state.

Passenger/crew isolation selected on an aircraft intercom.

Delivers text to the SayIntentions desktop client. This is intentionally a speech-delivery integration rather than a text-to-speech engine because the service performs playback and does not return synthesized audio to USI.

A named satellite-based augmentation receiver.

A named heater protecting one aircraft flight sensor.

Normalizes simulator-managed air-traffic-control state without exposing provider SimVars, DataRefs, or native Boolean encodings.

Preference-aware measurements whose nullable ATC semantics cannot be emitted by the scalar measurement generator.

Provider-neutral simulator aircraft-asset maintenance.

Keeps simulator-wide sound preferences separate from aircraft radios, warning-system volume, and application audio playback.

Reports a change to simulator-wide audio output.

Provider-authored build details for the simulator product and its native integration API. Descriptions are intentionally opaque because providers may publish dates, source revisions, or other human-readable build text.

Visibility of simulator-provided avionics layers that an application may replace with its own rendering.

Presents stable view concepts while native camera states and commands remain below the simulator boundary.

A portable name for one simulator-managed saved-view slot.

How long the simulator should honor a client camera lease.

Why a controlled simulator camera stopped being active.

Current camera elevations above mean sea level and local ground.

Discrete direction in which the active simulator view should look.

Current camera orientation in simulator-neutral aviation conventions.

How the simulator should present sound and panels for a controlled view.

Reports a change to the simulator's active camera view.

Provider-neutral category of the simulator's active camera view.

A directly selectable simulator camera presentation.

Stable IDs for simulator-level environment, clock, and runtime-state capabilities.

Flight-control functions currently backed by certified hardware.

Converts provider clock scalars into developer-friendly time values.

Additional in-cockpit camera transform relative to aircraft position and orientation, independently of the live cockpit head pose.

Live cockpit eyepoint pose relative to the aircraft center of gravity. Position uses forward, rightward, and upward feet; attitude uses positive yaw to the right, positive pitch nose-up, and positive roll right-wing-down.

The flight-deck crew position represented by an active cockpit view.

Selects the endpoint used by a simulator's real native adapter. Normal SDK connections use .

Simulator-neutral presentation-unit preferences.

Provides local atmospheric state in stable units and directions.

Preference-aware physical measurements for the simulator environment. The explicit-unit operations on remain available for deterministic calculations and interop.

Provider-neutral identity and current state of a loaded extension.

Simulator-neutral failure-generation and repair controls.

Whether the active flight is currently running or stopped.

Simulator-neutral rendering and visual-effect preferences.

Authoritative identity returned by the connected simulator and its native integration API. Version text is provider-authored and is not inferred from USI's selected provider type.

Simulator-observed availability of broad flight-control input sources.

Reports a changed simulator-observed input-source snapshot.

A physical input device currently visible to the simulator.

Default implementation of the unified simulator lifecycle service.

Scope of a provider-managed loaded-aircraft reload.

Broad measurement system selected for simulator presentation.

Simulator-neutral media-capture intents.

Reports completion of a simulator-managed mission.

Outcome reported when a simulator-managed mission ends.

Simulator-neutral network-session observations.

Horizontal and vertical scroll position of a two-dimensional aircraft panel, expressed in the simulator panel's pixel coordinate system.

Stable, extensible identity for a simulator provider. Provider IDs are lowercase dotted names so third-party providers can be added without a new USI release or a change to a closed enumeration.

Provider identities supplied with USI.

Instance-scoped provider catalog. Registering a provider here makes it selectable and eligible for automatic detection by that USI instance.

The crew audio panel currently feeding radio audio to the user's headset.

Simulator-neutral realism and flight-model policies.

A normalized simulator-rendered RGB light color.

Simulator-owned lighting presentation after exposure and time-of-day rendering have been applied.

A simulator replay transport request. The value describes transport intent, not an observed playback state.

Simulator-neutral resource-consumption policies.

Simulator-wide intensity selected for rendered runway lights.

Simulator-neutral preferences for simulator-generated safety alerts.

A simulator-managed quick-load saved-flight slot.

A simulator-managed scenario with a provider-neutral aviation intent.

Provider-neutral simulator scenario selection.

Simulator-owned capacity for aircraft other than the user aircraft.

