Autoflyte

Flight Director

The Autoflyte Control System (AFCS) is Orpex's flight-guidance and autopilot system for aircraft and aerospace vehicles. Its flight director shows attitude commands for the pilot to follow. Engaging Autoflyte couples the aircraft controls to those commands. Selecting a mode and engaging the autopilot are separate actions.

Controls

These are the default keyboard bindings. Check your configured controls or the local keycard if you have changed them or use a different keyboard layout.

Control	Action
F	Toggle the flight director.
F10	Engage or disconnect Autoflyte. If DOR or TVM is controlling the vehicle, disconnect that system.
C	Cycle the lateral mode.
V	Cycle the vertical mode.
[ / ]	Decrease/increase the selected bank, heading or NAV course.
; / ' (semicolon / apostrophe)	Increase/decrease the selected vertical target: pitch, flight-path angle, vertical speed, indicated airspeed or altitude.
Shift+C	Arm or disarm LOC standby.
Shift+V	Arm or disarm G/S standby.
T	Select takeoff/go-around guidance on both axes.
J	Toggle DOR; after an entry handoff, cancel the entry TAS hold.
K	Toggle TVM.

Holding Ctrl while adjusting an ordinary lateral or vertical target increases the adjustment rate. Shift+semicolon and Shift+apostrophe are pitch-trim controls; they are separate from vertical-target adjustment and disconnect the aircraft autopilot.

Flight Director

The flight director, also called the command bars, gives visual cues on the artificial horizon. It shows the attitude changes requested by the selected lateral and vertical modes. Fly those cues by hand, or engage Autoflyte to follow them automatically.

When the flight director is first turned on, an axis that has no selected mode receives:

• On the ground: T/O guidance.
• Airborne: ROL for the lateral axis and PIT for the vertical axis. PIT captures the current pitch. ROL captures the current bank, except that a bank of less than 5° captures wings level.

An already selected mode is retained when the missing axis is initialized. Turning the flight director off clears both active ordinary modes and disconnects the aircraft autopilot. Turning it on from DOR or TVM releases that special control mode.

Independent mode selection

C changes the lateral mode; V changes the vertical mode. Cycling one axis preserves the other axis's selected mode and target. For example, cycling vertical modes back to PIT while flying HDG leaves HDG selected. Cycling lateral modes back to ROL while flying an altitude mode leaves the altitude mode selected.

If the other axis has no selected mode, an ordinary vertical-mode selection supplies ROL, and an ordinary lateral-mode selection supplies PIT. Initial flight-director selection on the ground uses the T/O defaults described above.

Cycling out of T/O or G/A changes only the selected axis: V selects PIT, while C selects ROL. The separate T command deliberately selects takeoff/go-around guidance on both axes. It does not itself engage Autoflyte or advance the thrust levers.

Lateral Modes

The ordinary C-key cycle is ROL → HDG → NAV → ROL. LOC is armed separately; it is not a step in this cycle. Pressing C while LOC is active returns the lateral axis to ROL.

• T/O — Takeoff lateral guidance, selected at ground flight-director startup or by the takeoff/go-around command.
• ROL — Commands the selected bank angle. Use [ and ] to adjust it.
• HDG — Turns toward the selected heading. Selecting HDG captures the current heading; use [ and ] to change it.
• NAV — Intercepts and tracks the selected course to/from the navigation target. Selecting NAV initially sets a direct-to course; use [ and ] to change the course. For waypoint navigation, select the waypoint with the Waypoint Manager.
• LOC — Tracks the selected runway's localizer after capture. See Approach guidance.

Ordinary HDG, NAV and LOC commands normally allow up to 30° of bank. Above 9.63168 km MSL (31,600 ft), the limit is 15°. At lower MSL altitudes and below 0.1524 km AGL (500 ft), the limit tapers from 30° at 500 ft AGL to 5° at ground level. These are limits on commanded bank, not guarantees of the actual bank or a terrain-clearance system. DOR ascent uses its own bank limits.

Vertical Modes

The ordinary V-key cycle is PIT → FPA → VS → SPD → ALTm → ALTa → PIT, skipping unavailable modes. The display may label the altitude modes MSL/AGL or ALT with an M/A suffix, and vertical speed as VS or V/S. G/S is armed separately; it is not a step in this cycle. Pressing V while G/S is active selects PIT and captures the current pitch.