Identifies who currently owns a provider's exclusive traffic-control facility, when the provider exposes that concept.

Reports a change in the owner of a provider's exclusive traffic-control facility.

Simulator-neutral user-interface navigation intents.

Current simulator rendering viewport dimensions in pixels.

Keeps provider VR state on one discoverable service while preserving exact support differences between controller and hand-tracking implementations.

Reports entry to or exit from virtual-reality presentation.

Reason actual slat position does not match the selected position.

Combined slat/flap configuration shown by equipped aircraft.

Slung-load dimensions using the developer's selected length unit.

Axis-aligned dimensions of a slung load in feet.

Slung-load orientation using the developer's selected angle unit.

Current orientation of a slung load in degrees.

Provides simulator-neutral access to roll spoilers (spoilerons), kept distinct from the speed-brake surfaces that may share physical panels.

Electrical configuration used to power the engine starters.

A named pilot, copilot, or standby static-pressure sensor.

Preference-aware projections for structured physical values.

Configuration for the SimBrief provider owned by one USI session.

Core-owned implementation base for an additional simulator. Provider authors implement bottom-stack transport hooks; USI constructs and exposes the same aircraft and simulator object graph used by every built-in provider.

Identifies a normalized SDK diagnostic without exposing provider-native error codes or callback details.

Describes the provider-neutral outcome of an SDK operation.

Construction-time options for a USI session.

Per-USI-instance measurement preferences. Replacing is atomic, so an operation observes either the old or new complete profile.

The non-value result returned by USI writes, actions, and service requests. Expected simulator and aircraft limitations are represented by rather than provider-native exceptions.

The value-bearing result returned by USI reads and queries.

Built-in developer-facing unit profiles.

Immutable unit choices used to project USI's canonical physical values at the developer boundary. Simulator adapters never observe these choices.

A radio navigation aid from simulator scenery data.

The provider-neutral kind of a radio navigation aid.

Receiver-side state reported for backcourse navigation guidance. This is distinct from the autopilot's backcourse mode.

One named bearing pointer on a role-aware electronic flight display.

Navigation source shown by one electronic-flight-display bearing pointer.

A named integrated navigation/communication equipment unit. This is distinct from the independently usable NAV and COM receiver objects.

Navigation presentation selected on an electronic flight display.

Primary navigation receiver displayed by an electronic flight display.

A named navigation fix from simulator navigation data.

One currently audible element of a navigation-station identifier.

Map presentation selected on an electronic flight display.

Optional information layer presented on an electronic flight display's navigation map.

One coherent set of navigation-map overlay selections.

Lowest and highest terrain elevations currently represented by one navigation display.

North reference used by an electronic flight display's navigation map.

Navigation receiver previewed on an electronic flight display.

Selected electrical and interrogation mode of a navigation receiver.

Provider-neutral kind of navigation signal currently received by a navigation radio.

How a navigation receiver's frequency is being controlled.

Normalized TO/FROM indication reported by a navigation receiver.

The kind of nearby-aircraft change notification.

Describes a nearby-aircraft change or a provider request to refresh the complete snapshot.

A simulator-neutral snapshot of another aircraft reported near the user aircraft.

Provider-neutral exterior-light state for a nearby aircraft.

Provider-neutral aircraft-installed camera equipment.

Selected delivery mode for the crew oxygen regulator.

A normalized operational flight plan independent of its provider schema.

A provider-neutral TACAN channel selection.

Band suffix of a TACAN channel.

Provider-neutral tail-rotor transmission equipment.

Provider-neutral ice-protection equipment for one tailplane.

Determines whether tailplane protection follows the wing system or is selected independently.

Physical terrain or moving surface resolved at a geographic location.

Current operational availability of an engine thrust reverser.

Aircraft-wide thrust-vectoring selection and achieved position.

A named TKS fluid pump. Numbering preserves the authoritative aircraft channels without inventing primary or backup roles.

Selected delivery rate of a TKS fluid ice-protection system.

Provider-neutral aircraft-wide TKS fluid supply and pump state.

Reason the simulator reports for the most recent tow-cable release.

Aircraft towing and winch equipment. Provider-specific observations remain available on this single simulator-neutral component without changing its identity or requiring provider branches.

Altitude range shown by traffic-advisory equipment.

Current voice/display message from collision-avoidance equipment.

Normalized operating mode of traffic-advisory equipment.

Flight-deck pressure source used by traffic-advisory equipment.

Sensitivity level currently used by collision-avoidance threat logic.

A vertical-speed interval displayed by collision-avoidance equipment.

Current collision-avoidance vertical-speed guidance. A null band means the equipment is not displaying that interval.

A simulator-neutral aircraft model and livery that the provider can create as controlled traffic.

Collision-avoidance classification assigned to a nearby aircraft contact.

Discrete operating detent of a turbine-engine condition lever.

Selected operating mode of a turbine-engine ignition system.

A named source of aircraft instrument-vacuum pressure.

Observed presentation state of vacuum-driven instruments.

Configured vacuum-instrument pressure bands.

Selected combined nose-and-visor configuration.

An aircraft's movable nose and protective visor system.

Mixed-reality passthrough presentation selected by the simulator.

Allowed speed band around the VNAV economy descent target.

ICAO wake-turbulence category of an aircraft.

Aircraft water-ballast equipment. Releasable water carried by a water- bomber remains a separate control system.

One named water-ballast tank on the loaded aircraft.

Weapon firing sequence selected by the flight crew.

Current computed gun-sight aim and target range.

Atmospheric conditions sampled by the simulator at one location.

A modeled cloud layer. Providers that blend cloud forms expose the adjacent classifications and a zero-through-one blend ratio.

A provider-neutral cloud classification.

Structured regional atmospheric layers.

Provider-neutral onboard weather-radar equipment.

Multi-elevation scan strategy selected for weather radar on one display.

Weather-radar presentation controls and indications for one electronic flight display.

Operating presentation selected for weather radar on one flight display.

Coherent role-aware weather-radar presentation state.

Shared weather-radar antenna scan geometry and rate.

Typed angular-tilt or selected-altitude vertical targeting.

How a weather-radar presentation selects its vertical scan target.

A geodetic point at which simulator weather is sampled.

A modeled regional temperature and dew-point level.

A modeled regional wind layer.

A named pilot or copilot cockpit wind indication. This remains distinct from the simulator environment's actual local wind observation.

A named heater protecting one flight-deck window.

Windshear warning reported by the aircraft warning system.

A named non-wiper rain-repellent system serving one flight-deck windshield.

A named wiper serving one flight-deck windshield.

Selected speed of a flight-deck windshield wiper.

Aircraft-wide summaries of actual aerodynamic condensation around the loaded aircraft's wings. Native aerodynamic-wing slots remain internal.

Fixed wing planform and variable airframe geometry. Requested and achieved variable-geometry positions remain distinct.

Provider-neutral ice-protection equipment for one wing.

Fixed total wing area and span in the selected working units.

Physical constants and average sea-level reference conditions used by the simulator's world model. These are model inputs, not local weather.

Configuration for the real-world weather service owned by one USI instance.

Identifies the origin of normalized weather information.

A named bleed-air distribution duct on the aircraft.

Stable aircraft location of a bleed-air distribution duct.

A named valve that isolates part of the aircraft bleed-air ducting.

Stable aircraft location of a pneumatic isolation valve.

Angular motion around the aircraft roll, pitch, and yaw axes.

Force in the aircraft-relative right/up/forward frame.

Moment around the aircraft roll, pitch, and yaw axes.

Velocity of the surrounding air relative to the aircraft, expressed in the aircraft-relative right/up/forward frame.

Three-axis motion in the aircraft-relative right/up/forward frame.

A named cabin door or exit. Its logical number is stable developer-facing identity, not proof that the loaded aircraft physically installs the entry.

Physical role of a named aircraft cabin entry.

Selected operating mode of an electric cabin heater.

A named cabin-pressure pack on the aircraft pneumatic system.

Stable aircraft location of a cabin-pressure pack.

Selected operating mode of the cabin ventilation fan.

Actual operating level of the cabin ventilation fan.

Atmospheric and surface context at the simulation camera. Camera-relative wind angles preserve the provider's signed relative-angle convention and are intentionally distinct from true meteorological wind direction.

Describes a simulator-neutral capability and the operations declared by the selected provider adapter. Supported mappings do not guarantee that the currently loaded aircraft supplies a usable value; the operation result remains authoritative at runtime.

Identifies a stable, simulator-neutral USI capability.