• T/O / G/A — Takeoff/go-around pitch guidance. The commanded pitch depends on available engine condition; it is not a vertical-speed hold. Use V to change to PIT without changing the lateral mode.
• PIT — Holds the selected pitch attitude. Selecting PIT, including returning to it at the end of the cycle, captures the current pitch. Target adjustment is limited to 15° nose-down through 20° nose-up.
• FPA — Adjusts pitch to follow the selected ground-relative flight-path angle. It captures the current climb/descent angle, limited to −15° through +20°. Select −3° for a descending 3° path. See Flight path angle and hover.
• VS / V/S — Adjusts pitch to attain the selected climb or descent rate. Selecting it captures the current vertical speed.
• SPD — Adjusts pitch to maintain the selected indicated airspeed, initially captured from the current IAS. This is speed through pitch; selecting SPD does not engage an autothrottle. The selected IAS cannot be reduced below zero.
• ALTm / MSL — Holds the selected MSL altitude, initially captured from the current altitude.
• ALTa / AGL — Holds the selected height above the local ground, initially captured from the current AGL. The selected height cannot be reduced below zero. This mode is skipped above 10 km MSL, where the required ground-height data are unavailable. Climbing above that limit with ALTa active returns the vertical mode to PIT and disconnects Autoflyte; descending again does not automatically reselect ALTa.
• G/S — Follows the selected runway's glideslope after capture. See Approach guidance.

Altitude targets are in km; pitch and FPA targets are in degrees; the SPD target is IAS in m/s. Vertical-speed units depend on the instrument: the compact two-column FMA shows km/s, while the wide FMA shows m/s (for example, 0.010 km/s is 10 m/s).

Flight path angle and hover

FPA is the angle of travel relative to the local ground tangent, not nose pitch or angle of attack. Wind and aircraft performance affect the pitch and thrust needed to follow it. FPA does not control lateral course or speed, and provides no terrain avoidance, flare or touchdown.

The cycle skips FPA on the ground, below 0.010 km/s (10 m/s) horizontal groundspeed, or when the required path data are invalid. If those conditions occur with FPA active, it returns to PIT at the current pitch. It does not automatically re-arm: select FPA again after establishing suitable forward flight. This also applies during hover or nearly vertical VTOL flight; low IAS is not the FPA availability test.

Approach guidance

Select the appropriate runway navigation data and establish a suitable inbound approach. Use Shift+C to arm LOC and Shift+V to arm G/S. A gray standby indication means the mode is armed and waiting; the current ordinary mode continues to guide that axis until capture. Press the same shifted key again to disarm a standby mode. Selecting NAV or a LOM waypoint alone does not arm LOC or G/S.

• LOC capture requires LOC standby, an active lateral mode, operational localizer data, range no greater than 42.6 km, a heading within 35° of the runway course, and localizer angular deviation no greater than 1°. Capture replaces the active lateral mode with LOC and clears LOC standby. NAV and MSL are not required prerequisites.
• G/S capture requires G/S standby, LOC already active, operational glideslope data, range no greater than 42.6 km, and glideslope deviation within approximately 0.18° of the nominal 3° path. Capture replaces the active vertical mode with G/S and clears G/S standby.

Outside capture range, an armed mode remains in standby. Plan an intercept from below the glidepath and monitor the actual capture indications; arming is not confirmation of capture. Moving beyond 42.6 km with G/S active returns vertical guidance to PIT and disconnects Autoflyte. A LOM or IAF is an approach fix, not the origin of the runway beam. See GLS for the landing-system reference.

Ordinary C/V mode cycling does not by itself clear a separately armed standby mode. Disarm LOC or G/S explicitly when it is no longer wanted. Touchdown disconnects Autoflyte and selects T/O guidance on both axes; approach capture does not imply an automatic flare or landing.

Coupling

Press F10 to engage Autoflyte with the selected flight-director modes. Engagement requires cockpit power and a serviceable Autoflyte unit on an aircraft or aerospace vehicle. If the ordinary flight director is off, its initial modes are selected first. The A/F annunciation on the wide FMA indicates aircraft autopilot engagement; active mode labels alone do not mean that the aircraft controls are coupled.

Press F10 again to disconnect. In ordinary aircraft operation, disconnecting Autoflyte leaves the selected flight-director modes available for hand flying. Turning the flight director off with F clears both active modes and disconnects. Manual flight-control or pitch-trim input can also disconnect the autopilot; monitor engagement after taking control.

Normal pitch, flight-path, vertical-speed, altitude and heading guidance does not automatically manage thrust. Set suitable thrust for the requested flight path and speed. The entry TAS hold described below is a separate function.

Wide FMA indications

The wide FMA (FMA2) keeps active lateral and vertical guidance in the lower row and armed LOC/G/S in the upper row. During DOR operation, DOR occupies the upper engagement/source cell and WAIT, VTOL, BURN, BRAKE, RCS or COAST replaces A/T immediately below. DOR remains the source while it uses the aircraft AFCS during ascent. When DOR releases control, ordinary A/F or TVM and any engaged A/T return.