Provider-reported state of an aircraft-carrier catapult launch.

Aircraft carrier-launch equipment. Exact provider capabilities remain on this single domain object even where no truthful cross-provider equivalent exists.

Simulator-rendered sun and moon orientation plus normalized lunar state. Elevation is positive above the horizon and azimuth is clockwise from true north.

A short-duration named aircraft chronometer.

A named pilot or copilot instrument-lighting control whose selected brightness is independent from panel floodlights and achieved light output.

The flight-deck position served by an instrument-light rheostat.

A named cockpit-panel light whose selected brightness is independent from the aircraft-wide cockpit spotlight switch and actual lighting output.

The fixed cockpit-panel lighting role controlled by a rheostat.

Shared developer-facing behavior for a named cockpit timer.

Semantic kind of cockpit timing instrument.

Channel spacing supported by a communication radio.

Air-traffic service associated with a tuned COM station.

A signed minimum and maximum control authority in stable units.

Aircraft contrail-generation conditions. This does not claim that a visual effect is installed or currently visible.

An owned provider-neutral lease over the simulator camera.

A geographic camera pose in simulator-neutral conventions.

A provider-neutral handle for one traffic aircraft created and owned by this USI connection.

Geographic position and orientation commanded for a client-created traffic aircraft.

Normalized visual configuration and pilot-control presentation for a client-created traffic aircraft.

Why a client-created traffic-aircraft handle stopped being usable.

Reports that a controlled traffic aircraft is no longer active.

Provider-neutral aircraft communications datalink.

Describes a registered simulator provider whose simulator process is currently running. Process names and operating-system details remain private to the provider.

Selected magnetic coupling of an electric directional gyro.

Information presented by a dedicated DME receiver.

The aircraft's dedicated distance-measuring-equipment receiver. This is distinct from DME observations supplied by a paired NAV receiver.

NAV receiver supplying remote tuning to a dedicated DME.

Split drag-rudder (yaw-brake) surfaces, kept distinct from the centerline rudder and from roll spoilers even when an aircraft coordinates them.

A provider-neutral geographic point from facility data.

A navigation facility referenced by simulator scenery.

The kind of navigation facility referenced by procedure data.

The material modeled for a runway surface.

Power-lever gate currently requested from a full-authority digital engine controller. Gate labels are intentionally independent of aircraft-specific names such as CRZ, CLB, MCT, FLEX, and TOGA.

Primary quantity regulated by the aircraft's FADEC system.

Common flap deployment plus exact provider-authoritative topology.

Reason actual flap position does not match the selected position.

Describes a transition between running and stopped flight activity.

Current operating state of automated stall protection.

Category of nearby destination offered by the simulator flight assistant.

One readable nearby destination offered by the simulator flight assistant.

Flight-deck station whose primary-control inputs have priority.

Pilot input plus exact optional station and effective demand.

Signed roll, pitch, and yaw demand in normalized control ratios.

Exact mechanical failure modes reported for one control-surface section. Multiple flags may be present when the simulator reports concurrent damage.

Failure state for one numbered, aircraft-relative control-surface section. Section numbers are one-based and stable within the loaded aircraft.

Aircraft-relative lateral location of a control-surface section.

Flight-director channel selected as the guidance master.

Normalized annunciation state for an armable flight-guidance mode.

Selected operating mode of the aircraft load-factor limiter.

Raised after a loaded flight has produced a ready replacement aircraft graph.

Immutable, simulator-neutral snapshot of the leg currently being flown.

Navigation reference supplying the active final-approach solution.

Provider-neutral reason that the active flight plan changed.

A normalized notification raised after USI has observed a flight-plan change and refreshed its common plan metadata.

Provider-neutral coordinates for a user-defined flight-plan waypoint.

Immutable, simulator-neutral location of the calculated top of descent.

Operational vertical-planning advisory from the active flight-management solution.

Provider-neutral identity and location of a flight-plan waypoint. Additional provider data remains an implementation detail of USI.

Provider-neutral kind of an entry in a flight plan.

Common identity and health behavior for a flight-deck sensor.

Active flight-control law reported by an equipped fly-by-wire aircraft.

The aircraft's primary and optional secondary roll-control surfaces. Provider wing indexes and native angular units remain below this simulator-neutral component.

Flight-control computer selection, health, and protection state.

Forces currently authored for the primary yoke and pedal controls. Signed values preserve the modeled control direction.

Authored force-feedback behavior for the aircraft's physical controls.

Automatic crossfeed controller selection.

Direction and availability of aircraft fuel crossfeed.

A named routing junction in a component fuel network.

Named fuel-line access point. Logical discovery does not establish physical installation or associate a line number with an engine, tank or pump.

One common named fuel-pump type for every supported simulator.

Portable selected mode of a fuel pump.

Normalized role of a named fuel pump.

The aircraft's cockpit fuel-quantity presentation. Indicated values may differ from the physical contents reported by named components because the aircraft can apply gauge and display behavior.

One discoverable fuel selector on the loaded aircraft.

Tank or tank group selected to supply fuel.

Known target of a selector; Unspecified does not imply any engine association.

One discoverable fuel tank on the loaded aircraft.

A logical aggregation of every fuel tank on one side of an aircraft. This does not assert tank count, identity, or physical topology.

A normalized location used by an aircraft fuel-transfer route.

Aircraft-wide fuel-transfer operating mode.

Selected auxiliary fuel-transfer system test.

A named conditional trigger in a component fuel network.

One common named fuel-valve type. Network numbering and engine association are explicit roles, never inferred from one another.

Normalized role of a named fuel valve; identity does not imply achieved flow.

Non-operational provenance retained from the source planning service.

Configuration for external operational-flight-plan providers.

The published marking or operational purpose of a helipad.

The loaded aircraft's Hobbs meter, distinct from simulator uptime, current-flight elapsed time, and per-engine elapsed-time counters.

Horizontal earth-relative motion in feet per second. Positive values point east and north respectively, independent of the simulator's native axes.

A named hydraulic pressure accumulator.

A named hydraulic actuator.

A logical hydraulic-system access point. Its number identifies a provider target and does not, by itself, prove installation in the loaded aircraft.

Common lifecycle and validation for named hydraulic components.

Flow direction through a reversible hydraulic power-transfer unit.

A named hydraulic power-transfer unit.

Operating state of a hydraulic power-transfer unit.

Installed hydraulic power-transfer-unit flow arrangement.

A named pump in a component-based hydraulic network.

A named valve in a component-based hydraulic network.

Selects which jet-engine spool, if any, the aircraft-wide synchronization system attempts to match across engines.

Aircraft jettisonable or slung-load equipment. Multi-station payload and future sling topology remain separate named component concerns.

One discoverable landing-gear assembly on the loaded aircraft.

Authored construction of one landing-gear assembly.

Pilot-selected landing-gear handle detent. The neutral/off detent is optional; unsupported providers still expose the common up/down states.

An ILS or localizer facility from simulator navigation data.

A named landing-guidance receiver with distinct lateral and vertical channels.

Aircraft equipment that carries and releases liquid, including water-bomber refill and drop controls where the provider exposes those exact semantics.

Describes whether a usable loaded-aircraft graph is available.

Identifies why USI replaced the currently loaded aircraft component graph.

Raised only after the replacement component graph is ready to resolve.

Precipitation currently affecting the user aircraft.

Wind currently affecting the user aircraft, expressed both as the familiar meteorological direction/speed and signed earth-axis components.

A provider-neutral vector in local east, up, and north axes.

A velocity in local east, up, and north axes.

Airport and runway served by a received localizer.

A named magnetic-field sensor used by integrated avionics.

Current simulator-managed marine traffic. The total can exceed the individually described contacts when the provider exposes only aggregate information for some vessels.

Geographic position and motion for one simulator-managed marine vessel.

Known simulator-managed marine-vessel classifications.

Behavior requested when muting marker-beacon audio.

A marker beacon from simulator navigation data.

Marker-beacon lights currently indicated by the simulator. Multiple flags may be present because some simulators expose the lights independently.

The operational position of a marker beacon on an approach.

The aircraft's marker-beacon receiver. Provider-specific light and enum representations are normalized below this component.

Selected reception sensitivity of a marker-beacon receiver.

Warning, caution, and normal bands expressed as typed quantities.

A minimum and maximum expressed as typed physical quantities.

A named multifunction display hardware unit.

Hydraulic valve arrangement used to hold parking-brake pressure.