ALIGN in the lower guidance cells means DOR is acquiring or holding an attitude. It remains visible during a captured burn; absence of an alignment error is not permission to turn away from an active burn. In normal orbital WAIT/COAST, blank lower attitude cells indicate released attitude control, allowing the pilot to look around while the route stays armed. RCS may still appear for rotational pulses. HDG, PIT and FPA identify the corresponding aircraft guidance under DOR. See DOR phase indications and attitude control for ground-wait, entry and unavailable-guidance details.

An unused zero-altitude selection hides both the gray ALTm label and magenta 0.000. Nonzero selections and active or armed zero-altitude holds remain visible. This does not change the selected altitude or flight-control mode.

Special Modes

• DOR (Digital Orbital Resolver) plans and executes supported orbital missions. Ground RENDEZVOUS can fly launch, ascent, insertion and orbital transfer as one mission, ending with a TVM handoff at the trailing staging point. Choose RENDEZVOUS for the whole trip or PARKING ORBIT to stop after insertion; in orbit, ADJUST ORBIT replaces PARKING ORBIT. Ground RENDEZVOUS initially searches for the earliest accepted MEET estimate, which can be adjusted. See Ground-to-rendezvous mission and Orbit for planning, engagement and limitations.

During atmospheric ascent, DOR commands the ordinary AFCS heading and pitch controllers and manages thrust. The wide FMA shows DOR as the source, its current phase beneath, and normally HDG/PIT in the lower guidance cells. An assigned NAV departure can retain navigation steering with STEER AFCS; its lateral DOR indication is ALIGN. Changing C or V while DOR owns those aircraft controls releases DOR and its autopilot engagement, then selects the next ordinary flight-director mode. Re-engage Autoflyte deliberately if wanted. See ascent control and transition limits.

• Entry TAS hold can follow a completed DOR atmospheric-entry handoff. The aircraft autopilot controls the selected lateral and vertical modes while the separate autothrottle holds the selected TAS; the wide FMA shows A/T. This differs from the IAS-based SPD pitch mode. After handoff, TAS hold is compatible with HDG, NAV or LOC and PIT, FPA, VS, ALTm, ALTa or G/S. Selecting ROL, SPD, an off mode or TVM ends it. Cancel it with J or a physical throttle-lever movement; disconnecting the aircraft autopilot also ends it. Ordinary gear, flap and spoiler changes after handoff are permitted, but entry execution has separate clean-configuration requirements. See entry readiness and handoff for the full procedure and limits.

• ILS descent follows a completed DOR entry when FINAL ILS was selected for a runway or its locator outer marker. After the 30 km entry handoff, NAV and FPA guide the descent while A/T reduces TAS using the aircraft's IAS, stall speed and approach reference speed. The aircraft levels below the 3° glideslope near the loaded outer marker, or the planned fallback intercept, then leaves NAV and ALTm active with LOC and G/S armed. If the marker was selected, the navigation reference changes to its associated runway for ILS reception. Normal localizer and glideslope capture then takes over. Shift+C and Shift+V remain the manual LOC and G/S arm controls. Changing the target or flight-guidance modes cancels the automatic continuation. Configure the aircraft and monitor terrain and speed; this continuation does not automate the flare or touchdown. See arrival planning and the ILS handoff for the intercept geometry, limits and cancellation behavior.

• TVM (Target Velocity Match) uses thrust to match the selected target's velocity plus the commanded closing velocity. Zero commanded closing speed requests a velocity match, not a fixed separation, collision avoidance or automated docking. TVM is separate from ordinary lateral/vertical modes and the DOR transfer planner.

With a ground waypoint selected, TVM allows a controlled descent in a vehicle with suitable vertical thrust. At zero commanded closing speed it damps motion relative to the ground; the actual descent rate depends on the vehicle's mass and available thrust. Monitor vertical speed, height above ground and the landing area. TVM does not command a chosen descent rate, hold a fixed height or fly to the waypoint's position. See TVM vertical landings.

When matching a ground waypoint or grounded vehicle, TVM also uses enabled, serviceable thrust augmentation to bring the nose and wings level with the local horizon below stall speed during subsonic flight. Manual pitch or roll input overrides leveling on that axis; centering the control resumes it. The assistance fades out as IAS approaches the computed stall speed and as true airspeed approaches Mach 1. It does not apply when matching airborne or orbital targets. See TVM vertical landings for availability and limits.

Atmospheric and spaceflight use

Mode independence continues through ordinary atmospheric flight, high-speed ascent, suborbital coast, orbit and re-entry. Availability of a flight-director mode does not establish aerodynamic control authority: FPA geometry may remain valid at high speed while the aircraft cannot follow it with control surfaces. Use the documented DOR functions for orbital planning and powered ascent/entry, and TVM for target-relative velocity control.

Ground startup, VTOL/hover, approach capture, ALTa data availability and DOR transitions each have their own conditions. The 10 km ALTa limit is a ground-data limit, not a blanket cutoff for Autoflyte or other aircraft systems. See FPA in atmospheric and spaceflight operation for further guidance.