Provides the normalized pause state after a simulator state change.

One discoverable payload station on the loaded aircraft.

A named piston-cylinder access point. Installation is explicit, not inferred from readable temperature.

A graph snapshot of named cylinder access points, with installed count when known.

Selected piston-engine magneto combination.

Selected operating mode for a pitot-probe heater.

A named temperature-controlled area of the aircraft.

Selected operating mode of pneumatic deicing boots.

A named fan in the aircraft pneumatic network.

Common lifecycle and validation for indexed pneumatic components.

A named junction in the aircraft pneumatic distribution network.

A named line in the aircraft pneumatic distribution network.

Selected airflow schedule of a cabin-pressure pack.

A named valve in the aircraft pneumatic network.

Operating mode selected for a pneumatic valve.

Power-lever travel within a selected range, from zero at the range entrance to one at its far end. The reading method identifies whether this is hardware input or aircraft lever intent; neither represents measured thrust. Beta's far end and reverse's entrance share a detent; reads report that shared detent as Reverse with zero travel.

The operating interval selected by an engine power lever.

Active predictive-windshear phase reported by onboard weather radar.

Selected source supplying air to the pressurization system.

A named primary flight display hardware unit.

A normalized altitude constraint for a procedure leg.

The semantic form of a published altitude constraint.

The north reference used by a procedure leg's bearing and course.

A referenced procedure facility with its authored location.

One normalized path-termination leg in a published procedure.

The path-termination rule used by a published procedure leg.

A normalized indicated-airspeed constraint for a procedure leg.

The semantic form of a published indicated-airspeed constraint.

The permitted turn direction for a procedure leg.

Configured propeller response when governor oil pressure is lost.

Aircraft-authored propeller pitch limits as typed angles.

Aircraft-authored propeller pitch limits in degrees.

Direction a propeller rotates when viewed from behind the aircraft.

Selected operating mode for an engine's propulsive device.

Aircraft-wide throttle-control failures that may be reported together.

Direction requested from simulator-managed pushback service.

Maximum provider-addressable slots used only when loaded-aircraft installation evidence is unavailable. Counts do not claim that equipment is installed.

Provider-declared interpretation rules for native values whose literal representation does not always prove the corresponding physical fact. Ordinary SDK consumers do not need this bottom-stack metadata.

Immutable capability discovery catalog for an independently developed provider. Descriptors use the same simulator-neutral IDs seen by applications.

Maps one USI bottom-stack capability key to a provider-native variable. This type belongs to adapter development; ordinary SDK consumers never use it.

Simulator-neutral event meanings emitted by a bottom-stack provider. Provider-native event names never cross this boundary.

Simulator-neutral arguments for an optional structured provider query.

Optional structured query routed to a simulator provider.

Primitive value representation used by a bottom-stack provider mapping.

A named radio-altimeter receiver.

A role-aware radio-magnetic indicator. Native selector values and provider-specific pointer switches remain below this component.

Navigation source shown by a radio-magnetic indicator or pointer.

Named maneuvering-rocket control direction, not measured acceleration.

Aircraft-wide maneuvering reaction-control propulsion.

Aircraft-wide emergency recovery parachute equipment.

The loaded aircraft's logical ground-refueling connection point. Availability does not imply that simulator refueling service is active.

Editable base conditions for the simulator's regional weather model. These values describe the regional model, not necessarily the conditions currently affecting the user aircraft or simulation camera.

Selected position of a retractable-float control.

Aircraft-wide rocket-assisted takeoff equipment. The same named component is present for every simulator; unsupported providers return typed results.

Direction currently requesting roll-spoiler assistance.

A named rotor access point, independent of engine numbering. Installation may be Unknown; readable telemetry is not evidence of physically installed equipment.

Aircraft-wide rotor-brake selection and configured strength.

A named rotor-driven aircraft hydraulic pump.

Aircraft-wide rotor pre-rotation equipment.

Provider-neutral helicopter or gyrocopter rotor-drive clutch.

Aircraft-wide rotorcraft facts, separate from individual engine and rotor indexing.

The aircraft's primary and optional secondary directional-control surfaces.

A cloud layer reported by an aviation observation or forecast.

A physical yaw-string indication, distinct from aerodynamic sideslip and an instrument's slip/skid ball.